Metastases Size May Indicate Which Patients With Melanoma Will Benefit from Post-Surgical Treatment

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Patients with stage 3 melanoma who had metastases larger than 0.3 millimeters had poorer survival outcomes and may benefit from adjuvant therapy, recent findings showed.

Size of metastasis — not the number of affected lymph nodes — may be an indicator of which patients with stage 3a melanoma are at high risk for poorer survival outcomes and could benefit from adjuvant (post-surgical) treatment, according to recent study results published in the Journal of Clinical Oncology.

“There is ongoing debate regarding which subgroups of stage 3 patients may benefit from adjuvant systemic therapy,” the researchers wrote. “Given the heterogeneous (differed) nature of stage 3 patients, with a great diversity in prognosis, this is unsurprising.”

The study included 3,607 patients with early-stage primary melanoma who underwent a biopsy of their lymph node closest to the main tumor (the sentinel lymph node). Of those patients, 408 had stage 3a disease, meaning that there was microscopic evidence of disease in the lymph nodes.

After an average follow-up of 34 months, data showed that patients whose metastases were 0.3 millimeters or larger tended to have poorer survival outcomes than those who had metastases smaller than 0.3 millimeters.

The five-year disease-specific survival rate was 94.1% for patients with smaller metastases, and 80.3% for those with metastases at or greater than 0.3 millimeters. The researchers also determined that patients with low-risk stage 3a disease tended to have similar survival outcomes compared to those with stage 1a disease, where the melanoma is relatively thin and has not metastasized.

Number of metastases did not have any correlation with survival outcomes, according to the study data.

The study authors wrote that they hope that these findings could help better guide decisions on which patients with stage 3a melanoma should receive post-surgical treatment, and who can skip this therapy.

Currently, the authors noted, the National Comprehensive Cancer Network and the National Institute for Health and Care Excellence Guidelines do not include patients with larger metastases in their treatment protocols, missing out on about one-third of patients who could potentially benefit from adjuvant therapy.

“The main determinant for offering adjuvant systemic therapy is based on the risk of recurrence and/or death from melanoma, but the perception by some patients or clinicians may be that the risk of toxicity from the treatment outweighs the potential benefits,” they wrote.

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