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ONCOLOGICAL OUTCOMES FOR R1 POLYP CANCERS
Shahnoor -. Bil Bushra
*, Syeda Huda Fareed, Fazle Roghani, Joseph Welch, Christina Kinsella, Ulises Zanetto, Anil T. George
Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, United Kingdom
Background:
The detection of polyps harbouring malignancy during colonoscopy remains challenging. The expansion of bowel cancer screening programmes and the use of faecal immunochemical testing in primary care are set to increase endoscopic procedures and, consequently, polypectomies revealing underlying malignancy.
Methods:
This study evaluates the oncological outcomes of R1 (incomplete resection) polyp cancers over a 9-year period (2015–2024), with survival and disease-free intervals calculated as of 1 October 2024. Only patients with R1 polyp resections were included in this analysis.
Results:
40 patients (43%; M:F = 29:11; median age 60 years, range 39–96 years) out of the 93 patients with polyp resections in the above time period had an R1 polyp resection. Of these, 18 (45%) were detected on the National Bowel Cancer Screening Programme, while 22 (55%) were detected through the symptomatic pathway. 34 of the 40 polyps (85%) were located in the rectum or sigmoid colon. All patients were reviewed post-polypectomy, counselled, and offered surgery. Outcomes were analysed based on surgical versus non-operative management.
Seven (18%) patients opted for formal surgical resection. Of the seven formally resected surgery specimens, one had both residual cancer and involved lymph nodes (pT1; N1), and one had only involved lymph nodes (pT0; N1). Both patients received adjuvant chemotherapy. Over a median follow-up (FU) of 2.1 years (range 0.4–7.6 years), no disease recurrence was observed among patients who underwent surgical resection.
Thirty-three patients (83%) opted for non-operative management and surveillance, including check endoscopy. Six patients (15%) developed distant metastases within a median of 2.4 years (range 1–4.6 years), with two patients dying from metastatic disease within six months of detection. None of the patients had local recurrence at the polypectomy site during check endoscopy.
Our study suggests that polyp size ?30 mm was a significant predictor of disease recurrence risk, p=0.032. Other tumour characteristics as tumour differentiation, lymphovascular invasion nor deep submucosal involvement, were not significant predictors of recurrence (p=0.8, p=0.5 and p=0.17 respectively). No significant predictors for identifying residual disease at surgery were demonstrated.
Conclusions:
The incidence of R1 polyp resections is likely to rise with increasing endoscopic procedures. Though formal surgical resection remains the best approach for all R1 polyp cancers, our study suggests a formal surgical resection for all R1 polyp with size ?30 mm due to its higher risk for disease recurrence.
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