Surgical Resection Improves Survival in Melanoma Patients

Despite new advanced immunotherapies, surgical resection still is the most effective treatment for abdominal metastatic melanoma.

According to a study presented at the 2015 Clinical Congress of the American College of Surgeons, surgical removal of melanoma that has metastasized to the abdomen appears to help patients survive for more than twice as long as those who receive only medical therapy.

In the 1600 patients treated over 45 years, the results showed an overall survival benefit from surgery despite improvements made to drug-based regimens to treat metastatic melanoma.

Melanoma is an aggressive form of cancer that begins as skin cancer in most cases, but in rarer cases can begin in the eye. In the past, melanoma that metastasized to another abdominal organ, such as the liver, was considered incurable and was not likely to receive surgical resection.

In the past 10 years, the availability of immune therapies for advanced melanoma gave physicians other medical treatment options besides chemotherapy.

“Some of these immunotherapy drugs can take a long time to work, however, and may not be effective for everyone,” said lead author Gary B. Deutsch, MD, MPH, a surgical oncologist at North Shore — LIJ Health System in New York. “We have been trying to gauge the role of surgical resection for metastatic melanoma since the development of systemic immunotherapy. Today, metastatic melanoma is discovered earlier in a number of patients, likely because of better imaging techniques, so surgeons may be able to intervene before it becomes futile.”

This research is the first comprehensive study of all major abdominal locations of melanoma metastases conducted to assess trends in surgical management and overall survival.

In the study of 1623 patients from the John Wayne Cancer Institute, overall survival was indicated as the length of time a person survived following diagnosis of stage IV metastatic melanoma.

By measuring survival in this way, scientists got rid of the variability in time from treatment until the first cancer recurrence that can occur in patients with metastatic melanoma, according to Dr. Deutsch.

All patients involved had abdominal metastases that may possibly be operable and were referred for surgical evaluation.

Of the patients observed, 697 had cancer spread to the liver; 336 to the gastrointestinal tract; 138 to the adrenal glands; 109 in the spleen; and 38 in the pancreas. An additional 205 patients had multiple sites of abdominal metastases.

Metastases in 104 patients resulted from ocular melanoma rather than skin cancer.

Almost 25% of patients underwent surgical resection of the metastasis, or metastasectomy. The operation was either performed solitarily, in combination with medical therapy, or in some cases, included radiofrequency ablation or heat probe treatment to destroy cancer cells.

The surgical group’s median survival rate was 18 months, compared with just 7 months for the nonsurgical group of 1231 patients, as observed by investigators in all abdominal locations of melanoma metastasis.

“With our long-term follow-up, we believe that select patients can live longer with surgical treatment,” Dr. Deutsch said.

The scientists also wanted to test whether treatment era played any role in overall survival, so the investigators split the patients into groups of those treated before (1969 to 2003) and after (2003 to 2014) advances in systemic therapy.

To the researchers’ surprise, treatment in the era of more effective systemic immunotherapy did not significantly affect survival compared with earlier treatment.

“Despite new immunotherapies, surgical resection provides the longest survival in patients with abdominal metastatic melanoma,” said study senior investigator Anton J. Bilchik, MD, PhD, FACS, a professor of surgery and chief of medicine at the John Wayne Cancer Institute. “There is so much excitement about the new systemic immunotherapies, but there needs to continue to be multidisciplinary tumor boards to decide when to intervene surgically.”

The combination of surgical resection with medical therapy offers the chance to cure metastatic melanoma in a select group of patients.

Patients may be candidates for this mode of therapy if they have a long disease-free interval and a slow tumor doubling time, and are otherwise in good health.

Dr. Deutsch reported that individuals who had metastases to the gastrointestinal tract underwent complete, curative resection and had the longest median survival of any patient in the study. They survived for more than 2 years.

“Surgical resection can really make a difference in the patients with gastrointestinal tract metastases,” Dr. Deutsch said. “The operation can be performed laparoscopically, so it is minimally invasive.”