Sweden leads the United States and other nations in the use of active surveillance (AS) for low-risk prostate cancer (PCa), new findings suggest. The latest study examining trends found even greater adoption of AS by 2014 compared with 2011.
Using 2009 to 2014 data from Sweden’s National Prostate Cancer Register (NPCR), Stacy Loeb, MD, MSc, of NYU Langone Medical Center in New York, and colleagues found remarkable uptake of conservative management during that 5-year period. The proportion of patients of all ages choosing the strategy increased from 57% in 2009 to 91% in 2014 for very low risk disease, and from 40% to 74% for low-risk PCa, according to results published online ahead of print in JAMA Oncology. Among men aged 50 to 59 years, 88% with very-low-risk and 68% with low-risk disease opted for active surveillance in 2014. AS even increased for men younger than 50. Guidelines released in 2007 recommending AS for low-risk patients may have accounted for some of the rise, according to the researchers. A surge in adoption also occurred after 2011.
“These data should serve as a benchmark to compare the use of active surveillance for favorable-risk disease around the world,” Dr Loeb’s group concluded. Although AS has increased in the United States in the last decade, community-based registries have shown just a 40% to 50% rate of adoption, according to an accompanying editorial by Matthew R. Cooperberg, MD, MPh, of the University of California San Francisco.
Sweden’s NPCR captures 98% of PCa cases in that country. During 2009 to 2014, 32,518 men (median age 67) were diagnosed with favorable risk PCa. Of these, 4693 had very low risk disease—defined as clinical stage T1c; Gleason score 6 and below; PSA level less than 10 ng/mL; PSA density less than 0.15 ng/mL/cm3; and less than 8 mm of cancer in 4 or fewer positive biopsy cores—and 15,403 low risk PCa (very low risk patients plus men with T1 to T2; Gleason score 6 and below; and PSA less than 10 ng/mL). In addition, 17,115 men had intermediate-risk PCa, which includes T1 to T2 disease with Gleason score 7 and/or PSA 10 to 20 ng/mL.
AS generally involves monitoring with regular blood tests, physical exams, and occasional prostate biopsy. By comparison, use of watchful waiting, which involves no testing or treatment until symptoms surface, decreased in Sweden during the same period.
Among patients with intermediate-risk PCa, AS usage remained low at 19% in 2014. However, it increased from 31% in 2009 to 53% in 2014 for a subset of patients with Gleason 6 and PSA 10 to 20 ng/mL. AS remained low at 17% in 2014 for patients with Gleason 7 (3 + 4) and PSA less than 10 ng/mL.
Dr Loeb and colleagues found that older, unmarried patients diagnosed in a later year and who attended university hospitals were more likely to opt for AS. Comorbidity status and educational level did not appear to influence the decision.
“Our findings should encourage physicians and cancer care professionals in the United States to offer such close supervision and monitoring to their patients with low-risk disease,” Dr Loeb said in a press release. Greater adoption of active surveillance in the US, “could go a long way toward reducing the harms of screening by minimizing overtreatment of non-aggressive prostate cancer,” she added.
In his editorial, Dr Cooperberg highlighted some of the finer differences between AS in Sweden compared with the US: “By the one indicator of surveillance intensity reported in the study—repeat prostate biopsy—surveillance in Sweden tends to be quite lax, with only 31% and 26% of men younger than 70 years, and far fewer men older than 70 years, undergoing biopsy in the first and second year, respectively. The fact that these respective rates were 8% and 13% even for men on watchful waiting suggests some inconsistency in definitions and/or clinicians’ understanding of these terms.”