Unexpected Complete Response to Palliative Radiation Therapy in Non-Small Cell Lung Cancer

Abstract Locally advanced non–small cell lung cancer (NSCLC) is generally treated with chemotherapy, long-course radiotherapy, and surgery. The role of palliative radiotherapy is typically reserved for pain management and functional recovery. An elderly patient presented in October 2023 with thoracodorsal pain and functional impairment of the right upper limb. Imaging revealed a bulky mass in the right upper lung lobe with suspected costovertebral infiltration and no distant disease. The multidisciplinary tumor board recommended sequential chemoradiotherapy followed by surgery. Due to worsening pain, radiotherapy (8 Gy × 2 fractions) was administered between the second and third cycles of cisplatin–pemetrexed (with a 25% dose reduction for age) of the four planned cycles. Restaging demonstrated marked tumor shrinkage. Given persistent arm impairment and favorable tumor response, surgery was prioritized and achieved complete resection. Histopathologic examination unexpectedly revealed a complete pathologic response. This case suggests that short-course radiotherapy may contribute to tumor downstaging and raises important questions regarding radiosensitivity in NSCLC.