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Objective To evaluate the impact of daily fraction doses on late genitourinary (GU) toxicity after salvage radiotherapy (SRT) for prostate cancer. Methods This multi-institutional retrospective study included 212 patients who underwent SRT between 2008 and 2018. All patients received image-guided intensity-modulated SRT at a median dose of 67.2 Gy in 1.8-2.3 Gy/fraction. The cumulative rates of late grade ≥2 GU and gastrointestinal (GI) toxicities were compared using Gray test, stratified by the ≤2.0 Gy/fraction (n  =   137) and ≥2.1 Gy/fraction groups (n  =   75), followed by multivariate analyses. The total dose was represented as an equivalent dose in 2-Gy fractions (EQD2) with α/β = 3 Gy. Results After a median follow-up of 63 months, the cumulative rates of 5-year late grade ≥2 GU and GI toxicities were 14% and 2.5%, respectively. The cumulative rates of 5-year late grade ≥2 GU toxicity in the ≥2.1 Gy/fraction and ≤2.0 Gy/fraction groups were 22% and 10%, respectively (P  =  .020). In the multivariate analysis, ≥2.1 Gy/fraction was still associated with an increased risk of late grade ≥2 GU toxicity (hazard ratio, 2.37; 95% confidence interval, 1.12-4.99; P  =  .023), while the total dose was not significant. Conclusion The present results showed that ≥2.1 Gy/fraction resulted in a higher incidence of late grade ≥2 GU toxicity in SRT. Advances in knowledge The impact of fraction doses on late GU toxicity after SRT remains unknown. The results suggest that higher fraction doses may increase the risk of late GU toxicity in SRT. [ABSTRACT FROM AUTHOR]

Abstract Background Organizing pneumonia (OP), so called bronchiolitis obliterans organizing pneumonia after postoperative irradiation for breast cancer has been often reported. There is little information about OP after other radiation modalities. This cohort study investigated the clinical features and risk factors of OP after stereotactic ablative radiotherapy of the lung (SABR). Methods Patients undergoing SABR between 2004 and 2010 in two institutions were investigated. Blood test and chest computed tomography were performed at intervals of 1 to 3 months after SABR. The criteria for diagnosing OP were: 1) mixture of patchy and ground-glass opacity, 2) general and/or respiratory symptoms lasting for at least 2 weeks, 3) radiographic lesion in the lung volume receiving Results Among 189 patients (164 with stage I lung cancer and 25 with single lung metastasis) analyzed, nine developed OP. The incidence at 2 years was 5.2% (95% confidence interval; 2.6-9.3%). Dyspnea were observed in all patients. Four had fever. These symptoms and pulmonary infiltration rapidly improved after corticosteroid therapy. Eight patients had presented with symptomatic radiation pneumonitis (RP) around the tumor 2 to 7 months before OP. The prior RP history was strongly associated with OP (hazard ratio 61.7; p = 0.0028) in multivariate analysis. Conclusions This is the first report on OP after SABR. The incidence appeared to be relatively high. The symptoms were sometimes severe, but corticosteroid therapy was effective. When patients after SABR present with unusual pneumonia, OP should be considered as a differential diagnosis, especially in patients with prior symptomatic RP.

Abstract Background Radiation proctitis after intensity-modulated radiation therapy (IMRT) differs from that seen after pelvic irradiation in that this adverse event is a result of high-dose radiation to a very small area in the rectum. We evaluated the results of treatment for hemorrhagic proctitis after IMRT for prostate cancer. Methods Between November 2004 and February 2010, 403 patients with prostate cancer were treated with IMRT at 2 institutions. Among these patients, 64 patients who developed late rectal bleeding were evaluated. Forty patients had received IMRT using a linear accelerator and 24 by tomotherapy. Their median age was 72 years. Each patient was assessed clinically and/or endoscopically. Depending on the severity, steroid suppositories or enemas were administered up to twice daily and Argon plasma coagulation (APC) was performed up to 3 times. Response to treatment was evaluated using the Rectal Bleeding Score (RBS), which is the sum of Frequency Score (graded from 1 to 3 by frequency of bleeding) and Amount Score (graded from 1 to 3 by amount of bleeding). Stoppage of bleeding over 3 months was scored as RBS 1. Results The median follow-up period for treatment of rectal bleeding was 35 months (range, 12–69 months). Grade of bleeding was 1 in 31 patients, 2 in 26, and 3 in 7. Nineteen of 45 patients (42%) observed without treatment showed improvement and bleeding stopped in 17 (38%), although mean RBS did not change significantly. Eighteen of 29 patients (62%) treated with steroid suppositories or enemas showed improvement (mean RBS, from 4.1 ± 1.0 to 3.0 ± 1.8, p = 0.003) and bleeding stopped in 9 (31%). One patient treated with steroid enema 0.5-2 times a day for 12 months developed septic shock and died of multiple organ failure. All 12 patients treated with APC showed improvement (mean RBS, 4.7 ± 1.2 to 2.3 ± 1.4, p Conclusions After adequate periods of observation, steroid suppositories/enemas are expected to be effective. However, short duration of administration with appropriate dosage should be appropriate. Even when patients have no response to pharmacotherapy, APC is effective.

Abstract Background In stereotactic body radiotherapy (SBRT) for lung tumors, reducing tumor movement is necessary. In this study, we evaluated changes in tumor movement and percutaneous oxygen saturation (SpO2) levels, and preliminary clinical results of SBRT using the BodyFIX immobilization system. Methods Between 2004 and 2006, 53 consecutive patients were treated for 55 lesions; 42 were stage I non-small cell lung cancer (NSCLC), 10 were metastatic lung cancers, and 3 were local recurrences of NSCLC. Tumor movement was measured with fluoroscopy under breath holding, free breathing on a couch, and free breathing in the BodyFIX system. SpO2 levels were measured with a finger pulseoximeter under each condition. The delivered dose was 44, 48 or 52 Gy, depending on tumor diameter, in 4 fractions over 10 or 11 days. Results By using the BodyFIX system, respiratory tumor movements were significantly reduced compared with the free-breathing condition in both craniocaudal and lateral directions, although the amplitude of reduction in the craniocaudal direction was 3 mm or more in only 27% of the patients. The average SpO2 did not decrease by using the system. At 3 years, the local control rate was 80% for all lesions. Overall survival was 76%, cause-specific survival was 92%, and local progression-free survival was 76% at 3 years in primary NSCLC patients. Grade 2 radiation pneumonitis developed in 7 patients. Conclusion Respiratory tumor movement was modestly suppressed by the BodyFIX system, while the SpO2 level did not decrease. It was considered a simple and effective method for SBRT of lung tumors. Preliminary results were encouraging.

Aim: We aimed to identify the optimal candidates for early salvage radiotherapy (SRT) among patients with biochemical recurrence (BCR) after radical prostatectomy (RP). Methods: This multi‐institutional retrospective study included 371 patients treated using SRT after RP. The median (range) PSA level at BCR was 0.36 (0.10‐2.00) ng/mL. The association between early SRT (ie, starting PSA level < 0.50) and BCR after SRT was tested in each subgroup according to our own risk stratification. Results: The median follow‐up time was 51 months. By multivariate analysis, pT3b, Gleason score ≥ 8, negative surgical margins, PSA doubling time < 6 months, and non‐early SRT were associated with BCR after SRT. Patients were stratified by four risk factors other than non‐early SRT: (1) low risk (0 risk factor), (2) intermediate risk (1 risk factor), and (3) high risk (≥2 risk factors). The BCR‐free survival was higher in the early SRT group than the nonearly SRT group in the high‐risk subgroup (P = 0.020), whereas that was similar between two groups in the low‐risk and intermediate‐risk subgroups (P =.79 and.18, respectively). Multivariate analysis revealed that early SRT was beneficial for the high‐risk subgroup (P =.032), whereas early SRT was not associated with improved outcomes in the low‐risk and intermediate‐risk subgroups (P =.92 and 1.0, respectively). Conclusions: This study suggested that early SRT seemed to contribute to better biochemical control for patients with more adverse features, whereas no benefit was observed in men with no adverse features. [ABSTRACT FROM AUTHOR]

Background: In stereotactic body radiotherapy (SBRT) for lung tumors, reducing tumor movement is necessary. In this study, we evaluated changes in tumor movement and percutaneous oxygen saturation (SpO2) levels, and preliminary clinical results of SBRT using the BodyFIX immobilization system. Methods: Between 2004 and 2006, 53 consecutive patients were treated for 55 lesions; 42 were stage I non-small cell lung cancer (NSCLC), 10 were metastatic lung cancers, and 3 were local recurrences of NSCLC. Tumor movement was measured with fluoroscopy under breath holding, free breathing on a couch, and free breathing in the BodyFIX system. SpO2 levels were measured with a finger pulseoximeter under each condition. The delivered dose was 44, 48 or 52 Gy, depending on tumor diameter, in 4 fractions over 10 or 11 days. Results: By using the BodyFIX system, respiratory tumor movements were significantly reduced compared with the free-breathing condition in both craniocaudal and lateral directions, although the amplitude of reduction in the craniocaudal direction was 3 mm or more in only 27% of the patients. The average SpO2 did not decrease by using the system. At 3 years, the local control rate was 80% for all lesions. Overall survival was 76%, cause-specific survival was 92%, and local progression-free survival was 76% at 3 years in primary NSCLC patients. Grade 2 radiation pneumonitis developed in 7 patients. Conclusion: Respiratory tumor movement was modestly suppressed by the BodyFIX system, while the SpO2 level did not decrease. It was considered a simple and effective method for SBRT of lung tumors. Preliminary results were encouraging. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the relationship between waiting time (WT) and disease progression in patients undergoing stereotactic body radiotherapy (SBRT) for lung adenocarcinoma (AD) or squamous cell carcinoma (SQ). Methods and Materials: 201 patients with Stage I AD or SQ undergoing SBRT between January 2004 and June 2010 were analyzed. The WT was defined as the interval between diagnostic computed tomography before referral and computed tomography for treatment planning or positioning before SBRT. Tumor size was measured on the slice of the longest tumor diameter, and tumor volume was calculated from the longest diameter and the diameter perpendicular to it. Changes in tumor volume and TNM stage progression were evaluated, and volume doubling time (VDT) was estimated. Results: The median WT was 42 days (range, 5-323 days). There was a correlation between WT and rate of increase in volume in both AD and SQ. The median VDTs of AD and SQ were 170 and 93 days, respectively. Thirty-six tumors (23%) did not show volume increase during WTs >25 days. In 41 patients waiting for ≤4 weeks, no patient showed T stage progression, whereas in 25 of 120 (21%) patients waiting for >4 weeks, T stage progressed from T1 to T2 (p = 0.001). In 10 of 110 (9.1%) T1 ADs and 15 of 51 (29%) T1 SQs, T stage progressed (p = 0.002). N stage and M stage progressions were not observed. Conclusion: Generally, a WT of ≤4 weeks seems to be acceptable. The WT seems to be more important in SQ than in AD. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the reliability of the linear-quadratic (LQ) formalism and the magnitude of errors associated with its use in assessing biologic equivalence between single, high radiation doses and hypofractionated radiation doses. Methods and Materials: V79 and EMT6 single cells received single doses of 2–12 Gy or two or three fractions of 4 or 5 Gy, each at 4-h intervals. Single and fractionated doses to actually reduce the cell survival to the same level were determined by a colony assay. The α/β ratio was obtained from the cell survival curves. Using the α/β ratio and the LQ formalism, equivalent single doses for the hypofractionated doses were calculated. They were then compared with the actually determined equivalent single doses for the hypofractionated doses. The V79 spheroids received single doses of 5–26 Gy or two to five fractions of 5–12 Gy at 2 or 4-h interval, and then were assayed for cell survival. Next, equivalent single doses for the hypofractionated doses were determined, as were done for the single cells. Results: The α/β ratio was 5.1 Gy for the V79 single cells and 0.36 Gy for EMT6. In V79, the equivalent single doses for the hypofractionated doses calculated using the LQ formalism were 12–19% lower than the actually measured biologically equivalent single doses. In the EMT6 cells, this trend was also seen, but the differences were not significant. In the V79 spheroids, the calculated doses were 18–30% lower than the measured doses. Conclusion: Conversion of hypofractionated radiation doses to single doses using the LQ formalism could underestimate the effect of hypofractionated radiation by ≤30%. [Copyright &y& Elsevier]

Abstract: Influences of iodinated contrast media on dose calculation were studied in 26 patients. Mean increases in monitor units by contrast media administration were less than 1% and considered negligible in planning of whole-brain, whole-neck, mediastinal, and whole-pelvic irradiation. However, mean increases over 2% were seen in planning of upper-abdominal radiotherapy. [Copyright &y& Elsevier]