Propensity-Weighted Survival Analysis of SBRT vs. Conventional Radiotherapy in Unfavorable Intermediate-Risk Prostate Cancer.

BACKGROUND: Prostate stereotactic body radiotherapy (SBRT), which delivers high-dose precision treatment in ≤5 fractions, is a shorter, more convenient, and less expensive alternative to conventionally fractionated radiotherapy (CRFT; ∼44 fractions) or moderately hypofractionated radiotherapy (MFRT; 20-28 fractions). SBRT has not been widely adopted but may have radiobiologic advantages over CFRT/MFRT. We hypothesized that SBRT would be associated with improved overall survival (OS) versus CFRT or MFRT ± androgen deprivation therapy (ADT) for unfavorable-intermediate-risk prostate cancer (UIR-PCa). METHODS: Men with UIR-PCa treated with SBRT (35-40Gy in ≤5 fractions) or biologically equivalent doses of CFRT (72-86.4Gy in 1.8-2.0Gy/fraction) or MRFT (≥60Gy in 2.4-3.2Gy/fraction; biologically effective doses ≥120) were identified in the National Cancer Database (NCDB). Unweighted and propensity-weighted multivariable Cox analysis (MVA) was used to compare OS hazard ratios. RESULTS: Of 28,028 men with UIR-PCa who received CFRT with (n = 12,872) or without ADT (n = 12,984); MFRT with (n = 251) or without ADT (n = 281); and SBRT with (n = 212) or without ADT (n = 1,428) were identified. Relative to CFRT without ADT, CFRT+ ADT (HR 0.92, 95% CI 0.87-0.97, P = .002) and SBRT without ADT (HR 0.74, 95% CI 0.61-0.89, P = .002) were both associated with improved OS on MVA. Relative to CFRT+ADT, SBRT without ADT correlated with improved OS on MVA (HR:0.81, 95% CI 0.67-0.99, P = .04). Propensity-weighted MVA demonstrated that SBRT (HR:0.80, 95% CI 0.65-0.98, P = .036) and ADT (HR:0.91, 95% CI 0.86-0.97, P = .002) correlated with improved OS. SBRT was not associated with improved OS versus MFRT. CONCLUSION: SBRT, which offers a cheaper and shorter treatment course that mitigates COVID-19 exposure, was associated with improved OS versus CFRT for UIR-PCa. These results confirm guideline-based recommendations that SBRT is a viable option for UIR prostate cancer. The results from this large retrospective study require further validation in clinical trials.

Management of Muscle-Invasive Bladder Cancer During a Pandemic: Impact of Treatment Delay on Survival Outcomes for Patients Treated With Definitive Concurrent Chemoradiotherapy.

INTRODUCTION: During the coronavirus disease 2019 (COVID-19) pandemic, providers and patients must engage in shared decision making to ensure that the benefit of early intervention for muscle-invasive bladder cancer exceeds the risk of contracting COVID-19 in the clinical setting. It is unknown whether treatment delays for patients eligible for curative chemoradiation (CRT) compromise long-term outcomes. PATIENTS AND METHODS: We used the National Cancer Data Base to investigate whether there is an association between a ≥ 90-day delay from transurethral resection of bladder tumor (TURBT) in initiating CRT and overall survival. We included patients with cT2-4N0M0 muscle-invasive bladder cancer from 2004 to 2015 who underwent TURBT and curative-intent concurrent CRT. Patients were grouped on the basis of timing of CRT: ≤ 89 days after TURBT (earlier) vs. ≥ 90 and < 180 days after TURBT (delayed). RESULTS: A total of 1387 (87.5%) received earlier CRT (median, 45 days after TURBT; interquartile range, 34-59 days), and 197 (12.5%) received delayed CRT (median, 111 days after TURBT; interquartile range, 98-130 days). Median overall survival was 29.0 months (95% CI, 26.0-32.0) versus 27.0 months (95% CI, 19.75-34.24) for earlier and delayed CRT (P = .94). On multivariable analysis, delayed CRT was not associated with an overall survival difference (hazard ratio, 1.05; 95% CI, 0.87-1.27; P = .60). CONCLUSION: Although these results are limited and require validation, short, strategic treatment delays during a pandemic can be considered on the basis of clinician judgment.