Prostate cancer is the second most commonly diagnosed cancer in men (behind skin cancer), with varying levels of aggressiveness. It's also the second leading cause of cancer death, behind only lung cancer.

A new study led by Yale Cancer Center researchers at Yale School Medicine found a substantial increase in the adoption of active surveillance (AS) and watchful waiting (WW) treatment strategies over the past decade—an encouraging trend for men seeking less invasive treatment options.

AS and WW involve close monitoring of the cancer in which a patient receives regular tests and examinations, to avoid or delay the side effects of aggressive treatments while maintaining the option to intervene if the cancer worsens. The study results were published in JAMA on November 20.

"One of the challenges in managing localised prostate cancer is determining the risk posed to an individual patient," said the study's senior author Dr. Michael Leapman, the clinical program leader of the prostate and urologic cancers program at Yale Cancer Center and an assistant professor of urology at Yale School of Medicine.

"We know that many prostate cancers will not spread or cause symptoms if untreated. There have been major changes over the past decade with much more use of initial monitoring for cancers determined to be 'low risk.' We wanted to determine whether conservative management, including active surveillance or watchful waiting, has also increased for cancers with 'intermediate risk' features as well."

The researchers analysed data from the Surveillance, Epidemiology, and End Results (SEER) program, which collects cancer information from various parts of the U.S. They looked for people diagnosed with intermediate-risk prostate cancer based on certain criteria like their Gleason grade (which is a score that tells how aggressive the cancer looks under the microscope), PSA levels (a blood test that can indicate the presence of prostate cancer), and the stage of the cancer.

The data revealed that more people were diagnosed with intermediate-risk prostate cancer over the years, and more of them were choosing AS/WW instead of going immediately into treatment, showing a shift towards more conservative management. The number of men diagnosed with intermediate-risk prostate cancer opting for AS/WW more than doubled in 10 years, increasing from 5.0% in 2010 to 12.3% in 2020. There was not much change seen in those with the highest grade within the intermediate-risk group.

"These findings suggest growing interest and comfort in monitoring early-stage prostate cancers," said Leapman. "This is important progress in reducing the over-treatment of incidentally detected prostate cancers posing relatively low risks to patients. But it also raises many important questions regarding the long-term outcomes in these individuals, as well as the role of newer tools at our disposal to better personalise this decision for patients."

Leapman added that men with less aggressive cancer are increasingly likely to choose AS/WW, aligning with evidence that suggests favourable long-term outcomes. The research supports the trend of personalised cancer care, where patients with less aggressive forms of prostate cancer can avoid or delay the potential side effects of surgery or radiation. The findings underscore the importance of individualised treatment plans that consider the patient's specific cancer characteristics and personal preferences.

The authors advocate for national efforts to standardise and improve the quality of monitoring for men under AS/WW. Future research is encouraged to refine criteria for initiating and discontinuing AS/WW, potentially integrating biological markers of cancer risk.