The Comparative Toxicity of Focal Ablation vs. IMRT for Prostate Cancer.

Abstract

Introduction: Focal ablative therapy (FT) aims to treat prostate cancer (PCa) with reduced toxicity compared to standard radiotherapy. There is an absence of studies comparing FT and Intensity Modulated Radiation Therapy (IMRT) for PCa.

Methods: Using the SEER-Medicare database, we identified fee for service Medicare beneficiaries with PCa diagnosed from 2010-2017. Patients who underwent IMRT were Mahalanobis matched 2:1 to FT patients based on demographics, Medicaid eligibility, comorbidity, flu vaccination, primary care access, year, cancer characteristics, and androgen deprivation therapy. We used logistic regression models to assess the relation between treatment modality and presence of claims indicative of a gastrointestinal or genitourinary complication within 6, 12, and 24 months of treatment.

Results: We identified 9,928 IMRT and 800 FT patients. After matching, patients treated with FT were less likely to have gastrointestinal toxicity (6.2%) within 12 months compared to IMRT patients (9.5%; Odds ratio [OR], 0.63 [95%CI 0.45-0.88]; results were similar at 24 months (11.0% FT vs. 21.5% for IMRT; OR 0.45 [95%CI 0.35-0.58]). Most gastrointestinal toxicity was due to diagnoses of rectal bleeding and colitis. In contrast, there were more claims indicative of genitourinary toxicity for FT compared to IMRT during the 0-12 (34.6% vs. 15.8%; OR 2.69 [95%CI 2.21-3.28]), and 0-24 (41.7% vs. 29.3%; OR 1.69 [95%CI 1.42-2.01]) month periods. The largest difference was in incontinence therapy (17.4% vs 7.5%, P<.01) and erectile dysfunction (18.2% vs. 13.1%, P<.01), favoring IMRT.

Conclusion: Among older patients with prostate cancer, FT was associated with a higher risk of incontinence and impotence, compared to IMRT. There was more colitis and rectal bleeding with IMRT vs. FT, but related procedures were rare and not significantly different.