Higher-than-expected severe (Grade 3-4) late urinary toxicity after postprostatectomy hypofractionated radiotherapy: a single-institution analysis of 1176 patients.

BACKGROUND: Dose escalation and hypofractionation may have a role in postprostatectomy radiotherapy (RT), but at the risk of increasing urinary toxicity. OBJECTIVE: To address predictors of severe (Grade ≥3) late urinary toxicities (LGUTOX3) after postoperative irradiation. DESIGN, SETTING, AND PARTICIPANTS: A single-institution cohort of 1176 patients treated between 1993 and 2010 with adjuvant or salvage RT was analyzed. A total of 929 patients underwent conventionally fractionated (CF) RT (1.8 Gy per fraction; median dose to the prostatic bed: 70.2 Gy) with nonconformal RT (n=169), three-dimensional conformal RT (n=657), or intensity-modulated RT (n=103) technique, while 247 patients received hypofractionated helical TomoTherapy (median: 2.50 Gy per fraction) at the following doses: 117 patients at 65.8 Gy (2.35 Gy in 28 fractions), 80 patients at a median of 71.4 Gy (2.5-2.6 Gy in 28 fractions), and 50 patients at 58 Gy in 20 fractions. Total doses were converted into 2 Gy-equivalent doses (EQD2) following the linear quadratic model taking α/ß=5. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Univariable and multivariable Cox regression models tested the relationship between clinicodosimetric variables and the risk of LGUTOX3 retrospectively, graded according to Common Terminology Criteria for Adverse Events v.4.0. RESULTS AND LIMITATIONS: After a median follow-up of 98 mo, the 5-yr risk of LGUTOX3 was 6.9% and 18.1% in the CF and hypofractionated cohorts, respectively. At univariable analysis, the risk of LGUTOX3 was predicted by dose per fraction (hazard ratio [HR]: 2.96), acute Grade ≥2 toxicity (HR: 2.37), EQD2, pT4, and year of irradiation. At multivariable analyses, acute Grade ≥2 toxicity and dose per fraction independently predicted LGUTOX3 in the population, while an interaction analysis indicated a predictive role of hypertension in the hypofractionated cohort only. These findings are limited by their retrospective nature. CONCLUSIONS: In the postprostatectomy setting, the logistic convenience of hypofractionation should be carefully balanced against the risk of severe late urinary sequelae. PATIENT SUMMARY: This study investigated the causes of urinary adverse effects after postprostatectomy radiotherapy. Hypofractionation resulted in an increased risk of severe urinary toxicities.

Systematic evaluation of three different commercial software solutions for automatic segmentation for adaptive therapy in head-and-neck, prostate and pleural cancer.

PURPOSE: To validate, in the context of adaptive radiotherapy, three commercial software solutions for atlas-based segmentation. METHODS AND MATERIALS: Fifteen patients, five for each group, with cancer of the Head&Neck, pleura, and prostate were enrolled in the study. In addition to the treatment planning CT (pCT) images, one replanning CT (rCT) image set was acquired for each patient during the RT course. Three experienced physicians outlined on the pCT and rCT all the volumes of interest (VOIs). We used three software solutions (VelocityAI 2.6.2 (V), MIM 5.1.1 (M) by MIMVista and ABAS 2.0 (A) by CMS-Elekta) to generate the automatic contouring on the repeated CT. All the VOIs obtained with automatic contouring (AC) were successively corrected manually. We recorded the time needed for: 1) ex novo ROIs definition on rCT; 2) generation of AC by the three software solutions; 3) manual correction of AC.To compare the quality of the volumes obtained automatically by the software and manually corrected with those drawn from scratch on rCT, we used the following indexes: overlap coefficient (DICE), sensitivity, inclusiveness index, difference in volume, and displacement differences on three axes (x, y, z) from the isocenter. RESULTS: The time saved by the three software solutions for all the sites, compared to the manual contouring from scratch, is statistically significant and similar for all the three software solutions. The time saved for each site are as follows: about an hour for Head&Neck, about 40 minutes for prostate, and about 20 minutes for mesothelioma. The best DICE similarity coefficient index was obtained with the manual correction for: A (contours for prostate), A and M (contours for H&N), and M (contours for mesothelioma). CONCLUSIONS: From a clinical point of view, the automated contouring workflow was shown to be significantly shorter than the manual contouring process, even though manual correction of the VOIs is always needed.

Indications for pelvic nodal treatment in prostate cancer should change. Validation of the Roach formula in a large extended nodal dissection series.

PURPOSE: Previous studies have criticized the predicting ability of the Roach formula in assessing the risk of lymph node invasion (LNI) in contemporary patients with prostate cancer (PCa) due to a significant overestimation of LNI rates. However, all those studies included patients treated with limited pelvic lymph node dissection (PLND), which is associated with high rates of false negative findings. We hypothesized that the Roach formula is still an accurate tool for LNI predictions if an extended PLND (ePLND) is performed. METHODS AND MATERIALS: We included 3,115 consecutive patients treated with radical prostatectomy and ePLND between 2000 and 2010 at a single tertiary referral center. Extended PLND consisted of removal of obturator, external iliac, and hypogastric lymph nodes. We externally validated the Roach formula by using the area under the receiver operating characteristics curve and calibration plot method. Moreover, we tested the performance characteristics of different formula-generated cutoff values ranging from 1% to 20%. RESULTS: The accuracy of the Roach formula was 80.3%. The calibration showed only a minor underestimation of the LNI risk in high-risk patients (6.7%). According to the Roach formula, the use of 15% cut off would have allowed 74.2% (2,311/3,115) of patients to avoid nodal irradiation, while up to 32.7% (111/336) of all patients with LNI would have been missed. When the cut off was lowered to 6%, nodal treatment would have been spared in 1,541 (49.5%) patients while missing 41 LNI patients. The sensitivity, specificity, and negative predictive values associated with the 6% cut off were 87.9%, 54%, and 97.3%, respectively. CONCLUSIONS: The Roach formula is still accurate and does not overestimate the rate of LNI in contemporary prostate cancer patients if they are treated with ePLND. However, the recommended cut off of 15% would miss approximately one-third of patients with LNI. Based on our results, the cut off should be lowered to 6%.

Anatomical and clinical predictors of acute bowel toxicity in whole pelvis irradiation for prostate cancer with Tomotherapy.

PURPOSE: Assessing predictors of acute bowel toxicity after whole-pelvis irradiation (WPRT) Image-guided Tomotherapy with simultaneous integrated boost on prostate/prostate bed. METHODS AND MATERIALS: In the period March 2005-April 2009, 178 patients were treated with radical or adjuvant/salvage intent with WPRT Tomotherapy. Median dose to the pelvic nodes was 51.8 Gy/28 fractions while concomitantly delivering 65.5-74.2 Gy to prostate/prostatic bed. The impact of many anatomical and clinical parameters on ≥ Grade 2 acute bowel toxicity was investigated by logistic analyses. RESULTS: Only 15/178 patients (8.4%) experienced Grade 2 toxicity (none Grade 3). Main predictors at univariate analysis were nodal CTV (CTVN ≥ 380 cc; OR: 3.7, p=0.017), treatment duration (< 40 days; OR: 6.2, p=0.006) and Grade 2 acute rectal toxicity (OR: 6.5, p=0.015). A multivariate analysis including only pre-treatment variables revealed an independent role of CTVN and age; if including treatment-related factors the best predictors were age, treatment duration and Grade 2 rectal toxicity. This last was correlated with the overlap between PTVN and loops (OVPN ≥ 51 cc; OR: 14.4, p=0.0003) that is representative of the volume of loops receiving the prescribed dose (51.8 Gy, 1.85 Gy/fr). CONCLUSIONS: Acute bowel toxicity after WPRT Tomotherapy is mild, relatively rare and associated to larger CTVN and older age. While efforts to further reduce it do not appear to be relevant, the pre-treatment assessment of "high-risk" patients may help physicians in better managing symptoms. A prospective validation would be very important in confirming these results and in better refining dose-volume bowel effects including symptoms milder that the ones here investigated and retrospectively assessed.

Local α-tocopherol for acute and short-term vaginal toxicity prevention in patients treated with radiotherapy for gynecologic tumors.

INTRODUCTION: Data in literature about the use of adjuvant treatment to reduce acute adverse effects of radiotherapy on the pelvis are scant, with the exception of a few reports on the topical use of estrogen, which promotes proliferation of epithelium. MATERIALS AND METHODS: In this prospective trial, α-tocopherol acetate was topically administered to patients affected by endometrial and cervical cancer and undergoing radiation treatment to avoid acute vaginal complications. RESULTS: Vaginal application of α-tocopherol reduced vaginal toxicity and pain, although vaginal secretion was not significantly different in the 2 groups studied. The histological scoring system showed a significant reduction of inflammation, no difference in fibrosis, and an increase of acanthosis. CONCLUSIONS: The use of α-tocopherol as adjuvant treatment to reduce the acute adverse effects of radiotherapy on the vagina should be considered.