Improved Biochemical Control If Statins Used During Radiotherapy for Prostate Cancer

Fran Lowry

December 07, 2009

December 7, 2009 (Chicago, Illinois) — Statin use during high-dose radiation therapy for clinically localized prostate cancer was associated with a significant improvement in the prostate-specific antigen (PSA) relapse-free survival (PRFS) rate, according to the results of a retrospective study presented here at the Radiological Society of North America 95th Scientific Assembly and Annual Meeting.

The effect from statins was most pronounced in patients who had the most aggressive cancers, senior author Michael J. Zelefsky, MD, professor of radiation oncology at Memorial Sloan-Kettering Cancer Center in New York City, told Medscape Radiology.

The study looked at 1711 men with clinical stages T1 to T3 prostate cancer who were treated with radiotherapy between 1994 and 2007. The median radiation dose was 81 Gy.

Data on medication use before radiation therapy were available for 1681 patients, revealing that 385 (23%) were taking a statin at the time of their diagnosis and throughout their course of radiotherapy.

In addition to radiotherapy, 965 patients received a short course of neoadjuvant and concurrent androgen-deprivation therapy.

The study found that the 5- and 10-year PRFS rates for patients already taking statins were 89% and 80%, respectively, and were 83% and 71% for those not taking statins (P = .002).

In a subgroup analysis, a significant improvement in PRFS rates was observed in high-risk patients (hazard ratio [HR], 0.52; P = .02), but not in low- (P = .95) or intermediate- (P = .32) risk patients.

On multivariate analysis, increasing age (P = .004) and neoadjuvant hormone use (P = .002) were also associated with improved PRFS in high-risk patients.

However, the improved results in PRFS with statin use did not translate into improved survival, Dr. Zelefsky said.

"The only thing we have seen at this point is the improvement in biochemical tumor control. It's possible that with longer follow-up of these patients, we may indeed see an improved survival outcome, but longer follow-up will be required to know for sure," he said in an interview.

Dr. Zelefsky said the study has some important implications. "At least it serves as early evidence and supports the notion that statins may have an antitumor effect for prostate cancer, especially in high-risk patients or those with more aggressive cancers," he told Medscape Radiology.

The study, which is now in press in the International Journal of Radiation Oncology, provides information that can be used as the building blocks for future studies, he added. "I believe the data that we present here will be used as preliminary information to design a randomized trial that will look particularly at high-risk patients with more aggressive cancers, and randomize them to take a statin medication or not," Dr. Zelefsky said.

Asked by Medscape Radiology to comment on this study, Alan Pollack, MD, professor and chair of the Department of Radiation Oncology at the University of Miami in Florida, noted that the study had some unknowns. For example, there was no information on how long patients had been taking statins before their diagnosis or how long they were on statins after their treatment.

"These things could be important," he said.

Dr. Pollack agreed that the results from the study need to be explored in other trials.

"It certainly is hypothesis-generating. The problem with studies like this, and I do a lot of them, so I'm criticizing myself as well, is that you do multiple tests and you find something significant and you're not sure how meaningful it is. So the study needs to be repeated."

Dr. Pollack added that it was "interesting" that the high-risk patients had the biggest benefits from statins.

"This is something that could be tested easily in a randomized trial in which men who have high-risk prostate cancer are randomized to statins or no statins. That would be a very easy study to do and could be very informative."

Dr. Zelefsky and Dr. Pollack have reported no relevant financial interests.

Radiological Society of North America (RSNA) 95th Scientific Assembly and Annual Meeting: Abstract RO52-09. Presented December 3, 2009.

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