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.

The Novel Use of a Commercially Available Video-Conference Platform to Facilitate Multidisciplinary Target Volume Review and Delineation for Skull-Base Radiation Therapy During the Coronavirus Disease 2019 Pandemic.

Multidisciplinary involvement in radiation therapy (RT) treatment planning is currently underused. A radiation oncologist sought input for generating target contours from a neuro-radiologist (NR) and otolaryngologist (OL) for 3 patients requiring skull-base RT during the coronavirus disease 2019 pandemic. A Health Insurance Portability and Accountability Act compliant virtual meeting between the radiation oncologist, NR, and OL was arranged. Involvement of the OL and NR led to significant changes in the clinical target volume for all patients. Our experience highlights the feasibility of using commercially available video-conference platforms for multidisciplinary target volume delineation for complex RT cases. Further applications include interdisciplinary contour review for RT cases requiring special expertise and joint attending/resident physician contour review for resident education. The video-conference platform technology has demonstrated benefit during the coronavirus disease 2019 pandemic, and we believe it will remain an integral component of our field moving forward.