Aims

Adjuvant radiotherapy can be beneficial after regional lymph node dissection for high-risk stage III melanoma, as it has been shown to reduce the risk of recurrence in the node field. However, the optimal fractionation schedule is unknown and both hypofractionated and conventionally fractionated adjuvant radiotherapy are used. The present study examined the oncological outcomes of these two approaches in patients treated in an era before effective systemic immunotherapy became available.

Materials and methods

This retrospective cohort study involved 335 patients with stage III melanoma who received adjuvant radiotherapy after therapeutic regional lymph node dissection for metastatic melanoma between 1990 and 2011. Information on tumour characteristics, radiotherapy doses and fractionation schedules and patient outcomes was retrieved from the institution's database and patients' medical records.

Results

Hypofractionated radiotherapy (median dose 33 Gy in six fractions over 3 weeks) was given to 95 patients (28%) and conventionally fractionated radiotherapy (median dose 48 Gy in 20 fractions over 4 weeks) to 240 patients (72%). Five-year lymph node field control rates were 86.0% (95% confidence interval 78.4–94.4%) for the hypofractionated group and 85.5% (95% confidence interval 80.5–90.7%) for the conventional fractionation group (P = 0.87). There were no significant differences in recurrence-free survival (RFS) (41.7%, 95% confidence interval 32.5–53.5 versus 31.9%, 95% confidence interval 26.1–38.9; P = 0.18) or overall survival (41.2%, 95% confidence interval 32.1–52.8 versus 45.0%, 95% confidence interval 38.7–52.4; P = 0.77). On multivariate analysis, extranodal spread was associated with decreased RFS (P = 0.04) and the number of resected lymph nodes containing metastatic melanoma was associated with decreased RFS (P = 0.0006) and overall survival (P = 0.01).

Conclusion

Lymph node field control rates, RFS and overall survival were similar after hypofractionated and conventionally fractionated adjuvant radiotherapy. The presence of extranodal spread and an increasing number of positive lymph nodes were predictive of an unfavourable outcome.

中文翻译：

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高危 III 期黑色素瘤区域淋巴结清扫术后大分割或常规分割辅助放疗

宗旨

辅助放疗在高风险 III 期黑色素瘤的区域淋巴结清扫后可能是有益的，因为它已被证明可以降低淋巴结区域复发的风险。然而，最佳分割方案尚不清楚，大分割和常规分割辅助放疗均被使用。本研究检查了在有效全身免疫疗法可用之前的时代接受治疗的患者中这两种方法的肿瘤学结果。

材料和方法

这项回顾性队列研究涉及 335 名 III 期黑色素瘤患者，这些患者在 1990 年至 2011 年间接受了转移性黑色素瘤治疗性区域淋巴结清扫术后的辅助放疗。从该机构的数据库和患者中检索了有关肿瘤特征、放疗剂量和分割时间表以及患者结果的信息' 病历。

结果

95 名患者 (28%) 接受了大分割放疗（中位剂量 33 Gy，3 周内 6 次分割），240 名患者（72%）接受了常规分割放疗（中位剂量 48 Gy，3 周内 20 次分割）。大分割组的五年淋巴结野控制率为 86.0%（95% 置信区间 78.4-94.4%），常规分割组为 85.5%（95% 置信区间 80.5-90.7%）（P = 0.87 ）。无复发生存期 (RFS)（41.7%，95% 置信区间 32.5-53.5 对比 31.9%，95% 置信区间 26.1-38.9；P = 0.18）或总生存期（41.2%，95% 置信区间）无显着差异区间 32.1–52.8 对比 45.0%，95% 置信区间 38.7–52.4；P= 0.77）。在多变量分析中，结外扩散与 RFS 降低 ( P = 0.04)相关，包含转移性黑色素瘤的淋巴结切除数量与 RFS ( P = 0.0006) 和总生存率降低 ( P = 0.01)相关。

结论

大分割和常规分割辅助放疗后淋巴结野控制率、RFS 和总生存期相似。结外扩散的存在和阳性淋巴结数量的增加预示着不利的结果。