Population-based assessment of the outcomes in patients with postcolonoscopy colorectal cancers.
The potential for cancers to not be detected on colonoscopy is increasingly recognised, but little is known about patient outcomes. The objective of this study was to assess the outcomes of patients diagnosed with postcolonoscopy colorectal cancers (PCCRCs).



We conducted a population-based retrospective cohort study, including all patients diagnosed with colorectal cancer (CRC) in Ontario, Canada from 2003 to 2009. Patients were categorised into three groups: DETECTED (diagnosed within 6 months of first colonoscopy), PCCRC (diagnosed 6-36 months after first colonoscopy) or NOSCOPE (no colonoscopy within 36 months of diagnosis). Univariate and multivariable analyses were conducted to study overall survival, surgical treatment, emergency presentation and surgical complications.



Overall, 45 104 patients were included, with 2804 being classified as having a PCCRC. Compared with the DETECTED group, PCCRC was associated with a significantly higher likelihood of stage IV disease (17.2% vs 12.9%), worse overall survival (5 year OS: 60.8% vs 68.3%, p<0.0001; adjusted HR: 1.25, 95% CI 1.17 to 1.32, p<0.0001), a higher likelihood of emergency presentation (OR: 2.86, 95% CI 2.56 to 3.13, p<0.001) and lower likelihood of surgical resection (OR: 0.61, 95% CI 0.55 to 0.67, p<0.001). However, patients with PCCRC had significantly better outcomes than those in the NOSCOPE group (stage IV: 37.1%, 5 year OS: 38.9%)



Compared with CRC detected by colonoscopy, PCCRCs are associated with a higher risk of emergent presentation, a lower likelihood of surgical resection and most notably, significantly worse oncological outcomes. However, they have better outcomes than patients with no recent colonoscopy.
Department of Surgery, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
Anand
A
Govindarajan
Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada Cancer Care Ontario, Toronto, Ontario, Canada Department of Medicine, University of Toronto, Toronto, Ontario, Canada Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
Linda
L
Rabeneck
Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.
Lingsong
L
Yun
Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada Cancer Care Ontario, Toronto, Ontario, Canada Department of Medicine, University of Toronto, Toronto, Ontario, Canada Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
Jill
J
Tinmouth
Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.
Lawrence F
LF
Paszat
Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada Department of Surgery, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
Nancy N
NN
Baxter
D000368:Aged; D003113:Colonoscopy / Q000379:methods / Q000401:mortality; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000601:surgery; D055088:Early Detection of Cancer / Q000379:methods; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009864:Ontario; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D016896:Treatment Outcome
COLONOSCOPY; COLORECTAL CARCINOMA