Moderately hypofractionated radiotherapy has become a preferred option for localized prostate cancer based on multiple randomized trials demonstrating non‑inferiority to conventional fractionation. However, its adoption in Japan has been slower, partly due to limited domestic evidence. This study evaluated long‑term outcomes, toxicity, and dose–volume predictors of late gastrointestinal (GI) toxicity in patients treated with a uniform moderately hypofractionated regimen. We retrospectively analyzed 486 consecutive patients treated with intensity‑modulated radiation therapy (IMRT) delivering 70 Gy in 28 fractions between 2010 and 2023. Biochemical relapse‑free survival (bRFS) was assessed using the Phoenix definition. Toxicities were graded using CTCAE v5.0. Dose–volume histogram (DVH) parameters were extracted for all patients, and associations with grade ≥ 2 late GI toxicity were examined using receiver‑operating characteristic (ROC) curves. With a median follow‑up of 62 months, 5‑year bRFS rates were 100

The study aimed to assess the effect of a rectal spacer on the inter-fraction motion of the seminal vesicles (SV) during prostate stereotactic body radiotherapy (SBRT). Clinical data from 60 consecutive patients (300 fractions) with localized prostate cancer treated with definitive SBRT alone (five fractions), between June 2022 and January 2024 were retrospectively reviewed. Of the 60 patients, 44 had a spacer implanted. The residual displacement of SVs in the cone-beam CT relative to those in the planning CT was compared between with and without spacer. The maximum displacement of the proximal SV in 90% of the patients was also evaluated. Additionally, the relationship between the gel/prostate volume ratio and SV displacement was analyzed. The gel/prostate volume ratio was 30 ± 15%. Proximal SV displacement significantly differed with and without the spacer (2.0 vs. 3.8 mm, P < 0.001). Maximum proximal SV displacement also significantly differed with and without the spacer (3.0 vs. 5.1 mm, P < 0.001). In 90% of patients with the spacer, the maximum proximal SV displacement was within 4 mm. SV displacement did not change according to gel/prostate volume ratio. The spacer can limit inter-fraction motion of SVs. The gel/prostate volume ratio was not clinically significant.

This study aimed to compare toxicities, prostate volume and dosimetry, between patients who underwent intensity-modulated radiation therapy (IMRT) combined with ≥3 months of neoadjuvant androgen deprivation therapy (NADT) and those without NADT for prostate cancer. In total, 449 patients with intermediate- and high-risk prostate cancer received 78 Gy IMRT in 39 fractions, of which 129 were treated without any ADT (non-ADT group) and 320 with NADT ≥3 months (NADT group). Adverse events and dose-volume indices were compared between the two groups retrospectively. The NADT group had a lower rate of acute grade 2 gastrointestinal (GI) toxicities (17% vs 25%, P = 0.063) and late grade 2 GI toxicities (P = 0.055), including a significantly lower rate of late grade 2 rectal hemorrhage (P = 0.033), compared with the non-ADT group. There were no cases of late grade 3 or higher GI toxicities. The average volume of the prostate in the NADT group was 38% smaller than that in the non-ADT group (43.7 vs 27.0 cm3, P < 0.001). Bladder V40Gy and V50Gy, and rectum V40Gy, V50Gy, V60Gy and V70Gy were significantly smaller in the NADT group. In the NADT group, no significant difference was observed in adverse events or dosimetry between the subgroups with NADT ≥12 and <12 months. Acute and late rectal toxicities were reduced by NADT within ≥3 months in accordance with reduced prostate volume and improved rectal dosimetry. This suggests a merit of administering neoadjuvant ADT ≥3 months for reducing rectal toxicities.

Purpose: This study aimed to compare the outcomes and toxicities between patients treated with image guided radiation therapy (IGRT) using fiducial markers and non-IGRT in intensity modulated radiation therapy (IMRT) for prostate cancer. Methods and Materials: In total, 518 patients with intermediate- and high-risk prostate cancer received IMRT with 78 Gy in 39 fractions after neoadjuvant androgen deprivation therapy for at least 3 months. Of these patients, 371 were in the non-IGRT group and 147 in the IGRT group, including the IGRT-A group using the same margins as the non-IGRT group and the IGRT-B group using reduced margins. The median follow-up periods for the non-IGRT, IGRT-A, and IGRT-B groups were 99 months, 88 months, and 63 months, respectively. Results: The 5-year biochemical recurrence-free survival rates in the non-IGRT, IGRT-A, and IGRT-B groups were 88%, 95%, and 98% (non-IGRT vs IGRT-A, P = .396; IGRT-A vs IGRT-B, P = .426), respectively. Those for intermediate- and high-risk patients were 94%, 93%, and 96% (non-IGRT vs IGRT-A, P = .916; IGRT-A vs IGRT-B, P = .646), respectively, and 87%, 96%, and 100% (non-IGRT vs IGRT-A, P = .500; IGRT-A vs IGRT-B, P = .483), respectively. For the non-IGRT and IGRT-A groups, the rates of acute grade ≥ 2 gastrointestinal toxicities and late grade ≥ 2 genitourinary toxicities were 17% and 7% (P = .019), respectively, and 28% and 16% (P = .028), respectively. In the IGRT-A and IGRT-B groups, the rates of acute grade ≥ 2 genitourinary toxicities were 45% and 21% (P = .003), respectively. All V60Gy = the volume at least received 60Gy and V70Gy = the volume at least received 70Gy values of the bladder and rectal walls in the IGRT-B group were smaller than those in the IGRT-A group. Conclusions: IGRT with fiducial markers results in lower acute and late toxicities compared with non-IGRT in IMRT for intermediate- and high-risk prostate cancer. Moreover, the toxicities are further decreased by reducing the margins in the treatment planning under IGRT. These processes do not decrease the biochemical recurrence-free survival rates.

PurposeThis is a report of our initial experience using computed tomography (CT)-guided interstitial high dose rate (HDR) brachytherapy to treat bulky pelvic nodal metastases as a part of definitive radiotherapy.Material and methodsBetween February 2015 and April 2019, 14 cervical/endometrial cancer patients presenting with bulky pelvic node(s) underwent nodal interstitial brachytherapy boost in our institution. In total, 17 nodes were treated. The median maximum diameters of the positive nodes at the time of diagnosis and at the first nodal implant were 25 mm (range: 10–65 mm) and 16 mm (range: 9–51 mm), respectively. Dosimetry data of the lymph nodal target volume and small bowel were collected and compared using the paired-sample t-test. Treatment-related toxicities were classified using the Common Terminology Criteria for Adverse Events version 4.0.ResultsThe median follow-up time for all patients was 26 months. Local recurrence in pelvic nodes occurred in one patient (7%) after 16 months. One patient experienced grade 3 bladder bleeding, and one patient experienced grade 2 pubic bone fracture. No patient had grade 2 or greater gastrointestinal toxicity. In the dosimetric analysis, the mean nodal brachytherapy D90% in terms of the total equivalent dose of 2 Gy (EQD2) was 65.6 Gyαβ10. The mean small bowel dose (SBD)0.1cc and SBD1cc in terms of the total EQD2 were 60.4 and 56.5 Gyαβ3, respectively. Nodal D90% was significantly higher in terms of the total EQD2 than the SBD0.1cc (p = 0.003) and SBD1cc (p < 0.001). The Kaplan-Meier 2-year pelvic control estimate was 90%.ConclusionsCT-guided interstitial HDR pelvic nodal brachytherapy appears to be well tolerated with excellent local control in cervical or endometrial cancer patients with bulky pelvic nodes. This approach may offer a useful therapeutic option for unresected bulky pelvic nodes.

Purpose Bulky chest wall recurrence after mastectomy presents a therapeutic challenge because of high-dose of radiation required to control the disease, and its proximity to low-tolerance organs at risk. We report a case of successful computed tomography (CT)-guided high-dose-rate (HDR) salvage interstitial brachytherapy (ISBT) boost. Material and methods A 70-year-old female initially presented with a tumor in right breast, and was treated with mastectomy and adjuvant chemotherapy, followed by hormonal therapy for 5 years without adjuvant radiotherapy. In 2018, 20 years after the initial treatment, she developed unresectable chest wall recurrence that measured 10.5 cm × 7.3 cm × 4.5 cm, with bone and parietal pleura invasion. Biopsy revealed invasive pleomorphic lobular carcinoma [estrogen receptor (ER)-positive, progesterone receptor (PR)-negative, HER2-negative]. There was no evidence of metastatic disease. Results The patient underwent external beam radiotherapy (EBRT) plus ISBT. After EBRT of 50 Gy in 25 fractions was completed, CT-guided ISBT was performed as an outpatient treatment. HDR dose was 16 Gy delivered in 2 fractions with 2 implants. Dose was prescribed to gross tumor volume. ISBT plans were created using inverse planning simulated annealing (IPSA) algorithm. Gross tumor volume D90% plus EBRT dose was 82 Gy equivalent dose of 2 Gy (EQD2), assuming α/β of 4 for breast carcinoma. The patient continued on hormonal therapy. At the 30-month follow-up, the patient remains in remission. The tumor could not be detected by magnetic resonance imaging (MRI) or positron emission tomography (PET). There were no severe treatment-related complications. Conclusions CT-guided HDR ISBT boost can be a useful modality in individualizing treatment strategies for breast cancer patients with unresectable bulky chest wall recurrence.

Purpose We sought dosimetric predictors of a decreasing estimated glomerular filtration rate (eGFR) in gynecological oncology patients receiving extended-field radiation therapy (EFRT). Materials and methods Between July 2012 and April 2020, 98 consecutive cervical or endometrial cancer patients underwent EFRT or whole-pelvis radiation therapy (WPRT) with concurrent cisplatin chemotherapy in our institution. To explore the effect of concurrent cisplatin chemotherapy on renal function, the renal function of the WPRT patients was examined. Of the 98 patients, 34 cervical or endometrial cancer patients underwent EFRT including extended-field intensity-modulated radiation therapy (EF-IMRT) and 64 cervical cancer patients underwent WPRT with cisplatin. Of the 34 EFRT patients, 32 underwent concurrent cisplatin chemotherapy. Excluding patients exhibiting recurrences within 6 months, 31 EFRT patients were analyzed in terms of the dose-volume kidney histograms (the percentages of kidney volumes receiving 12, 16, 20, and 24 Gy) and the post- to pre-treatment eGFR ratios. We calculated Pearson correlation coefficients between the renal dose volume and the percentage eGFR reductions of the 31 EFRT patients, and those treated via EF-IMRT. Renal dose constraint significance was evaluated using the Mann–Whitney U test. Results The eGFR value after WPRT with cisplatin remained largely unchanged for 12 months, unlike that after EFRT. In EFRT patients, a strong correlation was evident between the KV 20Gy dose and the post- to pre-treatment eGFR ratio (correlation coefficients − 0.80 for all patients and − 0.74 for EF-IMRT patients). In EF-IMRT patients, the kidney volume receiving 20 Gy tended to correlate negatively with the eGFR reduction. The Mann–Whitney U test showed that patients with KV 20Gy values < 10% retained significantly better renal function than did patients with KV 20Gy values > 10% ( P = 0.002). Conclusions Imposition of a severe kidney dose constraint during EF-IMRT may reduce nephrotic toxicity. Future prospective investigations of kidney-sparing EF-IMRT are required.

Purpose To prospectively investigate the efficacy and feasibility of focal low-dose-rate (LDR) prostate brachytherapy for low- and intermediate-risk prostate cancer. Material and methods Between October 2014 and May 2019, nineteen low- and intermediate-risk prostate cancer patients who presented with abnormality on both diffusion-weighted and T2-weighted magnetic resonance imaging (MRI) underwent focal LDR brachytherapy at our institution. Focal gross tumor volume (F-GTV) was delineated on transrectal ultrasound, based on abnormality seen on fused T2-weighted MRI. F-GTV was expanded by 5 mm, as a safety margin, to create focal clinical target volume (F-CTV). Prescribed dose to F-CTV was 145 Gy. Biochemical recurrence (BCR) was determined using Phoenix criterion (prostate specific antigen nadir + 2 ng/ml). Pre- and post-implant dosimetry data were compared using non-parametric Wilcoxon’s rank sum test. Treatment-related toxicities were evaluated using common terminology criteria for adverse events. Results Mean F-CTV D90% was significantly lower in the post-implant evaluation than in intraoperative planning (p = 0.004). On post-implant dosimetry, the mean D90% for F-GTV and mean V100% for the entire prostate were 222 Gy and 35%, respectively. Median follow-up time for all patients was 31 months. BCR occurred in one patient after 23 months. Kaplan-Meier 2-year BCR-free rate was 92.9% (95% confidence interval [CI]: 79.4-100%). No patients had grade 1 or greater gastrointestinal toxicity. Three patients who were taking α-blockers to treat benign prostatic hyperplasia (present before brachytherapy), experienced no treatment-related genitourinary toxicities. Two patients suffered from temporary grade 2 urinary frequency. None of the remaining patients experienced grade 2 or higher genitourinary toxicity. Conclusions Focal LDR prostate brachytherapy appears acceptable for MRI-based index tumors, with a low cumulative incidence of BCR. Such brachytherapy might offer a feasible minimally invasive therapeutic option for localized prostate cancer.

Purpose: We designed a bi-valve vaginal speculum high-dose-rate (HDR) interstitial gynecologic brachytherapy applicator. This allows for both a direct view of the cervix and image-guided brachytherapy applicator placement. The purpose of this study was to assess the validity of the new applicator. Material and methods: The applicator was designed to have a 25-mm arc, which can be spread transversely to 35-mm wide, with 10 insertion holes; it was produced using a stereolithographic printer with biocompatible Dental SG resin. For resin radiodensity was measured in Hounsfield units (HU) using computed tomography (CT). Comparing the new applicator with a conventional intracavitary applicator, we evaluated the treated volume (including dimensions of 100% isodose volume at the central axis), V-100/D-90/D-98 for a hypothetical cervix (a 2-cm-long and 4-cm-diameter cylinder), and dose points of organs at risk (OARs) (at 25 and 30 mm from the tandem). Based on dose-volume histogram (DVH) analysis of the cervix and dose points of OARs, the range of tolerance for the percent dose difference in the prescription dose was set at 5%. Results: The mean radiodensity of the Dental SG resin, which was magnetic resonance imaging compatible, was 118 HU. Dimensions of the 100% isodose volume measured at the central axis were 4.4 x 6.6 x 7.4 cm for the new applicator and 4.3 x 6.0 x 7.7 cm for the intracavitary applicator. The 100% prescription dose volumes were 110 cc and 113 cc for the new and conventional applicator, respectively. The percent difference in the hypothetical cervix V-100, D-90, and D-98 between the new and intracavitary applicator were within 5%. The percent differences in dose points of OARs at 25 and 30 mm between the new and conventional applicators were within 5%. Conclusions: Our speculum applicator can reproduce a conventional pear-shaped dose distribution. Our current clinical practice will use this applicator, which can improve the patient's treatment results.

In patients with well-differentiated papillary thyroid carcinoma (PTC), late recurrence is very rare. It is unusual that 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (PET/CT) shows hypermetabolic lesions in patients with well-differentiated PTC metastases. We demonstrate an exceptional case exhibiting a first relapse 37 years after hemithyroidectomy to treat PTC. Recurrent metastasis of a PTC should be considered as a differential diagnosis even if the elapsed time from the initial treatment is great. A left cervical lymphadenopathy, which exceptionally exhibited a hypermetabolic lesion on PET/CT, should be considered a metastatically well-differentiated PTC.

Aim Late adverse effects following radiation therapy for prostate cancer involve the urinary and lower gastrointestinal tracts, with continuous rectal bleeding being the most serious issue. We focused on late adverse effects, particularly rectal bleeding after volumetric-modulated arc therapy (VMAT), for patients with locally advanced prostate cancer. Materials and Methods Seventy-three patients with localized prostate cancer were treated with radiation therapy using VMAT with an image-guided radiation therapy system. Patient age at the start of irradiation ranged from 54 to 81 years (median, 71 years). The follow-up period ranged from 23 to 87 months (median, 57 months). The prescribed total irradiation dose was 76 Gy in 38 fractions. Results Late rectal bleeding was observed in 14 (19%) patients, with nine (12.3%), four (5.5%), and one (1.4%) being classified as grades 1, 2, and 3, respectively. One grade 3 patient with rectal bleeding had severe diabetes and was administered intravenous warfarin for cardiomyopathy. Findings VMAT may provide better accuracy and involve fewer time constraints for patients compared with other intensity-modulated radiation therapy (IMRT) methods. The incidence of late rectal bleeding in VMAT is almost equivalent to that of other IMRT methods.

PURPOSE: The purpose of this study was to assess retrospectively the variability of the urethral dose optimized using a Foley catheter versus urethral contrast injected using a new modified triple-lumen catheter, in CT-based high-dose-rate (HDR) prostate brachytherapy of posttransurethral resection of prostate (TURP) patients. METHODS AND MATERIALS: At our institution, there were six post-TURP patients with prostate carcinoma between July 2014 and April 2016 who underwent transperineal interstitial HDR brachytherapy (16 needles). A custom modified triple-lumen catheter was placed to inject contrast into the TURP defect. Three-dimensional optimal plans using inverse planning simulated annealing algorithm was generated according to radiation therapy oncology group dose requirements. Alternative plans were retroactively generated for comparison using standard technique based on a Foley catheter as a urethral constraint volume for each patient with the same weighting factors. We compared the dosimetry parameters in each planning using Wilcoxon's ranked sum nonparametric test. RESULTS: The median followup of all patients was 17.5 months. No significant genitourinary or gastrointestinal toxicity was noted using this technique. In the dosimetric analysis, the prostate V-100 values and TURP urethral V100 were significantly different between plans with and without the contrast (V100 [mean]: 92.4 [%] vs. 94.4 [%], p = 0.046; TURP UV100 [mean]: 1.4 cc vs. 2.2 cc, p = 0.028). There were no statistical differences in the mean values of planning target volume V-150%, V(20)0%, and D-90, and each bladder V-75 and rectum (V75). CONCLUSIONS: Post-TURP HDR brachytherapy with urethral contrast showed significantly more volume effect of the TURP defect than that with a Foley catheter alone. Better visualization of the TURP defect should lead to more accurate urethral sparing administration of HDR brachytherapy which is necessary to prevent urethral complication. (C) 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

PURPOSE:To investigate the treatment results for focal partial salvage re-implantation against local recurrence after permanent prostate brachytherapy.MATERIAL AND METHODS:Between January 2010 and September 2015, 12 patients were treated with focal partial salvage re-implantation for local recurrence after low-dose-rate brachytherapy using (125)I seeds. The focal clinical target volume (F-CTV) was delineated on positive biopsy areas in a mapping biopsy, combining the cold spots on the post-implant dosimetry for initial brachytherapy. The F-CTV was expanded by 3 mm to create the planning target volume (PTV) as a margin to compensate for uncertainties in image registration and treatment delivery. The prescribed dose to the PTV was 145 Gy. The characteristics and biochemical disease-free survival (BdFS) rates were analyzed. Genitourinary (GU) and gastrointestinal (GI) toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 4.RESULTS:The median prostate-specific antigen (PSA) level at re-implantation was 4.09 ng/ml (range: 2.91-8.24 ng/ml). The median follow-up time was 56 months (range: 6-74 months). The median RD2cc and UD10 were 63 Gy and 159 Gy, respectively. The 4-year BdFS rate was 78%, which included non-responders. Biochemical recurrence occurred in two patients after 7 and 31 months, respectively. The former was treated with hormonal therapy after biochemical failure, and the latter underwent watchful waiting (PSA at the last follow-up of 53 months: 7.3 ng/ml) at the patient's request. No patients had grade 3 GU/GI toxicities or died after salvage re-implantation.CONCLUSIONS:The partial salvage low-dose-rate brachytherapy used to treat local recurrence after permanent prostate brachytherapy is well-tolerated, with high biochemical response rates. This treatment can be not only a method to delay chemical castration but also a curative treatment option in cases of local recurrence of prostate carcinoma after seed implantation.

Coplanar extended-field intensity-modulated radiation therapy (EF-IMRT) targeting the whole-pelvic and para-aortic lymph nodes in patients with advanced cervical cancer results in impaired creatinine clearance. An improvement in renal function cannot be expected unless low-dose (approximately 10 Gy) kidney exposure is reduced. The dosimetric method should be considered during EF-IMRT planning to further reduce low-dose exposure to the kidneys. To assess the usefulness of non-coplanar EF-IMRT with kidney-avoiding beams to spare the kidneys during cervical carcinoma treatment in dosimetric analysis between non-coplanar and coplanar EF-IMRT, we compared the doses of the target organ and organs at risk, including the kidney, in 10 consecutive patients. To estimate the influence of EFRT on renal dysfunction, creatinine clearance values after treatment were also examined in 18 consecutive patients. Of these 18 patients, 10 patients who were included in the dosimetric analysis underwent extended field radiation therapy (EFRT) with concurrent chemotherapy, and eight patients underwent whole-pelvis radiation therapy with concurrent chemotherapy to treat cervical carcinoma between April 2012 and March 2015 at our institution. In the dosimetric analysis, non-coplanar EF-IMRT was effective at reducing low-dose (approximately 10 Gy) exposure to the kidneys, thus maintaining target coverage and sparing other organs at risk, such as the small bowel, rectum, and bladder, compared with coplanar EF-IMRT. Renal function in all 10 patients who underwent EFRT, including coplanar EF-IMRT (with kidney irradiation), was low after treatment, and differed significantly from that of the eight patients who underwent WPRT (no kidney irradiation) 6 months after the first day of treatment (P = 0.005). In conclusion, non-coplanar EF-IMRT should be considered in patients with advanced cervical cancer, particularly in patients with a long life expectancy or with pre-existing renal dysfunction.

Purpose To assess the variability in rectal and bladder dosimetric parameters determined according to post-implant computed tomography (CT) images in patients with or without a urethral catheter. Material and methods Patients with prostate cancer who were scheduled to undergo CT after brachytherapy between October 2012 and January 2014 were included. We obtained CT series with and without a urinary catheter in each patient. We compared the rectal and bladder doses in 18 patients on each CT series. Results The shifts in the seed positions between with and without a catheter in place were 1.3 ± 0.3 mm (mean ± standard deviation). The radiation doses to the rectum, as determined on the CT series, with a urethral catheter were higher than those on CT without a catheter (p < 0.001). Radiation doses to the bladder with a catheter were significantly lower than those without a catheter (p = 0.027). Conclusions Post-implant dosimetry (PID) with no catheter showed significantly lower rectal doses and higher bladder doses than those of PID with a catheter. We recommend the PID procedure for CT images in patients without a catheter. Use of CT with a catheter is limited to identifying urethral position.

Purpose To develop an accurate method of fusing computed tomography (CT) with magnetic resonance imaging (MRI) for post-implant dosimetry after prostate seed implant brachytherapy. Material and methods Prostate cancer patients were scheduled to undergo CT and MRI after brachytherapy. We obtained the three MRI sequences on fat-suppressed T1-weighted imaging (FST1-WI), T2-weighted imaging (T2-WI), and T2*-weighted imaging (T2*-WI) in each patient. We compared the lengths and widths of 450 seed source images in the 10 study patients on CT, FST1-WI, T2-WI, and T2*-WI. After CT-MRI fusion using source positions by the least-squares method, we decided the center of each seed source and measured the distance of these centers between CT and MRI to estimate the fusion accuracy. Results The measured length and width of the seeds were 6.1 ± 0.5 mm (mean ± standard deviation) and 3.2 ± 0.2 mm on CT, 5.9 ± 0.4 mm, and 2.4 ± 0.2 mm on FST1-WI, 5.5 ± 0.5 mm and 1.8 ± 0.2 mm on T2-WI, and 7.8 ± 1.0 mm and 4.1 ± 0.7 mm on T2*-WI, respectively. The measured source location shifts on CT/FST1-WI and CT/T2-WI after image fusion in the 10 study patients were 0.9 ± 0.4 mm and 1.4 ± 0.2 mm, respectively. The shift on CT/FST1-WI was less than on CT/T2-WI (p = 0.005). Conclusions For post-implant dosimetry after prostate seed implant brachytherapy, more accurate fusion of CT and T2-WI is achieved if CT and FST1-WI are fused first using the least-squares method and the center position of each source, followed by fusion of the FST1-WI and T2-WI images. This method is more accurate than direct image fusion.

To evaluate the efficacy and safety of hypofractionated whole-breast irradiation (HF-WBI) compared with conventionally fractionated (CF) WBI.

Purpose: We examined the relationship between radiosensitivity, histone H2AX (gamma H2AX) phosphorylation, and apoptosis to develop a new predictive assay for radiosensitivity.Materials and methods: Seven human tumor cell lines, including one fibrosarcoma (HT1080), four oesophageal carcinomas (TE-9, KYSE30, KYSE150, and KYSE220), and two breast carcinomas (HCC70, and ZR75-1) were used. Cellular radiosensitivity was assessed using a standard colony-forming assay. To measure the frequency of gamma H2AX foci, we counted the number of foci per cell under fluorescence microscopy following immunofluorescence staining. DNA content was determined by a flow cytometric assay. To assess the frequency of apoptosis, we enumerated apoptotic cells by fluorescence microscopy 24 hours after irradiation.Results: All seven cell lines showed dose (0-9 Gy)-dependent increases in the number of gamma H2AX foci per cell 24 h after irradiation. When both the frequency of gamma H2AX foci normalized by DNA content and the frequency of apoptosis were used, a better correlation was observed between the actual cell survivals and the predicted ones.Conclusions: Our study shows that the number of gamma H2AX foci after normalization of the DNA content and apoptotic cell frequency can be used as a new predictive assay for cell survival.

【はじめに】転移性膀胱腫瘍による膀胱出血に対し,1%ミョウバン水持続灌流療法が奏功した中等度の腎機能障害例を報告する.【症例】64歳,女性.腎盂がんに対する右腎尿管摘出後に多発リンパ節転移,腰椎転移を認めていた.腰痛緩和目的の入院中に残尿感や排尿困難を認めた.膀胱内に多量の凝血塊を認め,用手的膀胱洗浄後に生理食塩水の持続灌流療法を施行したが改善せず,1%ミョウバン水による持続灌流療法を開始した.肉眼的血尿を認めなかったため,灌流は7日間継続し中止した.灌流開始後9日目の採血では,血清アルミニウム値の上昇はなく,その後腰痛も軽減し,退院となった.退院3カ月後に自宅で死亡したが,その間に肉眼的血尿や尿閉はみられなかった.【考察】腎機能障害例ではミョウバン水持続灌流療法によりアルミニウム脳症などの重篤な副作用も報告されているが,灌流量の減量により安全で有効な治療法である可能性が示唆された.