Rise of colorectal cancer in Singapore: An epidemiological review

Background: Over the past three decades, Singapore has seen a dramatic increase in the incidence of colorectal cancer and this is now the most frequent cancer when both genders are combined. Methods: In light of this alarming trend, a review of colorectal cancer in Singapore was conducted, using data from the Singapore Cancer Registry from 1968 to 2002. Our research has shown that among Southeast Asian countries, Singapore has the highest age-standardized incidence rates, 35.1% in men and 29.9% in women, more than twice that of the next country; these rates have been increasing at a startling average annual rate of approximately 2.6 and 2.35%, for men and women, respectively. Results: Between 1998 and 2002, deaths from colorectal cancer constituted 19% of all cancer mortalities in men and 14% in women, accounting for the second highest cause of cancer mortality in both genders. In the same period, more than three quarters (75.6%) of colorectal cancers occurred in the distal colon (including splenic flexure, descending, sigmoid colon and rectum), with the predominant histological subtype being adenocarcinoma (approximately 90%). The age-specific rates for colorectal cancer begin to increase sharply in the 40- to 45-year age group. It remains the most common primary site of cancer in men aged between 35 and 64 years but lies a distant second after breast cancer in women. In individuals aged 65 years and above, colorectal cancer remains prominent in both genders. Conclusion: Despite the dramatic increase in incidence of colorectal cancer in Singapore, there has also been significant progress in survival of colorectal cancer patients with localized disease (limited to large bowel), with 5-year, age-standardized relative survival improving from 36 to 66% in men and 32 to 71% in women; in rectal cancer, improvements from 25 to 66% in men and 23 to 66% in women were also observed. Similar improvements were noted in patients with regional disease (lymph node involvement) but not with distant metastases. This has paralleled the dramatic national development in socioeconomic and health-care services.