Euskadiko Baheketa Programa 50 eta 69 urte bitarteko biztanleei zuzenduta dago. Gorozkietan ezkutuan dagoen odola detektatzeko testaren (FIT) bidez egiten da, bi urtean behin, eta kasu positiboetan kolonoskopia egiten da sedazioarekin. Metodoa: analisi-kita etxera bidalita gonbidatzen dira indibidualki ikerketako adin-taldeko biztanle oro. Osakidetzako Historia Elektroniko, Minbizi Erregistro eta Heriotza Erregistroko datuak erabiltzen dira informazio-iturri. 2009-2016 bitartean egindako gonbidapen guztien azterketa sexuaren eta adinaren arabera eta biziraupenaren azterketa 2014. urteraino. 2011ko Europako Kalitate Gidan azaltzen diren irizpide eta adierazleak erabiliaz. R eta SPSS aplikazioak erabili dira deskribapen estatistikoa eta biziraute-kurbak (Kaplan-Meyer) lortzeko. Emaitzak: 1.426.846 baliozko gonbidapen, parte-hartzeak joera positiboa (p<0,001), emakumezkoen parte-hartzea gizonezkoena baino handiagoa, 2016an % 74,5 vs % 69,9. Lesio aurreratuei dagokienez (adenoma aurreratuak eta minbizi inbaditzailea), detekzio-tasa handiagoa da gizonezkoen artean. Kolonoskopiarekiko batez besteko atxikidura % 95ekoa izan zen; kolonoskopien % 89,1ean prestakuntza egokia izan zen. 2.856 minbizi-kasuetatik % 69,2 hasierako estadioetan aurkitu ziren. 377 negatibo faltsu erregistratu ziren, horietatik 85 kasu 69 urtetik gorako pazienteekin. Testaren sentsibilitatea 88,38koa izan zen (% 95eko konfiantza-maila 87,22-89,45 konfiantza-tartean) eta iragarpen-balio negatiboa, berriz, 99,96koa (% 95eko konfiantza-maila 99,95-99,96 konfiantza-tartean). Programak detektatutako kasuen biziraupena 1, 3 eta 5 urtetara behaketa-programak detektatu gabeko kasuen edo kasu sintomatikoen biziraupena baino handiagoa izan zen nabarmenki (% 97,8 vs % 87,4, % 93,4 vs % 73,0 eta % 90,1 vs % 66,7 hurrenez hurren). Ondorioak: Programak balantze positiboa erakusten du, onurei dagokienez; alabaina, beharrezkoa da prozesuaren kalitatean inbertitzen jarraitzea.

Gako-hitzak: Koloneko eta ondesteko minbizia, Baheketa, Test immunokimiko kuantitatiboa, Detekzio goiztiarra, Biziraupena, Kolonoskopia, Kalitatea

The Basque Colorectal Cancer Screening programme is aimed at 50 to 69 year-old citizens. It involves a biennial Faecal Immunochemical quantitative test (FIT) and colonoscopy under sedation as a confirmatory diagnosis in positive cases. Methods: a retrospective cohort study of individuals who were invited to participate by sending the kit to their home. We used the Basque medical record (Osabide), as well as the Cancer and Mortality registers as information sources. All invitations issued between 2009 and 2016 were analyzed by sex, age and survival till 2014. Criteria and indicators were based on the corresponding 2011 European Guidelines. Descriptive statistical analysis and Kaplan-Meyer curves. Results: 1,426,846 valid invitations were evaluated. Positive trends in participation were found (p<0.001) to be higher in women than men, being 74.5% vs. 69.9% respectively in 2016. Advanced neoplasia (advanced adenomas and invasive cancer) were more frequently detected in men. Colonoscopy compliance after a positive test was 95%; appropriate cleansing preparation was carried out in 89.1% of the colonoscopies performed. Out of the 2,856 cancers detected, 69.2% were found to be initial stage cancers. However 377 cases were registered as false negative cases; of these, 85 cases were older than 69 years. FIT sensitivity was 88.38 (IC95% 87.22-89.45), with 99.96 (IC 95% 99.95-99.96) as a negative predictive value. Survival of patients with cancer detected by this programme at 1, 3 and 5 years was significantly higher than for patients whose cancers were detected outside this programme or due to symptomatic presentation (97.8% vs. 87.4%, 93.4% vs. 73.0 and 90.1% vs. 66.7% respectively). Conclusions: This screening programme has more benefits than disadvantages, but it is clearly necessary to continue investing in the quality of the screening process.

Key words: Colorectal cancer, Mass screening, Faecal Immunochemical test, Early detection, Survival, Colonoscopy, Quality