Bronchopulmonary Carcinoids and Neuroendocrine Tumors: Is Stereotactic Ablative Radiotherapy a Reasonable Approach?

Abstract

We aimed to test the hypothesis that stereotactic radiotherapy (SRT) can effectively and safely ablate bronchopulmonary carcinoids and tumors with neuroendocrine features (BPCNE), excluding small cell carcinoma. We analyzed patients BPCNE who were included in an Institutional Review Board approved study of lung SRT at 20 community-based centers. Details were retrospectively extracted from medical records. Overall survival (OS) and progression–free survival (PFS) were estimated by Kaplan-Meier method using SAS statistical software. 27 patients (median age 79.2 years (range 57-93) were treated from 2008-2017 for tumors with median size 2cm (range 0.8 – 4.6). The Table summarizes the reasons for not undergoing resection, patient, treatment, toxicity and outcome details. 78% received 50-60Gy/5Fr and 96% received BED 100 – 180. Toxicity rate was 11.1%, all grade 2 or less: acute in 2 patients (weakness and exacerbation of COPD), and late in 1 patient (grade 2 rib pain). At median follow-up 19.5 months (range 1.4 - 66.9 months), no patient recurred locoregionally while 3 (11.1%) metastasized distally: PFS at 24 months was 87% and OS was 60%. Among the 22 patients who had follow-up radiographic evaluation, 81.8% had complete or partial response. PFS curves were lower for T2, males, lower Karnofsky performance status (KPS), and higher metabolic activity (SUV>6) but not statistically significant. 100% of patients had locoregional control of their BPCNE with minimal toxicity. Most were elderly, with poor performance and high comorbidity. We recommend further study of SRT in medically operable patients to enable longer follow-up. Given its cost-effectiveness and increasing use, it is a reasonable option in developing countries where resources for advanced surgical techniques are often limited.Abstract 2252; TableN (%)N (%)N (%)N (%)N (%)Reason for no resectionAge1(3.7)KPS80 or less15 (55.6)HISTOLOGYCarcinoid12 (44.4)Dose (BED)50Gy/5Fr (100)10 (37.0)Acute toxicity (grade)11 (3.7)Poor condition5 (18.5)907 (25.9)Neuroendocrine8 (29.6)60Gy/5Fr (132)10 (37.0)21 (3.7)Poor lung function/COPD8 (29.6)1005 (18.5)Large cell with neuroendocrine2 (7.4)30Gy/5Fr (48)2 (7.4)Late toxicity (grade)11 (3.7)Refused Surgery7(25)LOBEUpper11 (40.7)Adenocarcinoma with neuroendocrine2 (7.4)52Gy/4Fr (120)1 (3.7)StatusAlive13 (48.1)Patient/physician choice6(22.2)Lower8 (29.6)Non-small cell with neuroendocrine2(7.4)55Gy/5Fr (115)1 (3.7)Locoregional Failure0 (0.0)STAGET120 (74.1)Middle8 (29.6)Squamous with neuroendocrine1 (3.7)48Gy/4Fr (106)1 (3.7)Distant Metastases3 (11.1)T27 (25.9)Female21 (77.8)Grade(10, 37.0% unknown)Well9 (33.3)64Gy/3Fr (151)1 (3.7)Nonsmoker6 (22.2)N025 (92.6)Male6 (22.2)Moderately2 (7.4)60Gy/3Fr (180)1 (3.7)Smoker21(77.7)N1/22 (7.4)RACEWhite27 (100.0)Poorly6 (22.2) Open table in a new tab