Association between time to colonoscopy after a positive guaiac fecal test result and risk of colorectal cancer and advanced stage disease at diagnosis. Issue 6 (4th July 2019) - Beshara, Amani
Abstract : We evaluated time to colonoscopy after a positive guaiac‐based fecal occult blood test (gFOBT) result and its association with the risk of overall colorectal cancer (CRC) and advanced‐stage disease at diagnosis. We conducted a retrospective cohort study (2011–2013) within the Clalit Health Services, Israel. Participants were patients between 50 and 74 years old with a positive gFOBT result who had follow‐up colonoscopies within 24 months. The exposure was time to colonoscopy, and the main outcome measure was a risk for overall and advanced CRC (defined as Stages III–IV). Odds ratios (ORs) and 95% confidence intervals (CIs) were adjusted for patient demographics and baseline risk factors. Of the 17, 958 patients with positive gFOBT results (median age, 61 years [interquartile range, 56–67 years]; women, 52.2%), there were 685 cases of CRC and 156 cases of an advanced‐stage disease diagnosed. The rate of cancer diagnosis at 0–3, 4–6, 7–9, 10–12 and 13–24 months was 3.9%, 2.5%, 3.5%, 4.2% and 7.3%, respectively ( p < 0.001). Compared to colonoscopy follow‐up within 0–3 months, risks for any CRC and advanced stage disease were higher for a follow‐up of 12–24 months: OR, 1.97 (95% CI, 1.51–2.56) and 1.88 (95% CI, 1.43–2.46), respectively. For right‐sided cancer ( n = 194), an increased risk starts at 10 months, OR, 1.91 (95% CI 1.03–3.56). A result of 3–6 positive fields was significantly associated diagnosis of cancer (OR, 5.52; 95% CI, 4.71–6.46) and advanced stage disease (OR, 8.07; 95% CI, 5.74–11.36). Encouraging an early uptake of colonoscopy and targeting those with 10–24 months delay and a 3–6 positive fields is warranted. Abstract : What's new? One current recommendation regarding colorectal cancer (CRC) is to perform a colonoscopy within 90‐180 days of a positive fecal occult blood test (FOBT). Data about the effect of the delay between a positive test and colonoscopy remain scarce, however. In this study, the risk for overall and advanced CRC increased significantly after 12 months compared to 0‐3 months. For right‐sided cancer, the risk started increasing at 10 months. A result of 3‐6 positive fields was significantly associated with cancer diagnosis. Encouraging an early uptake of colonoscopy and targeting patients with a 10‐24 months' delay and 3‐6 positive fields is warranted.