Cancer Trends and Incidences in Singapore

Transcription

1 Review Article: Cancer Trends in Asia Jpn J Clin Oncol 2013;43(3) doi: /jjco/hys230 Advance Access Publication 9 January 2013 Cancer Trends and Incidences in Singapore Melissa C.C. Teo * and Khee Chee Soo Department of Surgical Oncology, National Cancer Centre, Singapore, Singapore *For reprints and all correspondence: Melissa C.C. Teo, 11 Hospital Drive, Singapore , Singapore. melteo1@gmail.com Received March 18, 2012; accepted December 7, 2012 Cancer is the leading cause of mortality in Singapore. The age-standardized incidence rates continue to increase as the population grows and ages, and the influence of environmental and lifestyle choices bear their consequences. The increase is most marked in colorectal, breast and prostate cancers, mirroring the most common cancers seen in other developed countries. The eradication of infectious disease such as hepatitis B, through the implementation of the hepatitis B immunization programme in 1985, has led to the decline in liver cancer. The Singapore Cancer Registry collates detailed information on newly diagnosed and existing cancer cases, enabling the study and understanding of cancer trends in the population and across the different ethnic groups. A coordinated approach to address cancer prevention and treatment through public education and increased awareness, screening and early detection, and the institution of appropriate multidisciplinary care, on a background of continued basic and clinical research is required to deliver quality cancer care. Key words: cancer trends Singapore INTRODUCTION Cancer is a major healthcare problem worldwide, with an annual incidence of more than 10 million (1). It has overtaken heart disease as the leading cause of mortality and at present, 6 million deaths are attributed to it annually (2). The International Agency of Cancer Research estimates that the incidence of cancer will double in the next two decades, with 17 million cancer deaths per year by 2030 (3). Cancer is the number one cause of death in Singapore, constituting 29.3% of total deaths in 2009 (4). The cancer death rate increased from 78.2/ in 1970 to 111.9/ in 1995 (5), reaching a peak of 122/ in 1997 and over the past 10 years has shown a slow decline with a rate of 94.9/ in the period of (6). Singapore has the highest age-standardized rate (ASR) of cancer in Southeast Asia (7). The incidence rates in males and females have increased for the period , compared with that reported for the period and currently stand at and per person-years in males and females, respectively (6). This translates into a total number of incident cancer cases diagnosed in the resident population during the period % of these cases were reported in males Tables 1 and 2. METHODS Data were retrieved from the Singapore Cancer Registry. The Singapore Cancer Registry was started in 1968, and is part of the National Registry of Diseases Office. It collects epidemiological and clinical data of all newly diagnosed cancer cases, whilst tracking the cancer deaths. It provides a comprehensive database for the study of cancer survival and allows a better understanding of the cancer trends in the country (8, 9). Notification of cancer is mandatory under the National Registry of Diseases Act All cases of cancers diagnosed or treated in Singapore have to be reported. These notifications are performed via the submission of hard or soft copies of cancer notification forms, pathology reports, # The Author Published by Oxford University Press. All rights reserved. For Permissions, please journals.permissions@oup.com

2 220 Cancer trends in Singapore Table 1. Notification of new cases by year of diagnosis Year of diagnosis No. of notifications Table 2. Incidence of cancers by gender Gender No. % CR (95% CI) a ASR (95% CI) b Male ( ) ( ) Female ( ) ( ) a CR, crude rate per per year. b ASR, age-standardized rate per per year. ASR derived by the direct method using the World Population. laboratory results, hospital records and death certificates. Notification through death certificates only account for 3.2%, reflecting the wide coverage and high quality of the data in the Singapore Cancer Registry (10). RESULTS The types of cancer prevalent in Singapore have changed over the years, with lung, colorectal and liver cancers being reported as top-ranked cancers in However, the incidence of liver cancer has decreased dramatically whilst prostate cancer continued its ascension. Colorectal, lung and prostate cancers are now the top ranked among the male population, whilst breast, colorectal and lung cancers feature most prominently in the female population. This composition and order have remained the same for the past 10 years, even with the increasing incidence of cancer. Overall, colorectal cancer is the commonest cancer in the community but the highest mortality is seen in lung and breast cancers in males and females, respectively, contributing to 28.1 and 18.0% of cancer deaths in the respective genders (6). The 10 most frequent cancers in Singapore males and females are summarized in Tables 3 and 4. DISCUSSION DIFFERENCES IN CANCER TRENDS IN THE DIFFERENT ETHNIC GROUPS Singapore is a multiracial and multicultural community, with its population constituted by 75% Chinese, 13% Malays, 9% Indians and 3% others. The difference in cancer incidences is interesting and allow for an evaluation of cancer trends across chronological periods, as well as across varying genetic backgrounds and lifestyle differences. The ASR remains the highest in the Chinese, standing at 243.4/ , followed by and per per year in the Malays and Indians, respectively (6). Colorectal, lung and prostate cancers are the three most common male cancers across the different ethnic groups. In the female population, the first and second most common cancers are breast and colorectal cancers in the Chinese and Malay populations, whilst uterine cancer came in second in the Indian women, after breast cancer. The third most common cancers in women of Chinese, Malay and Indian descent are lung, ovarian and colorectal cancers, respectively (6). Although access to health care is universal across the ethnic groups in Singapore, there remains a disparity in cancer incidence that has spanned through the decades. For example, the colorectal cancer incidence rates have increased by more than 55% in Malays and by 10 30% in Chinese when comparing the periods of and , with a less impressive increase seen in the Indian population (11). Environmental, genetic and lifestyle practices are thought to have contributed to this trend. A similar pattern is displayed in the trends for prostate cancer, whereby the increase in incidence is limited to 1.9% in Indians and 4.0 and 5.6% in Malay and Chinese males, respectively (12). Lifestyle, particularly diet effects may be a major factor resulting in this disparity, as it is postulated that the closer adherence to a traditional diet with a higher percentage of vegetarians who consume more legumes, in the Indian community, has curtailed the increase in prostate cancer incidence (13) (Table 5). BREAST CANCER Breast cancer is the commonest cancer in females and its ASR stands at 60/ annually. The highest incidence is seen in Chinese women, followed by Malays and Indians, with ASRs of 60.8, 58.7 and 53.8 per , respectively. Unfortunately, the incidence has continued to increase over the last 40 years, tripling from 20/ in to its current level (6). This charts a trajectory of more than 3% increase annually and 5.7% in the pre-menopausal cohort, resulting in Singapore women having the highest breast cancer incidence rates in Asia (14). The lifetime risk for a Singaporean woman is 6.12%, with 1 in 16 females developing breast cancer. As this trend continues, it will not be long before the rates match those seen in Western countries (15). Most of these cases are diagnosed in the age group and a pilot breast cancer screening project was conducted from 1994 to 97 that showed that breast screening is just as effective in an Asian population. As a result, Breast Screen Singapore was adopted as a national screening programme in It provides subsidized mammograms at many governmental centres to women who are 50 years and older, with the specific aim to reduce breast cancer mortality by 10% by At present, ductal carcinoma in situ (DCIS), a preinvasive disease constitutes more than 30% of all breast cancers detected in pre-menopausal women. This is

3 Jpn J Clin Oncol 2013;43(3) 221 Table 3. Ten most frequent cancers in Singapore males, Colo-rectum ( ) 39.9 ( ) 2 Lung ( ) 37.3 ( ) 3 Prostate ( ) 27.1 ( ) 4 Liver ( ) 17.0 ( ) 5 Stomach ( ) 15.6 ( ) 6 Skin (including melanoma) ( ) 12.8 ( ) 7 Lymphoma ( ) 11.2 ( ) 8 Nasopharynx ( ) 9.5 ( ) 9 Kidney and other ( ) 7.2 ( ) 10 Urinary bladder ( ) 6.8 ( ) Others All sites ( ) ( ) b Age-standardized rate per per year; derived by the direct method using the World Population. Table 4. Ten most frequent cancers in Singapore females, Breast ( ) 60.7 ( ) 2 Colo-rectum ( ) 28.2 ( ) 3 Lung ( ) 15.3 ( ) 4 Corpus uteri ( ) 12.4 ( ) 5 Ovary ( ) 12.0 ( ) 6 Skin (including melanoma) ( ) 10.3 ( ) 7 Stomach ( ) 8.0 ( ) 8 Cervix uteri ( ) 7.2 ( ) 9 Lymphoma ( ) 7.5 ( ) 10 Thyroid ( ) 6.8 ( ) Others All sites ( ) ( ) b Age-standardized rate per per year; ASR derived by the direct method using the World Population. contributed to in part by the relatively high proportion of representation by women aged years in the screening programme. It has been found that breast screening has led to the detection of the disease at an earlier stage, with a resultant increase in breast cancer survival (16). There is a suggestion that Malay women and those without a family history of breast cancer may require more outreach efforts to ensure greater enrolment in the Breast Screening Programme. Breast cancer age-standardized mortality rate, at 14.1 per annually, is the highest amongst all the cancers in women Table 6. COLORECTAL CANCER Colorectal cancer is the commonest cancer in Singapore, accounting for 17.8 and 14.1% of all cancers in males and females. The ASRs are correspondingly 39.9 and 28.2 per annually (17). The incidence of colorectal cancer

4 222 Cancer trends in Singapore Table 5. Age-standardized incidence rates for all cancers by ethnic groups and gender, Gender Race No. CR (95% CI) a ASR (95% CI) b Male Chinese ( ) ( ) Malay ( ) ( ) Indian ( ) ( ) All ( ) ( ) Female Chinese ( ) ( ) Malay ( ) ( ) Indian ( ) ( ) All ( ) ( ) b Age-standardized rate per per year; derived by the direct method using the World Population. Table 6. Ten most frequent cancer deaths in Singapore females, Breast ( ) 14.1 ( ) 2 Lung ( ) 12.6 ( ) 3 Colo-rectum ( ) 11.1 ( ) 4 Stomach ( ) 4.4 ( ) 5 Liver ( ) 4.3 ( ) 6 Pancreas ( ) 3.8 ( ) 7 Ovary ( ) 3.8 ( ) 8 Cervix uteri ( ) 2.7 ( ) 9 Leukaemia ( ) 2.1 ( ) 10 Lymphoma ( ) 1.9 ( ) All sites ( ) 75.5 ( ) b Age-standardized rate per per year; derived by the direct method using the World Population. increases substantially with age, especially after 50 years. The lifetime risk for Singapore males and females was estimated to be 3.9 and 2.9%, respectively (17). The age-standardized incidence rates have doubled in both males and females over the past 40 years and the trend showing the increase looks to continue at an average of 2% per year. Environmental and lifestyle changes shoulder the blame for the increased rates, as more partake of the western diet (18). The age-standardized mortality rates have increased at a rate of 1% annually, and currently stand at 12.1 and 9.0 per annually in males and females. The relative improvement in mortality rate, in comparison with the incidence rate, may be explained by earlier detection and advances in treatment (19). Colorectal cancer screening guidelines were released by the Health Promotion Board and endorsed by the Ministry of Health in 2003 (20). Colorectal cancer screening with faecal immunochemical test (FIT) became part of the integrated Screening Programme in Singapore in Singapore citizens and Permanent Residentsaged50yearsandaboveareinvitedtoattend health screening at multiple governmental health centres at a subsidized rate. The percentage of participants between the ages of 50 and 69 years who have ever undergone a faecal occult blood test has increased from 20.2 and 14.4% to 25.0 and 19.9% in males and females in 2004 and 2007 (21). At present, most colorectal cancers are diagnosed at Stage two or higher. The age-standardized 5-year survival rates for colorectal cancer have increased from 25.3 and 26.4% to 57.0 and 58.9% in males and females in the periods of and The improvement is largely as a result of the development of adjuvant chemotherapy, contributed to by the application of pre-operative radiotherapy and total mesorectal excision for better local control of the disease. There has also been an increase in the awareness of colorectal cancer amongst the local community, with the month of March being designated the Colorectal Cancer Awareness Month every year, during which forums for public education and free FIT kits are given to eligible individuals. LUNG CANCER The age-standardized incidence rates for lung cancer in males and females have seen a decline since and currently are 37.3 and 15.3 per per year, respectively (6). However, it is a significant cause of mortality and is the leading cause of cancer death in males and the second most common cause in females. In the period , there were 5255 deaths attributed to lung cancer. The prevalence of smoking is 14.3% in Singapore (22) andisacause for concern as the highest increase in prevalence is amongst young adults aged The Singapore government has taken a stern stance on this issue of smoking, setting in place legislation that prohibits smoking in public places and advertisement by tabacco companies in the 1970s, in addition to the public health education programmes that it already had in place, with the aim of helping smokers quit and preventing young people from starting. The National Tobacco Control Programme, spearheaded by the Ministry of Health was introduced in 1986 and since then, the Health Promotion Board has been even more active in its endeavor to encourage smoking cessation and reduce the number of new smokers (23). An initiative to ban tobacco access and smoking in those born after the year 2000, is currently being studied and if found feasible, would be revolutionary in curbing the existence of smoking in Singapore in the near future. The anti-smoking climate that allows the garnering of support for such a proposal is well depicted in a survey that

5 Jpn J Clin Oncol 2013;43(3) 223 Table 7. Ten most frequent cancer deaths in Singapore males, Lung ( ) 32.8 ( ) 2 Colo-rectum ( ) 17.0 ( ) 3 Liver ( ) 14.4 ( ) 4 Stomach ( ) 8.4 ( ) 5 Pancreas ( ) 5.6 ( ) 6 Prostate ( ) 5.3 ( ) 7 Nasopharynx ( ) 4.5 ( ) 8 Oesophagus ( ) 3.3 ( ) 9 Lymphoma ( ) 3.1 ( ) 10 Leukaemia ( ) 2.9 ( ) All sites ( ) ( ) b Age-standardized rate per per year; derived by the direct method using the World Population. reveals a.70% approval from the community for such a ban (24) Table 7. CANCER CARE IN SINGAPORE The pattern of illnesses has changed as Singapore transitioned from a developing to a developed country in the space of a few decades. With the elimination of infective diseases, cardiovascular disease and cancer rose in prominence. Cancer soon overtook cardiovascular disease as the leading cause of mortality in the country. In 1992, the Review Committee on National Health Policies recommended the creation of a national cancer centre that could coordinate multidisciplinary cancer care. It should also fulfill the objectives of training oncologists and other allied health workers, centralizing costly expertise, equipment and technologies, facilitate and conduct basic and clinical research and develop cancer databases (25). Singapore has 5 public and 12 private hospitals that are equipped to diagnose and initiate the treatment of newly diagnosed cancers. At present, there are two public institutional centres specializing in cancer care in Singapore, the National Cancer Centre Singapore (NCCS) and the National University Cancer Institute. In addition, the private sector has several small cancer centres. The aim of these institutions is to function as a comprehensive cancer centre, providing multidisciplinary services, within their organizations. The NCCS, co-located with the 1600-bedded general hospital, the largest in Singapore, began operations in The NCCS fulfills its three components of clinical service, research and education through its five clinical departments (surgical, medical, radiation oncology, oncologic imaging and palliative medicine), three research divisions (clinical trials and epidemiological sciences, medical sciences and cellular and molecular research) and education of the public, students from the two medical schools in Singapore, residents, local and overseas fellows, as well as, pre- and postdoctoral graduate students. It has grown in strength and numbers and currently treats 60 70% of all subsidized patients and 50% of all cancer patients in Singapore. There are many charitable and welfare organizations that provide support for patients and their families, in addition to organizing public education forums and clinics. The Singapore Cancer Society, endorsed by the Ministry of Health, was established in 1964 and has played a prominent role in the support of patients with cancer. CONCLUSION In general, there has been an improvement in the cancer mortality rates, with the dramatic improvement in healthcare services over the past few decades, development of comprehensive cancer centres to coordinate cancer care, the application of adjuvant therapy and the increased awareness amongst the Singapore population leading to early detection (26). However, with the rising incidence of cancer in Singapore, it is crucial that a multifaceted approach, with the provision of clinical and palliative care on the background of biomedical research, is taken, in order to administer holistic care for the cancer patient. Conflict of interest statement None declared.

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