P3.04-022 Unexpected Residual Carcinoma in the Bronchial Stump after Surgery for Lung Cancer: Topic: Miscellaneous I

Abstract

Surgery for lung cancer should result in no residual carcinoma in pulmonary vessels and the bronchial stump of the isolated lung. Intraoperative frozen diagnosis of the surgical bronchial stump is usually not scheduled unless there is a short distance between the tumor and the predetermined bronchial cutting line in postoperative chest computed tomography (CT). Rarely, unexpected microscopic residual carcinoma in the surgical bronchial stump is observed after surgery. Additional radiation therapy for the bronchial stump in such cases is controversial because of the high risk for bronchopleural fistula. From April 2000 to March 2015, 1169 consecutive patients with non-small lung cancer underwent surgeries (133 segmentectomy, 986 lobectomy, 13 bilobectomy, 37 pneumonectomy) for non-small cell lung cancer at our hospital. Among these cases, 7 (0.6%) had a bronchial stump with residual cancer cells. The clinicopathological characteristics and outcomes of these patients were investigated retrospectively. Six of the 7 cases had undergone lobectomy and one received pneumonectomy. Histologically, there were 4 cases of adenocarcinoma and 3 of squamous cell carcinoma. Four cases were stage IIIA (pT1aN2M0, pT3N2M0, pT2aN2M0, pT1bN2M0), two were IIA (pT1aN1M0, pT2aN1M0), and one was IB (pT2aN0M0). All cases had lymphatic invasion microscopically. All 7 cases developed recurrence or distant metastasis. One had local recurrence at the bronchial stump and 6 had distant metastasis (2 in brain, and 1 each in lymph nodes, chest wall, ribs, and pericardium). Three cases received postoperative treatment of radiotherapy for the bronchial stump only, radiotherapy for the mediastinum and chemotherapy, and cytotoxic chemotherapy only, respectively. Bronchopleural fistula did not occur as an adverse effect. Six of the patients died due to cancer progression. The patient with lymph node metastasis is alive and under treatment with TKI therapy. In all cases, bronchial wall thickness suggesting tumor invasion was not found on a preoperative CT scan, and preoperative bronchoscopic findings showed a normal bronchial mucosa. In surgical cases of non-small cell lung cancer, microscopic residual cancer at the surgical bronchial stump was found at a rate of 0.6%. Such cases tended to have relapse as distant metastasis, rather than local recurrence. Preoperative evaluation of bronchial invasion is straightforward, but the postoperative treatment strategy is uncertain. In postoperative follow-up, systemic evaluation of the local region and distal organs is necessary.