Abscopal effect of radiation on lymph node metastasis in esophageal carcinoma: A case report and literature review

The Abscopal effect is a rare phenomenon observed in the treatment of metastatic cancer, where localized irradiation causes a response in non-irradiated tumor sites. Due to the recent success of immunotherapies, the Abscopal effect of radiation therapy has received renewed clinical interest. However, there is limited knowledge regarding the Abscopal effect and radiotherapy treatment of patients with esophageal carcinoma. The present study reports the case of a 65-year-old male patient, who presented with esophageal carcinoma and lymph node metastasis. A transthoracic esophagectomy with left cervical, mediastinal and abdominal lymphadenectomies was performed. A total of 4 cycles of chemotherapy and maintenance therapy with Pembrolizumab was performed until September 2016. Metastases in the left retroperitoneal lymph node in addition to extensive metastases to the pelvic lymph node were observed. The patient received Cyberknife radiotherapy with a dose of 42 Gy in 6 daily fractions targeted at the left retroperitoneal lymph node. Two months after radiation therapy, a positron emission tomography-computed tomography scan revealed complete regression of all lymph node metastases. There is increasing clinical evidence supporting the efficacy of the Abscopal effect, which may be initiated by high-dose radiation. Further research is required to make the Abscopal effect clinically relevant, however it may have potential as a treatment option.