Cancer is a leading cause of death worldwide and about 70 per cent of all cancer deaths occur in low and middle income countries. SADE OGUNTOLA, in this report, writes that the disease can be prevented, if detected early. THE development of cancer is influenced by many factors in the environment, including diet and exposure to chemicals that are generated in different ways. Scientists have also found many genes that cause different types of cancer. This happens when there is a fault in these genes.
Some people have an increased risk of some types of cancer, because they already have a gene fault when they are born, but they are one step further along the road to developing cancer than people without gene fault. For instance, the BRCA1 gene increases the risk for breast and ovarian cancer. BRAC2 has also been
named for prostate and pancreatic cancers. With a known gene fault, it is possible to have regular monitoring for particular cancers, and may point the way to an effective treatment or preventive method for these cancers.
Researchers from the Wellcome Trust Sanger Institute in England also discovered what triggers triple-negative breast cancer, which is fast growing and difficult to treat, as one of the most deadly forms of breast cancer. This form of very aggressive breast cancer accounts
for nearly 20 per cent of all breast cancer cases, and usually strikes women while they are in their 20s and 30s. Worst of all, the majority of breast cancer fighting drugs are useless against it. Regardless of race, age or ethnicity, Dr Abu Okolo, a consultant pathologist, University College Hospital (UCH), Ibadan, said genes basically served two important roles in terms of cancer. Some genes, according to him, suppress cancer, while some enhance it. The genes that suppress cancers are also to prevent it. Although genes are not the absolute factors that determine who ends up with cancer, Dr Okolo stated that there was a delicate balance between genes that support cancer formation and genes that inhibit cancer formation. “If the genes that suppress cancer becomes mutated and if that genes that enhance or allow cancer to form also become active, then the individual is likely to progress to cancer,” he stated.
Given that some genes under the right environment may manifest as cancer, he said testing for cancer genes could help individuals to know their susceptibility to the different types of cancers. “For instance, those with breast cancer genes have a higher risk of for this cancer, and as such for them you follow up closely. If they ever develop a lump in their breast, you do not waste time taken care of it. “And in some, when the risk is very significant, they even opt to have their breast removed and by cosmetic surgery have a replacement. These are some of the extreme measures people take when they see that they have a genetic profile that predisposes them to breast cancer.” Moreover, Dr Okolo stated that in a bid to prevent development of breast cancer, some often take tamoxifen, a hormonal anti-oestrogen drug used in treating cancer in some instances. The drug reduces the rate of development of the cancer. Even though a gene, prostate cancer susceptibility gene, was not so well delineated with prostate cancer, and as such men with the gene may not necessarily develop prostate cancer, he declared that the best way forward for prostate cancer prevention was by prostate specific antigen (PSA) test, digital rectal examination and ultrasound scan of the prostate. Much as PSA test value is suggestive of a possible problem with the prostate, including cancer, he
declared that PSA test alone was not the best determiner for medical doctors to know who to treat for prostate cancer.
According to him, “PSA test is specific, but it would turn up more cancers other than treatment. There are some people who may develop prostate cancer, but it is subclinical, meaning it does not give them
any troubles and as such no symptoms and sign.
Such men would live their normal lives and die at 80 or 90 without the cancer really causing any problem.” On colon cancer, one cancer that is now occurring more in younger age groups, he said its prevention is on general medical check-up. “Such symptoms as diarrhoea, constipation, bloody stool and abdominal pain individuals should not overlook. It should be investigated and the surest way to find out if anything is wrong in the colon is to do an endoscopic assessment called a colonoscopy.”
But are all cancers curable?
There are some cancers that if detected early are curable or that can be managed so that the individual lives a nearly normal life. “But the problem in Nigeria is that diagnosis is often late. If for example, a small breast lump is cancer and this is treated, the patient can live a full life. I know people who have lived over 15 years after treatment from breast cancer. “But when the breast cancer is advanced and has spread to other parts of the body, even if surgery is done, the chances of the patient surviving for long is much less.” Dr Okolo added that saying that the claim that cancer is curable was tenable. However, there is yet to be one cure for all cancer. “When you say a patient has been cured, basically we are saying the patient is cancer free for five years. It does not mean that the cancer cannot recur. When someone is disease free for five years in medicine, we say he is cured. If anything happens again, we say it is some kind of recurrence.”
Why do blacks tend to die more from some cancers than whites?
Studies are suggesting that the chances of being diagnosed with early breast cancer, as well as surviving it, vary greatly depending on the race and ethnicity. In fact, Dr Okolo added that cancer tends to occur more early in blacks than whites for reason that science is yet to explain. “Colon and prostate cancer occurred a decade earlier in blacks compared to whites, breast cancer also occurred almost two decades earlier in black women than their white contemporaries. Genes explains why this is so as well as the more aggressive nature of cancer in blacks than in whites,” he explained.
But all is not gloomy about cancer, Director of University of Ibadan Cancer Registry, Professor Olufemi Ogunbiyi, stated that significant gains had been made in the world of cancer, including increased understanding of the biology of cancers and their prospects for improved outcomes. “More people are now surviving longer following improvements in the treatment modalities worldwide. This is detectable in a few cases in Nigeria
also, especially with gains following focal screening for cervical cancer and for prostate cancer,” said Professor Ogunbiyi.
However, he declared that treatment of cancer can be expensive, and as such the provision of both anti-cancer drugs and radiation therapy is something that governments and philanthropic individuals need to concentrate their efforts on at this time. “The significant gains made in the world of cancer have created a new challenge of dealing with cancer survivors and the issue of quality of life in persons treated for cancer,” he declared. He said some individuals had genes that could predispose them to cancer, adding that it was important that everyone got screened for early detection and took preventive measures against cancer.
“Screening for breast cancer by self-breast examination, mammography and ultrasound/clinical examination by experts are well tested methods of early detection. Also, screening using tumour markers in blood are also well tested methods in certain conditions.” In addition, choosing health lives, including maintaining healthy body weights, exercising, and avoiding exposures to chemicals, he stated, was important in the prevention of cancer. Preventable factors, especially infections such as hepatitis and human papilloma virus (HPV) account for many common cancer and as such better avoided. Cancers causing viral infections such as hepatitis B and C, EBV, and HPV are responsible for up to 20 per cent of cancer deaths in low and middle-income countries. Currently, testing for cancer susceptibility genes in concerned and high-risk individuals is the good thing to do to curtail deaths from cancer. Facilities like this are already springing up in places like Lagos University Teaching Hospital (LUTH).