Melanoma is a type of skin cancer that forms in skin cells called melanocytes, which are responsible for producing the pigment that gives skin its color.

Melanoma in-transit metastases occur when melanoma skin cancer spreads through the dermal/skin lymphatic channels. There are many treatment options for this type of disease metastasis, including surgery, intratumoral injections, isolated-limb infusion or perfusion and immune checkpoint inhibitors (immunotherapy).

Intratumoral injection involves directly injecting the tumor site, and isolated-limb infusion involves isolating the vasculature of the limb and perfusing it with super high doses of cytotoxic chemotherapy. Immunotherapy involves stimulating the immune system throughout the body.

Until now, a study has never been conducted to determine which of these therapies is the best choice for first-line treatment of surgically unresectable melanoma in-transit metastases.

Dr. Danielle DePalo, a surgical research fellow at Moffitt Cancer Center, conducted a retrospective study evaluating more than 500 patients across 12 institutions spanning five countries who received these therapies as first-line treatment. DePalo presented her results at the 2023 American Society of Clinical Oncology Annual Meeting.

“When we looked at response rates, the local regional therapies — the intratumoral and limb perfusion therapies — had the highest overall response rates,” DePalo said. “When we looked at the progression-free survival, melanoma-specific survival and overall survival, we saw that intratumoral injections and systemic immune checkpoint therapy had better outcomes.”

DePalo says those results remained true on a multivariable analysis.

“In part these findings are related to the fact that limb infusions and perfusions have been available for the treatment of in-transit metastases much longer than the intratumoral and systemic therapies,” DePalo said. “When people progressed a long time ago, we didn’t have the same options to treat them after progression that we have for them now.”

DePalo and her colleagues plan to conduct a follow-up analysis evaluating patients treated in just the past decade when all three therapies were mainstay treatments and widely available. “About half of the patients in this study have actually been treated in the last decade, so we’re going to look at that subset to see if our findings still hold true.”

While at #ASCO23, I got to chat with Dr. Danielle DePalo, one of our rockstar @Moffittnews fellows, to learn about her work with unresectable #melanoma in-transit metastases. Check out her abstract #9574 here: https://t.co/PAIiLw5L6q #MoffittASCO23 #MoffittASCO23 pic.twitter.com/Ja0RpWC6bv

— Dr. Patrick Hwu (@PatrickHwuMD) June 4, 2023