Careful patient selection improves prostate salvage brachytherapy outcomes
MedWire News: Salvage brachytherapy (BT) for failed initial prostate radiation is most beneficial in terms of oncologic and quality-of-life outcomes in patients with low pre-salvage prostate-specific antigen (PSA) levels, and no previous pelvic lymph node dissection (PLND), say researchers.
The team highlights the importance of careful patient selection for salvage BT in light of its potential to induce toxicities including rectal injury, incontinence, and impotence.
"Improved freedom from biochemical failure (FFbF) was associated with a pre-salvage PSA below 6 ng/ml," report Richard Stock and colleagues from Mount Sinai School of Medicine in New York, USA. Patients who underwent PLND before salvage BT had a significantly higher risk for grade 2 or worse toxicities compared with non-PLND patients.
The team investigated oncologic outcomes (including FFbF, and cause-specific survival [CSS]) and toxicity rates over a median period of 86 months in 37 patients with locally recurrent prostate cancer.
Patients received salvage BT at an average age of 70 years, and were examined every 6 months. Toxicities were graded according to the Common Toxicity Criteria version 3.0.
Five- and 10-year FFbF rates for the cohort were 65% and 54%, respectively, and CSS and overall survival rates were high, at 96% and 96%, and 94% and 74%, respectively, at 5 and 10 years.
Multivariate analysis adjusting for factors including age, PSA at initial diagnosis, and PSA at salvage therapy revealed that, compared with a higher PSA, having a PSA below 6 ng/ml at the time of salvage therapy was significantly associated with FFbF at 5 and 10 years, with a hazard ratio of 8.44.
The overall rate of Grade 2 or higher toxicities was 47%. However, only three patients developed a Grade 3 toxicity (two obstructive uropathies, one gross hematuria), one patient developed a Grade 4 toxicity (prostatorectal fistula), and there were no Grade 5 toxicities (death) reported.
The researchers evaluated pre-BT clinical factors for their impact on the development of Grade 2 or higher toxicities and only found an association for previous PLND. A total of 73% of PLND patients experienced a Grade 2 or higher toxicity compared with 35% of non-PLND patients.
"Improvement in patient outcomes [after salvage BT] could be further enhanced by careful patient selection," conclude Stock et al in the International Journal of Radiation Oncology Biology Physics.
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By Sarah Guy