16 June 2008

Nigeria: Why Cancer is on the Rise in Country

Lagos — The burden of cancer in Nigeria is appreciable. According to the World Health Organisation, there are an estimated 100,000 new cancer cases in the country each year although observers believe the figure could become as high as 500,000 new cases annually by 2010.

It is feared that by 2020, cancer incidence for Nigerian males and females may rise to 90.7/100,000 and 100.9/100,000 respectively. It is also anticipated that by 2020, death rates from cancer in Nigerian males and females may reach 72.7/100,000 and 76/100,000 respectively.

But this only represents a tip of the iceberg if projections by the World Health Organization (WHO) are anything to go by.

The health organisation recently predicted that global cancer rates could further increase by 50 per cent to 15 million new cases in the year 2020. This is the gloomy prediction by the 2008 World Cancer Report - a 351-page, comprehensive global examination of the disease to date issued by the IARC - part of the World Health Organization (WHO).

As a concise manual, it describes the global burden, causes, and major types of malignancies, early detection and treatment of cancer.

Providing clear evidence that healthy lifestyles and public health action by governments and health practitioners could stem this trend, and prevent as many as one third of cancers worldwide, the report reveals that in recent times, cancer has emerged as a major public health problem in developing countries, matching its effect in industrialized nations. The bottom line of the report is that except urgent action is taken by governments, health practitioners and the general public; cancer rates are set to increase at an alarming rate globally.

Prof. Clement Adebamowo of the Division of Oncology, Department of Surgery, University of Ibadan, discloses that while infectious diseases such as HIV & AIDS are the most significant contributors to disease burden in Nigeria, complex diseases such as cancer are fast emerging as an important health care priority for the future. Adebamowo states that, ironically, while improvements in public health and increased funding for health care initiatives are leading to a decrease in incidence of communicable diseases, the attendant increase in life expectancy is precipitating an increase in the incidence of all cancers, as a higher proportion of the population reaches the complex diseases-bearing age.

His words: "Several other factors are likely to change the pattern and prevalence of cancer in Nigeria in the coming decades: greater awareness of cancer, improved access to health care through new programmes such as the National Health Insurance Scheme, empowerment of women, and steadily improving economic and social factors will increase rates of cancer diagnosis, at the same time that an increased rate of obesity, reduced physical activity, and more "Westernized" diets are likely to contribute to the development of more types of cancer."

Worse still, clinical services for cancer are grossly inadequate and poorly distributed. Only a few centers have functioning radiotherapy equipment. Radiologic services are generally available, but access is seriously limited by high cost.

The same argument of high cost goes for chemotherapy. Pathology services are generally available, but the scope of services is limited. Molecular diagnostic methods are not widely available. Surgery is often performed by surgeons whose primary clinical practice is not oncology, and there is a very limited scope for multidisciplinary cancer care.

There is increasing awareness of modern palliative care and pain management, which is particularly useful as patients often present with advanced disease, and physicians have limited access to treatments that offer the prospect of prolonged survival.

But it's not all gloom. A Consultative Committee on National Cancer Control exists to formulate policy guidelines relating to the prevention and management of cancer in Nigeria. But even with existence of professional bodies such as the Nigerian Cancer Society, the Society of oncology and Cancer Research in Nigeria, and several other local and international bodies actively promoting cancer control and prevention, the incidence of cancer has continued to escalate. So there is ongoing cancer research in Nigeria.

The country is participating in the International Haplotype Mapping Project - a partnership of scientists and funding agencies from Canada, China, Japan, the United Kingdom, and the United States designed to develop a public resource that will help researchers find genes associated with human disease. There are collaborating centers to increase access to high-quality cancer clinical trials for Nigerian patients with cancer, monitored by a national ethics regulatory infrastructure to ensure that research is conducted according to the highest ethical and scientific standards.

Essentially, the most common cancers documented in Nigeria to date are cancers of the uterus and breast for women and liver and prostate cancers for men. Medical records indicate that cancer registration in the country officially began in 1960 but it was not until 1990 that a National Headquarters of Cancer Registries was established in Ibadan. But the institution has witnessed little or no activity. According to the International Association of Cancer Registries (IACR) publication Cancer Incidence in Five Continents, Volume III, the Ibadan Cancer Registry was initiated in 1960 and covers all persons with cancer diagnosed in the different clinics and hospitals in the city.

It notes that coverage is achieved by notification of cases to the Registry by the clinics and hospitals, and regular visits to all the hospitals and treatment centres in the city by the Registry staff. "The lists of surgical operations and surgical pathology records are consulted and visits made to wards.

The majority of cancer patients and all biopsies taken from cancer patients are referred to the University College Hospital, where the Cancer Registry is based. This hospital is the main treatment and care centre. It is considered that most patients suffering from malignant diseases attending either private practitioners or hospitals will be registered.

Investigations showed that only very few hospitals operate screening programmes for cervical cancer, even then, they are poorly funded, unsystematic, and incomprehensive. The country lacks an established national mammographic screening programme and available mammographic services are hard to come by. The pattern is that most breast and cervical cancer patients present at a younger age than in developed countries. Problems of impeded access to health care, ignorance, poverty and a general lack of coordination of issues of health education complicate matters.

In Nigeria, without doubt, breast cancer is currently the most common malignancy. Adebamowo, who is also Director of the Institute for Advanced Medical Research and Training (IAMRT) at the University of Ibadan notes: "In our 1999 case-control study of 250 consecutive breast cancer cases seen in our Oncology Clinic between 1992 and 1995, we found that breast cancer patients tended to be taller, weighed more, had a later age at onset of first pregnancy and had a higher mean number of children than controls. That last finding was particularly interesting because it is known that multiparity protects against breast cancer.

"However, pregnancy has a complex relationship with breast cancer. On the short term, on account of the stimulatory effect on breast epithelial growth, pregnancy increases short term risk of breast cancer. The protective effect of pregnancy is seen decades after the pregnancy - often after the age of 40 years. In a country with low life expectancy like Nigeria therefore, case control studies are likely to highlight the early pro-carcinogenic effect of pregnancy since few women survive to the age where the protective effect of pregnancy is more prominent."

A retrospective review data of breast cancers between 2001 and 2005 in the University of Maiduguri Teaching Hospital Cancer Registry revealed that a total of 1,216 cases of cancers were registered within the study period and breast cancer accounted for 13.9 per cent. There were 161 females and eight males with breast cancer within the study period, giving a female to male ratio of 20:1. There were four cases of bilateral breast cancers. The ages ranged between 17 and 85 years and the peak age group was 40-49 years which accounted for 61 cases (36.1 per cent). The commonest type of breast cancer was invasive ductal carcinoma (stage 0) which accounted for 82.6 per cent. Conclusion was that breast cancer is on the increase in the environment and therefore necessitated public enlightenment, screening of all women at risk, early detection and proper management in the public health institutions.

A similar research involving 116 Nigerian women with breast cancer over a five-year period, 1974 to 1979, at the University of Benin Teaching Hospital, Benin, Edo, State, indicated that breast cancer is mainly a disease of premenopausal and perimenopausal women. According to the lead researcher: "Reflecting their relative youthfulness, more than 10 per cent of them were pregnant or lactating on presentation. Breast cancer does not seem to have a different biologic behaviour in Nigerians, but it carries a truly bleak prognosis because many of the patients present with incurable disease that is close to its end stages."

Experts readily accede to the fact that incidence of breast cancer in Nigeria is increasing just like in other developing countries and those advanced countries that used to have a low incidence. His words: "I estimate that between 7,000 and 10,000 new cases of breast cancer developed in Nigeria in 2005. Several factors are responsible for this increasing incidence, but the most important in my view are increasing average life expectancy, increased access to diagnostic facilities, empowerment of women which is increasing women's ability to make independent decisions about their own health care, increasing westernization of dietary, physical activity and obstetric and gynecological factors among others."

The case of prostate cancer is just as serious. Indeed an increased incidence of prostate cancer among Nigerian men (and African-American men generally) has been attributed mainly to the introduction of screening techniques, which have enabled earlier diagnosis of patients. Two sets of registry reviews of male cancer patients to assess the current trends in prostate cancer in Nigeria showed that from 1980-1988 and 1989-1996, prostate cancer had gained prominence as one of the most common causes of cancer death.

An analysis of adult male cancers examined every decade since independence actually confirmed that prostate cancer is the number one cancer in Nigerian men and constitutes 11-12 per cent of all male cancers. The average age of onset of symptoms is 64-71. The inference from these findings is that despite the absence of adequate screening programmes in Nigeria, the number of prostate cancer cases has increased. But there is argument that known risk factors probably contribute to a varying degree. For instance it is often said that men who are generally of average build or in the low-to-normal range for body mass index are likely to be more at risk. Also, the role of genetics cannot be underplayed. Actually, it is believed that more cases of prostate cancer probably would be recorded if regular and extended screenings were undertaken.

On its own, cervical cancer has been proven to be due to a virus called the Human Papilloma Virus (HPV). According to Prof. Isaac Folorunsho Adewole, a consultant obstetrician and gynaecologist at the University College Hospital (UCH) Ibadan, screening with a pap test can detect changes in the cervix or detect cancer when it is still at a very early stage. Screening and vaccination with HPV vaccine is credited with reducing both the incidence and death rate from cervical cancer.

Adewole notes that cervical cancer is the leading cause of cancer mortality in women worldwide and is gaining importance in Nigeria.

With 80 per cent of cases arising in the developing world. Nigeria, home to nearly a quarter of all persons on the African continent, accommodates a substantial portion of those adversely impacted by the incidence of cervical cancer. Says Adewole: "In Nigeria the incidence rate of cervical cancer is 25/100,000. There are 32 million women aged 15-64 years old. If we were to conduct a one-time screen over one year, 8,000 new invasive cervical cancers would be detected.

Currently, 80 per cent of cases present in Stage III. While a one-time screen should detect some earlier stages, there could be as many as 6,400 Stage III cancers to treat. Strategies to enable a one-time screen are being considered."

He notes that routine screening is a problem. "Here, very few women are screened for cervical cancer in fact, it is estimated that only 10 per cent of female physicians in Nigeria have ever had a Pap smear themselves." Delays in screening and treatment arise from a number of reasons including cultural constraints (e.g. emotional distress with in having male doctors perform tests) and poor governmental funding for medical facilities.)"

It was to impact on the fortunes of cervical cancer in the country that, in 2006, an organisation - Operation Stop Cervical Cancer Nigeria (SCCAN) - a joint effort of MD Anderson Cancer Center, the British Columbia Cancer Agency, Rice University Department of Bioengineering, and the University of Ibadan School of Medicine, sought to improve the screening and treatment of cervical cancer in the women of Nigeria.

The effort made possible by a generous grant from the ExxonMobil Foundation, spearheaded clinical research of advanced diagnostic technologies at the University College Hospital in Ibadan, involving medical leaders from the six geopolitical zones in Nigeria to outline a work plan and assess needs and limitations in the provision of medical care.

At the end of it all, the international representatives provided their Nigerian counterparts in-person intensive instruction in all aspects of conducting an effective national cervical cancer screening programme.

Other cancers are equally traumatizing. For instance, an unusually high prevalence of bladder cancer is recorded in the cancer registry of Usmanu Danfodiyo University Teaching Hospital, Sokoto.

Several areas of the region had previous history of endemicity for urinary schistosomiasis. A retrospective review of clinical and histopathogical records of bladder cancer cases seen at the hospital from January 1999 to December 2004 indicated a 4.7 fold rise in the number of bladder cancer cases between 1999 and 2004. The male to female ratio was 11.1:1.0. The mean age was 46.0 years and ranged from 20 to 82 years. Majority, 107 (80.5 per cent) were farmers and fishermen from regions of the distribution of surrounding river or their smaller tributaries.

Without doubt, bladder cancer is a common malignancy in Sokoto and probably most of North-Western Nigeria. Experts agree that the association with chronic urinary schistosomiasis is very strong and the hospital incidence appears to be rising.

It is known that many stomach cancers are related to an infection with a bacterium called Helicobacter pylori which comes from food and water and is also responsible for stomach ulcer. Following a multi-disciplinary study, tagged Reducing Childhood Lead Exposure (RECLES) study of childhood lead exposure in South Western Nigeria, Adebomowo noted that the studies showed that there was a general lack of knowledge in the population about the health hazards associated with exposure to lead in general and in the domestic environment in particular.

"We have followed these studies up with examination of lead levels in paint sold on Nigerian markets and we found that of the 25 paints whose lead levels were measured, only one had lead level below the international recommended level (indoor and built environment - in press). While others had lead levels up to five times or more higher than recommended.

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