Surgical resection still important in abdominal melanoma metastases
medwireNews: Patients who undergo surgical resection of abdominal visceral melanoma metastases have significantly better overall survival than those who do not, and the outcome is not greatly improved by modern systemic treatments, study findings indicate.
This demonstrates that “surgical resection remains an important treatment consideration even in the systemic treatment era,” say Gary Deutsch (Hofstra Northwell School of Medicine, Lake Success, New York, USA) and co-researchers.
Deutsch and team retrospectively reviewed data for 1623 patients with melanoma diagnosed at a single tertiary-level melanoma referral center as having potentially resectable abdominal metastases before (1969–2003, n=1303) and after (2004–2014, n=320) the introduction of systemic therapy such as ipilimumab and PD-1 inhibitors.
The most common metastatic site was the liver (42.9%) followed by the gastrointestinal tract (20.7%), adrenal glands (8.5%), spleen (6.7%), and pancreas (2.3%). Multiple sites were involved in 18.8% of the patients.
The researchers report in JAMA Surgery that the 392 patients who underwent surgery had significantly better overall survival (OS) than the 1231 who did not, at 18 versus 7 months.
Patients with metastases to the gastrointestinal tract undergoing complete, curative resection derived the greatest benefit from metastasectomy, with a 64-month median OS. Surgery for gastrointestinal tract metastases also gave the best 1- and 2-year OS rates, at 52% and 41%, respectively.
“This could in part be owing to improved imaging techniques (ie, thin-slice computed tomography and positron emission tomography), allowing asymptomatic patients with [gastrointestinal] tract involvement to have an earlier diagnosis and surgical treatment,” Deutsch et al remark.
However, patients with liver, pancreas, spleen, and even multiple abdominal metastases also derived considerable survival benefit from metastasectomy up to 10 years post treatment versus those treated nonsurgically.
Multivariable analysis showed that treatment with metastasectomy and metastases involving the gastrointestinal tract (vs multiple sites) were associated with significantly better OS, at respective hazard ratios (HRs) of 0.59 and 0.65, whereas OS was significantly worse with older age at stage IV diagnosis (HR=1.01) and the presence of ulceration (HR=1.21).
Notably, the era of systemic treatment (1969–2003 vs 2004–2014) had no significant impact on OS.
In an accompanying commentary, Danielle DePeralta and Jonathan Zager, both from the H. Lee Moffitt Cancer Center and Research Institute in Tampa, Florida, USA, say the findings are “a humbling reminder that despite advances in systemic therapy, there remains much work to be done. As systemic options for melanoma evolve, continued attention to the role and timing of systemic therapy and surgical resection will be of paramount importance.”
They conclude: “We […] congratulate the authors on compiling their institutional experience with an impressive number of patients and long-term follow-up.”
By Laura Cowen
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