Postoperative lymph node radiotherapy versus observation for melanoma patients with a high risk of cancer relapse

The present article evaluated the benefits of adjuvant radiotherapy (RT) compared to observation alone after therapeutic lymphadenectomy (TL) for melanoma patients with a high risk of lymph node relapse (return of cancer to the lymph nodes).

Patients with a history of melanoma are at increased risk of developing recurrences (return of the cancer). Melanoma usually returns in a lymph node group (or field) close to the primary tumor. Melanoma-invaded lymph nodes are usually treated with surgery to remove them – a procedure called therapeutic lymphadenectomy (TL). However, even after TL some patients with more advanced disease maintain a high risk of developing further recurrences. In such cases, patients may benefit from adjuvant (postoperative) treatments such as radiotherapy (RT), biological therapy or chemotherapy. 

Overall, 217 melanoma patients were included in the study. All patients underwent TL for melanoma-invaded lymph nodes. Of these, 109 patients received adjuvant RT and 108 were closely monitored (observation group).  The main objectives of the study were the detection of lymph node relapses and determining relapse-free survival (RFS – defined as the percentage of patients who have survived for a certain period of time, without any relapse of their disease), overall survival (defined as the percentage of patients who have survived for a certain period of time) and treatment-related side effects.

After a median follow up period of 40 months, there was a 44% reduction in the risk of lymph node relapse for patients in the RT group compared to the observation group. Median RFS was 15 months in the RT group and 14 months in the observation group. There was no significant difference in overall survival between the two groups. The most common treatment-related side effects were seroma after surgery (a pocket of clear fluid that sometimes develops after tissue has been surgically removed), dermatitis (inflammation of the skin) and pain after RT.

In summary, adjuvant RT after complete removal of cancer-affected lymph node groups in melanoma patients significantly reduced the risk of lymph node relapse. However, there was no benefit of RT in overall survival.