Whole Pelvic Radiotherapy With Stereotactic Body Radiotherapy Boost vs. Conventionally Fractionated Radiotherapy for Patients With High or Very High-Risk Prostate Cancer

Abstract

Background: Whole pelvic radiotherapy (WPRT) with stereotactic body radiotherapy (SBRT) boost has been shown to be effective in patients with high-risk prostate cancer (PC). However, no study has directly compared the efficacy of WPRT with SBRT boost with that of conventionally fractionated radiotherapy (CFRT). We compared the clinical outcomes between CFRT and WPRT with SBRT boost in patients with high or very high-risk PC (National Comprehensive Cancer Network definition). Methods: In total, 132 patients treated with CFRT and 121 patients treated with WPRT followed by SBRT boost were retrospectively analyzed. For the CFRT group, the prescribed dose range was 74-79.2 Gray (Gy) administered at 1.8-2 Gy per fraction. For WPRT with SBRT boost, the prescribed doses were 45 Gy administered in 25 fractions to the whole pelvis followed by 21 Gy boost (3 fractions of 7 Gy each) to prostate and seminal vesicles. The overall survival (OS) and biochemical failure (Phoenix definition) free survival (bFFS) were assessed by using the Kaplan-Meier method or the Cox proportional hazards regression model. The gastrointestinal (GI) and genitourinary (GU) tract toxicity were assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) v3.0. Results: The estimated 4-years overall survival in the CFRT and WPRT with SBRT boost groups was 91.6 and 97.7%, respectively (P = 0.18). The estimated 4-years biochemical failure-free survival in the CFRT and WPRT with SBRT boost groups was 89.1 and 93.9%, respectively (P = 0.41). No acute grade 3 or higher GI and GU toxicity was observed in both groups. Late grade 3 GI and GU toxicity occurred in 2.3 and 2.3% in the CFRT group, and in 1.7 and 0.8% in the WPRT with SBRT boost group, respectively. There was no significant between-group difference with respect to acute or late toxicity. Wang et al. SBRT Boost for Prostate Cancer Conclusions: In patients with high or very high-risk localized PC, compared with CFRT, WPRT with SBRT boost resulted in similar biochemical-free and overall survival rate with minimal toxicity. WPRT with SBRT boost is a feasible option for patients with high or very high-risk PC.

Towards optimal heterogeneous prostate radiotherapy dose prescriptions based on patient‐specific or population‐based biological features

“…For the fractionation schedules shown in Table 2, the minimum allowed dose was obtained from the dose level that has commonly been used in conventional radiotherapy with each corresponding fractionation schedule (EH, 10,11,26,27 MH, 12 CF, 28 WPRT + SBRT 29 ). The average dose was set to the boost dose reported in studies where a boost dose was prescribed, [30][31][32][33][34][35][36] or to the highest dose reported in dose escalation studies. 28 The highest allowed dose was from the maximum prescribed dose in studies that included prostate sub-volume dose escalation (EH and CF 26,37,38 ) or 125% of average dose level (MH and WPRT + SBRT).…”

“…28 The highest allowed dose was from the maximum prescribed dose in studies that included prostate sub-volume dose escalation (EH and CF 26,37,38 ) or 125% of average dose level (MH and WPRT + SBRT). 33 45 28 25 + 3 [34][35][36] T exp (days) 29 26 28 12 1.4 × 45 28 1.4 × 25 + 6 34,36 Max. dose (Gy) 28 21.0 (7.0) [34][35][36] Min.…”

“…33 45 28 25 + 3 [34][35][36] T exp (days) 29 26 28 12 1.4 × 45 28 1.4 × 25 + 6 34,36 Max. dose (Gy) 28 21.0 (7.0) [34][35][36] Min. dose (Gy) 35.0 (7.0) 10,11,26,27 57.0 (3.0) 12 68.6 (1.5) 28 18.0 (6.0) 29 For CF, the average, maximum allowed, and minimum allowed doses were referenced from published PCa fractionation schedules of 81 Gy in 45 fractions, 95 Gy in 35 fractions and 64.8 Gy in 36 fractions.…”

Assessment of the optimal number of positive biopsy cores to discriminate between cancer‐specific mortality in high‐risk versus very high‐risk prostate cancer patients

“…This recommendation is based on a study by Sundi et al, 2 where Kaplan–Meier methodology showed that very high‐risk PCa patients treated with radical prostatectomy (RP) have worse biochemical‐free, metastasis‐free, cancer‐specific, and overall survival, than their high‐risk PCa counterparts 2 . Moreover, several publications investigated oncological outcomes in different treatment modalities of very high‐risk PCa patients 3–12 …”

Simultaneous Integrated Boost Intensity-Modulated Radiotherapy for Locally Advanced Drug-Resistant Gastrointestinal Stromal Tumors: A Feasibility Study

“…This technique has been successfully applied to the several types of bulky tumors, such as esophageal cancer, head and neck tumors, lung cancers, pelvic tumors, and soft tissue sarcomas (18)(19)(20)(21)(22). A better biochemical control can be achieved in SIB-IMRT by increasing dose (23). Therefore, SIB-IMRT may offer a valuable alternative option for patients of moderately radiosensitive GISTs.…”