Ferini Gianluca, Zagardo Valentina, Critelli Paola, Santacaterina Anna, Sava Serena, Harikar Mandara Muralidhar, Venkataram Tejas, Umana Giuseppe Emmanuele, Viola Anna, Valenti Vito, Forte Stefano
REM Radioterapia srl, Via Penninazzo 11, 95029 Viagrande, Italy.
Department of Biomedical, Dental Science and Morphological and Functional Images, University of Messina, 98122 Messina, Italy.
J Pers Med. 2023 May 17;13(5):841. doi: 10.3390/jpm13050841.
To investigate the ability of radiotherapy (RT) to prolong progression-free survival (PFS) and to report treatment-related toxicities among oligoprogressive metastatic Merkel cell carcinoma (mMCC) patients on avelumab.
We retrospectively collected clinical data on mMCC patients who underwent radiotherapy for limited progression on avelumab. Patients were categorized as primary or secondary immune refractory depending on the time of onset of resistance to immunotherapy (at the first or subsequent follow-up visits after avelumab initiation). Pre- and post-RT PFS were calculated. Overall survival (OS) from the first progression treated with RT was also reported. Radiological responses and toxicities were evaluated according to the irRECIST criteria and RTOG scoring system, respectively.
Eight patients, including five females, with a median age of 75 years, met our inclusion criteria. The median gross tumor and clinical target volumes at first progression on avelumab were 29.85 cc and 236.7 cc, respectively. The treatment sites included lymph node, skin, brain, and spine metastases. Four patients received more than one course of RT. Most patients were treated with palliative radiation doses (mainly 30 Gy in 3 Gy/day fractions). Two patients were treated with stereotactic RT. Five/eight patients were primary immune refractory. The objective response rate at the first post-RT assessment was 75%, whereas no local failure was reported. The median pre-RT PFS was 3 months. The pre-RT PFS was 37.5% at 6 months and 12.5% at 1 year. The median post-RT PFS was not reached. The post-RT PFS was 60% at 6 months and 1 year. The post-RT OS was 85.7% at 1 year and 64.3% at 2 years. No relevant treatment-related toxicity was observed. After a median follow-up of 18.5 months, 6/8 patients are still alive and continuing on avelumab therapy.
Adding radiotherapy to mMCC patients with limited progression on avelumab seems to be safe and effective in prolonging the successful use of immunotherapy, regardless of the type of immune refractoriness.
研究放疗（RT）延长寡进展性转移性默克尔细胞癌（mMCC）患者无进展生存期（PFS）的能力，并报告接受阿维鲁单抗治疗的患者的治疗相关毒性。
我们回顾性收集了因阿维鲁单抗治疗出现局限性进展而接受放疗的mMCC患者的临床数据。根据对免疫治疗耐药的发生时间（在阿维鲁单抗开始后的首次或后续随访中），将患者分为原发性或继发性免疫难治性。计算放疗前后的PFS。还报告了从首次接受放疗治疗的进展开始计算的总生存期（OS）。分别根据irRECIST标准和RTOG评分系统评估放射学反应和毒性。
8例患者符合纳入标准，其中包括5名女性，中位年龄为75岁。阿维鲁单抗首次进展时的中位肿瘤总体积和临床靶体积分别为29.85立方厘米和236.7立方厘米。治疗部位包括淋巴结、皮肤、脑和脊柱转移。4例患者接受了超过一个疗程的放疗。大多数患者接受姑息性放疗剂量（主要为30 Gy，分3 Gy/天）。2例患者接受立体定向放疗。八分之五的患者为原发性免疫难治性。放疗后首次评估时的客观缓解率为75%，而未报告局部失败。放疗前的中位PFS为3个月。放疗前6个月的PFS为37.5%，1年时为12.5%。放疗后的中位PFS未达到。放疗后6个月和1年的PFS为60%。放疗后1年的OS为85.7%，2年时为64.3%。未观察到相关的治疗相关毒性。中位随访18.5个月后，8例患者中有6例仍存活并继续接受阿维鲁单抗治疗。
对于阿维鲁单抗治疗出现局限性进展的mMCC患者，加用放疗似乎安全有效，可延长免疫治疗的成功使用时间，无论免疫难治性类型如何。
