An Abscopal Response to Radiation Therapy in a Patient with Metastatic Non-Small Cell Lung Cancer: A Case Report

Abstract

IntroductionThe Abscopal effect refers to radiation-induced tumor regression in lesions that are distant from a targeted site, and has been recognized for six decades as a rare, unexplained phenomenon in patients receiving local radiotherapy [1]. According to our knowledge, the radiation therapy is not available in patients with multiple metastatic cancer. The abscopal effect is observed outside the treated field of radiation, but it is underrecognized in the clinical practice [2,3]. Recent studies have suggested that the Abscopal effect may result from radiotherapyinduced immune system-mediated cancer cell death [4][5][6]. In support of this hypothesis, the Abscopal effect was reported in a patient who was treated with ipilimumab and fractionated radiotherapy [7]. However, the possibility that ipilimumab alone might be responsible for the patient's response cannot be ruled out, because some non-small cell lung cancer (NSCLC) patients receiving immunotherapeutic agents such as nivolumab achieved good responses and longer progressionfree survival rates [8,9].We encountered a patient with metastatic NSCLC who experienced the Abscopal effect after whole-brain radiotherapy (WBRT) and palliative radiation for vertebral metastasis in a patient. Case PresentationA 63-year-old man who was a current smoker (40 cigarettes a day for 43 years) presented with worsening dysgraphia and memory impairment. Chest radiography and computed tomography (CT) revealed a 4 cm solitary tumor in the upper lobe of the left lung with mediastinal lymphadenopathy, and magnetic resonance imaging (MRI) revealed a 3 cm solitary tumor, assumed to be a metastatic lesion, with cerebral edema extending from the left temporal lobe to the occipital lobe. Bronchoscopic cytology from the lung tumor revealed malignant cells that were consistent with NSCLC. Bone scintigraphy with AbstractIntroduction: The Abscopal effect refers to radiotherapy-induced tumor regression in lesions distant from a targeted site, and is a rare phenomenon in patients receiving local radiotherapy. This report is the first to describe an Abscopal response in a chemotherapy-naïve non-small cell lung cancer (NSCLC) patient following whole-brain radiotherapy as well as palliative radiotherapy.

Extracranial Abscopal Responses after Radiation Therapy for Intracranial Metastases: A Review of the Clinical Literature and Commentary on Mechanism

“…While most patients who experienced an abscopal response were treated with immunotherapy, there were a small number of individual cases in which abscopal responses were observed following radiation alone [7-8,10]. This is consistent with the prevailing theories of cancer immunosurveillance as an inherent function of the immune system [47].…”

“…Forty-eight of 53 patients were diagnosed with metastatic melanoma and received a combination of radiation therapy and ipilimumab. Three patients with melanoma, non-small cell lung cancer, and likely colorectal adenocarcinoma metastatic to the brain experienced an abscopal response with radiation therapy alone, without any systemic therapy [7-8,10]. In addition, abscopal responses were observed in one patient with melanoma treated with vemurafenib and one patient with non-small cell lung cancer treated with cytotoxic chemotherapy [14,17].…”

Systemic Effects of Radiation Therapy-Induced Abscopal Responses in Patients with Advanced Lung Cancer

“…Katayama et al [33] reported abscopal effects of radiation therapy in a patient with metastatic NSCLC. This case study included a 63-year-old male patient who had presented with worsening dysgraphia and memory impairment.…”

The Abscopal Effect Exists in Non-small Cell Lung Cancer: A Case Report and Review of the Literature

“…In two of the six cases [10-11], radiation therapy alone to either the primary lung cancer or a metastatic lesion leads to regression and represent a bona fide abscopal effect. Of these two patients, one had a short-lived abscopal effect [10], the other patient reported [11] had a long-lived response.…”

“…In two of the six cases [10-11], radiation therapy alone to either the primary lung cancer or a metastatic lesion leads to regression and represent a bona fide abscopal effect. Of these two patients, one had a short-lived abscopal effect [10], the other patient reported [11] had a long-lived response. In the remaining four patients [9,12-13], including the current case, the abscopal effect was augmented by either ipilimumab [9] or nivolumab [12-13].…”