1668 Background: Peer support effectiveness for breast cancer survivors has reportedly varied, and no study has examined patient–supporter matching. This decentralized, multicenter, non-blinded pilot randomized controlled trial aimed to assess online peer support effectiveness and explore factors for a matching algorithm. Methods: Breast cancer survivors within three years of completing initial treatment were recruited and provided electronic informed consent. Based on the sample size estimation, the target sample size was set at 50. Participants were randomly assigned either to the peer support group, which scheduled an online peer support session immediately after registration, or to the waitlist group, which scheduled their session two weeks later. Participants could choose their preferred time and date through a web-based scheduling system. Peer support sessions were conducted online by two trained peer supporters. The primary outcome was the UCLA Loneliness Scale score, assessed one week after the session in the peer support group and at the end of the 2-week waiting period in the waitlist group. Secondary outcomes included satisfaction with peer support and other psychosocial measures, all collected through an electronic patient-reported outcome system. Effect sizes for outcomes were calculated to inform sample size estimation for future trials. Analyses were performed to explore factors associated with satisfaction. The study protocol was registered in the UMIN Clinical Trials Registry (UMIN000056741). Results: From February to July 2025, 54 participants enrolled and 52 individuals completed the study (27 peer support group, 25 waitlist group). At the primary endpoint, the mean (standard deviation) UCLA Loneliness Scale scores were 38.4 (11.2) in the peer support group and 41.3 (13.3) in the waitlist group (Cohen’s d = 0.24; t-test, P = 0.40). The change from baseline corresponded to a Cohen’s d = 0.32. Among the secondary outcomes, the changes in Generalized Anxiety Disorder-7 scores differed between groups (mean difference [MD] = -1.3; 95% CI = -2.5 to -0.1), and the changes in Patient Health Questionnaire-9 scores tended to be greater in the peer support group (MD = -1.2; 95% CI = -2.5 to 0.1). The global health status on EORTC QLQ-C30 did not differ between groups (MD = 1.0; 95% CI = -6.6 to 8.7). The median (IQR) satisfaction score was 46 (41.5, 50) on a 50-point scale. A linear mixed-effects model indicated that sharing ≥1 topic and age proximity between the participant and peer supporter were significantly associated with higher satisfaction. Conclusions: Results demonstrate the feasibility of future decentralized randomized trials on online peer support and provide effect size estimates to guide sample size planning. Shared topics and age proximity between participants and peer supporters may be considered when scheduling sessions.

We previously reported the 21-gene Oncotype DX® assay results from TransNEOS in patients enrolled in the phase 3 NEOS trial. However, the association between assay results and long-term prognosis has remained unclear. Of the 296 patients registered in TransNEOS, 226 patients were enrolled in this study. Multigene assay results were categorized into three groups based on Recurrence Score® (RS): RS low < 11, RS intermediate 11–25, RS high > 25. Kaplan–Meier methods evaluated the association between RS results and DDFS and OS across treatments and clinical response to neoadjuvant endocrine treatment (NET). The clinical efficacy of NET was judged as CR, PR, and SD in 4 (1.8

Although taxanes are a mainstay treatment for locally advanced or metastatic breast cancer (LABC/MBC), they often impair quality of life (QoL). Treatments that avoid taxane-related QoL deteriorations would be valuable. The JBCRG-M06/EMERALD trial (NCT03264547, UMIN000027938) compared eribulin with a taxane, each combined with trastuzumab and pertuzumab, in patients with human epidermal growth factor receptor type 2 (HER2)-positive LABC/MBC. QoL was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Module C30 (EORTC QLQ-C30) version 3.0. QoL deterioration was defined as a decrease in the Global Health Status (GHS) score by ≥ 10 points (minimum clinically important difference), disease progression, or death. QoL data were available for 210 (of 224 randomized) and 205 (of 222 randomized) patients in the eribulin and taxane groups, respectively. The median (95

e12601 Background: Based on the Norton-Simon model, dose-dense (dd) chemotherapy with shortened intervals between administrations has been adopted in perioperative chemotherapy for breast cancer. However, the safety and efficacy of dd chemotherapy in neoadjuvant settings have not been thoroughly investigated. Methods: The aim of this study is to evaluate the efficacy and safety of dd versus standard regimen in neoadjuvant chemotherapy. The patients with HER2-negative breast cancer who underwent neoadjuvant chemotherapy (NAC) with anthracycline-taxane were continuously identified between 2014 and 2023. These patients were divided into a triple negative breast cancer (TNBC) cohort with HR < 10% and a luminal cohort with hormone receptor (HR) ≥ 10%, and pathologic complete response (pCR) and relapse-free survival (RFS) were evaluated in each group. Results: A total of 525 patients with HER2-negative breast cancer were identified from 11 institutions in Japan. In the overall cohort, 229 patients were in the dd group and 296 patients were in the standard group, with no significant differences between the two groups in terms of age, nuclear grade (NG), T and N categories. In the dd group, 100% of the cases received dd AC/EC, and 75% of the cases received dd PTX. The pCR rate in the TNBC cohort was 42% in the dd group and 32% in the standard group (p=0.101), and in the subgroup with HR < 1%, it was 39% and 30%, respectively (p=0.167). In the Luminal cohort, the pCR rate for NG3 vs. NG1 or 2 was 27% and 5%, respectively (p=0.005), but in NG3 was 12% in the dd group and 16% in the standard group each(p=0.445). Regarding RFS in the dd group and the standard group, no significant differences were observed in either the TNBC cohort or the Luminal cohort (Logrank P =0.516, 0.946, with median follow up periods of 33 months and 56 months, respectively). The average relative dose intensity of chemotherapy was 96.5% in the dd group, and 95.3% in the standard group. The mean period from the first NAC administration to surgery was 140 days in the dd group and 191 days in the standard group. The incidence of adverse events (AEs) was significantly higher in the standard group compared to the dd group, with a particularly higher incidence of Grade 3 or higher neutropenia and peripheral neuropathy. When analyzed by age, the incidence of neutropenia was significantly higher in the standard group in patients under 65 years of age. Conclusions: This study is the first to demonstrate the safety and efficacy of the dd regimen in NAC for Japanese breast cancer patients. The dd regimen, compared to the standard, showed comparable results in terms of AEs, pCR rate, and prognosis. With a shorter treatment duration, the dd regimen should be considered a preferred NAC regimen for breast cancer. Further evaluation is needed to assess the long-term survival.

In the primary analysis of the open-label phase III PRECIOUS study, pertuzumab retreatment combined with trastuzumab plus chemotherapy of physician's choice (PTC) significantly improved investigator-assessed progression-free survival (PFS) compared with trastuzumab plus physician's choice chemotherapy (TC) in patients with human epidermal growth factor receptor 2 (HER2)-positive locally advanced/metastatic breast cancer (LA/mBC). Here, we report final overall survival (OS) at the median follow-up of 25.8 months. Patients who have previously received pertuzumab-containing regimens as first-/second-line treatment for LA/mBC were randomly assigned 1:1 to two groups, PTC group (n = 110) and TC group (n = 109). Median OS was longer in the PTC group (median OS 36.2 v 26.5 months; hazard ratio [HR], 0.73 [one side 95% CI upper limit, 0.97]). Updated median investigator-assessed PFS (5.5 v 4.2 months; HR, 0.81 [one side 95% CI upper limit, 1.02]) were also better in the PTC group. Median PFS by independent review did not show the difference between the two groups (4.4 v 4.4 months; HR, 1.03 [one side 95% CI upper limit, 1.36]). These findings suggest that dual HER2 blockade with pertuzumab plus trastuzumab could contribute to improving OS in patients who have previously been treated with pertuzumab-containing regimens for HER2-positive LA/mBC.

Abstract Background: Eribuliln (ERI), a microtubule polymelization, is approved for locally advanced or metastatic breast cancer. However, its effects on drug-naive cancers are not well understood. In EMBRACE trial, ERI improves overall survival (OS) of the patients with metastatic breast cancer. This result might suggest that ERI could be involved in the immune system. In particular, there are a few reports on the effects of ERI on the innate immune system. This study aimed to investigate how ERI influences the innate immune system, focusing on the cyclic-GMP-AMP synthase (cGAS), a DNA sensor that triggers the production of type-I interferons. Methods: Clinical samples from the JONIE-3 trial were analyzed using immunohistochemistry (IHC). 121 patients were assigned to 2 different neoadjuvant chemotherapy (NAC) groups receive ERI (Group E) or paclitaxel (Group P) followed by FEC. The patients of both groups were performed biopsy before and after chemotherapy. We performed IHC on 56 samples and examined for association with pathological complete response (pCR), which was defined as no invasive redidual tumor tissue in the breast. Additionally, 5 different cell lines were established to evaluate the acute and chronic effects of ERI treatment. The cell lines were as follows: no treatment (control), PTX for short time (PTX short), PTX for long time (PTX long), ERI for short time (ERI short) and ERI for long time (ERI long). We evaluated the acute effects of short-term dosing, while the chronic effects of long-term dosing, which mimic resistance to treatment. Protein expression of the cGAS-STING pathway was examined, along with cGAS and IFNβ expression levels and their impact on cell division in the above cell lines. Then at the cellular level, each cell lines were evaluated for differences in cGAS and IFNβ expression and their effects on cell division. The differences in cGAS expression between cytoplasmic and nuclear fractions were verified by the cell fractuation assay. In addition, mitotic abnormalities and cell proliferation were also assessed. Results: In the clinical trial, ERI did not significantly differ from paclitaxel in terms of pathological complete response (pCR). However, high cGAS expression in Group E (ERI) correlated with increased pCR rates, while no such correlation was observed in Group P (PTX) (Figure). Additionally, High IFNβ expression in Group E also correlated with increased pCR rates, differed from Group P. In vitro, ERI upregulated cGAS, STING, pIRF3, and IFNβ protein expression compared to PTX. Notably, ERI induced elevated cGAS expression in the nucleus, as confirmed by immunofluorescence and cell fracturation assays. Additionally, PTX and ERI differed in their ability to cause mitotic abnormalities. PTX induced more micronuclei cells than ERI, on the other hand ERI induced more micronuclei cells and mitotic slippage. These results were also verified by live cell imaging. Finally, the knockdown of cGAS resulted in accelerated cell proliferation. Conclusion: ERI promoted chromosomal instability, leading to increased cGAS expression, particularly in the nucleus. These findings contribute to our understanding of ERI's effects on the innate immune response in triple-negative breast cancer, potentially paving the way for improved therapeutic strategies. The differences in intensity scores between GroupP and GroupE in the immunostaining of cGAS High cGAS expression in Group E correlated with increased pCR rates (p=0.0375), while no such correlation was observed in Group P (p=0.2983). Citation Format: Hideyuki Yamada, Mamoru Takada, Aussie Suzuki, Yu Muhan, Takeshi Nagashima, Hiroshi Fujimoto, Junta Sakakibara, Masaharu Kasuya, Takahiko Kawate, Daishu Miura, Masato Suzuki, Masaru Miyashita, Kazutaka Narui, Yoshie Hasegawa, Takashi Ishikawa, Masayuki Otsuka. Eribulin Induces Chromosomal Instability and Enhances cGAS Expression in the Nucleus of Triple-Negative Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-25-05.

Eribulin (ERI), clinically utilized for locally advanced or metastatic breast tumors, has shown potential links to the immune system. Notably, the cGAS-STING pathway, a key component of innate immunity, has gained prominence. Yet, limited reports explore ERI's effects on the cGAS-STING pathway. Additionally, the nuclear presence of cGAS remains poorly understood. This study uniquely delves into ERI's impact on both the cytosolic cGAS-STING pathway and nuclear cGAS. ERI enhances nuclear localization of cGAS, resulting in hyper-activation of the cGAS-STING pathway in triple-negative breast cancer cells. Reduction of cGAS heightened both cell proliferation and ERI sensitivity. In clinical data using ERI in a neo-adjuvant setting, patients with low cGAS cases exhibited reduced likelihood of achieving pathological complete response after ERI treatment. These findings illuminate the potential of cGAS and IFNβ as predictive biomarkers for ERI sensitivity, providing valuable insights for personalized breast cancer treatment strategies.

Abstract Background The role of endocrine therapy in the treatment of patients in a postmenopausal hormonal state and with estrogen receptor (ER)‐positive, human epidermal growth factor receptor 2 (HER2)‐positive advanced or metastatic breast cancer (AMBC) is unclear. Methods We analyzed the data from 94 patients with ER‐positive HER2‐positive AMBC enrolled in the Safari study (UMIN000015168), a retrospective cohort study of 1072 ER‐positive AMBC patients in a postmenopausal hormonal state who received fulvestrant 500 mg (F500): (1) to compare time to treatment failure (TTF) and overall survival (OS) by treatment group, and TTF by treatment line; (2) in patients who received endocrine therapy (including F500) or anti‐HER2 therapy as initial systemic therapy before chemotherapy, to investigate relations between TTF for the first‐line therapy or time to chemotherapy (TTC) and OS; (3) to investigate factors associated with OS. Results The TTF was longer in the patients treated with F500 as first‐ or second‐line therapy (n = 20) than in those who received later‐line F500 therapy (n = 74) (6.6 vs. 3.7 months; HR, 1.98; p = 0.014). In the 59 patients who received endocrine therapy or anti‐HER2 therapy as initial systemic therapy before chemotherapy, those with TTC ≥3 years had longer median OS than those with TTC <3 years (10.5 vs. 5.9 years; HR, 0.32; p = 0.001). Longer TTC was associated with prolonged OS. Conclusions In patients with ER‐positive HER2‐positive AMBC enrolled in the Safari study, TTF was longer in patients who received F500 as first‐ or second‐line therapy. In patients who received chemotherapy‐free initial systemic therapy, the prolonged OS in those with TTC ≥3 years suggests that this value may be a helpful cut‐off for indicating clinical outcomes.

Besides an industrial pollutant, 2,4-dinitrophenol (DNP) has been used illegally as a weight loss drug that had claimed human lives. Little is known about the metabolism of DNP, particularly among Gram-negative bacteria. In this study, two non-contiguous genetic loci of Paraburkholderia (formerly Burkholderia ) sp. strain KU-46 genome were identified and four key initial genes ( dnpA , dnpB , and dnpC1C2 ) were characterized to provide molecular and biochemical evidence for the degradation of DNP via the formation of 4-nitrophenol (NP), a pathway that is unique among DNP utilizing bacteria. Reverse transcription PCR analysis indicated that the dnpA gene encoding the initial hydride transferase (28 kDa), and the dnpB gene encoding a nitrite-eliminating enzyme (33 kDa), are inducible by DNP and the two genes are organized in an operon. Purified DnpA and DnpB from overexpression clones in Escherichia coli effected the transformation of DNP to NP via the formation of hydride-Meisenheimer complex of DNP. The function of DnpB appears new since all homologs of DnpB sequences in the protein database are annotated as putative nitrate ABC transporter substrate-binding proteins. The gene cluster responsible for the degradation of DNP after NP formation was designated dnpC1C2DXFER. DnpC1 and DnpC2 were functionally characterized as the respective FAD reductase and oxygenase components of the two-component NP monooxygenase. Both NP and 4-nitrocatechol were shown to be substrates, producing hydroquinone and hydroxyquinol, respectively. Elucidation of the hqdA1A2BCD gene cluster allows the delineation of the final degradation pathway of hydroquinone to ß-ketoadipate prior to its entry to the tricarboxylic acid cycle.Importance This study fills a gap in our knowledge and understanding of the genetic basis and biochemical pathway for the degradation of 2,4-dinitrophenol (DNP) in Gram-negative bacteria, represented by the prototypical Paraburkholderia sp. strain KU-46 that metabolizes DNP through the formation of 4-nitrophenol, a pathway unseen by other DNP utilizers. The newly cloned genes could serve as DNA probes in biomonitoring as well as finding application in new biocatalyst development to access green chemicals. By and large, knowledge of the diverse strategies used by microorganisms to degrade DNP will contribute to the development of bioremediation solutions since DNP is an industrial pollutant used widely in the chemical industry for the synthesis of pesticides, insecticides, sulfur dyes, wood preservatives, and explosives, etc. (119 words)

1015 Background: We previously reported that pertuzumab (P) retreatment in combination with trastuzumab (T) + chemotherapy based on physician’s choice (C) (PTC) significantly improved investigator-assessed progression-free survival (PFS) compared with T + C (TC) in patients with HER2-positive locally advanced/metastatic breast cancer (LA/MBC) previously treated with P-containing regimens in the phase III PRECIOUS study. Here we report updated OS at the median follow-up of 27.4 mo. Methods: Patients previously treated with P-containing regimens as 1 st /2 nd -line treatment for LA/MBC were randomly assigned 1:1 to two groups, PTC group and TC group, stratified by estrogen receptor (ER) status, previous treatment duration of P, number of previous chemotherapy regimens, and presence or absence of visceral metastasis. The primary endpoint was investigator-assessed PFS. The key secondary endpoints included OS, independent reviewer assessed PFS and safety. Superiority of PTC to TC will be tested using a log-rank test and a one-sided P-value of less than 0.05 will be considered an indicator of superiority. The distribution of OS will be estimated using the Kaplan-Meier method. In addition, the hazard ratio and one-sided 95% CI of the therapeutic effect between the groups will be calculated using the Cox proportional hazard model. Results: Of the 219pts enrolled, 217 (108 PTC, 109 TC) were included in the intent-to-treat analysis. At the data cutoff (Dec 31, 2021), OS and PFS events were 138 (63.6%) and 190 (87.6%), respectively. Updated median OS was significantly longer in the PTC group (median OS 36.2 vs. 26.5 mo.; HR = 0.73 [one side 95%CI upper limit, 0.97]; log-rank test p = 0.0323). In a prespecified subgroup analysis for OS including ER, visceral metastases, number of previous chemotherapy regimen was broadly constant without disease-free interval. Updated median investigator-assessed PFS (5.5 vs. 4.2 mo.; HR = 0.81 [one side 95%CI upper limit, 1.03]; stratified log-rank test p = 0.019) were also significantly better in the PTC group. Median PFS by independent review did not show the difference between two groups (4.4 vs. 4.4 mo.; HR = 1.03 [one side 95%CI upper limit, 1.36]; log-rank test p = 0.561). The serious adverse event rate did not differ between the groups (19.0% vs. 23.1%). There were no new safety signals in the two groups. Conclusions: Retreatment of P in combination with TC demonstrated significantly improved OS compared to TC. HER2 dual blockade with PT can contribute to improve survival in patients previously treated with P-containing regimens as 1 st /2 nd -line treatment for LA/MBC. Clinical trial information: NCT02514681 .

Purpose Neoadjuvant endocrine therapy (NET) is a treatment option for estrogen receptor-positive (ER+) postmenopausal early breast cancer (EBC). This phase III trial evaluated the prognosis of EBC patients treated with/without chemotherapy (CT) following NET. Methods ER+/HER2−, T1c-2, and clinically node-negative EBC patients were enrolled in 2008–2013 and treated with endocrine therapy (ET) in weeks 24–28. All patients, excluding those with progressive disease (PD) during NET or ≥ 4 positive lymph nodes after surgery, were randomized to ET for 4.5–5 years with/without CT. The primary endpoint was disease-free survival (DFS). Secondary endpoints included distant DFS (DDFS), overall survival (OS), and DFS/DDFS/OS according to clinical response to NET. Results Of 904 patients, 669 were randomized to CT+ET ( n = 333) or ET alone ( n = 336). The median follow-up was 7.8 years. DFS (CT+ET, 47 events; ET alone, 70 events) and DDFS did not reach the planned numbers of events. Eight-year DFS/DDFS rates were 86%/93% and 83%/92%, respectively. DFS was significantly better in CT+ET than ET alone in subgroups aged < 60 years ( P = 0.016), T2 ( P = 0.013), or Ki67 > 20% ( P = 0.026). Progesterone receptor and histological grade were predictive markers for clinical responses to NET. Conclusion NET may be used as standard treatment for patients with ER+EBC. Although it is difficult to decide whether to administer adjuvant CT based solely on the effect of NET, the response to NET may help to inform this decision. Trial registration This study was registered at the UMIN Clinical Trials Registry under UMIN000001090 (registered 20 March 2008).

e13031 Background: Pertuzumab (P) was an effective first-line treatment for HER2 positive metastatic breast cancer (MBC) in the CLEOPATRA study, improving both overall and progression-free survival (PFS). However, it is challenging to provide intravenous docetaxel to MBC patients over long term at a dosage of 75 mg/m 2 every three weeks. Eribulin (E) is a well tolerated cytotoxic agent. In a multicenter, open-label phase II research (UMIN000012232), we have shown the effectiveness and safety of E combined with trastuzumab (T) with P as first- and second-line treatment for metastatic or advanced BC. Methods: The study included HER2 positive MBC patients with no or one previous treatment, including advanced or recurrent chemotherapy. All patients were administered with T and taxane as perioperative or first-line chemotherapy. E (1.4 mg/m 2 ) along with T (8 mg/kg loading dosage > 6 mg/kg), and P (840 mg loading dose > 420 mg) was administered intravenously on days 1 and 8 of a 21-day cycle, once every three weeks. The primary end point was PFS and the secondary endpoints were the response rate (RR) based on RECIST ver1.1. Overall patient survival effectiveness following P administration, E compliance, and success of follow-up therapies were observed. Results: A total of 50 patients were enrolled, with 49 of them qualifying for the safety analysis. However, the full analysis set (FAS) consisted of 46 individuals. The average patient age was 56 years old (range 23–70), and 9 (18%) and 40 (82%) patients received care in first- and second-line settings, respectively. The median PFS for patients who received main therapy was 20.5 months, whereas the median PFS for patients who received subsequent treatment was 8.6 months. Thirty-five patients (76.1%) were able to receive concomitant E until the end of protocol treatment. The overall RR was 56.5% among the 46 patients in the FAS. Nine patients (19.5%) responded completely, whereas 17 patients (37.0%) responded partially. There were 13 cases of stable disease (28.2%), six cases of progressing disease (13.0%), and one case was not evaluable (1.2%). The median survival of the primary treatment population was not reached; however, the median survival of the secondary treatment population was 42.4 months. Twenty three patients received T-DM1 as a follow-up treatment, 13 patients received TP plus chemotherapy, and five patients received additional therapies. The average duration of treatment with T-DM1 as a consequent therapy was approximately four months, whereas the average duration of treatment with HP plus chemotherapy was 11 months. Conclusions: For HER2positive MBC, E in combination with T plus P was well tolerated and may be an alternative to docetaxel-based combination therapy. Results from the JBCRG M06 trial research, which compares taxanes combination with T plus P with E combined with T plus P in first-line therapy, are still pending. Clinical trial information: UMIN000012232 .

PURPOSE Treatment with an aromatase inhibitor for 5 years is the standard treatment for postmenopausal hormone receptor–positive breast cancer. We investigated the effects of extending this treatment to 10 years on disease-free survival (DFS). PATIENTS AND METHODS This prospective, randomized, multicenter open-label phase III study assessed the effect of extending anastrozole treatment for an additional 5 years in postmenopausal patients who were disease-free after treatment with either 5 years of anastrozole alone or 2-3 years of tamoxifen followed by 2-3 years of anastrozole. Patients were allocated randomly (1:1) to continue anastrozole for an additional 5 years or stop anastrozole. The primary end point was DFS, including breast cancer recurrence, second primary cancers, and death from any cause. This study is registered with University Hospital Medical Information Network, Japan (UMIN) clinical trials registry (UMIN000000818). RESULTS We enrolled 1,697 patients from 117 facilities between November 2007 and November 2012. Follow-up information was available for 1,593 patients (n = 787 in the continue group, n = 806 in the stop group), who were defined as the full analysis set, including 144 patients previously treated with tamoxifen and 259 patients who underwent breast-conserving surgery without irradiation. The 5-year DFS rates were 91% (95% CI, 89 to 93) in the continue group and 86% (95% CI, 83 to 88) in the stop group (hazard ratio, 0.61; 95% CI, 0.46 to 0.82; P < .0010). Notably, extended anastrozole treatment reduced the incidence of local recurrence (continue group, n = 10; stop group, n = 27) and second primary cancers (continue group, n = 27; stop group, n = 52). There was no significant difference in overall or distant DFS. Menopausal or bone-related all-grade adverse events were more frequent among patients in the continue group than those in the stop group, but the incidence of grade ≥3 adverse events was <1% in both groups. CONCLUSION Continuing adjuvant anastrozole for an additional 5 years after 5 years of initial treatment with anastrozole or tamoxifen followed by anastrozole was well tolerated and improved DFS. Although no difference in overall survival was observed as in other trials, extended anastrozole therapy could be one treatment choice in postmenopausal patients with hormone receptor–positive breast cancer.

PURPOSEFear of cancer recurrence (FCR) is a common distressing condition. We investigated the efficacy of smartphone problem-solving therapy and behavioral activation applications in breast cancer survivors.METHODSThis was a decentralized randomized trial. Participants were disease-free breast cancer survivors age 20-49 years who were randomly assigned to the smartphone-based intervention or waitlist control. Both groups received treatment as usual. The control group could access the smartphone apps during weeks 8-24. The intervention comprised smartphone problem-solving therapy and behavioral activation apps. The primary end point was the Concerns About Recurrence Scale at week 8. Secondary outcomes included the Fear of Cancer Recurrence Inventory-Short Form (FCRI-SF), the Hospital Anxiety and Depression Scale (HADS), the Short-form Supportive Care Needs Survey (SCNS-SF34), and the Posttraumatic Growth Inventory at weeks 8 and 24 (trial registration: UMIN-CTR: UMIN000031140).RESULTSThe intervention group included 223 participants, and the control group included 224 participants. Primary outcome data were obtained for 444 participants, and 213 participants in the intervention arm completed the week 24 assessment. The intervention group had statistically greater improvements than controls at week 8 on the Concerns About Recurrence Scale (difference –1.39; 95% CI, –1.93 to –0.85; P < .001), FCRI-SF (difference –1.65; 95% CI, –2.41 to –0.89; P < .001), HADS depression (difference –0.49; 95% CI, –0.98 to 0; P < .05), and SCNS-SF34 psychological domain (difference –1.49; 95% CI, –2.67 to –0.32; P < .05). These scores at week 24 were not statistically significant compared with week 8 although the HADS depression score at week 24 was significantly reduced ( P = .03).CONCLUSIONNovel smartphone psychotherapy offers a promising way to reduce FCR given the large number of survivors and a limited number of therapists to competently conduct psychotherapy.

BACKGROUND:Only old evidence exists to back up the use of medroxyprogesterone acetate. Therefore, this study aimed to explore the factors that influence the time to treatment failure of medroxyprogesterone acetate in real-world settings as late-line treatment. METHODS:This was a cohort study that used the database of the Safari study on oestrogen receptor-positive post-menopausal advanced breast cancer (UMIN000015168). We created Kaplan-Meier curves for time to treatment failure with medroxyprogesterone acetate. Further, univariate and multivariate analyses were performed using a Cox hazard model of the clinicopathological factors involved in the time to treatment failure of medroxyprogesterone acetate. RESULTS:From the 1031 patients in the Safari study, 279 patients were selected as the population for the analysis of effectiveness of medroxyprogesterone acetate monotherapy. In the analysis of medroxyprogesterone acetate by treatment line, the median time to treatment failure was 3.0 months for third-line treatment and 4.1 months for fourth and subsequent treatment lines. In cases where medroxyprogesterone acetate was used as a third-line or later endocrine treatment, multivariate analysis showed that the length of the disease-free interval was correlated with the length of time to treatment failure of medroxyprogesterone acetate (P = 0.004). With medroxyprogesterone acetate monotherapy as the fourth-line or later treatment, 20% of the patients achieved a time to treatment failure of 12 months or longer. CONCLUSION:In actual clinical practice, patients treated with medroxyprogesterone acetate alone as the fourth or subsequent treatment lines showed a time to treatment failure of 4 months, suggesting that there is merit in using medroxyprogesterone acetate even in late treatment lines, especially in patients with long disease-free interval and those who are difficult to treat using other antineoplastic agents.

<p>Supplementary Table S1 Association between all <i>CYP2D6</i> genotype and ER status in pre-treatment tissue.</p>

Background: Only old evidence exist to back up the use of medroxyprogesterone acetate (MPA) in endocrine therapy. Therefore, this study aimed to explore the factors that influence the time to treatment failure (TTF) of MPA in real world settings as late-line treatment following aromatase inhibitors and fulvestrant. Methods: This was a cohort study that used the database of the Safari study, on estrogen receptor-positive (ER+) post-menopausal advanced breast cancer previously treated with fulvestrant (UMIN000015168). We created Kaplan-Meier curves for TTF treated with MPA. Further, univariate and multivariate analyses were performed using a Cox hazard model of the clinicopathological factors involved in the TTF of MPA. Results: Fist, we made Kaplan-Meier curves by treatment line for MPA in TTF analysis population 1 (n = 244), excluding HER2+ and HER2 with unknown status. The median TTF for MPA was 8.2 months (95% CI 5.1–14.9) for first- and second-line treatments, 3.0 months (95% CI 2.5–3.9) for third-line treatment, and 4.1 months (95% CI 3.5–5.0) for fourth or later treatment lines. The first- and second-line treatments had significantly longer TTF than the third-line treatment (P < 0.001) and fourth-line or later treatments (P < 0.001). No difference in TTF was observed between the third and fourth or later treatment lines. Similar results were obtained in the analysis population 2 (n = 203) for TTF, excluding cases in which MPA was considered to have been used in palliative care. The median TTF for MPA was 7.9 months (95% CI, 5.1-16.0) for first- and second-line treatments, 3.0 months (95% CI 2.8–4.6) for third-line treatment, and 4.3 months (95% CI 3.7–5.6) for fourth or later treatment lines. The first- and second-line treatments had significantly longer TTF than the third-line treatment (P < 0.001) and the fourth-line or later treatments (P < 0.001). No difference in TTF was observed between the third and fourth or later treatment lines. Second, Table 1 shows the clinicopathological factors involved in the TTF of MPA. In univariate analysis, long DFI (≥ 6 years), small nuclear or histological grade, and the presence of visceral metastases correlated with significantly long TTF (P < 0.05). Whereas PgR, adjuvant chemotherapy, and adjuvant endocrine therapy did not affect the TTF of patients treated with MPA. However, in the multivariate regression analysis, only longer DFI (≥ 6 years) was correlated with a significantly longer TTF. Third, we compared the clinicopathologic factors in the groups that received MPA as the fourth or later treatment lines and achieved a TTF of more than 1 year with those that did not. There were no characteristic clinicopathological factors distinct between the two groups. Conclusion: In actual clinical practice, patients treated with MPA alone as the fourth or subsequent treatment lines showed a TTF of 4 months, suggesting that there is merit in using MPA even in late treatment lines, especially in patients with long DFI and those who are difficult to treat with other antineoplastic agents. Table 1. Univariate and Multivariate analyses to investigate association between clinicopathological factors and TTF of MPA (n=170) Citation Format: Kaho Utsunomiya, Hidetoshi Kawaguchi, Yutaka Yamamoto, Shigehira Saji, Norikazu Masuda, Takahiro Nakayama, Kenjiro Aogi, Keisei Anan, Shoichiro Ohtani, Nobuaki Sato, Toshimi Takano, Eriko Tokunaga, Seigo Nakamura, Yoshie Hasegawa, Masaya Hattori, Tomomi Fujisawa, Satoshi Morita, Miki Yamaguchi, Toshinari Yamashita, Daisuke Yotsumoto, Masakazu Toi, Shinji Ohno. Retrospective study using database for the effectiveness of medroxyprogesterone acetate in patients with ER-positive/HER2-negative postmenopausal advanced breast cancer: An additional analysis of the JBCRG-C06 Safari study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-03-15.