A retrospective review of colorectal cancer patient outcomes

Abstract

Colorectal cancer (CRC) occupies the second highest spot of the leading cause of cancer related mortalities in Canada. It is heterogenous in development and presentation, therefore, treatment strategies must be personalized to best treat the individual conditions of each patient. Prognostic factors are used by physicians as a guiding tool in creating treatment strategies. For that reason, it is important to understand the value that each prognostic factor provides in estimating prognosis. Prognostic molecular biomarkers have recently demonstrated their importance in predicting response to systemic therapies. In this study, a retrospective chart review was conducted at a single institution located in New Brunswick, Canada, in order to evaluate the demographic, clinical, and pathologic prognostic factors and their individual influence on patient outcome in terms of overall survival and reoccurrence free survival. This study also determined the simultaneous effect of multiple prognostic factors, lymph node yield and resection margins, on patient outcome. In addition, adherence to specific CRC guidelines at this institution were assessed for compliance in regards to lymph node yield and resection margins. This study showed that for the relatively small sample of patients, the strongest prognostic factors for overall survival was histologic grade of the tumour, while the strongest prognostic factors for reoccurrence free survival were age at diagnosis, distal resection margin and circumferential resection margin. When lymph node yield and resection margins were assessed simultaneously their influence on patient outcome was not significant in improving reoccurrence free survival even with adherence to guidelines. There was relatively high compliance to CRC guidelines for both lymph node yield and circumferential resection margins. Furthermore, this study also assessed the practicality of molecular investigating for a potential prognostic biomarker, the RAD18 gene, in formalin fixed paraffin embedded (FFPE) tissue. This was done by evaluating a method for retrieving high quality DNA from FFPE. Gel electrophoresis indicated high DNA fragmentation and unsuccessful amplification as a result of the protocol used for FFPE tissue. Overall, these results allow for recognition of survival and reoccurrence trends. Because there is no central database of CRC patient outcome after surgery in the province of New Brunswick, our study may point to areas where further investigation is needed. In the future, we hope this will provide a foundation for a larger survival analysis that will increase knowledge on OS and RFS, allowing for more successful CRC patient outcome in New Brunswick.