Prostate-only Versus Whole-pelvis Radiation with or Without a Brachytherapy Boost for Gleason Grade Group 5 Prostate Cancer: A Retrospective Analysis
[2020, Full Text]
From the Abstract:
When men with a high Gleason grade prostate cancer receive radiation with external radiation and brachytherapy, the addition of radiation to the pelvis results in a longer duration of prostate-specific antigen control. However, we did not find a difference in their survival from prostate cancer or in their survival without metastatic disease. We also did not find a benefit for radiation to the pelvis in men who received radiation without brachytherapy."
From the Discussion:
"Contrary to an increased push toward extended lymphadenectomy within the urologic community , , enthusiasm for WPRT has dwindled over the years among radiation oncologists . In this series of patients with aggressive GG 5 disease, only 53% received WPRT, despite the known high incidence of pathologic node positivity in patients with GG 5 disease who undergo surgery (17% in a companion cohort) ."
The role of WPRT remains a contentious topic in PCa radiation oncology. In this study, we analyzed the benefit of WPRT in patients with GG 5 disease, a group at a much higher a priori risk of having occult nodal metastases, based on prostatectomy series and emerging data with advanced imaging agents. Overall, WPRT was not associated with a benefit in bRFS. However, on subgroup-specific analysis, WPRT was associated with a significant benefit in patients receiving EBRT + BT, but not EBRT alone. These data suggest that in the highest-risk patients, if local control is achieved in the prostate, WPRT may be valuable in sterilizing regional microscopic disease. The lack of an association with clinical outcome benefits could be attributed to lack of power and may become apparent with time. Further studies designed to optimize WPRT, including with the use of more potent radiosensitizing ADT agents and/or optimization with advanced imaging, are warranted."
("lack of power" refers to statistical power, basically the number of cases examined relative to the number needed to test a hypothesis)
The interesting Discussion section brings up a number of yet-unresolved questions as to who may see benefit and why. ASCO Post editorial about this study
This study brings up an issue that I usually mention when discussing, for example, the 15-year results of newer RT modalities like SBRT: improved BCR numbers may or may not translate into an improvement in clinical recurrence or PCa-specific survival.
Post Edited (DjinTonic) : 1/11/2020 9:05:11 AM (GMT-7)