Big Drop in Prostate Cancer Treatment in Recent Years in US

Pam Harrison

January 18, 2017

Treatment rates for prostate cancer have declined significantly since the US Preventive Services Task Force first sounded the alarm about harms from routine use of prostate-specific antigen testing in 2008 (for older men) and again in 2012 (for all men), a new study concludes.

However, among men diagnosed with the disease, treatment rates have changed very little, the researchers report.

The study, which was published in the January issue of Health Affairs, is the first population-level analysis of curative prostate cancer treatment rates.

"Treatment rates were actually decreasing prior to the task force's first recommendation in 2008, and that probably highlights the fact that physicians were already thinking about ways to minimize overdiagnosis and overtreatment," lead author Tudor Borza, MD, research fellow, Institute for Healthcare Policy and Innovation, the University of Michigan Health System, Ann Arbor, told Medscape Medical News.

"So that in part is responsible for the 42% decline in the treatment rates we saw over the study interval," he commented.

"But the largest drops in treatment rates occurred following recommendations made in 2008 and then again in 2011 to 2012, so this makes us think that screening recommendations certainly have had a significant overall impact on treatment for prostate cancer across the population as a whole," he added.

National Sample of Men

Investigators carried out a retrospective study of a national sample of men covered by Medicare to assess whether treatment of newly diagnosed prostate cancer had changed between 2007 and 2012.

The sample was restricted to fee-for-service beneficiaries aged 66 years and older. Patients in Medicare managed care plants were excluded.

"We aimed to assess trends in both the population-based rate of treatment (which is sensitive to changes in both diagnosis and treatment patterns) and the rate of treatment among diagnosed men (which is sensitive to changes in treatment patterns only)," Dr Borza and colleagues write.

More than 67,000 patients with newly diagnosed prostate cancer were identified, almost three quarters of whom (72%) received curative treatment within a year of their being diagnosed.

Most men were younger than 75 years at the time of their diagnosis, although close to 16% were at least 80 years of age or older.

Approximately one third of men who underwent treatment received radiation therapy followed by surgery and brachytherapy, the researchers report.

In real numbers, curative treatment rates per 1000 men decreased from 4.3 in 2007 to 2.5 in 2012, the team reports, which is a 42% reduction in treatment rates for newly diagnosed prostate cancer during that period. The largest decreases in curative treatment rates at the population level were seen between 2007 to 2008, during which time the rates dropped 15%, and again between 2011 to 2012, during which time they declined by 21%.

"By comparison, over the same time period, the rate per 1000 diagnosed men decreased by only 8%, from 718 to 659," researchers add. The largest decrease in treatment rates among men diagnosed with prostate cancer was 3.5%, which occurred between 2011 and 2012.

Dr Borza noted that what happened to men diagnosed with prostate cancer between 2007 and 2012 deserves a more nuanced analysis.

"Firstly," he explained, "that 8% decrease in treatment rates in the overall population of diagnosed men is still a substantial decrease," he said, "because it means that 8% fewer diagnosed men were getting treatment between 2007 to 2012, and that's a significant change."

He also pointed out that by the end of the study in 2012, about one third of men diagnosed with prostate cancer were undergoing surveillance. That rate is reflected in the 8% decrease in treatment rates in the diagnosed population overall.

Dr Borza acknowledged that any reduction in prostate cancer treatment was not observed among men who did not have much to gain from prostate cancer treatment because of advanced age or comorbidities.

He pointed out that this group of men had the lowest treatment rates to start out with — only about half were receiving treatment at the beginning of the study. That percentage remained low until study endpoint.

When treatment rates were assessed among men in the lowest three quartiles for nonmortality cancer risk ― in other words, the healthiest men who were diagnosed with prostate cancer ― there was about a 10% reduction in treatment rates between 2007 to 2012, which is encouraging, Dr Borza commemnted.

Dr Borza emphasized that one of the study's limitations is that investigators did not know how severe the diagnosed disease was, "so we didn't know if the right decision for these men was aggressive initial treatment or observation or something in between," he said.

He also emphasized that diagnostic technology for stratifying low- vs high-risk disease is less than perfect and that many men who are originally diagnosed with low-risk disease often have more aggressive disease than initially thought. This makes diagnostic information even less reliable and thus decisions to watch and wait or go ahead and treat even more difficult.

"Most primary care physicians and urologists as well as radiation and medical oncologist do agree that there is an overdiagnosis and treatment problem in prostate cancer," Dr Borza acknowledged.

 
We don't want to miss a chance to cure someone of cancer. Dr Tudor Borza
 

"On the other hand, specialists see men who are dying from their disease all the time, and even though they may agree with the use of active surveillance, not having the most reliable of diagnostic techniques is a big barrier to its use, because we don't want to miss a chance to cure someone of cancer. That weighs on a specialist's mind when making a treatment decision," he added.

"So we found that the 42% drop in treatment rates in the overall population surprising — it's a big drop over a short period of time ― while the 8% drop in diagnosed men reflects what would be replacement treatment with initial surveillance, which is a good start," he concluded.

The study was supported by the National Cancer Institute. Dr Borza has disclosed no relevant financial relationships.

Health Aff. 2017;36:108-115. Abstract

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