Breast cancer is now the commonest malignancy affecting women in Nigeria. It is likely to become an important public health issue in the next millennium. The overall survival rate among Nigerian women with breast cancer is low and patients with early breast cancer tend to have better survival than those with advanced disease. Most breast cancer patients in Nigeria tend to be young pre-menopausal women with advanced breast cancer. However, recent years have witnessed an explosion in knowledge about the basic sciences of the disease, including the genetic basis and the pathology. These changes are leading to revisions in the management of the disease with a positive impact on prognosis.
In Nigeria, cancer causes more than 70,000 deaths per year (28,414 males and 41,913 females). The estimated incidence of the five most common types of cancer are: breast cancer (25.7%), cervical uterus (14.6%), prostate (12.8%), non-Hodgkin lymphoma (5.3%) liver (5.0). The estimated mortality proportions are breast cancer (18.6%), cervical uterus (16.8%), prostate (9.4%), liver (8.3%), and non-Hodgkin lymphoma (6.0%). Breast cancer is currently the deadliest cancer type in Nigeria, while cervical cancer is second and prostate cancer is third.
PAFs (population attributable fractions)
(aPAF, cancer deaths bPAF, cancer cases cPAF, melanoma cases)
Tobacco (2017)a :%3.6
Alcohol (2016)a: %6.6
Infections (2012)b %28.5
Obesity (2012)b %1.5
UV (2012)c %9.6
Occupational risk (2017)a %0.4
Lack of early diagnosis and, as a result, early detection of breast cancer increases the burden of the disease in Nigeria. Mammography, a form of X-ray of the breast, can detect growth or changes in the breast that are still very tiny as not to be felt by hand examination of even the expert. Mammograms also have a rate of false negative. Estimates of the false negative rate depend on close follow-up of many patients for many years. This is difficult in practice particularly in Nigeria because many women do not return for regular mammography, making it impossible to know if they ever developed a cancer. Women aged 40 to 49 have one in four instances of cancer missed at each mammography.
Triple negative breast cancer (TNBC) refers to any breast cancer that does not express the genes for estrogen receptor (ER), progesterone receptor (PR) or Her2/neu. With immunohistochemistry (IHC), breast cancer is classified into four groups based on IHC profile of estrogen receptor (ER)/progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2/neu) expression, positive (+) and/or negative (-). The IHC classification correlates well with intrinsic gene expression microarray categorization. ER positive tumors may benefit from being treated with selective ER modulators and aromatase inhibitors, whereas patients with HER2/neu positive tumors have been shown to experience a significant survival advantage when treated with humanized monoclonal antibodies against HER2/neu. This makes it more difficult to treat TNBC since most chemotherapeutic agents target one of the three receptors.
Triple negative breast cancers have a relapse pattern that is very different from hormone positive breast cancers: the risk of relapse is much higher for the first years but drops sharply and substantially below that of hormone positive breast cancers. Triple negative breast cancer tends to be very aggressive, metastasizes soon after therapy. Studies show that hormone receptor negative breast cancer is predominant in West African countries. Triple-negative breast cancer (TNBC) is known to be associated with aggressive biologic features and a poor clinical outcome. Therefore, early detection of TNBC with few false negatives is considered mandatory to improve prognosis
Breast Cancer Survival Rate depending on state stage of diagnosis and management
Stage of Breast Cancer Survival Rate
Stage 0 100%
Stage I 98%
Stage II 56%
Stage IIIA 49%
Stage IV 16%
Moreover, there is a lack in cancer treatment equipment. Radiotherapy is one of the fundamental parts of breast cancer treatment. Some examples of treatment sequences involving radiation; surgery followed by radiation and then possibly hormonal therapy, surgery followed by chemotherapy, then radiation and possibly hormonal therapy, and chemotherapy followed by targeted or hormonal therapy then surgery, radiation and possibly hormonal therapy. Newer technologies used in the developed countries such as Intensity Modulated Radiotherapy (IMRT), Image Guided Radiotherapy (IGRT), Volumetric Arc Therapy (VMAT) and Stereotactic Body Radiotherapy (SBRT) are often beyond the reach of many patients in Nigeria.