Home > Health Information > All Categories > Breast Cancer Statistics

Breast Cancer Statistics
By: Neri Blanco, M.D.

by Neri M. Blanco, M.D.


Statistics: The Bad News

- Breast cancer is the most common malignancy in women and the second leading cause of death in this country. It is the leading cause of death in women aged 40 - 55 years.

- Every 2 minutes a woman is diagnosed with breast cancer.

- 200,000 new cases of breast cancer in women are diagnosed annually and 43,000 will die from the disease.

- 1,600 new cases of breast cancer are diagnosed in men every year and 43,000 deaths are expected annually.

Statistics: The Good News

- 8 out of 10 breast lumps are NOT cancerous.

- 70% of all breast cancers are diagnosed by breast self-exams.

- Mammography can detect breast cancer up to two years before a cancer is large enough to be palpable.

- Breast cancer that is detected and treated early has a five-year survival rate greater than 96%.

- Over 2 million women in the U.S. alone are breast cancer survivors!

Risk Factors

- Female gender: female to male breast cancer cases are 100:1.

- Personal history of breast cancer.

- Family history of breast cancer.

- Early onset of menses (first menstruation; age less than 12) or late menopause (age greater than 50): prolonged exposure to estrogen.

- Late (greater than 35) or no pregnancies.

- Estrogen replacement therapy: unopposed monotherapy may increase the risk over a 10-year period, but estrogen benefits in reducing osteoporosis, heart disease, Alzheimer’s, and colon cancer need to be evaluated against the breast cancer risk on an individual basis.

- High fat diet: polyunsaturated fats like that in corn oil are believed to pose a threat, but monounsaturated fats do not increase the risks.

- Radiation to the chest wall for other reasons increases the breast cancer risk 10 years later.

- Genetics: certain genes (BRCA1 and 2) can increase the risk, but only accounts for about 5% of cases.

- Unclear associations: alcohol, smoking, obesity.

Signs/Symptoms:

- A lump is felt.

- Swelling is felt on the skin of the breast or the armpit/axilla.

- The vascularity or network of veins on the breast become more pronounced.

- The appearance of the nipple changes in texture, the nipple can become inverted, or abnormal bloody drainage occurs.

- The surface of the breast becomes irregular with areas of dimpling.

Diagnosis:

- History: personal and family history of breast cancer, sudden changes in the appearance of the breast, abnormal nipple discharge, and complaints of constitutional symptoms like pain and weight loss can be clues to the diagnosis of breast cancer.

- Breast exam; a large irregular mass that is fixed, nipple inversion or skin dimpling, a rash over the superficial skin of the breast with swelling of the skin, and associated breast and axillary masses are all findings suspicious for breast cancer. Only 75% of breast cancers are associated with a palpable lump and 75% of these are detected in routine breast self-exams.

- Mammogram is cheap, accessible, and accurate in properly selected patients.

- Ultrasound is an excellent way to differentiate between a cyst and a nodule, which can appear the same on mammography.

- Cat-scan is limited, not preferred mode of diagnosis.

- MRI is expensive, but is able to differentiate between a tumor and dense breast tissue. Good choice in evaluating high risk young women with dense breasts that are difficult to assess by regular mammography.

- Needle biopsy can help detect malignancy in a minimally-invasive manner. However, if cancer is found or if results are inconclusive, surgical biopsy is necessary.

- Surgical or open biopsy is used to both diagnose and treat cancer. The palpable tumor is completely excised, although microscopic disease is not seen. Laboratory assessment of the specimen can later reveal complete excision requiring no further treatment or cancer cells at the margins requiring more extensive surgery.

Treatment

- Breast biopsy is a sampling of a portion or the entire tumor to check for cancer. This is a diagnostic test, and if cancer is confirmed, the patient may need further surgical treatment.

The biopsy can be done by making an incision over a palpable mass and removing the specimen. If there is no palpable mass, mammographic abnormalities such as a visible nodule or calcifications can be used to place a needle into the core of the tumor with mammographic guidance. The biopsy is then performed by cutting around the needle to excise the tumor.

- Lumpectomy (or segmental/partial mastectomy or quadrantectomy or wide-local excision) are descriptive terms indicating the removal of the cancer with a surrounding rim of normal breast tissue. All the margins need to be free of tumor. The surgery is only part of a multidisciplinary approach to treatment that involves breast-conserving surgery that removes the tumor but does not take all of the breast tissue and preserves the nipple/areola. This is combined to postoperative radiation therapy to the whole breast and a boost to the tumor bed.

Axillary dissection, or removing the armpit lymph nodes to check for cancer, is done through a separate small incision in some patients based on the presence of invasive cancer.

Chemotherapy may be added to the treatment depending on node status, presence of metastatic disease, and tumor characteristics.

- Modified radical mastectomy (MRM) refers to removing the breast tissue (total mastectomy) and some but not all the axillary nodes in continuity with the specimen. There are two variations, the Patey procedure that preserves the pectoralis major muscle and sacrifices the minor muscle while the Scanlon modification divides but does not remove the pectoralis minor muscle. The Auchincloss mastectomy preserves both muscles while limiting a high axillary node dissection. Survival after the mastectomy is dependent of the size, differentiation of the tumor, and presence of metastatic disease. Despite staging breast cancer, there is no difference in survival and disease-free intervals between the MRM and the radical mastectomy while the MRM has improved cosmesis.

Radiation is not needed unless it is used to control advanced chest wall disease and determined on an individual basis. The use of chemotherapy is dependent to positive node status and tumor size and location.

- Radical and extended radical mastectomies are no longer the standard of care unless there is invasion of the chest wall (ribs) by the cancer. This involves a total mastectomy, extensive node dissection, and removal of the pectoralis muscles. This leaves significant disfigurement, decreased shoulder strength, and abnormal lymph drainage of the upper extremity. Complete breast cancer removal can certainly be achieved, but the same rates of five-year survival and local control can be achieved with less radical surgery.

Prognosis

- Tumor size: the smaller the tumor, the greater the survival rate and the risk of recurrence.

- Grade: tumors are judged to be well, moderately, or poorly differentiated depending on their appearance under the microscope. The more differentiated, the more it looks like the patient’s native cells, the better the prognosis.

- Estrogen and Progesterone receptors: these are proteins or hormones checked from the tumor tissue. If the breast cancer has positive receptors, then medicine (Tamoxifen) that attaches to these receptors is given to patients to treat residual or recurrent disease.

- Nodes removed from the armpit in certain patients are checked for cancer. If negative, the better the prognosis.

- The stage of a breast cancer takes into account the size of the primary tumor, the node status, skin or chest wall involvement, and distant cancer metastases. This correlates into 4 stages with very different survival and local recurrence risks as well as different therapies involving chemotherapy, radiation, and immunotherapy or hormone therapy. The five-year survival rate for stage I is over 90% while stage IV has a dismal 15% survival. The message is early diagnosis and surveillance of prior breast cancer translate into improved survival.

Recommendations

- Monthly breast exams by patient, age greater than 20.

- Breast exams by a medical professional every three years, ages 20 - 39. Annual exams age 40 or greater.

- Baseline mammogram at age 40, younger if strong family history of breast cancer. Mammogram every one to two years age 40 - 49, then every year age greater than 50.

- Follow a low-fat diet.

- Avoid smoking and excessive alcohol use.

Neri Blanco, M.D.