Half of men with low-risk prostate cancer remained free from progression or treatment 10 years after diagnosis when followed in a protocol-directed active surveillance program.

At 10 years, 43% of more than 2,000 patients had biopsy grade reclassification, and 49% had treatment for prostate cancer. Patients who received treatment after confirmatory or subsequent surveillance biopsies had a low rate of recurrence and distant metastasis, suggesting that delayed treatment did not lead to worse outcomes versus earlier treatment.

The results added to evidence for active surveillance in selected patients with favorable-risk prostate cancer, reported Lisa F. Newcomb, PhD, of Fred Hutchinson Cancer Center in Seattle, and co-authors in JAMA.

“Our study showed that using active surveillance that includes regular PSA exams and prostate biopsies is a safe and effective management strategy for favorable-risk prostate cancer,” Newcomb said in a statement from JAMA. “An important finding was that adverse outcomes such as recurrence or metastasis do not seem worse in people treated after several years of surveillance versus 1 year of surveillance, alleviating concern about losing a window of curability.”

“We hope that this study encourages the national acceptance of active surveillance instead of immediate treatment for prostate cancer,” she added.

Although active surveillance has emerged as the preferred management strategy for low-grade prostate cancer, only about 60% of eligible patients undergo surveillance. Reasons for the low uptake are multifaceted but include fear of undertreatment and missing a window of curability for cancers that initially appear indolent but exhibit aggressive features during surveillance, the authors noted. Additionally, current clinical guidelines provide little guidance for an optimal approach to surveillance.

Increased use of active surveillance requires a better understanding of how to achieve an optimal balance between avoidance of overtreatment and prevention of undertreatment. To address that issue, Newcomb and colleagues analyzed data from the Canary Prostate Active Surveillance Study (PASS), a collaborative observational study involving 10 North American centers that enrolled patients with favorable-risk prostate cancer from 2008 through 2022.

The study’s primary objective was to describe long-term oncologic outcomes of patients enrolled in Canary PASS. Primary endpoints were biopsy grade reclassification, treatment, metastasis, prostate cancer mortality, overall mortality, and recurrence after treatment following a first or subsequent surveillance biopsies.

The analysis included 2,155 men who had a median age of 63 and a median follow-up of 7.2 years. The patients had grade group 1 disease in 90% of cases, and median prostate-specific antigen was 5.2 ng/mL.

The results showed that 927 patients had biopsy grade reclassification at 10 years. Treatment occurred after a confirmatory biopsy (median 1.5 years) in 425 cases and after subsequent surveillance biopsies (median 4.6 years) in 396 cases. Patients treated early during active surveillance had a 5-year recurrence rate of 11%, whereas later treatment was associated with a recurrence rate of 8% at 5 years.

Progression to metastatic cancer occurred in 21 study participants, and three patients died of prostate cancer. The estimated 10-year rates of metastasis or prostate cancer-specific mortality were 1.4% and 0.1%, respectively. The 10-year overall mortality was 5.1%.

The authors noted that the Canary PASS cohort had high adherence to biopsy schedules, as 88% of participants had a first follow-up biopsy within 2 years of diagnosis and 97% within 5 years. High adherence to the biopsy schedule might have contributed to the low rates of metastasis, as compared with other studies that did not require regular biopsies.

“These results are consistent with the premise that surveillance with regular monitoring is a safe management strategy for favorable-risk prostate cancer,” they stated

Newcomb and co-authors acknowledged that enrollment in the study began before the introduction of multiparametric prostate MRI and biomarker tests beyond PSA and continued through the adoption phase of the diagnostic advances. The study’s current protocol requires MRI before biopsy, and about half of the cohort has undergone MRI. Continued early use of MRI might lead to further reductions in recurrence and metastasis.

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