Population-based screening improves histopathological prognostic factors in colorectal cancer

Diagnosis of colorectal cancer (CRC) based on clinical symptoms is usually established in its advanced stages. One strategy for reducing mortality is the early detection and removal of preneoplastic and initial neoplastic lesions, even before the first symptoms appear, by means of population-based screening campaigns. The aim of the present study is to determine whether CRC diagnosed via a screening campaign has more favourable histopathological prognostic factors than when diagnosed in the symptomatic phase. The prospective study of all the patients undergoing programmed CRC surgery at the JM Morales Meseguer Hospital (Spain) is between 2004 and 2010. The patients were divided into two groups: one diagnosed from clinical symptoms and one through a screening campaign. The following factors were compared: tumour size; degree of tumour invasion of the wall; lymph node, perineural and lymphovascular involvement; tumour stage; and grade of differentiation. Compared to the symptomatic group, the screen-detected patients had smaller-sized tumours (lesions of less than 5 cm in 84 vs 69.55%, p < 0.001), a lower degree of colorectal wall invasion (T0-1 in 36 vs 9.02%, p < 0.001), less lymph node involvement (N0 in 72 vs 58.76%, p > 0.05), less vascular invasion (7.20 vs 15.22%, p = 0.79) and less perineural invasion (6.4 vs 20.70%, p < 0.001). The TNM staging in the screening group was lower than in the symptomatic group (stage 0-1 in 50.40 vs 18.58%, p < 0.001). CRC diagnosed through a population-based screening programme presents more favourable histopathological characteristics than that diagnosed from the appearance of symptoms.