Melanoma Imaging Unreliable in Patients Without Metastases

October 15, 2012 (Atlanta, Georgia) — Routine imaging is unreliable for the staging and surveillance of patients with malignant melanoma who are asymptomatic for metastases, according to a literature review.

Daniel Eisen, MD, and Ekama Onofiok, MD, both from the University of California at Davis, reported their findings in an oral presentation here at the American Society for Dermatologic Surgery 2012 Annual Meeting.

"Interest in the early detection of metastatic melanoma has risen since the introduction of more effective treatment methods," Dr. Eisen told Medscape Medical News. "Most physicians are unfamiliar with the effectiveness or harms of imaging in patients with asymptomatic primary cutaneous melanoma," he noted. "These findings contradict the recommendations of some societal guidelines with respect to when imaging is appropriate, but are generally consistent with the outcomes of most studies," he added.

Drs. Eisen and Onofiok reviewed evidence on the use of imaging in malignant melanoma staging and surveillance. They searched the MEDLINE, Web of Science, and Google Scholar databases for studies on use of chest x-ray, magnetic resonance imaging (MRI), positron emission tomography (PET), computed tomography (CT), and ultrasonography in malignant melanoma.

They were surprised by the very low number of true-positive results and the very high number of false-positive results, Dr. Eisen explained. "Furthermore, the absence of compelling evidence that early detection actually improves survival in patients was interesting," he noted.

Drs. Eisen and Onofiok evaluated true-positive and false-positive rates in various imaging tests used for staging.

imaging-tests-table

The proportion of patients with true- and false-positive rates were similar for patients undergoing surveillance. In addition, few patients had resectable disease when chest x-ray (0.97%; n = 4852), PET (10%; n = 30), or ultrasonography (4.5%; n = 1852) were used.

Study limitations include the variations in disease stage, Breslow thickness, and follow-up intervals in the studies, Dr. Eisen noted.

In the absence of symptoms, most imaging methods have low true-positive and high false-positive rates, Dr. Eisen explained. "The potential for these exams to help patients appears to be very low, and the possibility for psychologic and iatrogenic harm is high," he noted.

In addition, "convincing evidence that the early detection of metastatic melanoma improves outcomes is currently lacking, which calls into question the routine use of most staging or surveillance exams in the absence of symptoms," he said.

The findings are not surprising, said Jeremy S. Bordeaux, MD, MPH, assistant professor of dermatology at Case Western Reserve University in Cleveland, Ohio, who was not involved in the work. "I personally see this very often," he told Medscape Medical News.

He agrees that the use of these surveillance exams can cause undue stress on the patient and can be very costly to our healthcare system. "Patients frequently undergo screening tests that turn up random findings not related to their diagnosis of melanoma. These cause increased stress in the patient and lead to the patient undergoing more unnecessary tests," he noted.

The study was not commercially funded. Dr. Eisen, Dr. Onofiok, and Dr. Bordeaux have disclosed no relevant financial relationships.

American Society for Dermatologic Surgery (ASDS) 2012 Annual Meeting: Oral Abstract session AO321. Presented October 13, 2012.

Source: www.medscape.com