Immune checkpoint blockade treatment is highly effective in microsatellite-instable (MSI) colorectal cancer. However, microsatellite-stable (MSS) tumors, which represent 95% of metastatic colorectal cancer, are intrinsically resistant to immunotherapy. In this study, we sought to better understand the mechanisms of resistance to anti-PD-L1 therapy in colorectal cancer by characterizing the immune profiles of MSS and MSI tumor models. Although both tumor types presented intratumoral CD8+ T-cell responses and PD-L1 expression, the exhausted CD8+ T-cell phenotypes differed. In MSS tumors, exhausted CD8+ T cells coexpressed PD-1 and T-cell immunoglobulin and ITIM domain (TIGIT) and exhibited a terminal exhausted profile with low cytokine secretion and limited cytotoxic function. In contrast, PD-1+ CD8+ T cells in MSI tumors did not express TIGIT and displayed higher cytokine and cytotoxic activities. Interestingly, immunosuppressive M2-like tumor-associated macrophages (TAM) accumulated in MSI tumors and positively correlated with PD-1+ TIGIT+ CD8+ T-cell frequency. M2-like TAM depletion reduced TIGIT expression, increased CD8+ T-cell function, and improved efficacy of PD-L1 blockade. Transcriptomic analysis revealed elevated COX1/2 expression in TAMs in MSS tumors compared with MSI tumors. COX2 and prostaglandin E2 (PGE2) receptor inhibition impeded TIGIT expression and restored CD8+ T-cell activity, whereas PGE2 triggered TIGIT upregulation in CD8+ T cells. Single-cell, spatial, and bulk transcriptomic data from patients with colorectal cancer substantiated the correlation between elevated TIGIT in CD8+ T-cell and COX1/2 in TAMs. Together, these data uncover the role of the TAM axis in inhibiting PD-L1 efficacy in MSS colorectal cancer and support the utility of combining anti-PD-L1 therapy with TIGIT blockade, PGE2 treatment, or M2-like TAM inhibition in colorectal cancer.Significance: Targeting PGE2 signaling activated by tumor-associated macrophages sensitizes microsatellite-stable colon tumors to immune checkpoint blockade by limiting the emergence of an exhausted PD-1+ TIGIT+ CD8+ T population.
PURPOSE:/objective: Limited pelvic/para-aortic nodal relapse of prostate cancer after radical local treatment remains a major challenge for locoregional salvage strategies. Salvage Elective Nodes radiotherapy (ENRT) is an appealing option, but concerns persist regarding its toxicity. This study evaluates the 18-months toxicity profile of salvage ENRT combined with intermittent androgen deprivation therapy (iADT) in patients with pelvic and para-aortic oligometastatic disease, compared with iADT alone. MATERIAL:/Methods: OLIGOPELVIS-2/GETUG P12 was a prospective, multicenter, randomized phase III trial. Patients were randomized 1:1 to arm A (6-months iADT alone) or arm B (6-months iADT + ENRT: 54 Gy/1.8 Gy per fraction to the pelvic lymph nodes and 66 Gy/2.2 Gy per fraction to pathological nodes). ENRT started after three months of iADT. After analyzing relapse patterns in the OLIGOPELVIS GETUG P07 study, a December 22, 2021 amendment permitted the inclusion of para-aortic lymph nodes and extended irradiation fields up to the renal arteries. Toxicity was defined using NCI-CTCAE v4.0. RESULTS:A total of 256 patients were enrolled across 17 French centers between 12/2018 and 05/2023. The safety population included 127 patients in arm A and 121 in arm B. Eight patients in arm B were excluded as they did not ultimately receive radiotherapy. Prior prostate or prostatic bed irradiation was reported in 57% and 55% of patients, respectively. In arm B, 39 patients also received para-aortic irradiation. At 6 months, grade ≥ 2 genitourinary (GU) and gastrointestinal (GI) toxicities occurred in 2.4% vs 9.9% (p = 0.02) and 0% vs 19.8% (p < 0.001) of patients in arms A and B, respectively. At 18 months, grade ≥ 2 GU toxicity was 4.1% vs 10.7%, (p = 0.04) in arms A and B, respectively, while no difference in GI toxicity was observed. Prior prostate or prostatic bed irradiation did not increase toxicity at any time point. Among patients receiving para-aortic irradiation, compared to those without : grade ≥ 2 toxicity was similar at 6 months (GU: 12.8% vs 8.5%, p = 0.8; GI: 20.5% vs 19.5%, p = 0.9), or at 18 months (GU: 10.3% vs 11%, p = 1.0; GI: 0% vs 6.1%, p = 0.17), though 6 months upper grade ≥ 1 GI disorders were more frequent (25.6% vs 9.8%, p = 0.02). CONCLUSIONS:Eighteen-month toxicity of salvage ENRT with a simultaneous boost to the pathological lymph nodes, associated with 6-months iADT was acceptable, even among patients with prior prostate irradiation or additional para-aortic irradiation (NCT03630666- RCB 2018-A00551-54; FundingPHRC-K 16-129).
European Organization for Research and Treatment of Cancer trial EORTC 22922/10925 evaluated internal mammary and medial supraclavicular (IM-MS) lymph node irradiation (IM-MS-RT) in patients with stage I-III breast cancer. Eligible patients had involved axillary nodes and/or centrally/medially located tumors regardless of nodal involvement. The primary end point was overall survival, secondary end points were disease-free survival, distant metastases-free survival, breast cancer mortality, and any breast recurrence. Between 1996 and 2004, 4004 patients were randomized. The median patient age was 54 years. At a median follow-up of 22.2 years, 1550 (38.7%) patients died, of whom 796 (51.4%) died from breast cancer. At 20 years, the overall survival rate was 61.8% in the control group versus 61.0% in the IM-MS-RT group (hazard ratio [HR], 1.00; p = .967); the disease-free survival rate was 49.0% versus 48.2%, respectively (HR, 0.97; p = .515); and the distant metastases-free survival rate was 59.8% versus 58.9%, respectively (HR, 0.97; p = .578). The breast cancer mortality rate was 22.4% in the control group and 18.6% in the IM-MS-RT group (HR, 0.82; p = .006), whereas the rate of deaths not from breast cancer or from unknown causes was 15.8% versus 20.4%, respectively (HR, 1.26; p = .002). Lung fibrosis, cardiac fibrosis, and cardiac diseases were more frequent after IM-MS-RT versus no IM-MS-RT (6.3% vs. 3.2%, 2.7% vs. 1.7%. and 15.2% vs. 11.7%, respectively); and the rates of severe cardiac and lung morbidities (scores of 3 or 4) were 1.9% versus 1.7% and 0.3% versus 0.0%, respectively. Breast cancer mortality at 20 years was statistically significantly lower after IM-MS-RT, but deaths not from breast cancer increased after 15 years, resulting in no long-term benefit of IM-MS-RT on overall survival. Therefore, the authors strongly call for very long-term follow-up of treatments for prognostically favorable cancers such as breast cancer.
BACKGROUND:The efficacy of neoadjuvant chemoimmunotherapy in patients with non-metastatic triple-negative inflammatory breast cancer (TN-IBC) remains unclear, as patients with IBC have been poorly represented in pivotal clinical trials. PATIENTS AND METHODS:We conducted an observational, retrospective/prospective, multicenter cohort study from 2023 to 2024 of patients with non-metastatic TN-IBC who received at least one cycle of neoadjuvant pembrolizumab plus multi-agent chemotherapy from September 2018 to April 2023. The median follow-up was 1.4 years [95% confidence interval (CI) 1.2-1.7 years]. The primary endpoint was pathological complete response (pCR). RESULTS:Overall, 63 female patients with TN-IBC were included from four cohorts. The most common regimen was pembrolizumab, taxane/carboplatin, and anthracycline/cyclophosphamide (61.9%). Among all patients, 59 (94%) underwent surgery and 4 (6.4%) experienced local and/or distant disease progression during the neoadjuvant treatment. The pCR rate was 31.7% (20/63; 95% CI 20.6% to 44.7%). CONCLUSIONS:The combination of neoadjuvant chemotherapy and pembrolizumab resulted in a pCR rate of 31.7% in patients with non-metastatic TN-IBC. Compared with triple-negative non-IBC, the lower pCR rate with this combination regimen highlights the need for biomarkers for better patient selection and more active treatment options for this rare and aggressive breast cancer subtype.
BACKGROUND:Hypofractionated radiotherapy is standard for whole-breast radiotherapy, but 50 Gy in 25 fractions (5-week radiotherapy) is still standard in many countries when nodal radiotherapy is needed for morbidity concerns. The UNICANCER HypoG-01 trial aimed to assess morbidity and efficacy of hypofractionated locoregional radiotherapy delivering 40 Gy in 15 fractions (3-week radiotherapy) versus 5-week radiotherapy. METHODS:This non-inferiority, open-label, multicentre, randomised phase 3 trial, conducted in 29 centres in France, included female patients 18 years and older, with invasive breast carcinoma requiring nodal irradiation after complete microscopic resection of the primary tumour. Patients were randomly allocated in a 1:1 ratio to either 3-week radiotherapy (experimental group) or 5-week radiotherapy (control group) to the regional nodes and thoracic wall or breast. The primary endpoint was ipsilateral arm lymphoedema, defined as a 10% or greater increase in arm circumference at 15 cm proximal, 10 cm distal, or both, to the ipsilateral olecranon relative to baseline and contralateral arm, with a non-inferiority margin on the hazard ratio (HR) of 1·545. This trial was registered at ClinicalTrials.gov (NCT03127995) and is closed to recruitment. FINDINGS:Between Sept 26, 2016, and March 27, 2020, 1265 patients were enrolled, and 1221 were included in per-protocol analysis (median follow-up 4·8 years [IQR 4·01-5·02]), 614 assigned to 3-week radiotherapy and 607 to 5-week radiotherapy. The median age was 58 years (IQR 49-68). Arm lymphoedema occurred in 275 (25%) patients (143 with 3-week radiotherapy and 132 with 5-week radiotherapy). 3-week radiotherapy was non-inferior to 5-week radiotherapy regarding arm lymphoedema risk (HR 1·02 [95% CI 0·79-1·31] pnon-inferiority<0·001), with a 3-year cumulative incidence of 23·4% (95% CI 19·7-27·6) and 22·2% (95% CI 19·5-26·3), respectively. Safety profiles were similar between groups; grade 3 or worse adverse events frequencies were 8% and 13%, respectively. Following French regulation, data on race and ethnicity were not collected. INTERPRETATION:3-week radiotherapy (40 Gy in 15 fractions) was found to be non-inferior to 5-week radiotherapy (50 Gy in 25 fractions) for arm lymphoedema risk and was comparably safe regarding other late normal tissue effects for patients prescribed locoregional radiotherapy for early-breast cancer. FUNDING:French National Cancer Institute.
