Abstract 504P
Background
Primary tumour location has emerged as a prognostic factor for colorectal cancer. Approximately 38% of patients will develop liver metastases, yet evidence on the impact of sidedness after resection is lacking.
Methods
This is a retrospective review of 2100 cases of metastatic colon cancer diagnosed from 2008 to 2018, with identified colorectal liver metastases resected with curative intent. Overall survival (OS) was calculated by Kaplan-Meier method. Right colon (RC) is from cecum to transverse colon and left colon (LC) from splenic flexure to rectum sigma.
Results
We selected 80 patients. 49 (61%) were male. Median age was 65 years. 17 (21%) had a RC tumour and 63 (79%) LC. RAS status was: 41 (52%) native, 26 (32%) mutated and 13 (16%) unknown. There were no differences in RAS status between RC and LC. 34 (43%) had irresectable liver metastases. 91% of patients with irresectable disease received chemotherapy before surgery compared to 48% of patients with resectable disease (P<0.0001). 56 (77%) received FOLFOX, 13 (18%) Capecitabine, 2 (3%) FOLFIRI, 1 (2%) TOMOX. In irresectable disease: 13 (38%) received Bevacizumab, 12 (35%) Cetuximab and 9 (26%) Panitumumab. Patients with irresectable liver metastases showed worse survival (55 vs 147 months; P=0.008). Median survival differed significantly between RC and LC in patients with liver metastasectomy (55 vs 147 months respectively, P<0.0001). Irresectable liver metastasis did not show clinically significant differences in OS stratified by sidedness (RS 55 vs LS 73 months). However, patients with resectable liver metastases and right-sided tumours showed clinical and statistically significant differences in OS compared to left-sided tumours (68 vs 147 months, respectivly P=0.006). Multivariate analysis demonstrated sidedness is an independent prognostic factor (Hazard Ratio 0.42, Confidence Interval 95% (0.18 - 0.96), P=0.04) RAS and resectability status at diagnosis were not independent prognostic factors.
Conclusions
In colorectal cancer patients with liver metastasectomy who were resectable at diagnosis, right-sided primary tumours showed a worse prognosis. Future controlled studies should evaluate the prognostic relevance of primary tumour location according to liver metastasis resectability.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
V.E. Pacheco-Barcia: Travel/Accommodation/Expenses: AstraZeneca; Travel/Accommodation/Expenses: Novartis; Travel/Accommodation/Expenses: MSD; Travel/Accommodation/Expenses: Bayer; Travel/Accommodation/Expenses: Amgen; Travel/Accommodation/Expenses: Roche; Travel/Accommodation/Expenses: Bristol Myers Squibb. All other authors have declared no conflicts of interest.