Prostatectomy Improves Survival of Screen-Detected Cancer

Becky McCall

March 02, 2012

March 2, 2012 (Paris, France) — Men whose prostate cancer is detected with prostate-specific antigen (PSA) screening have significantly better progression-free survival, metastasis-free survival, and cancer-specific survival after prostatectomy than men not diagnosed through screening. In addition, tumor volume is associated with surgical outcome.

The results of the study — by Stacy Loeb, MD, from New York University in New York City, and her colleagues Xiaoye Zhu, Fritz Schroder, and Monique Roobol, from Erasmus University Medical Center, Rotterdam, the Netherlands — were presented here at the European Association of Urology 27th Annual Congress.

Whereas a previous study showed that prostatectomy improved "survival for men who were diagnosed clinically, our study shows that prostatectomy is very beneficial in screen-detected cases," Dr. Loeb told Medscape Medical News.

Study participants were drawn from the European Randomized Study for Screening for Prostate Cancer (ERSPC), which is the largest study of prostate cancer screening to date. "Previous data from ERSPC have shown that screening reduces prostate cancer death by 20% and metastatic disease by 41% at 9 years," noted Dr. Loeb.

However, she explained that there are concerns about screening leading to false-positive PSA tests, adverse effects from biopsies (such as infections), and overtreatment because of overdiagnosis. These issues all affect the risk/benefit ratio for screening in individual patients. Dr. Loeb added that in the United States, the majority of men receive active treatment, but in Europe, a greater proportion of men undergo active surveillance.

"It's very important to determine the true value of screening. Specifically, we needed to evaluate the true effects of treatment for men diagnosed through screening," she remarked.

A randomized trial conducted last year in Sweden compared radical prostatectomy with watchful waiting (N Engl J Med. 2011;364:1708-1717). The researchers found that survival outcomes were better with radical prostatectomy.

"That study suggests that treatment is effective because it improved survival, but the majority of patients in that study were not diagnosed through PSA testing, so they may have had higher-risk disease or greater tumor volume [at diagnosis]," Dr. Loeb cautioned.

Dr. Loeb's team randomized 42,376 men during the first round of ERSPC Rotterdam (1993 to 1999). There were 1151 prostate cancers diagnosed in the screening group and 210 in the control group.

More cases were diagnosed and there were more radical prostatectomies in the screening group than in the control group (420 vs 50), Dr. Loeb reported. Fewer men in the control group underwent prostatectomy, "probably because significantly more had advanced disease because they weren't screened and, as a result, were not candidates for radical prostatectomy," she explained.

The researchers compared progression-free survival, metastasis-free survival, and cancer-specific survival in the 2 groups after radical prostatectomy.

Patients in the screening group had significantly better progression-free, metastasis-free, and cancer-specific survival. "This means that men whose cancer was detected through screening were less likely to die from prostate cancer after surgery," Dr. Loeb said.

The researchers also looked at PSA level, tumor stage, Gleason score, and age to help predict prognosis after surgery. Even after accounting for all these factors, screening status was found to provide better progression-free and metastasis-free survival, she noted.

One finding surprised the investigators and provided useful insight into factors affecting prognosis. "Everything changed with the tumor volume of the prostatectomy specimen. After accounting for this, screening status was no longer significant," Dr. Loeb reported.

These findings suggest that tumor volume makes the difference between outcomes in screened and nonscreened men. "It seems [that] screening led to diagnosis at a time when tumor volume was significantly less. A lower burden of disease at diagnosis made the men more likely to be helped by surgery," she said.

Dr. Loeb said that the study showed that screening and treatment go together. "They are arm in arm; patients did better after treatment if they were diagnosed through screening. So earlier detection does allow treatment to be more effective."

She emphasized the importance of selecting the right men for the wide-scale implementation of a screening program. "If we do not select who is screened carefully, then we may cause more harm than benefit."

Screening may be overused in elderly men with significant health issues. "Younger, healthier men would benefit most from early detection and effective treatment, so they should be the focus of screening efforts," said Dr. Loeb.

Commenting on the study, Patrick Walsh, MD, from the Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland, told Medscape Medical News that "this is a very important study because it provides further evidence that PSA testing is valuable."

"Having practiced in the pre-PSA era, I've seen too many men who missed the window of curability. This study demonstrates...[that] it doesn't help to remove the prostate in men who are not curable, and provides further evidence that PSA saves lives."

Dr. Loeb and Dr. Walsh have disclosed no relevant financial relationships.

European Association of Urology (EAU) 27th Annual Congress: Abstract 682. Presented February 26, 2012.

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