Active Surveillance for Incidental (cT1a/b) Prostate Cancer: Long-Term Outcomes of the Prospective Noninterventional HAROW Study

Abstract

Introduction: Optimal treatment for incidental prostate cancer (IPC) after surgical treatment for benign prostate obstruction is still debatable. We report on long-term outcomes of IPC patients managed with active surveillance (AS) in a German multicenter study.

Methods: HAROW (2008-2013) was designed as a noninterventional, prospective, health-service research study for patients with localized prostate cancer (≤cT2), including patients with IPC (cT1a/b). A follow-up examination of all patients treated with AS was carried out. Overall, cancer-specific, and metastasis-free survival and discontinuation rates were determined.

Results: Of 210 IPC patients, 68 opted for AS and were available for evaluation. Fifty-four patients had cT1a category and 14 cT1b category. Median follow-up was 7.7 years (IQR: 5.7-9.1). Eight patients died of which 6 were still under AS or watchful waiting (WW). No PCa-specific death could be observed. One patient developed metastasis. Twenty-three patients (33.8%) discontinued AS changing to invasive treatment: 12 chose radical prostatectomy, 7 radiotherapy, and 4 hormonal treatment. Another 19 patients switched to WW. The Kaplan-Meier estimated 10-year overall, cancer-specific, metastasis-free, and intervention-free survival was 83.8% (95% CI: 72.2-95.3), 100%, 98.4% (95% CI: 95.3-99.9), and 61.0% (95% CI: 47.7-74.3), respectively. In multivariable analysis, age (RR: 0.97; p < 0.001), PSA density ≥0.2 ng/mL2 (RR: 13.23; p < 0.001), and PSA ≥1.0 ng/mL after surgery (RR: 5.19; p = 0.016) were significantly predictive for receiving an invasive treatment.

Conclusion: In comparison with other AS series with a general low-risk prostate cancer population, our study confirmed the promising survival outcomes for IPC patients, whereas discontinuation rates seem to be lower for IPC. Thus, IPC patients at low risk of progression may be good candidates for AS.

Keywords: Active surveillance; HAROW study; Health-service research; Incidental prostate cancer; T1a prostate cancer; T1b prostate cancer.