Prognostic assay allows physicians to forecast melanoma recurrence risk

Key Points

New Haven, Conn. - A prognostic assay, expected to be available to practices in late 2010, helps to predict melanoma recurrence risk in some of hardest-to-predict melanoma cases - those patients who qualify for sentinel node biopsy but have negative nodes, according to a new study.

"This is a classic clinic problem that dermatologists will appreciate: the fact that not all small melanomas are benign and cured by a simple resection," says the study's senior author, David L. Rimm, M.D., Ph.D., professor of pathology, Yale University School of Medicine, New Haven, Conn. "Specifically, these are patients who have disease that is greater than 0.8 mm on the Breslow score, which is thick enough to be considered candidates for sentinel node biopsy, but then negative at sentinel node biopsy. A moderate percentage of those patients still recur, and they frequently die from the disease."

In fact, the literature suggests that from 20 percent to 60 percent of patients with stage 2 melanoma will later be diagnosed with metastatic melanoma due to a recurrence of their disease, according to Dr. Rimm.

Physicians and their patients could then make more educated decisions about the need for adjuvant therapy, Dr. Rimm says.

The study

Dr. Rimm and colleagues created the model by searching the literature for proteins associated with melanoma metastasis. They ended up with 20 properties and tested those in more than 550 patients to develop a model that would work.

The researchers, in this National Institutes of Health-funded study, then retested the model in a validation cohort - a completely separate set of patients, all of whom had been operated on by the same surgeon in a series of sentinel node biopsies. All of those 246 patients had melanomas that were at least 0.8 mm thick and qualified for sentinel node biopsy.

In the study, published in the Dec. 1, 2009, issue of the Journal of Clinical Oncology, Dr. Rimm and colleagues found that if patients had four or five markers positive in the test, they only had a 10 percent chance of recurrence during the next eight years. Those who had three or fewer positive markers, using the AQUA system, had a 40 percent chance of recurrence in eight years.

"The test will help to triage those sentinel node negative patients into patients who need to try adjuvant therapy, versus patients who really are cured by surgery," Dr. Rimm says.