Colon cancer: You can test negative… and have it

Colon cancer - which starts in the large intestine - is Kenya’s third commonest after cervical and breast cancer. This type is not as hyped as breast, lung, prostate and cervical cancer. It is considered taboo for the invasive nature of diagnosis and treatment, says Devani Smita, a consultant gastroenterologist at the Aga Khan University Hospital (AKUH), Nairobi.

There are different types of colon cancer. Incidental cancer occurs on either right or left side of the colon, or in the rectum, while anal cancers are right at the bottom. Rectal cancer and anal cancers are treated differently.

Colon cancer is more prevalent in older people due to the boy’s wear and tear. Dr Smita explains that such cancers can be incidental or hereditary “especially having a first degree relative like parents, brothers and sisters case,” says Dr Smitta, adding that those who develop cancer between 50 years and 80 years may not have genetic predisposition to it.

One may not know they have colon cancer, cautions Smita. The cancer develops in a hollow bubble, unlike breast cancer, which can be felt.

“In other instances, you can start bleeding or feeling pain. Bleeding can have different types of colour, such as bright red, purple, dark red or black,” says Smita, adding that some patients experience diarrhoea or a change in bowel habits.

“You can have a positive result and not have colon cancer, or have a negative result and still have it,” notes Smita. “There are other tests that are more reliable, but not available here, like a fitness and DNA test, which is more accurate on stool.”

Kenyan doctors carry out colonoscopy largely on patients with symptoms at the age of 50 or first-degree relatives when a review is conducted if one has a personal history or a polyp is detected.

Colonoscopy entails looking at the aerial canal all the way to the appendix area, where they look at polyps, - small growth in the colon - and are precancerous.

“Once the polyps have been removed, they are sent to the laboratory for diagnosis because there are several polyps whereby some don’t have pre-malignant potential and some have high malignant. A doctor will then advise when you next need colonoscopy, which can be either in one, five or 10 years,” the doctor says.

Having one colonoscopy in a lifetime reduces colon cancer risk by 70 per cent and the reason those aged between 40 and 45 need to have it.

Dr Abdul Karim Abdallah, associate professor of surgery at AKUH, says treatment is slightly costly, but simple and safe.

“Surgical options depend on the stage and spread of the cancer. Cancer stages are from zero to four; zero being cancer limited to the inside lining of the colon and this can be taken out by local removal called polypectomy,” explains Dr Abdallah.

He adds: “Curability and survivability depends on the stage. The higher the stage, the lesser the survival figures. Stage four disease, which is spread out colon 10 per cent to 12 per cent, mostly come to three and four, and if it could be done earlier, will achieve a higher curative rate.”

Majority of the patients are aged between 40 and 50, which constitutes 33 per cent of patients, and 20 per cent are below 40, with obesity as the promoter of all these three cancers. This is attributed to excessive consumption of red meat and lack of exercise, says Dr Mohammed Saleh, the director Colon Cancer Centre at AKUH.

He explains that chemotherapy stops cell divide by working on tumors and any cells dividing rapidly are detected. Chemotherapy works by allowing the blood cells to recover and the tumor lacks a chance to recover.

Colon cancer is also given a combination of target and chemotherapy, but even then, Saleh explains that the immunity kills the virus and not the colon cancer “because the immune systems need to be programmed to look at the tumor as foreign.”