Clinical and molecular biologic characteristics of early-onset versus late-onset colorectal carcinoma in Filipinos.

A case-control study of Filipino patients who underwent surgical resection for colorectal cancer (CRC) during a 1-year period was undertaken. Thirty-five patients under age 40 years were identified. Paraffin blocks of these and 35 randomly selected patients over age 40 underwent histologic and immunohistochemical evaluation. Markers chosen for evaluation included the apoptosis-associated gene products (p53 and bcl-2), a tumor proliferation activity-related factor (Ki-67), and the markers (MLH1 and MSH2) of DNA microsatellite instability (MSI). Results were correlated with age and the stage and location of the tumor. The average age of the early-onset group was 30.7 years compared to the late-onset group at 67.0 years; and the male/female ratio was equivalent. The younger patients had a significantly higher Dukes' stage, the tumors were more poorly differentiated, and they were more frequently of the mucinous and signet ring cell histopathologic type. Expression of p53 was higher in the younger patients ( p < 0.001) and was independent of the degree of differentiation or the stage of the tumor. No differences of expression were noted for the other markers measured. The increased frequency of CRC in Filipino patients less than 40 years of age offers a unique opportunity to gain a better understanding of carcinogenesis, which might be exploited during diagnosis and management. The differences noted between the early- and late-onset CRC are provocative and provide an impetus for increased screening in Filipinos.

Surgical pathology of colorectal cancer in Filipinos: implications for clinical practice.

BACKGROUND: A number of studies published in the Philippine literature have demonstrated certain peculiar clinicopathologic characteristics of colorectal cancer among Filipinos. This study presents the latest data and analyzes their implications for clinical practice. STUDY DESIGN: The pathology reports of all patients who underwent operation for colorectal cancer at the Philippine General Hospital over a period of 7 years were reviewed. RESULTS: One thousand two hundred seventy-seven patients were included. The male to female ratio was almost 1:1. The majority of patients were in the sixth and seventh decades of life, with a mean age of 55.3 years. Patients 40 years of age and younger made up 17% of the total. The site of cancer in order of frequency was rectum (49.8%), left colon (27.9%), and right colon (21.4%). Cancers of the right colon were more common in women, and rectal cancers were more frequent in men. Seventy-six percent of the tumors were well to moderately differentiated adenocarcinomas, and 6.7% were poorly differentiated. Mucinous and signet ring carcinomas were found in 11% and 1% of cases, respectively. Forty-four percent of patients had localized disease at the time of operation, 54% had regional disease, and 2% had disseminated disease. Associated predisposing conditions noted were polyps (4.7%), schistosomiasis (3%), and tuberculosis (1.5%). CONCLUSIONS: Colorectal cancer in Filipinos exhibits a number of unique clinicopathologic features, such as a higher proportion of early age of onset tumors, more advanced stage at presentation, an association with chronic granulomatous diseases, and relatively rare occurrence with polyps. This might suggest the possibility of a different pathway for tumor development of colorectal cancer in this population of patients. Also, current screening guidelines advocated for the Western population might not be appropriate for Filipinos.