Stage IIIA lung adenocarcinoma: complete metabolic remission after chemoradiotherapy, complicated by radiation esophagitis

What happened, in summary

This 75-year-old man with a 40 pack-year smoking history presented in February 2024 with cough and hoarseness. Chest CT showed emphysema and a 2.5 cm mass in the left upper lobe. Transbronchial biopsy confirmed lung adenocarcinoma. FDG PET-CT showed uptake in the lung nodule and mediastinal lymph nodes, consistent with Stage IIIA disease, cT2N2M0. He received concurrent chemoradiotherapy with thoracic intensity-modulated radiation therapy, delivering 60 Gy in 30 fractions over 6 weeks to the primary tumor and ipsilateral mediastinal lymph nodes. Chemotherapy consisted of 2 cycles of cisplatin and S-1, with cisplatin 60 mg/m2 intravenously on days 1 and 8 and S-1 40 mg orally twice daily for 14 days. Two weeks after chemoradiotherapy, PET-CT showed complete metabolic remission of the lung cancer. At the same time, he developed anterior chest pain, and PET-CT showed a rare tube-like FDG uptake pattern along the mid-esophagus within the radiation field. The pattern was important because it could mimic other esophageal conditions on imaging. Esophagography confirmed severe esophageal stricture associated with radiation esophagitis. Biopsy ruled out Candida esophagitis. Conservative treatment with sodium alginate improved the symptoms and imaging over several months. The esophageal findings were followed with PET-CT, esophagography, and endoscopy to distinguish radiation injury from infection or malignancy. At 7 months after chemoradiotherapy, PET uptake had resolved, but chronic radiation esophagitis with dysphagia still limited solid food intake. Dilation and surgery were considered but avoided because of rupture risk. By 16 months, endoscopy showed no recurrent stricture, and his swallowing had improved to a normal diet without endoscopic dilation or surgery.