Objective It is difficult to predict the presence of histological risk factors for lymph node metastasis (LNM) before endoscopic treatment of T1 colorectal cancer (CRC). Therefore, endoscopic therapy is propagated to obtain adequate histological staging. We examined whether secondary surgery following endoscopic resection of high-risk T1 CRC does not have a negative effect on patients' outcomes compared with primary surgery.
Design Patients with T1 CRC with one or more histological risk factors for LNM (high risk) and treated with primary or secondary surgery between 2000 and 2014 in 13 hospitals were identified in the Netherlands Cancer Registry. Additional data were collected from hospital records, endoscopy, radiology and pathology reports. A propensity score analysis was performed using inverse probability weighting (IPW) to correct for confounding by indication.
Results 602 patients were eligible for analysis (263 primary; 339 secondary surgery). Overall, 34 recurrences were observed (5.6%). After adjusting with IPW, no differences were observed between primary and secondary surgery for the presence of LNM (OR 0.97; 95% CI 0.49 to 1.93; p=0.940) and recurrence during follow-up (HR 0.97; 95% CI 0.41 to 2.34; p=0.954). Further adjusting for lymphovascular invasion, depth of invasion and number of retrieved lymph nodes did not alter this outcome.
Conclusions Our data do not support an increased risk of LNM or recurrence after secondary surgery compared with primary surgery. Therefore, an attempt for an en-bloc resection of a possible T1 CRC without evident signs of deep invasion seems justified in order to prevent surgery of low-risk T1 CRC in a significant proportion of patients.
- COLORECTAL CARCINOMA
- COLORECTAL SURGERY
- THERAPEUTIC ENDOSCOPY
- COLONIC POLYPS
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Contributors AO, AvdB, PS and LM conceived and designed the study. PS and LM are the principal investigators. AO, KK, AvdB, BS, TS, HP, WdV, JvB, MK, JMJG, JNG, NL, FB and FW are responsible for patient accrual and inclusion. ML and GO are the expert GE pathologists. SE is the study statistician. AO, KK and LM drafted the manuscript. AvdB, BS, TS, HP, WdV, JvB, MK, JMJG and PS all analysed and interpreted the data, and critically revised the manuscript. All authors approved the study protocol and read and approved the manuscript.
Competing interests None declared.
Ethics approval This study has been approved by the Medical Ethics Review Committee of the University Medical Center Utrecht (reference number WAG/om/15/031817).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No unpublished data relating to this study exist. The data for this study were obtained from the Dutch Comprehensive Cancer Organisation as well as from the electronic medical records of the participating centres.