A recent discovery of five married couples afflicted with colorectal cancer have prompted a team of researchers from NUS Medicine and National University Cancer Institute, Singapore (NCIS) to study whether genetic or environmental factors are culpable.
Colorectal cancer is the most common cancer in Singapore with 9,807 new cases diagnosed between 2011 and 2015, despite a gradual decline in the incidence and mortality rates from 2001 to 2015 due to earlier detection and advances in treatment methods.
The disease occurs when small growths known as polyps on the walls of the colon or rectum become cancerous, although its exact cause remains unknown.
“Some of the well-established risk factors of colorectal cancer include unhealthy lifestyles and dietary habits,” said Assistant Professor Tan Ker Kan from the Department of Surgery, NUS Medicine and consultant in NCIS’ Division of Surgical Oncology. He is also the lead investigator of the research study.
“And with the majority of the colorectal cancer patients being in their late 60s and early 80s, it would be sensible to assume that part of their lifestyle and dietary habits would be shared by their spouses, whom they have typically been married to since they were in their 20s and 30s,” added Asst Prof Tan.
In fact, a commonality among four of the five couples was that they developed colorectal cancer in the same part of the body. Hence, the NCIS will be working with public hospitals such as Ng Teng Fong General Hospital for the study to recruit 200 spouses and 150 to 200 siblings of colorectal cancer patients, who have not been screened, to get checked over the next three years. They hope to learn if certain bacteria, either formed genetically or from environmental factors, are linked to polyps and colorectal cancer by comparing the absence or presence of the bacteria from the screening results.
A separate study led by Asst Prof Tan from 2016 to 2017 also found that despite knowing the benefits of colorectal cancer screening, only 58 per cent of the spouses of 50 studied colorectal cancer patients underwent screening, citing reasons such as fear, cost, inconvenience and a feeling of invulnerability.
It is recommended that those at lower risk of developing colorectal cancer should start being screened at the age of 50, and those with a family history of colorectal cancer and have colorectal polyposis syndromes to do so before they turn 50.