Retrospective Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Nov 15, 2018; 10(11): 410-420
Published online Nov 15, 2018. doi: 10.4251/wjgo.v10.i11.410
Prognostic significance of primary tumor localization in stage II and III colon cancer
Abdullah Sakin, Serdar Arici, Saban Secmeler, Orcun Can, Caglayan Geredeli, Nurgul Yasar, Cumhur Demir, Osman Gokhan Demir, Sener Cihan
Abdullah Sakin, Department of Medical Oncology, Yuzuncu Yil University Medical School, Van 65090, Turkey
Serdar Arici, Saban Secmeler, Orcun Can, Caglayan Geredeli, Nurgul Yasar, Cumhur Demir, Sener Cihan, Department of Medical Oncology, University of Health Sciences, Okmeydani Training and Research Hospital, Istanbul 34384, Turkey
Osman Gokhan Demir, Department of Medical Oncology, Acıbadem University, Istanbul 34396, Turkey
Author contributions: All authors helped perform the research; Sakin A wrote the manuscript, and performed procedures and data analysis; Sakin A and Secmeler S wrote the manuscript, drafted study conception and design, and performed experiments and data analysis; Arici S and Geredeli C contribution to writing the manuscript, drafting conception and design; Sakin A, Yasar N, Demir OG, Demir C and Cihan S contribution to writing the manuscript; Sakin A, Cihan S, Yasar N and Can O contribution to writing the manuscript, drafting conception and design.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of the University of Health Sciences, Okmeydani Training and Research Hospital.
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous clinical data that were obtained after each patient agreed to treatment by written consent.
Conflict-of-interest statement: All authors declare no conflicts-of-interest related to this article.
Data sharing statement: No additional data are available.
Open-Access: This is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Abdullah Sakin, MD, Doctor, Department of Medical Oncology, Yuzuncu Yil University Medical School, Tuşba/Van 65090, Turkey. drsakin@hotmail.com
Telephone: +90-555-4809988
Received: August 13, 2018
Peer-review started: August 13, 2018
First decision: August 24, 2018
Revised: September 14, 2018
Accepted: October 17, 2018
Article in press: October 17, 2018
Published online: November 15, 2018
ARTICLE HIGHLIGHTS
Research background

It is well known that metastatic right colon cancer (RCC) is more aggressive than left colon cancer (LCC). However, the effects of tumor location on the decision of adjuvant therapy and survival are not clearly known in early stage disease.

Research motivation

In recent trials, prognosis data of early stage RCC and LCC are conflicting. The uncertainty of whether tumor localization is functioning as an important additional risk factor for patients and clinicians in locoregional disease is still present.

Research objectives

In our study, we examined the effect of tumor localization on survival in patients who received or did not receive adjuvant therapy for stage II and III colon cancer. We also investigated the effects of chemotherapy regimens in stage III disease on survival in terms of tumor site.

Research methods

In the study, a total of 942 patients with stage II-III colon cancer, excluding rectal cancer, were included. Comorbidities (diabetes mellitus, hypertension), family histories, adjuvant therapy status and chemotherapy regimens were added to the analysis. The tumors from the caecum to the splenic flexure were defined as RCC and those from the splenic flexure to the sigmoid colon as LCC.

Research results

There was no difference for age and gender in the groups. Mucinous adenocarcinoma rate and the number of removed lymph nodes was higher in the RCC group. Recurrence and mortality risk was lower in patients with adjuvant treatment for all stages. In patients with stage II and III disease with or without adjuvant therapy, disease free survival and overall survival were similar in terms of primary tumor localization. In stage III disease, there was no statistically significant difference for disease free survival and overall survival in patients receiving 5-Fluorouracil (commonly known as 5-FU)-based or oxaliplatin-based regimens according to tumor location. After recurrence, RCC was more aggressive.

Research conclusions

In conclusion, our study showed no association of tumor localization with either disease free survival or overall survival in patients with stage II or III colon cancer managed with or without adjuvant therapy. However, after recurrence, RCC was more aggressive.

Research perspectives

Further large and prospective studies also involving microsatellite instability and BRAF status are needed to determine the effectiveness of tumor location on decision of adjuvant therapy in patients with stage II-III colon cancer.