Academic journal article Asian Social Science

Investigating Geographic Distribution of Colorectal Cancer Cases: An Example from Penang State, Malaysia

Academic journal article Asian Social Science

Investigating Geographic Distribution of Colorectal Cancer Cases: An Example from Penang State, Malaysia

Article excerpt


The map has widely been used to depict and disseminate information on the spatial distribution of various diseases, including cancer cases. Increasingly, population-based cancer data need to incorporate spatial information that enables various spatial and proximity analyses to be conducted whereby results can be graphically presented. Yet, disease maps as a communication form remain largely unexamined. This is probably due to the confidentiality of the disease cases and the cost of incorporating the spatial component in the database. In the state of Penang, Malaysia, although Penang Cancer Registry (PCR) collects and collates data of all cancer cases diagnosed in the state as well as cancer cases diagnosed elsewhere whose home address is given as a Penang address, geographical location is not included. Mapping of cases using information from PCR will give a fairly complete picture of spatial distribution of cancer cases from Penang State and clustering of cases can be readily evaluated. This study demonstrates the application of spatial analysis methods and GIS in mapping and understanding the spatial distribution of Colorectal cancer cases in Penang State. The cases were mapped to identify spatial clustering of cancer cases and measure distance from existing health facilities. This study finds that spatial information is pertinent to be included as part of the database kept by Cancer Registry since this information can effectively be used for communications with and education of the public, as well as for planning health care delivery.

Keywords: colorectal cancer, point-pattern analysis, geographic information system(GIS), disease mapping, penang state, Malaysia

1. Introduction

Cancer is a major health problem in many countries. It is a leading cause of death worldwide, accounted for 7.4 million deaths (around 13% of all deaths) in 2004. Furthermore, the deaths from cancer worldwide are estimated to reach 12 million deaths in 2030 where lung, stomach, liver, colorectal, esophagus and prostate are common types of cancer among men, while breast, lung, stomach, colorectal and cervical cancers are more frequent among women (WHO, 2009). In Iran, Babaei et al. (2009) studied cancer incidence and mortality in Ardabil and found that this area has one of the highest rate of gastric cardia cancer in the world with more than 4300 new cases during the 3 years of the study. Jafari et al. (2010) studied cancer mortality by evaluation of asbestos fibers concentrations in an asbestos-cement products factory in Iran and found that asbestos mills have the highest mortality rate, with an expected 1198 deaths per 100,000 workers after one year exposure and 14,665 deaths per 100,000 workers after 20 years of occupational exposure. In Malaysia, for example, the incidence of cancer is approximately 30-40 thousand cases per year (Ministry of Health, 2000). In 2006, for example, there was 3525 female breast cancer cases registered with the National Cancer Registry, which accounted for 16.5% of all cancer cases registered (Omar et al., 2006). Colorectal cancer, colon cancer or large bowel cancer includes cancerous growths in the colon, rectum and appendix accounted for 14.2% of male cancers making it the commonest cancer among men. This cancer accounted for 10.1% of female cancers making it the third most common cancer among women (Lim, Yahya & Lim, 2003; Lim & Yahya, 2004). The statistics from National Cancer Registry shows an alarming rate of cancer cases in Malaysia. It is, however, viewed in tabular form which limits its ability to be analyzed spatially such as in assessing clusters of cases to look for possible aetiological factors or planning of health services for screening or treatment.

According to National Cancer Society (2006), 80% of cancer cases are curable if detected early. However, most cancer cases in Malaysia were detected at stage III, which makes it difficult to achieve a cure. This is probably due to low awareness among the population regarding cancer screening or low accessibility of the people to screening facility. …

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