Is Active Surveillance for Prostate Cancer Safe?

Pam Harrison

June 05, 2019

CHICAGO — Only a fraction of men who chose active surveillance (AS) instead of immediate treatment for early stage prostate cancer actually undergo monitoring as recommended when treated outside of a controlled trial setting, a population-based cohort study indicates.

"What we thought upfront was that adherence to monitoring would not be perfect, but what we found was that adherence to monitoring was only about 15% [in our group of men]," Ronald Chen, MD, MPH, associate professor at the University of North Carolina School of Medicine, Chapel Hill, told Medscape Medical News.

It raises the question as to whether AS is a good option for patients and whether it's safe. Ronald Chen, MD, MPH

"So if that's the case, it raises the question as to whether AS is a good option for patients and whether it's safe," he added.

The study (abstract 6512) was presented June 2 at the 2019 American Society of Clinical Oncology Annual Meeting.

Guidelines established by the National Comprehensive Cancer Network (NCCN) recommend that men undergoing AS for low- to intermediate-risk prostate cancer need to have their prostatic specific antigen (PSA) levels tested at least once every 6 months, have an annual digital rectal exam (DRE), and a repeat biopsy of the prostate within 18 months of their initial diagnosis.

In this study, a total of 346 men with low- or intermediate-risk prostate cancer diagnosed between 2011 and 2013 were followed for 2 years to see how compliant they were with each of these three components of prostate cancer monitoring.

The authors found that the majority of men who chose AS had their PSA tested in the first 6 months, as well as between 6 to 12 months following their diagnosis — but these numbers dropped with longer-term follow-up.

DRE rates were also relatively high across the 2-year follow-up, but biopsy rates were poor to start with and continued to drop over time.

Table. NCCN Guideline Adherence in Prostate Cancer Cohort Over 2-Year Follow-Up

 

0-6 months

6-12 months

18-24 months

0-18 months

0-24 months

PSA tested

67%

73%

55%

34%

27%

DRE

--

70%

59%

77%

80%

Prostate biopsied

--

35%

7.9%

37%

43%

Adherence to all NCCN guidelines

--

--

--

15%

15%

Conversion to Active Treatment

Chen and colleagues also found that within the first 2 years of their diagnosis, 16% of patients who originally chose AS converted to active treatment — almost half of whom chose active treatment in the absence of disease progression, Chen pointed out.

Chen suspects that anxiety is among the main drivers behind the decision to stop AS and pursue active treatment — anxiety that he feels could be identified early on during the course of AS and, if found, patients counseled or referred for further support so as to better cope with disease-related anxiety.

"I want to emphasize our message with this study is not to discourage AS, as we recognize that patients with low-risk prostate cancer are being overtreated, and with AS we can monitor them instead and avoid treatment in a lot of patients," Chen said.

"But I think AS requires more coordination of care to make sure people are getting the proper monitoring they need," he said. "If we are going to offer it, we must make sure that patients are reminded about their appointments, that someone is tracking the fact that they are getting the monitoring they need."

He suggested that the model of using patient navigators, which had been used in other cancer types, might be needed for men with prostate cancer.

Consequences of Not Monitoring

There is some evidence from clinical trials to suggest that AS may not be as effective as immediate treatment if patients are not well monitored.

In the ProtecT trial, for example, there were no differences in prostate cancer-specific mortality between immediate treatment groups and those assigned to AS. However, the incidence of disease progression and metastases in the surgery and radiotherapy arms was lower at a median follow-up of 10 years in the immediate treatment group than in the AS arm.

"I think many clinicians reading that trial would say [lack of] rigorous monitoring led to inferior outcomes in the AS arm, so we can use the ProtecT trial to suspect that AS in men in the real world may not do as well as patients who are treated immediately," Chen observed.

Low Compliance Rate

Approached by Medscape Medical News to comment on the study, Jim Hu, MD, MPH, Ronald P. Lynch professor of urologic oncology, Weill Cornell Medicine in New York City, said that it wasn't clear from the study whether it was the patients themselves who were less compliant with monitoring guidelines or the fault of the providers who did not reach out to patients to make sure their follow-up visits were appropriately scheduled to ensure men did get additional PSA testing or biopsy.

The study was also done at a time (2011 - 2013) when providers were much less comfortable with the idea of AS than they are now and thus might have been more reluctant to offer it.

"What's surprising is that you have such a low compliance rate relatively early on the in the widespread acceptance of AS, so you might wonder if the compliance rate has changed now that there is a greater comfort level with AS or if it might be even lower now that providers are more comfortable with it," Hu observed.

On the other hand, the median age at which men die from prostate cancer in the United States is 80, as he pointed out.

Older patients are more likely to die with rather than from their disease, Hu added, so they may have simply chosen not to bother with repeat PSA screening or biopsy because of their age.

In contrast, if these were younger men whose cancer was diagnosed in their early or mid-50s and they have "fallen off the wagon," then their time at risk for developing more aggressive cancer is much longer than it is for older men who are placed on AS, as Hu argued.

"It is important to do population-based studies because randomized trials are high-level studies done in an idealistic setting," Hu observed.

"And this is an important study because it shows that there is significant noncompliance with continued monitoring and if you don't monitor [men with prostate cancer more closely] then unfortunately, it becomes blissful ignorance," he noted.

The study was funded by Patient-Centered Outcomes Research Institute (PCORI) and the Agency for Healthcare Research and Quality (AHRQ). Chen and Hu have disclosed no relevant financial relationships.

2019 American Society of Clinical Oncology Annual Meeting: Abstract 6512. Presented June 2, 2019.

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