KEY POINTS
- This multicentre retrospective study identified 58 melanoma patients receiving adjuvant nodal radiotherapy at five Austrian and Swiss centres between 2018 and 2021, with a median follow-up of 26 months.
- Radiotherapy was used for high-risk nodal features including trans-capsular extension in 56.9%, at least three involved lymph nodes in 36.2%, and lymphogenic recurrence in 17.2%. Median total dose was 48 Gy, and 70.7% received hypofractionated treatment.
- Most patients also received modern systemic treatment: nivolumab in 60.3%, pembrolizumab in 12.1%, and BRAF/MEK inhibition in 27.6%. Radiotherapy was delivered upfront in 53.5%, concurrently in 31%, and after systemic therapy in 15.5%.
- Concurrent systemic therapy did not increase acute radiotherapy toxicity compared with upfront radiotherapy: 77.8% versus 74.2%, p = 0.456. Most events were grade 1-2 radiodermatitis.
- Severe toxicity was uncommon: only two patients (3.5%) experienced grade 3-4 acute toxicity, and one patient developed persistent grade 3 lymphedema as a late event.
- Among upfront and concurrent radiotherapy patients, one- and two-year recurrence-free survival was 58.4% and 32.3% with upfront treatment versus 66.7% and 38.9% with concurrent treatment, with no significant difference (p = 0.536).
- Compared with 88 stage-matched non-irradiated patients who also met formal radiotherapy criteria, adjuvant radiotherapy produced no significant improvement in recurrence-free survival (p = 0.725) or overall survival (p = 0.986). The comparison was exploratory and unadjusted.
CLINICAL TAKEAWAY
Routine adjuvant nodal radiotherapy appears difficult to justify in melanoma when effective systemic therapy is available, because no recurrence-free or overall survival advantage emerged. Its remaining role is likely selective, where locoregional control is particularly important or systemic options have failed, and concurrent delivery appears feasible.