Expandable Metallic Stent for Endobronchial Metastasis from Colorectal Cancer: Reports of 2 Cases.

In recent years, there have been many reports about the efficacy of stenting for central bronchial stenosis. When central bronchial stenosis is due to metastasis of a malignant tumor to the trachea and/or bronchi (endobronchial metastasis: EM), it is classified as "narrow EM" and "broad EM." [1] We managed two patients in whom bilateral stent placement was required for narrow and broad EM arising from colorectal cancer. Case 1: In September 2011, a 66-year-old man underwent low anterior resection for advanced colorectal cancer associated with unresectable liver metastasis. The liver metastasis became resectable after chemotherapy, with two resection procedures and radiofrequency ablation (RFA) being performed. Thereafter, lung metastasis occurred and a tumor in the left lung was resected. In May 2015, he developed respiratory distress. CT identified multiple lesions protruding into the lumen of the trachea and the left and right main bronchi. There was no evidence of mediastinal relapse or local relapse at the resection margin, and tumors were only detected in the tracheobronchial walls. Accordingly, narrow EM was diagnosed. An expandable metallic stent (EMS) was placed on the right side where stenosis was more severe, and radiation therapy was conducted for the non-stented tumors. The patient died 8 months later. Case 2: A 69-year-old woman had undergone laparoscopic right hemicolectomy and adjuvant chemotherapy for Stage lllb cancer of the ascending colon. Due to subsequent elevation of tumor markers, PET-CT was conducted and abnormal uptake was seen in the apex of the right lung and right upper abdomen. Both lesions were resected, and omental and lung metastases were diagnosed. She received treatment with UFT / calcium folinate, but relapse occurred at the resection margin in the right lung. At 7 years and 5 months after initial surgery, she complained of respiratory distress at an outpatient visit. CT demonstrated displacement of the trachea and right main bronchus due to enlargement of upper mediastinal lymph nodes. There was also severe stenosis of the right main bronchus due to tumor infiltration. Because there was both infiltration from local recurrence after resection and upper mediastinal lymph node enlargement, broad EM was diagnosed. An EMS was placed at the site of severe stenosis in the right main bronchus. Similar to Case 1, radiation therapy was also conducted, but respiratory distress occurred after 3 months due to tumor re-growth at the stent margin. Accordingly, stent-in-stent placement was performed and her respiratory symptoms improved. However, superior vena cava syndrome occurred 1 month later and the patient died. We consider that placing an EMS is effective in patients with tracheal stenosis due to EM that is judged to be an oncological emergency.