Tackling oesophageal cancer risk in Kenya

Two years ago, Esther Cheruto lost her elder brother to oesophageal cancer at the age of 35. "At first, he would complain of heartburn. Then he had difficulties swallowing food. This made him loose so much weight. He died a few months after being diagnosed with the disease."

Dr Alfred Kiragu, the director of the National Cancer Institute, notes that unlike other cancers, most cases of oesophageal cancer are usually diagnosed at advanced stages, thereby leading to poor treatment outcomes.

Indeed, statistics from the 2018 GLOBOCAN report by the World Health Organisation (WHO) show that despite being the third most common cancer in Kenya (after breast and cervical), oesophageal cancer causes the highest number of cancer related deaths in the country — killing over 4,000 people annually.

This has piqued the interest of local researchers who are keen on studying environmental and behavioural factors that could be contributing to the high cases of the disease.

Research presented at the recently concluded Developing Excellence in Leadership, Training and Science (DELTAS) 2019 Conference organised by the African Academy of Sciences points to risk factors for the disease in Kenya.

Key among them is dental fluorosis, characterised by brown teeth that is caused by exposure to high fluoride levels during childhood.

Based on a study conducted in Eldoret, researchers found a nine-fold risk of developing oesophageal cancer among individuals with moderate or severe dental fluorosis.

This condition is common in the Rift Valley and parts of Western Kenya, with water bodies or sources that have high fluoride levels such as Nakuru, Naivasha and Baringo.

The study, which has been published in the International Journal of Cancer also revealed that oesophageal cancer risk increases with poor oral hygiene, including the use of mswaki stick (African brush) cut from wild trees for brushing.

"We have a high burden of oesophageal cancer in our country. So it’s important for us to know the contributing factors," said Dr Diana Menya, senior lecturer and researcher at the Moi University College of Health Sciences, who was the lead author of the study.

She states that knowing what is likely to cause cancer helps in primary prevention by empowering people to adopt behaviour or lifestyles that reduce their risk of getting the disease.

For instance, to minimise the risk of oesophageal cancer associated with bad oral health, people can simply start practising good oral hygiene by brushing their teeth (with recommended tooth brushes and paste after meals).

County governments could also enact policies that promote access to treated and piped water systems among residents.

In areas where boreholes are sunk, defluoridation systems are needed to reduce high fluoride levels in affected areas.

According to another study published in the same journal by the university, researchers established that there was an increased oesophageal cancer risk associated with drinking hot and very hot beverages (predominantly tea).

These findings are in line with previous research conducted in other high burden countries.

For instance, a study done at Iran's Golestan Province (hotspot for the cancer) revealed an eight-fold risk of getting the disease among drinkers of hot tea compared to warm tea.

The enhanced risk was also observed in South America among consumers of hot mate (a type of caffeinated drink).

Reasons why such hot liquids cause cancer are still unclear. But it is thought that they cause constant irritation and damage of cells in the lining of the oesophagus.

In another local study published in the International Journal of Cancer, Dr Menya found that alcohol consumption - particularly local brews like chang'aa and busaa contribute to half (50 percent) of oesophageal cancer burden in Western Kenya.

"You see, these are some of the behaviours that people can change so as to reduce their chances of developing the disease. But they need to be sensitised about these risks," said Dr Menya whose local research on cancer has been supported by the International Agency for Research on Cancer (IARC), National Institutes of Health (NIH), Kenya National Research Fund, African Academy of Sciences (AAS) and the Consortium for Advanced Research Training in Africa (CARTA).

The United States Cancer Institute discourages people from alcohol consumption to reduce their oesophageal cancer risk.

Those who choose to drink are advised to do so in moderation. This means up to one drink a day for all women. Men below the age of 65 can take two drinks daily while those above 65 years are advised to stick to one drink daily.

As a major risk factor for oesophageal cancer, the use of tobacco products (including cigarettes, cigars, pipes and chewing tobacco) is also totally discouraged.

Other contributors to the cancer include: untreated gastroesophageal reflux disease (GERD), having bile reflux, undergoing radiation treatment to the chest or upper abdomen, being obese and consuming insufficient fruits and vegetables.

Oesophageal cancer occurs when abnormal cells in the food pipe (oesophagus) grow in an uncontrolled way.

Major symptoms of the disease include difficulty swallowing, indigestion or heartburn that don't go away, weight loss, pain in your throat or behind your breastbone and a cough that won't go away.