Imaging Recommendations Largely Ignored in Prostate Cancer


ORLANDO – Costly and unnecessary imaging studies are being performed in men with low-risk and medium-risk prostate cancer, whereas a worrisome number of men with high-risk disease do not receive adequate imaging prior to treatment.

An analysis of 30,183 patients found that 36% of men who were diagnosed with low-risk and 49% of those with intermediate-risk prostate cancer underwent at least one imaging study for staging.

The National Comprehensive Cancer Network (NCCN) and the American Urological Association (AUA) recommend using CT, MRI, and bone scan studies following the diagnosis of prostate cancer only in the setting of high-risk pathological features.

Only 61% of men who were diagnosed with this type of cancer, however, received the recommended imaging prior to treatment, Dr. Sandip M. Prasad, a urologic oncology fellow at the University of Chicago Medical Center, reported.

"Given that the risk of having non–organ confined disease is higher in men with higher Gleason scores, [prostate specific antigen level], or clinical stage, it is critical that these men have appropriate staging to rule out metastatic disease before undergoing local therapy," he said in an interview.

During the study period, men with low- and intermediate-risk prostate cancer did not require any additional imaging per NCCN guidelines; however, the most recently revised (January 2011) NCCN practice guideline allows for some men with intermediate-risk prostate cancer to undergo bone scan.

Dr. Prasad hypothesized that defensive medicine – or a lack of awareness of the AUA and NCCN guidelines – may have played a role in the overuse of the tests. Imaging may also provide reassurance for lower-risk patients that they do not have evidence of metastatic disease, although the likelihood that they would is very low.

The unnecessary tests do expose patients to harmful radiation, and may have cost American taxpayers $35 million, based on a low rate of Medicare reimbursement, he said. The cost may actually be greater because private insurers often reimburse at a higher rate for younger men.

"The gap seen in men with high-risk disease is harder to explain, although one could hypothesize that patient desire to rapidly be treated may drive early treatment without complete staging," Dr. Prasad said. "Men may also choose to have no additional imaging or treatment following diagnosis."

The analysis was based on SEER (Surveillance, Epidemiology, and End Results)–Medicare linked data on 30,183 men who were diagnosed with prostate cancer in 2004-2005. In all, 9,640 men had low-risk prostate cancer, 12,966 men had medium-risk prostate cancer, and 7,577 men had high-risk prostate cancer. Their median ages were 71 years, 73 years and 75 years, respectively.

A multivariate analysis revealed that imaging was less common in men who were educated (odds ratio, 0.084) and was more common in men who were older than 75 years (OR, 1.25), black (OR, 1.11), had a median income of more than $60,000 (OR, 1.19) and lived in rural areas (OR, 1.22), Dr. Prasad and his associates reported in a poster at the Genitourinary Cancers Symposium.

Among low-risk men, imaging was significantly more common in those treated with radiation/brachytherapy (46%; OR, 1.82) or cryotherapy (37%; OR, 1.44), but significantly less common with watchful waiting (14%; OR, 0.27).

Among high-risk patients, imaging was significantly more common in those treated with proton beam therapy (80%; OR, 2.14), radiation/brachytherapy (79%; OR, 2.21), and cryotherapy (74%; OR, 1.64), but significantly less common when men received androgen therapy (44%; OR, 0.62) or watchful waiting (21%; OR, 0.16), the researchers reported at the meeting, which was cosponsored by the American Society for Clinical Oncology, the American Society for Radiation Oncology, and the Society of Urologic Oncology.

Dr. Prasad and his coauthors report no conflicts of interest.

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