Surgical resection prolongs survival for patients whose melanoma has spread to the abdomen

Melanoma is an aggressive type of cancer that usually starts as skin cancer, but in rare cases can start in the eye. In the past, melanoma that spread to the liver or another abdominal organ was considered incurable and seldom received surgical resection, an operation to remove the cancerous part of the organ. In the last decade, 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. He performed the research while a surgical oncology fellow at John Wayne Cancer Institute at Providence Saint John's Health Center in Santa Monica, Calif.

"We have been trying to gauge the role of surgical resection for metastatic melanoma since the development of systemic immunotherapy," Dr. Deutsch continued. "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."

He said the 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 this study of 1,623 patients* from the John Wayne Cancer Institute, overall survival (also called survival) was defined as how long the patient lived after diagnosis of stage IV (metastatic) melanoma. By measuring survival from this point, the researchers eliminated any variability in disease-free interval (time from treatment until the first cancer recurrence) that can occur in patients with metastatic melanoma, Dr. Deutsch said.

All patients had abdominal metastases that might be operable and were referred for surgical evaluation. The liver was the sole site of cancer spread in 697 patients; gastrointestinal (GI) tract, in 336; adrenal glands, in 138; spleen, in 109; and pancreas, in 38. Another 305 patients had multiple sites of abdominal metastases. Metastases in 104 patients resulted from ocular melanoma rather than skin cancer.

Nearly one in four patients (392 of 1,623) underwent surgical resection of the metastasis, or "metastasectomy." The operation was performed alone, combined with medical therapy, or in some cases, included radiofrequency ablation or heat probe treatment to destroy cancer cells.

When the investigators combined all abdominal locations of melanoma metastasis, they found that the surgical group's median survival was 18 months compared to only seven months for the nonsurgical group of 1,231 patients.

"With our long-term follow-up, we believe that select patients can live longer with surgi-cal treatment," Dr. Deutsch said.

To determine whether treatment era affected survival, the investigators divided patients into groups of before (1969 to 2003) and after (2003 to 2014) advances in systemic therapy. The latter group contained 320 patients. Contrary to what the researchers expected, treatment in the era of more effective systemic immunotherapy did not significantly affect survival compared to earlier treatment, said Anton J. Bilchik, MD, PhD, FACS, the study's senior investigator and a professor of surgery and chief of medicine at the John Wayne Cancer Institute.

"Despite new immunotherapies, surgical resection provides the longest survival in patients with abdominal metastatic melanoma," Dr. Bilchik said. "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."

Both Dr. Bilchik and Dr. Deutsch said surgical resection combined with medical therapy offers the chance to cure metastatic melanoma in selected patients. Patients may be candidates for curative surgical resection, according to Dr. Deutsch, if they have a long disease-free interval and a slow tumor doubling time (time in which the tumor doubles in size), and are otherwise healthy.

In this study, individuals with GI tract metastases who underwent complete, curative resection had the longest median survival of any patients--more than two years--Dr. Deutsch reported.

"Surgical resection can really make a difference in the patients with GI tract metastases," he said. "The operation can be performed laparoscopically, so it is minimally invasive."

Even patients with GI tract metastases who underwent palliative surgical resection to improve symptoms, such as bleeding and pain, had a slightly longer survival than patients who had no operation, Dr. Bilchik noted.

Other study coauthors, all from John Wayne Cancer Institute, are: Daniel D. Kirchoff, MD; Devin C. Flaherty, DO, PhD; Jihey Lee, PhD; Leland Foshag, MD, FACS; and Mark B. Faries, MD, FACS.

"FACS" designates that a surgeon is a Fellow of the American College of Surgeons.

This study was funded by the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation, Boston, and the John Wayne Cancer Institute Auxiliary, Santa Monica, Calif. Dr. Faries received funding from the Borstein Family Foundation, Los Angeles; John E. Connor; and George W. Ogden.

Note:

* Data have been updated since the abstract was accepted by the American College of Surgeons. Data for GI tract metastasis were previously presented in January at the 2015 Gastrointestinal Cancers Symposium, San Francisco, Calif. Adrenal metastasis data were presented at the Annual Scientific Meeting of the ACS Southern California Chapter in January 2015. Liver metastasis data were published in the Journal of the American College of Surgeons (May 2014).