Pulmonary carcinoid tumours: incidence, histology, and surgical outcome. A population-based study

Background Pulmonary carcinoids (PCs) represent only a minority of all primary pulmonary malignancies but they are the most common type of pulmonary malignancy diagnosed in children and adolescents. In this nationwide study, we analyzed data on all PC tumours in the Icelandic population over a 60-year period and concentrated especially on incidence and patient outcomes. Methods We studied all cases of PCs diagnosed in Iceland in the period 1955‒2015. Histological specimens were re-evaluated and the tumours were staged according to the TNM system (seventh edition). Survival was estimated using the Kaplan–Meier method, with a mean follow-up of 15.7 years. Results Altogether, 88 patients (median age 51.0 years, 65.9% women) were diagnosed with PCs in the study period. The incidence increased from 0.19/100,000/year in the first decade (1955‒1964) to 0.58/100,000/year in the last decade (2005‒2015), with a mean increase of 29.0% per decade of the study period ( p < 0.001). The rise in incidental detection was, however, not significant. The median tumour diameter was 2.2 cm (range 0.4‒7.0) and typical histology was seen in 74 patients (84.1%). The other 14 patients (15.9%) had atypical histology. In all, 90.9% of the patients underwent pulmonary resection, 81.2% of them with lobectomy, with all of them surviving at least 30 days postoperatively. Most patients ( n = 52, 62.7%) were stage IA at diagnosis, 15 (18.1%) were stage IB, nine (10.8%) were stage IIA, and three were stage IIIA (3.6%). Four patients (4.8%) had distant metastases (stage IV), two of whom had typical histology. Five-year survival was 89.8% for all patients: 93.2% for patients with typical histology and 70.7% for those with atypical histology. Conclusion The incidence of PCs in Iceland has increased significantly over the last six decades, which cannot be explained by a rise in incidental detection at chest imaging. Most patients have localized disease and a favourable histology, where the long-term outcome is excellent.