Reduced toxicity with intensity modulated radiation therapy (IMRT) for desmoplastic small round cell tumor (DSRCT): an update on the whole abdominopelvic radiation therapy (WAP-RT) experience.

PURPOSE: Desmoplastic small round cell tumor (DSRCT) is a rare malignancy typically involving the peritoneum in young men. Whole abdominopelvic radiation therapy (WAP-RT) using conventional 2-dimensional (2D) radiation therapy (RT) is used to address local recurrence but has been limited by toxicity. Our objectives were to assess the benefit of intensity modulated radiation therapy (IMRT) on toxicity and to update the largest series on radiation for DSRCT. METHODS AND MATERIALS: The records of 31 patients with DSRCT treated with WAP-RT (22 with 2D-RT and 9 with IMRT) between 1992 and 2011 were retrospectively reviewed. All received multi-agent chemotherapy and maximal surgical debulking followed by 30 Gy of WAP-RT. A further focal boost of 12 to 24 Gy was used in 12 cases. Boost RT and autologous stem cell transplantation were nearly exclusive to patients treated with 2D-RT. Toxicities were assessed with the Common Terminology Criteria for Adverse Events. Dosimetric analysis compared IMRT and simulated 2D-RT dose distributions. RESULTS: Of 31 patients, 30 completed WAP-RT, with a median follow-up after RT of 19 months. Acute toxicity was reduced with IMRT versus 2D-RT: P=.04 for gastrointestinal toxicity of grade 2 or higher (33% vs 77%); P=.02 for grade 4 hematologic toxicity (33% vs 86%); P=.01 for rates of granulocyte colony-stimulating factor; and P=.04 for rates of platelet transfusion. Post treatment red blood cell and platelet transfusion rates were also reduced (P=.01). IMRT improved target homogeneity ([D05-D95]/D05 of 21% vs 46%) and resulted in a 21% mean bone dose reduction. Small bowel obstruction was the most common late toxicity (23% overall). Updated 3-year overall survival and progression-free survival rates were 50% and 24%, respectively. Overall survival was associated with distant metastasis at diagnosis on multivariate analysis. Most failures remained intraperitoneal (88%). CONCLUSIONS: IMRT for consolidative WAP-RT in DSRCT improves hematologic toxicity in particular. Although the long-term efficacy of current treatment options remains disappointing, the improved therapeutic index of IMRT may aid in generalizing its use and allowing the addition of novel approaches such as intraperitoneal immunotherapy.

Toxicity and outcomes of thoracic re-irradiation using stereotactic body radiation therapy (SBRT).

BACKGROUND: Patients treated for a thoracic malignancy carry a significant risk of developing other lung lesions. Locoregional control of intrathoracic recurrences is challenging due to the impact of prior therapies on normal tissues. We examined the safety and efficacy of thoracic re-irradiation using high-precision image-guided stereotactic body radiation therapy (SBRT). METHODS: Records of 39 patients with prior intra-thoracic conventionally fractionated radiation therapy (RT) who underwent SBRT for a subsequent primary, recurrent or metastatic lung tumor from 11/2004 to 7/2011 were retrospectively reviewed. RESULTS: Median dose of prior RT was 61 Gy (range 30-80 Gy). Median biologically effective prescription dose (α/ß = 10) (BED(10)) of SBRT was 70.4 Gy (range 42.6-180 Gy). With a median followup of 12.6 months among survivors, 1- and 2-year actuarial local progression-free survival (LPFS) were 77% and 64%, respectively. Median recurrence-free (RFS) and overall survival (OS) were 13.8 and 22.0 months, respectively. Patients without overlap of high-dose regions of the primary and re-irradiation plans were more likely to receive a BED(10) ≥100 Gy, which was associated with higher LPFS (hazard ratio, [HR] = 0.18, p = 0.04), RFS ([HR] = 0.31, p = 0.038) and OS ([HR] = 0.25, p = 0.014). Grade 2 and 3 pulmonary toxicity was observed in 18% and 5% of patients, respectively. Other grade 2-4 toxicities included chest wall pain in 18%, fatigue in 15% and skin toxicity in 5%. No grade 5 events occurred. CONCLUSIONS: SBRT can be safely and successfully administered to patients with prior thoracic RT. Dose reduction for cases with direct overlap of successive radiation fields results in acceptable re-treatment toxicity profile.

Quantifying the impact of immediate reconstruction in postmastectomy radiation: a large, dose-volume histogram-based analysis.

PURPOSE: To assess the impact of immediate breast reconstruction on postmastectomy radiation (PMRT) using dose-volume histogram (DVH) data. METHODS AND MATERIALS: Two hundred forty-seven women underwent PMRT at our center, 196 with implant reconstruction and 51 without reconstruction. Patients with reconstruction were treated with tangential photons, and patients without reconstruction were treated with en-face electron fields and customized bolus. Twenty percent of patients received internal mammary node (IMN) treatment. The DVH data were compared between groups. Ipsilateral lung parameters included V20 (% volume receiving 20 Gy), V40 (% volume receiving 40 Gy), mean dose, and maximum dose. Heart parameters included V25 (% volume receiving 25 Gy), mean dose, and maximum dose. IMN coverage was assessed when applicable. Chest wall coverage was assessed in patients with reconstruction. Propensity-matched analysis adjusted for potential confounders of laterality and IMN treatment. RESULTS: Reconstruction was associated with lower lung V20, mean dose, and maximum dose compared with no reconstruction (all P<.0001). These associations persisted on propensity-matched analysis (all P<.0001). Heart doses were similar between groups (P=NS). Ninety percent of patients with reconstruction had excellent chest wall coverage (D95 >98%). IMN coverage was superior in patients with reconstruction (D95 >92.0 vs 75.7%, P<.001). IMN treatment significantly increased lung and heart parameters in patients with reconstruction (all P<.05) but minimally affected those without reconstruction (all P>.05). Among IMN-treated patients, only lower lung V20 in those without reconstruction persisted (P=.022), and mean and maximum heart doses were higher than in patients without reconstruction (P=.006, P=.015, respectively). CONCLUSIONS: Implant reconstruction does not compromise the technical quality of PMRT when the IMNs are untreated. Treatment technique, not reconstruction, is the primary determinant of target coverage and normal tissue doses.

Variability of gross tumor volume delineation in head-and-neck cancer using PET/CT fusion, Part II: the impact of a contouring protocol.

The purpose of this study was to assess the efficacy of a gross tumor volume (GTV) contouring protocol on interobserver variability between 4 physicians in positron emission therapy/computed tomography (PET/CT) treatment planning of head-and-neck cancer. A GTV contouring protocol for PET/CT treatment planning was developed utilizing 4 stages: Preliminary contouring on CT alone, determination of appropriate PET windowing, accurate image registration, and modification of CT contouring with correctly formatted PET/CT display and rules for modality disagreement. Two neuroradiologists and 2 radiation oncologists (designated as A, B, C, and D, respectively) were given a tutorial of PET/CT coregistered imaging individualized to their skill level, which included a step-by-step explanation of the protocol with clinical examples. Opportunities for questions and hands-on practice were given. The physicians were asked to re-contour 16 head-and-neck patients from Part I on PET/CT fusion imaging. Differences in volume magnitude were analyzed for statistical significance by analysis of variance (ANOVA) and paired t-tests (alpha<0.05). Volume overlap was analyzed for statistical significance using Wilcoxon signed-rank tests (alpha<0.05). Volume overlap increased significantly from Part I to Part II (p<0.05). One previously significant difference between physicians disappeared with the protocol in place. The mean fusion volume of Physician C, however, remained significantly larger than that of Physician D (p<0.01). This result is unchanged from Part I. The multidisciplinary contouring protocol significantly improved the coincidence of GTVs contoured by multiple physicians. The magnitudes of the volumes showed marginal improvement in consistency. Developing an institutional contouring protocol for PET/CT treatment planning is highly recommended to reduce interobserver variability.

Preliminary results of radiation therapy for prostate cancer in human immunodeficiency virus-positive patients.

OBJECTIVES: The purpose of this study was to report on the clinical outcomes of patients treated at our institution for prostate cancer (PCa) who had been previously diagnosed as Human immunodeficiency virus (HIV) positive. METHODS: The authors conducted a retrospective study of 14 PCa/HIV patients who were being treated for PCa with external beam radiotherapy, brachytherapy, or a combination of the two. Each patient's prostate-specific antigen (PSA) level, CD4 count, and viral load were obtained before the initial radiation treatment and at the time of their most recent follow-up. In addition, 13 of 14 patients completed a quality of life survey with a social worker on staff and were examined by their radiation oncologist to assess the complications after treatment. RESULTS: Comparing pretreatment data with the data at last follow-up, only 1 patient's PSA level remained above 1.1 ng/mL. The average CD4 count remained stable, increasing from 523 to 577 cells/mm(3), with the lowest final count at 200 cells/mm(3). Viral load increased in only 2 of 14 patients. There were no unusual rectal, urinary, or sexual complications, and no infections related to treatment. CONCLUSIONS: Based on changes in viral load and CD4 count, radiotherapy does not appear to have a long-term negative effect on the immune system. Treatment complications are consistent with HIV-negative patients, giving no evidence that the subset of PCa/HIV patients should be treated differently from PCa patients without HIV when considering radiation therapy. More investigation will be necessary before reliable mortality and morbidity data can be assessed.