The detection of interval colorectal cancers following screening by fecal immunochemical test may predict worse outcomes and prompt ethical concerns: a 6-year population-based cohort study in a full district

Abstract

The rates of colorectal cancer (CRC) interval surveyed in screen-detected patients using a fecal immunochemical test (FIT) are not negligible. The aim of this study was to assess the effect of interval cancer on outcomes compared with a population with cancer diagnosed after a positive test result. All patients between 50 and 71 years of age, who were residents of the Mantua district, affected by CRC and operated on from 2005 to 2010 were reviewed. Other than patient-related, disease-related, and treatment-related factors and tumor location, this population was differentiated as either participating or not to screening and then into populations developing interval cancer after a negative FIT result. Mortality was investigated by univariate analysis and by overall survival rates. The mean age of the 975 patients enrolled was 62 years (61.7% males). Most patients (n=575, 59%) were not screen detected, and 400 (41%) were screen detected. Fifty-six (5.7%) patients in the latter group, representing 14% of the participants, developed interval cancer after a negative FIT result. Their cancer was mostly localized in the right colon (41.1%) instead of the left colon and rectum (P=0.02). They also showed higher stages (P=0.001), a moderate degree of differentiation (P=0.001), and overall higher mortality rates than patients with cancer diagnosed after a positive test result (P=0.001). The effect of interval CRC after screening with FIT resulted in worse outcomes compared with the FIT-positive group. With such findings, patients who had negative results for FIT should be informed of the risk of developing cancer within the rounds of screening to independently gain educational skills in the area of health prevention.

Positive impact of a faecal-based screening programme on colorectal cancer mortality risk

“…Idigoras et al [ 26 ] reported a 5-year survival rate of 90.1% in screen-detected group, 76.3% in interval group and 60.5% in non-uptake group (P = <0.001). Corrado et al [ 29 ] found an average overall survival in non-uptakers of 60.5%, whereas for participants, the overall survival was 85.1% (P = 0.001). Among the participating subjects, patients with interval cancers had worse overall survival rates (68.5%) than patients with screen-detected cancers (87.0%, P = 0.001).…”

Optimizing the colorectal cancer screening programme using faecal immunochemical test (FIT) in Flanders, Belgium from the “interval cancer” perspective

“…Tumour location was classified as right side (from the cecum to the transverse colon), left side (from the splenic flexure to the sigmoid colon) or rectum [ 8 , 9 , 18 ]. Differentiation grade was classified as well-differentiated (grade 1), moderately differentiated (grade 2) and poorly/undifferentiated (grade 3–4) [ 8 , 14 , 31 , 32 ].…”

Occurrence and characteristics of faecal immunochemical screen‐detected cancers vs non–screen‐detected cancers: Results from a Flemish colorectal cancer screening programme

“…The importance of investigating ICs became clear when several studies described varying FIT-IC proportions between 6.9% and 50.8% (24-month invitation interval and FIT-positivity thresholds between 10 and 80 lgHb/g). 7,9,[11][12][13] In addition, ICs are associated with more severe outcome and reduced chances of survival, 9,14 which is substantiated by the strong relation between tumour stage and survival. In Flanders (2011-2015) the five-year survival for CRC in the general population was 96% for tumournode-metastasis (TNM) stage I CRC compared with 19% for stage IV CRC.…”