Institution: | 1. EPIUnit — Instituto de Saúde Pública, Universidade do Porto, Porto, Portugal;2. Serviço de Epidemiologia — Instituto Português de Oncologia do Porto, Porto, Portugal;3. Departamento de Ciências da Saúde Pública e Forenses e Educação Médica, Faculdade de Medicina da Universidade do Porto, Porto, Portugal |
Abstract: | BackgroundThe growing number of gastric cancers together with improved survival resulted in an increasing population of survivors at risk of multiple primary cancers.AimsTo estimate the 10-year risk and survival of third primary cancers (TPCs) among gastric first primary cancers (FPCs).MethodsGastric FPCs from the Portuguese North Region Cancer Registry, diagnosed in 2000-2006 (n?=?7409), were followed for a TPC (31/12/2012), and for all-cause death (31/12/2017). The cumulative incidence of TPCs was estimated. Patients with a TPC were matched (1:1, by sex, age group, years between FPC and second primary cancer SPC] diagnosis, and SPC location) to FPC?+?SPC patients without a TPC.ResultsOverall, 25 (0.3% of FPCs and 6.8% of SPCs) TPCs were diagnosed. The most common sites were tobacco-related, mainly including digestive organs. Among all FPCs, 10-year cumulative incidence (95% confidence interval CI]) of a TPC was 0.4% (0.2–0.5%) and among SPCs 7.6% (4.4–10.8%). For TPCs, compared to matched patients, age-adjusted hazard ratio (95%CI) for death was 1.68 (0.77–3.67). The 10-year cumulative mortality of TPCs and matched patients was 92.6% and 67.9%, respectively.ConclusionsA clustering of tobacco-related cancers was observed in TPCs, with a 10-year cumulative incidence of 0.4% among FPCs. TPCs had worse survival than patients without a TPC. |