[Colorectal cancer in a population with a guaiac-based screening programme]

Colorectal cancer (CRC) screening effectiveness depends on the degree of implementation and population adherence. The goals of this study were to determine the number of CRC cases diagnosed in L'Hospitalet of Llobregat (Spain) and to identify the features of those cases detected by the population-based screening programme initiated in 2000 in this city.

Patients aged 50-69 year-old with a CRC diagnosis identified by cancer registries from the hospitals of L'Hospitalet were included. Patients were classified in 4 groups according to participation in the screening programme: 1, no participants; 2 diagnosed by screening; 3 participants with a negative screening result; and 4, participants with an incomplete screening process.

We found 510 patients diagnosed of CRC, 88% of whom had been invited to the screening programme. The distribution by tumour stage was: 0, 50 (9.8%); I, 53 (10.4%); II, 135 (26.5%); III, 154 (30.2%); IV, 105 (20.6%); and unknown, 13 (2.5%). The number of patients in each group was: 1, 350 (78.0%); 2, 58 (12.9%); 3, 29 (6.5%); and 4, 12 (2.7%). CRC detected by screening and by clinical diagnosis differed in some characteristics: cancer of colon (89.7% vs 66.2%, P<.001), symptoms (32.8% vs 84.3%, P<.001) and stages (0-II 75.9% vs 42.9%, III-IV 24.1% vs 54.2%, P<.001).

These results show the benefit of a population-based screening programme. CRC detected by the screening programme is diagnosed in early stages and before disease symptoms appear.