Abscopal effect following palliative radiotherapy after cemiplimab in recurrent cervical cancer: a case report.

Background: The abscopal effect is a rare phenomenon in which localized radiotherapy induces regression of distant, non-irradiated metastatic lesions through systemic immune activation. Although immune checkpoint inhibitors may enhance this response, reports in recurrent cervical cancer remain limited. Case Presentation: A 56-year-old woman with stage IVA squamous cell carcinoma of the cervix underwent definitive concurrent chemoradiotherapy. Six months later, computed tomography (CT) revealed recurrence with para-aortic lymph node, liver, and lung metastases. Following systemic chemotherapy, she received three cycles of cemiplimab; however, progressive disease developed, including new bone metastases. Palliative radiotherapy was administered to the symptomatic bone lesions. Three months after radiotherapy, follow-up CT demonstrated marked regression of the liver and lung metastases outside the irradiated field, consistent with an abscopal effect. Based on this favorable systemic response, cemiplimab therapy was resumed. The clinical course suggests that radiotherapy may have enhanced systemic antitumor immunity in the setting of prior PD-1 blockade. Conclusion: This case demonstrates a radiographically significant abscopal effect following palliative radiotherapy after cemiplimab therapy in recurrent cervical cancer. The combination of radiotherapy and immune checkpoint inhibition may provide synergistic antitumor activity; however, further studies are needed to determine its clinical significance and optimal use in advanced gynecologic malignancies. Further studies are warranted to clarify the mechanisms, predictive biomarkers, and optimal treatment sequencing to maximize the likelihood of inducing the abscopal effect.