Evaluation of the left-to-right shift of colon tumors in Iran: Is the trend changing?

Anatomical Distribution of Colon Cancer: A Retrospective 10-year Study to Evaluate Rightward Shift in Two Referral Hospitals in Iran

Background: In Iran, the incidence of colorectal cancer has been increasing over the last 25 years. Although left-sided colon cancers are still more common, several studies in recent years have shown a shift toward right colon. This rightward shift could have important clinical and healthcare consequences, as right-sided tumors generally have poorer prognoses compared to left-sided tumors and besides, are more likely to be missed in screening colonoscopy. Objectives: This retrospective study aimed at describing the demographic and clinicopathologic characteristics of patients with colon cancer based on tumor sidedness in two referral hospitals in Tehran. Methods: Data of the patients with colon cancer who had been treated from 2010 to 2020 in two referral hospitals in Tehran, Iran were retrospectively reviewed. Collected data included patients’ demographics, tumor histology and differentiation, tumor location, stage, and disease-free survival (DFS). Results: A total of 1535 cases entered the study including 849 (55.3%) males and 686 (44.7%) females with a mean age of 58.22 years (range: 22 - 89). Regarding the sidedness, 800 (52.1%) had left-sided and 735 (47.9%) had right-sided tumors. Although there were more cases of left-sided tumors compared to right-sided ones on total, there existed a trend toward shifting to the right side, which was statistically significant. There existed more cases of poorly differentiated tumors in the right side and besides, right-sided tumors had poorer DFS compared to the left-sided tumors (68.3% vs 78.3%). Conclusions: Left and right colon tumors differ in molecular mechanisms involved in tumorigenesis. These differences in epidemiological, molecular and histological parameters can have clinical implications. Tumor-sidedness should be acknowledged as an important epidemiological parameter with significant impacts on screening, tumorgenesis, response to treatment, and prognosis.

Conversion to resectability using transcatheter arterial chemoembolization alternating with mFOLFOX6 in patients with colorectal liver metastases

Background:

Colorectal cancer is one of the most common malignancies in the world, and about 25% of colorectal cancer patients present with colorectal cancer liver metastases (CRCLM) even at new diagnosis. The study was to evaluate the safety and efficacy of transcatheter arterial chemoembolization (TACE) alternating with mFOLFOX6 in Chinese patients with unresectable CRCLM.

Materials and Methods:

In this study, by combining the systemic and regional treatment, the resectability rate, overall survival, and progression-free survival were measured with addition of TACE. Included patients had Eastern Cooperative Oncology Group performance status 0–2. Sixty-two patients received mFOLFOX6 plus one TACE after 2 weeks of chemotherapy; after 2 weeks, the next periodical treatment repeated. Patients received operation when the liver metastases were converted to resectability or severe tumor-associated complications occurred.

Results:

We found that 28 patients (45.2%) patients received operation after the treatment of TACE combined with systemic chemotherapy. The median time from initial treatment to the operation was 6 months. The median follow-up period was 41 months in all the patients. The 3-year survival rate of resected patients and unresected patients was 54% and 17%, respectively. Post-TACE syndrome was the major adverse reaction (81%). Other adverse reactions were neutropenia, nausea, and neurotoxicity. No patient died of the adverse reactions. The resection rate was related to hepatic segments and vasculature involvement.

Conclusion:

Taken together, TACE alternating with mFOLFOX6 has been proved to be safe and effective for CRCLM treatment to improve resection rate and prolong the survival time.

Prevalence and risk factors of colorectal cancer in Asia

Globally, colorectal cancer (CRC) is a substantial public health burden, and it is increasingly affecting populations in Asian countries. The overall prevalence of CRC is reported to be low in Asia when compared with that in Western nations, yet it had the highest number of prevalent cases. This review described the prevalence of CRC in Asia according to the International Agency for Research on Cancer from World Health Organization (WHO) database and summarized its major risk factors. Non-modifiable factors include genetic factors, ethnicity, age, gender, family history and body height; smoking, alcohol drinking, weight, Westernized diet, physical inactivity, chronic diseases and microbiota were involved in environmental factors. These risk factors were separately discussed in this review according to published literature from Asian countries. CRC screening has been playing an important role in reducing its disease burden. Some recommendations on its screening practices have been formulated in guidelines for Asia Pacific countries.

Gut microbiota, epigenetic modification and colorectal cancer

Micro-organisms contain 90% of cells in human body and trillions foreign genes versus less than 30 thousand of their own. The human colon host various species of microorganisms, appraised at more than 10¹⁴ microbiota and contained of over a thousand species. Although each one's profile is separable, the relative abundance and distribution of bacterial species is the same between healthy ones, causing conservation of each person's overall health. Germline DNA mutations have been attributed to the less than 5% of CRC occurrence while more than 90% is associated with the epigenetic regulation. The most ubiquitous environmental factor in epigenetic modification is gut microbiota. Disruptive changes in the gut microbiome strongly contributed to the improvement of colorectal cancer. Gut microbiota may play critical role in progression of CRC via their metabolite or their structural component interacting with host intestinal epithelial cell (IEC). Herein we discuss the mechanism of epigenetic modification and its implication in CRC development, progression even metastasis by gut microbiota induction.