Active Surveillance ‘Underused’ for Prostate Cancer

Active surveillance is ‘underused’ in men with low-risk prostate cancer and could be extended to those with favourable intermediate-risk disease

medwireNews: Results of two studies published in JAMA Oncology highlight the underuse of active surveillance in low-risk prostate cancer patients and demonstrate the potential for this strategy in men with favourable intermediate-risk disease.

Researcher Jim Hu, from the David Geffen School of Medicine at UCLA in Los Angeles, California, USA, and co-authors report that radiotherapy remains the most commonly used treatment in the USA, regardless of cancer stage or grade, prostate-specific Antigen (PSA) level or risk, with active surveillance “underused” even in men with low-risk disease.

Of the 37, 621 men who were diagnosed with prostate cancer between 2004 and 2007 according to the Surveillance, Epidemiology, and End Results (SEER)–Medicare records, 57.9%, 19.1%, 10.8%, 9.6% and 2.6% underwent radiotherapy, radical prostatectomy, androgen deprivation therapy, watching waiting or active surveillance, and cryotherapy, respectively.

Multivariate analysis showed that patients aged 70 to 74, 75 to 79 and 80 years or above were significantly more likely to undergo watchful waiting or active surveillance than those in the 65 to 69 year age group.

Consultation with a medical oncologist also significantly increased the likelihood of watchful waiting or active surveillance. By contrast, consultation with a radiation oncologist, Asian ethnicity and married status were associated with a significant decrease in the use of this treatment option, as were a Gleason score higher than 6 and high-risk disease as per D’Amico risk stratification.

Unexplained factors, attributed either to patients (58%) or surgeons (12%), were the major contributors to the variation in the decision to pursue watching waiting or active surveillance, with tumour characteristics, SEER region and year accounting for only a small proportion.

The researchers say that “irrespective of prostate cancer risk stratification, most low-risk patients are being treated with radiotherapy”, a finding they describe as “striking” because their study focused on men aged over 65 years with a greater risk of death from competing risks than from prostate cancer.

They add: “Further research into identifying determinants that drive decision-making recommendations for patients diagnosed with low-risk prostate cancer are needed.”

In a second study published in the journal, Ann Raldow, from Brigham and Women’s Hospital in Boston, Massachusetts, USA, and team find that mortality risk is comparable for men with favourable intermediate-risk and low-risk cancer, and suggest that active surveillance could be feasible for patients in the former category.

After a median follow-up of 7.69 years, 605 deaths were recorded in a cohort of 5580 men with localised prostate adenocarcinoma who had received brachytherapy. Just 5.62% of these deaths were attributed to prostate cancer.

The risk of prostate cancer-specific and all-cause mortality did not vary significantly between men with favourable intermediate-risk and those with low-risk disease, even after adjusting for patient age and year of brachytherapy.

Eight-year adjusted point estimates for prostate cancer-specific and all-cause mortality were 0.48% and 10.45%, respectively, in the favourable intermediate-risk group, which compared well with the 0.33% and 8.68% estimates for the low-risk group.

Ann Raldow et al conclude that until the findings of the randomised ProtecT trial comparing active surveillance with treatment are available, their results “provide evidence to support [active surveillance] as an initial approach for men with favorable intermediate-risk [prostate cancer]”.

Reference

Chamie K, Williams SB, Hu JC. Population-Based Assessment of Determining Treatments for Prostate Cancer.JAMA Oncol 2015; Advance online publication 19 February. doi:10.1001/jamaoncol.2014.192

Raldow AC, Zhang D, Chen M-H, et al. Risk Group and Death From Prostate Cancer Implications for Active Surveillance in Men With Favorable Intermediate-Risk Prostate Cancer. JAMA Oncol 2015; Advance online publication 19 February. doi:10.1001/jamaoncol.2014.284

medwireNews (www.medwireNews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2015