1.1 BACKGROUND OF THE STUDY.
Cancer of the breast is a disease that affects a part of the body that is central to women’s sense of womanliness and femininity .It is a complex disease with the cause not yet fully understood. It is most likely caused by a number of factors interacting with each other, rather than any one factor .The main identified risk factor of breast cancer is age, with woman aged 50 years or over being at risk.
There are many different types of breast cancer, with different stages or spread, aggressiveness and genetic makeup. The implementation of mass screening would result in increased caseload for radiologists .This will increase chances for improper diagnosis .The prediction using LOGISTIC REGRESSION would aid the radiologist to detect breast cancer.
1.1.1 TYPES OF BREAST CANCER (BC).
The type of breast cancer is important in determining most of the treatment approach. The most common way to classify breast tumors is according to the status of the three specific cell surface receptors.
These are the estrogen receptor (ER), the progesterone receptor (PR), and the Human Epidermal Growth Factor Receptor (HER) 2 or neu receptor.
The most common type of breast cancer is known as Hormone Receptor-Positive breast cancer, accounting for about 75% breast cancer. This type of cancer grows in response to the hormones estrogen and progesterone, and such is likely to respond to the therapies that aim to inhibit growth effects of hormones.
Another type of breast cancer classified by the system is ‘HER2-positive breast cancer’ which is typified by cell that make too much of protein known as HER2/neu. It represents 20-30 of Hormone Receptor positive breast cancer. Tumors that do not over express HER2/neu are described as HER2-negative.
Triple negative breast cancer (TNBC) is a rare form of negative breast cancer, which is a sub-type of HER2-negative disease. TNBC refers to tumor cells which lacks estrogen and progestogen receptors, and do not overexpress the HER2-protein. This cancer this accounts for around 15% of all breast cancers.
1.1.2 CAUSES AND RISK FACTORS.
There are number of factors that have been shown to increase a woman’s risk of developing breast cancer.
- Age: The majority of breast cancer cases occur in women over age 50.
- Family history: If a woman has a personal or family history of breast cancer, she is at increased risk of developing breast cancer.
- Clinical history: Women who have previously suffered with benign breast cancer are at greater risk of developing breast cancer in future.
- A late first pregnancy: Women who have a late first pregnancy (after the age of 35) are more likely to develop breast cancer.
- Prolonged hormone exposure: A long menstrual life or possibly use of hormone replacement therapy after the menopause expose women to an increased risk of developing cancer.
- Life style factors: For example, being overweight or obese after the menopause, physical inactivity, a high fat diet and high alcohol consumption can play an important role in the development of cancer.
1.1.3 SYMPTOMS AND DIAGNOSIS.
The symptoms of the early stage breast cancer can often go undetected. There are 12 common signs of breast cancer, these are summarized below:
A hard lump developing in the breast or armpit- typically painless and occurring in one side only.
A change in the size or shape of the breast, including indentation, ‘growing’ (particularly prominent) veins or skin erosion.
Change in the skin such as hardening, dimpling, bumps, redness or heat or any orange peel like appearance.
Changes in nipple such as retraction, the secretion of unusual discharge or a rash around the nipple area.
In simple terms, the stage of a cancer describes the size of tumor and determines whether it spreads and how far it spread. The stage is important because it helps cancer specialists to decide on best treatment option.
Adjacent is simplified description of a staging system for breast cancer.
Stage1: The tumor is not larger than two centimeters and has not spread to the lymph nodes.
Stage 2: The tumor is around five centimeters in size and may have spread to the lymph node under the arm.
Stage 3: The tumor(s) may have spread to the lymph nodes, be clumped together or sticking to other structures. The tumor(s) may have also spread to surrounding breast tissue.
Stage 4: Tumor(s) that have spread to other organs in the body e.g. lungs, liver or bone. This is sometimes referred to as ‘invasive cancer’.
1.1.5 TREATMENT OF BREAST CANCER.
Breast cancer treatment option vary depending on the stage of the cancer- its size, position, whether it spreads to the other parts of the body and physical health of the patient. Current treatments for breast cancer include:
- Hormonal therapy.
- Targeted therapy.
1.2 STATEMENT OF THE PROBLEM
Breast cancer is a leading cause of cancer related mortality in women worldwide. Almost half of annually diagnosed women with breast cancer belong to developing countries, where they present younger age and advanced-stage disease. These women also have poor overall outcomes compared to women in developed countries.
The advanced stage of presentation of cancer in developing countries was attributed to the lack of mass education and screening programs, poverty, poor access to health care facilities, lack of expertise, and poor country infrastructures.
1.3 SCOPE OF THE STUDY.
Descriptive analysis was performed to examine the distribution of the data, and logistic regression analysis is used to describe and analyze the data set. The data is summarized under different classification of gender (sex), length of stay in the hospital during treatment, and the outcome after treatment.
1.4 AIM AND OBJECTIVES OF THE STUDY
The purpose of this study is to model a logistic regression on cancer patients. Thus, the objectives are to;
- examine the distribution of all the factors involve;
- identify the factors that influences the survivability of cancer patients; and
- state an appropriate model for the survivability of the patients.