Keating Matthew, Giscombe Lisa, Tannous Toufic, Hartshorn Kevan
Department of Hematology/Oncology, Roger Williams Medical Center, Providence, RI, USA.
Department of Hematology/Oncology, Boston University School of Medicine, Boston, MA, USA.
Case Rep Oncol Med. 2019 Sep 2;2019:3847672. doi: 10.1155/2019/3847672. eCollection 2019.
Pembrolizumab and other immunotherapies now play a prominent role in the treatment of metastatic colon cancer. Clinicians have achieved significant response rates even in heavily pretreated patients, particularly those with mismatched repair deficiencies. The endpoint of pembrolizumab treatment for patients who enjoy a strong response remains unclear. Herein, we present the case of a 33-year-old man with pretreated metastatic colon cancer and a prolonged treatment response of over three years to single-agent pembrolizumab even after treatment discontinuation in July 2018. Prior to pembrolizumab, he was found to have lung and liver metastases despite multiple lines of chemotherapy. With pembrolizumab, there was a persistent downtrend in CEA level and uptrend in weight. After nearly three years of pembrolizumab treatment from October 2015 through July 2018, PET scan showed no FDG-avid disease, and further treatment was placed on hold. He remains under surveillance, with CT scan in February 2019 again showing no evidence of local or metastatic disease. In patients whose treatment duration and disease course are not defined by toxicities/progressive disease but rather by sustained treatment responses, we propose that immunotherapy treatment duration be guided by close monitoring of CEA levels, weight, and clinical exams in addition to traditional imaging.
帕博利珠单抗和其他免疫疗法目前在转移性结肠癌的治疗中发挥着重要作用。即使在经过大量前期治疗的患者中，尤其是那些存在错配修复缺陷的患者，临床医生也取得了显著的缓解率。对于反应强烈的患者，帕博利珠单抗治疗的终点仍不明确。在此，我们报告一例33岁男性患者，其患有前期治疗的转移性结肠癌，即使在2018年7月停止治疗后，单药帕博利珠单抗治疗仍有超过三年的延长治疗反应。在使用帕博利珠单抗之前，尽管接受了多线化疗，他仍被发现有肺和肝转移。使用帕博利珠单抗后，癌胚抗原（CEA）水平持续下降，体重上升。从2015年10月到2018年7月经过近三年的帕博利珠单抗治疗后，正电子发射断层扫描（PET）显示无氟脱氧葡萄糖（FDG）摄取性病变，进一步治疗被暂停。他仍在接受监测，2019年2月的计算机断层扫描（CT）再次显示无局部或转移性疾病的证据。对于那些治疗持续时间和病程不是由毒性/疾病进展而是由持续的治疗反应所决定的患者，我们建议除了传统影像学检查外，还应通过密切监测CEA水平、体重和临床检查来指导免疫治疗的持续时间。
