Long-term data support active surveillance as effective strategy for prostate cancer
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Key takeaways:
- Results refute criticisms about “losing a window of curability when delaying treatment.”
- Researchers estimated extremely low rates of metastasis and prostate cancer-specific mortality at 10 years.
Active surveillance for men with favorable-risk prostate cancer is an effective management strategy, according to data from a prospective cohort study published in JAMA.
Ten years after diagnosis, nearly half of men participating in the Canary Prostate Active Surveillance Study (PASS) remained free of progression or treatment, researchers said, with less than 2% having developed metastatic disease and less than 1% having died of their disease.
“Prostate cancer is the most commonly diagnosed cancer in men, but many — maybe even half — of the cancers that are diagnosed are low grade and will not cause harm if left untreated,” Lisa F. Newcomb, PhD, Canary PASS deputy director at Fred Hutch Cancer Center and University of Washington, told Healio. “Yet many of these slow-growing cancers are treated immediately using surgery or radiation. Treatments have side effects such as urinary incontinence, urinary irritative symptoms, and erectile or bowel dysfunction. They are also expensive.”
Background, methodology
The Canary PASS cohort includes men with favorable-risk prostate cancer who had not received prior treatment. Researchers evaluated prospectively collected data from the study to characterize the long-term oncologic outcomes of patients receiving active surveillance.
The study included patients enrolled at 10 North American centers through August 2022.
The cumulative incidence of biopsy grade reclassification, treatment, metastasis, prostate cancer mortality, overall mortality and recurrence after treatment in patients after the first or subsequent surveillance biopsies served as the study’s main outcomes.
Researchers noted a median follow-up of 7.2 years among 2,155 men (median age, 63 years; 83% white) with localized prostate cancer, 90% of whom received an initial grade 1 diagnosis.
Results
Ten years after diagnosis, researchers observed the incidence of biopsy grade reclassification to be 43% (95% CI, 40-45) and the incidence of treatment to be 49% (95% CI, 47-52) — 425 patients received treatment after confirmatory surveillance biopsies (median, 1.5 years after diagnosis) and 396 received treatment after subsequent surveillance biopsies (median, 4.6 years after diagnosis).
Patients who received treatment following confirmatory surveillance biopsies had a 5-year recurrence rate of 11% (95% CI, 7-15), and those who received treatment after subsequent surveillance biopsies had a 5-year recurrence rate of 8% (95% CI, 5-11).
Progression to metastatic cancer occurred in 21 patients and three prostate cancer-related deaths occurred.
Researchers estimated the rate of metastasis at 10 years to be 1.4% (95% CI, 0.7-2) and the rate of prostate cancer-specific mortality at 10 years to be 0.1% (95% CI, 0-4).
They also noted overall mortality during the same time span of 5.1% (95% CI, 3.8-6.4).
Noted limitations of the study, according to the researchers, included that study accrual began in 2008 and had spanned the length of time in which multiparametric prostate MRI and biomarker tests beyond PSA have since started being used to diagnose and manage prostate cancer; therefore, with half the original cohort having undergone an MRI, the early use of MRIs could further reduce rates of recurrence and metastasis than observed in the current study.
Additionally, they said that since enrollment included only patients at study sites, the cohort primarily consisted of white, educated and insured patients, making it difficult to generalize the results to a broader population.
Lastly, although the PASS cohort represents the largest prospective, protocol-driven surveillance study in North America, prostate cancer has a long natural history, and longer follow-up would very likely show an increase in metastases and deaths due to the disease.
Next steps
According to researchers, the results show the benefit of active surveillance as a safe strategy for treatment of prostate cancer for a large portion of diagnosed men, although improvements can be made to better help men with more aggressive forms of cancer that may require earlier treatment.
“Active surveillance that includes regular PSA exams and prostate biopsies is a safe and effective management strategy for favorable risk prostate cancer,” Newcomb told Healio. “Importantly, adverse outcomes such as recurrence or metastasis do not seem worse in people treated after several years of surveillance versus 1 year of surveillance. This alleviates concern about losing a window of curability when delaying treatment.”
Nevertheless, Newcomb said risk stratification could be improved to reduce the number of unnecessary prostate biopsies while also identifying those whose disease is likely to become more aggressive, requiring an early treatment approach.
“We are evaluating biomarkers for this purpose,” she added. “We hope that this study encourages the national acceptance of active surveillance instead of immediate treatment for prostate cancer.”
For more information:
Lisa F. Newcomb, PhD, can be contacted at lnewcomb@fredhutch.org.
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Newcomb LF, et al. JAMA. 2024;doi:10.1001/jama.2024.6695.
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