Department of Radiation Oncology, Brigham & Women's Hospital/Dana-Farber Cancer Institute, Boston, United States.
Department of Radiation Oncology, Brigham & Women's Hospital/Dana-Farber Cancer Institute, Boston, United States; Merkel Cell Carcinoma Center of Excellence, Dana-Farber/Brigham & Women's Cancer Center, Boston, United States.
Radiother Oncol. 2022 Aug;173:32-40. doi: 10.1016/j.radonc.2022.05.012. Epub 2022 May 17.
Limited data exists regarding the efficacy of curative hypofractionated radiotherapy (hypo-RT) regimens compared to conventionally-fractionated radiotherapy (conv-RT) for Merkel cell carcinoma (MCC).
A retrospective analysis of 241 patients diagnosed with non-metastatic MCC from 2005-2021 and who received RT at Dana-Farber/Brigham & Women's Cancer Center. The primary outcome was cumulative incidence of in-field locoregional relapse using Gray's test with competing risks of death and isolated out-of-field recurrence. Secondary outcomes included overall survival (OS) and MCC-specific survival using log-rank tests, and risk factors of recurrence using Cox-proportional hazards regression.
There were 50 (20.6 %) and 193 (79.4 %) courses of hypo-RT and conv-RT, respectively. The hypo-RT cohort was older (≥73 years at diagnosis: 78.0 % vs 41.5 %, p < 0.01), and received a lower equivalent total RT dose in 2 Gy per fraction (<50 Gy: 58.0 % vs 5.2 %, p < 0.01). Median follow-up was 65.1 months (range: 1.2-194.5) for conv-RT and 25.0 months (range: 1.6-131.3) for hypo-RT cohorts. Two-year cumulative incidence of in-field locoregional relapse was low in both groups (1.1 % conv-RT vs 4.1 % hypo-RT, p = 0.114). While two-year OS was lower for the hypo-RT group (62.6 % vs 84.4 %, p = 0.0008), two-year MCC-specific survival was similar (84.7 % vs 86.6 %, p = 0.743). On multivariable analysis, immunosuppression, clinical stage III disease, and lymphovascular invasion were associated with any-recurrence when controlling for sex, age, and hypo-RT.
There was no difference in cumulative incidence of in-field locoregional relapse or MCC-specific survival between hypo-RT and conv-RT. Prospective studies are needed to confirm hypo-RT as an efficacious treatment option for MCC.
关于与常规分割放疗（conv-RT）相比，有疗效的短程根治性放疗（hypo-RT）方案治疗 Merkel 细胞癌（MCC）的疗效，数据有限。
对 2005 年至 2021 年间在 Dana-Farber/Brigham & Women's Cancer Center 接受放疗的 241 例非转移性 MCC 患者进行回顾性分析。主要结局是使用 Gray 检验，用死亡和孤立的场外出乎意料的复发的竞争风险来评估场域内局部复发的累积发生率。次要结局包括使用对数秩检验的总生存（OS）和 MCC 特异性生存，以及使用 Cox 比例风险回归的复发风险因素。
分别有 50 例（20.6%）和 193 例（79.4%）接受 hypo-RT 和 conv-RT。hypo-RT 队列年龄较大（诊断时≥73 岁：78.0% vs. 41.5%，p<0.01），并且接受的 2 Gy 等剂量总 RT 剂量较低（<50 Gy：58.0% vs. 5.2%，p<0.01）。conv-RT 组的中位随访时间为 65.1 个月（范围：1.2-194.5），hypo-RT 组为 25.0 个月（范围：1.6-131.3）。两组场域内局部复发的两年累积发生率均较低（conv-RT 为 1.1%，hypo-RT 为 4.1%，p=0.114）。虽然 hypo-RT 组的两年 OS 较低（62.6% vs. 84.4%，p=0.0008），但两年 MCC 特异性生存率相似（84.7% vs. 86.6%，p=0.743）。多变量分析表明，在控制性别、年龄和 hypo-RT 后，免疫抑制、临床 III 期疾病和淋巴管血管侵犯与任何复发有关。
hypo-RT 与 conv-RT 之间场域内局部复发或 MCC 特异性生存率无差异。需要前瞻性研究来证实 hypo-RT 作为 MCC 的有效治疗选择。
