PHENOTYPIC CHARACTERISTICS OF HEREDITARY NON-POLYPOSIS COLORECTAL CANCER BY THE AMSTERDAM CRITERIA: AN ASIAN PERSPECTIVE

• Published in: ANZ journal of surgery Vol. 78; no. 7; pp. 556 - 560
• Main Authors: Chew, Min-Hoe, Koh, Poh-Koon, Ng, Kheng-Hong, Lim, Jit-Fong, Ho, Kok-Sun, Ooi, Boon-Swee, Tang, Choong-Leong, Eu, Kong-Weng
• Format: Journal Article
• Language: English
• Published: Melbourne, Australia Blackwell Publishing Asia 01.07.2008; Blackwell Publishing Ltd
• Subjects: Adult; Aged; Amsterdam criteria; Asian; Asian people; Colorectal cancer; Colorectal Neoplasms, Hereditary Nonpolyposis - diagnosis; Colorectal Neoplasms, Hereditary Nonpolyposis - ethnology; Colorectal Neoplasms, Hereditary Nonpolyposis - pathology; Epidemiology; Female; Genotype & phenotype; hereditary non-polyposis colorectal cancer; Humans; Male; Middle Aged; Risk factors; Singapore - epidemiology; Survival Analysis; Singapore
• ISSN: 1445-1433; 1445-2197
• DOI: 10.1111/j.1445-2197.2008.04570.x

Background:  Hereditary non‐polyposis colorectal cancer (HNPCC) is an autosomal disease with a 68–82% lifetime risk of colorectal cancer (CRC). This study examined the phenotypic characteristics of CRC in Amsterdam criteria‐positive Asian patients from the Singapore Polyposis Registry. Methods:  Hereditary non‐polyposis CRC patients, defined by the Amsterdam I and II criteria, prospectively monitored in the Singapore Polyposis Registry over a 16‐year period were reviewed. Clinical data were obtained from a computerized database and parameters, such as age of diagnosis, type and location of CRC, other associated cancers in the pedigree, cancer recurrence and survival were analysed. Results:  Fifty‐two patients (31 men and 21 women) from 42 unrelated families, with a median age of 44.5 years (range 27–73 years), fulfilled either Amsterdam I or II criteria and were included in our analysis. The racial distribution was 91% (n = 47) Chinese and 9% (n = 5) Malays, with a median follow up of 44.9 months (range 2–183 months). Significantly, 69% of tumours in this Amsterdam‐defined cohort were left sided, with most being sigmoid cancers. Sixty per cent of all the tumours presented at a late stage (Dukes’ C or D). Left‐sided tumours presented with more advanced Dukes’ stage (P = 0.096) and a higher rate of metastatic disease (P = 0.08) compared with right‐sided lesions. There were, however, no significant differences in either disease‐free or overall survival between right‐sided and left‐sided tumours. Conclusion:  This study emphasized the significant left‐sided predominance of CRC in Amsterdam I and II‐defined patients from our predominantly Chinese population, in contrast to those classically described in Lynch syndrome. Amsterdam criteria thus may not be suitable for diagnosing HNPCC in Asian populations and a greater emphasis should be made towards routine molecular diagnosis of mismatch repair gene defects in suspected HNPCC patients of Asian decent.