Department of Dermatology, University of Washington, Seattle, Washington; Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri.
Department of Radiation Oncology, University of Washington, Seattle, Washington; Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, Washington.
J Am Acad Dermatol. 2024 Feb;90(2):261-268. doi: 10.1016/j.jaad.2023.07.1047. Epub 2023 Sep 30.
Merkel cell carcinoma (MCC) is often treated with surgery and postoperative radiation therapy (PORT). The optimal time to initiate PORT (Time-to-PORT [ttPORT]) is unknown.
We assessed if delays in ttPORT were associated with inferior outcomes.
Competing risk regression was used to evaluate associations between ttPORT and locoregional recurrence (LRR) for patients with stage I/II MCC in a prospective registry and adjust for covariates. Distant metastasis and death were competing risks.
The cohort included 124 patients with median ttPORT of 41 days (range: 8-125 days). Median follow-up was 55 months. 17 (14%) patients experienced a LRR, 14 (82%) of which arose outside the radiation field. LRR at 5 years was increased for ttPORT >8 weeks vs ≤ 8 weeks, 28.0% vs 9.2%, P = .006. There was an increase in the cumulative incidence of MCC-specific death with increasing ttPORT (HR = 1.14 per 1-week increase, P = .016).
The relatively low number of LRRs limited the extent of our multivariable analyses.
Delay of PORT was associated with increased LRR, usually beyond the radiation field. This is consistent with the tendency of MCC to spread quickly via lymphatics. Initiation of PORT within 8 weeks was associated with improved locoregional control and MCC-specific survival.
默克尔细胞癌（MCC）通常采用手术和术后放射治疗（PORT）进行治疗。启动 PORT 的最佳时间（Time-to-PORT [ttPORT]）尚不清楚。
我们评估 ttPORT 延迟是否与预后不良有关。
采用竞争风险回归分析，评估前瞻性登记处 I/II 期 MCC 患者的 ttPORT 与局部区域复发（LRR）之间的关系，并调整协变量。远处转移和死亡是竞争风险。
该队列包括 124 例患者，中位 ttPORT 为 41 天（范围：8-125 天）。中位随访时间为 55 个月。17 例（14%）患者发生 LRR，其中 14 例（82%）发生于放疗野外。ttPORT >8 周与≤8 周相比，5 年 LRR 增加，分别为 28.0%和 9.2%，P=0.006。随着 ttPORT 的增加，MCC 特异性死亡的累积发生率也增加（每增加 1 周，HR=1.14，P=0.016）。
LRR 的数量相对较少，限制了我们多变量分析的程度。
PORT 的延迟与 LRR 的增加有关，通常超出放疗范围。这与 MCC 通过淋巴管快速扩散的趋势一致。在 8 周内启动 PORT 与改善局部区域控制和 MCC 特异性生存相关。
