Published online Apr 26, 2020. doi: 10.12998/wjcc.v8.i8.1424
Peer-review started: December 27, 2019
First decision: February 18, 2020
Revised: February 28, 2020
Accepted: April 17, 2020
Article in press: April 17, 2020
Published online: April 26, 2020
Processing time: 118 Days and 19 Hours
Left and right colon cancer present differences at histopathological, molecular and embryological level, blood supply and exposure to microbial populations. Different pathogenic pathways may contribute to the difference in disease behaviour and overall survival between them.
The absence of data regarding differences between right and left colon cancer in the Greek population was the study’s main concern. The outcomes may assist clinicians to define a therapeutic treatment plan based on molecular biology and primary tumour location.
The aim of this study was to investigate significant differences among Greek patients with right and left colon cancer based on epidemiological, clinical, histological and molecular characteristics as well as differences between them in terms of disease progression and overall survival as response to targeted therapy.
A total of 144 patients with colon cancer of any stage were enrolled in this observational study. Data were collected retrospectively and prospectively during a 2.5-year period. Comparative analysis between and left and right colon cancer patients was performed. Multivariate Cox regression analysis was used to determine the independent predictive factors for progression free survival and disease specific survival.
Right colon cancer patients presented more comorbidities, worse histological and molecular characteristics as well as an insidious disease onset. Shorter overall survival, higher tumour relapse rate and poor response to targeted regimens of right colon cancer patients dictates different clinical, diagnostic and therapeutic approaches.
We investigated the differences between left and colon cancer in terms of clinical presentation, histopathology and molecular biology in Greek colon cancer patients. Right colon cancer patients presented a higher rate of mucinous differentiation, infiltrated lymph nodes and KRAS mutation, as well as more silent clinical presentation of the disease and a higher rate of coronary artery disease and diabetes. The KRAS gene revealed its predictive value since RAS-wild-type colon cancer patients who received panitumumab exhibited a better response than patients who received bevacizumab, a result that was also enhanced by the results regarding primary tumour location, as among patients with RAS-wild-type disease who received panitumumab, left colon cancer patients exhibited a better response than right colon cancer patients. On the other hand, the prognostic value of the BRAF gene was confirmed, as BRAF mutant patients demonstrated a shorter progression-free survival time period than BRAF-wild-type patients. Disease stage at the time of diagnosis was confirmed as an important factor for survival in both univariate and multivariate analyses, while primary tumour location was found to play an important role in disease recurrence, as well as in overall survival among patients with initial stage I-III disease. Despite the relatively small size of this study and its partial retrospective nature we suggest that primary tumor location and molecular biomarkers should be taken in into account in therapeutic decision making.
A personalized treatment plan should be based on histological and molecular characteristics of the tumor in association with primary tumor location. Large randomized control trials are needed to evaluate tumor response rate based on new emerging molecular biomarkers.