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Evaluation and Analysis of Colon Cancer in Kingdom of Bahrain: A Retrospective Study in a Tertiary Care Center

Objectives: To provide an analysis for colorectal (CRC) cases including the incidence, pathological and molecular features for all cases that are diagnosed in a main tertiary hospital in Bahrain for the last four years. This will help in provide statistics about the incidence of colorectal cancer in Bahrain, also it will help in reducing the mortality and improving the patient prognosis by proper screening and genetic testing. Design: A Retrospective study. Materials and Methods: Data from our lab information system (LIS) was collected and analyzed for all patients diagnosed with colon cancer in Salmaniya Medical Complex for the period 2016-2019 and stratified according to the clinical information, histopathology and molecular testing results. Results: Between January 2016 2019, patients were diagnosed colorectal carcinoma, 93 were males and 79 were females. The median age at presentation was 60 years. The most common mutated genes were TP53, KRAS, and APC genes. Limitations: The study included colorectal cancer cases that were only diagnosed by histopathology in Salmaniya Medical Complex. Patients without diagnostic biopsy excision were not Conclusion: Colorectal cancer presents at a Due to lack of colorectal screening, we have a higher proportion of advanced stage cancer at presentation.

https://doi.org/10.30654/MJCS.10032 of normal colorectal epithelium into a benign adenoma, and then progress through a stepwise accumulation of genetic aberrations into a subsequent carcinoma. It occurs anywhere in the colon. However, sigmoid colon and rectum are the commonest sites. The pathologists classified CRC into: well-differentiated, moderately differentiated and poorly differentiated. The staging system is important to determine the prognosis of cancer and the outcome. In early stages (T1 and T2), the tumor invades submucosa (T1) or invades muscularis propria (T2), while in late stages (T3 and T4), the tumor invades subserosa or into non peritonealized pericolic or perirectal tissues (T3) or the tumor directly invades other organs or structures and/ or perforates visceral peritoneum(T4). Also, it is important to determine the lymph node (N) status and to determine if there is metastasis or no. The last important parameter in staging system is the distal metastasis (M) to another organ [3].
CRC is a heterogeneous disease driven by multiple genetic and epigenetic abnormalities. The most common mutated genes are TP53, KRAS, and APC genes. About 65% of CRC cases are sporadic with no family history or apparent genetic predisposition [4,5,23].
In this study, we provide an overview of the current knowledge on incidence and pathological features of colon cancer in Bahrain, as well as on molecular and genetic features, which will help in decreasing mortality rate by proper and early screening.

MATERIALS AND METHODS
This is a retrospective descriptive study. The data were obtained from our lab information system and includes all patients with colorectal cancer that have specimens sent to pathology department at Salmaniya Medical Complex, between Jan, 2016 to Dec, 2019.

Incidence, age, and sex:
Worldwide, CRC is the third in the term of incidence, comprising of 10% of all cancer diagnoses and second in term of mortality (9.4%) [1].
In Bahrain, colorectal cancer is the second most common cancer following lung cancer in male and breast cancer in female, while in USA it is the fourth most common cancer [2,22].
The age standardized ratio in Bahrain is between 13.4-18.8 per 100000, which is similar to KSA and lower than USA rate which is 25.2-32.1 per 100000 [2,7,8].
The number of cases is continued to rise over the past years and the incidence has been steadily rising worldwide. Over the period 2016-2019, the age at the time of presentation of CRC ranged from 27 to 86 years. The median age was around 60 years for men and 58 years for women.
In our institute, among the 172 CRC cases, the incidence rate was slightly higher for men (54%, n=93) than for women (46%, n=79). Worldwide, CRC is more common among men than women and it is 3-4 times more common in developed countries than developing countries [21].
In Saudi Arabia Over the period 1994-2010, the median age for the development of CRC was 60 years for men and 55 years for women which is almost similar to our result [8].
In USA the median age for CRC for men and women was 68 and In our study, the most common site of colorectal tumor is distal colon, which account for sixty five (38%) patients followed by rectum in thirty eight patients (22%) and proximal colon in thirty five patients (20%). However, in thirty four patients (20%), the site of tumor were not mentioned in the report (Table 2). These results are different from the results found in a study done in USA where the proximal colon is the most common location of colon cancer [11] (Figure 1).
There is difference in sub-site distribution by sex and age.
Thus, the higher proportion of proximal tumors found more in women compared with men (25% vs 16%, respectively).