ORLANDO, Florida — More than one third of men who underwent active surveillance for prostate cancer at a community hospital eventually dropped out and may have been lost to medical management, according to the results of a study from Switzerland.
"Active surveillance is a wonderful opportunity, but we need to improve the dropout rate," said lead author Kurt Lehmann, MD, a urologist at Cantonal Hospital in Baden.
Dr. Lehmann discussed the new study at a press conference today here at the American Urological Association (AUA) 2014 Annual Scientific Meeting.
The dropout rate is a "major concern," he said. "I am personally responsible for what's going on [with the patients who drop out and their health]."
Dr. Lehmann started a watch-and-wait cohort in 1999 because of his concern about the adverse effects of prostate cancer treatment, especially erectile dysfunction, in men with low-risk disease.
All of the men in the cohort had been diagnosed with low-risk prostate cancer and enrolled in the study at the small hospital that employs 4 urologists.
"They sign a consent form…and the story begins," said Dr. Lehmann about the patients.
The dropout rate was 36% among the 157 men in the study, which had an average follow-up time of 48 months.
Nearly half of the patients dropping out did so within the first 3 months of enrollment, before they were scheduled to return to the clinic for a confirmatory biopsy.
The men ultimately refused to have the planned second biopsy for a variety of reasons, including pain and discomfort from the original diagnostic biopsy, said Dr. Lehmann.
The second biopsy is important because a limited amount of tissue is removed initially and a second biopsy may improve the accuracy of disease staging, he explained.
Subsequently, at the 6-, 12-, and 18-month follow-up visits, the attrition continued. "Some do not return," said Dr. Lehmann. Some of the dropout rate was due to patients' having a more urgent medical issue, such as cardiac disease.
Also, about 11% of the 157 study participants became unreachable and thus were "lost to follow-up."
Dr. Lehmann and his colleagues describe the dropout phenomenon as "malcompliance" and believe it is an impediment to the safety of the protocol.
"Long-term follow-up of men with prostate cancer shows active surveillance, as a treatment option, may not be as safe as thought, due to men not following up with their physician," the authors write in the presentation abstract.
"The patients who dropped out — where are they? Did they progress or not? We don't know," said Dr. Lehmann.
"This is more of a real-world experience," said Stacey Loeb, MD, from the New York University Medical Center in New York City, who moderated the AUA press conference.
She was comparing the Swiss study, which has followed some patients for as long as 15 years, with another long-term active-surveillance cohort from the University of Toronto.
Outcomes from the Toronto cohort, which has nearly 1000 men, were recently updated at the 2014 European Association of Urology annual meeting.
But only 2.5% of men in the Toronto cohort have been lost to follow-up, said principal investigator Lawrence Klotz, MD, who also attended the AUA press conference. "You tell a patient they have cancer and they are motivated to be followed," he said.
Active surveillance at an academic center benefits from staff, including nurses, whose work includes study protocol management, observed Dr. Klotz.
"I think it is an important issue," he said about the active surveillance dropout rate seen in the Swiss study.
However, he did not want to overemphasize patient dropouts because much of prostate cancer is a "pseudodisease," he said. "You could argue, how much does it really matter?" he asked, referring to the low disease-specific mortality rates seen with low-risk disease.
He reported that only 2.7% of the Toronto cohort has developed metastatic disease, with a median follow-up of about 10 years.
In the Swiss cohort, 32 men ultimately underwent definitive treatment for prostate cancer — 62% underwent radical prostatectomy and 34% were treated with external-beam radiotherapy.
One man required direct androgen-deprivation therapy and has since died.
After radical prostatectomy, about half of the men had their Gleason score (GS) upgraded to either intermediate or high-risk disease: 37% had GS 7, 5% GS 8, and 10% GS 9.
After 13 years, only 50% of the men remained in the active surveillance group; the others dropped out, were treated with surgery or radiation, or died.
American Urological Association (AUA) 2014 Annual Scientific Meeting. Abstract MP45-02. To be presented Monday, May 18, 2014.
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