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The diagnosis and treatment of breast cancer have changed dramatically during the past two decades. Screening programs did not exist 25 years ago. The preferred treatment was radical mastectomy, and adjuvant therapy did not exist breast cancer, brest cancer. This is in marked contrast to the current situation of well-organized screening programs, effective adjuvant therapy.
The most recent figures from the National Cancer Institute reveal that after a sharp rise in the percentage of women diagnosed with breast cancer from 1980 to 1987, there has been a decline in incidence, especially among women 50 years of age.
The American Cancer Society predicted 180,200 new cases of breast cancer and 43,900 deaths for 2006, representing 31% of all new cases of cancer and 17% of cancer deaths. The mortality rate for breast cancer has been unchanged since 1930, increasing on an average of 0.2% per year.
The most important risk factor for breast cancer is advancing age. In women older than age 45 years, breast cancer occurs more frequently in upper socioeconomic classes, and whites are affected more than African Americans. Identified risk factors, either alone or in combination, explain only 21%.
Early detection is associated with increased survival and more cosmetic local treatment. Women should undergo screening and routine surveillance at timely intervals to assess risks and aid in early diagnosis. It is recommended that screening mammography be offered routinely every 1-2 years.
Epidemiology
The risk factors currently identified for breast cancer do not present a significant potential for control, nor are they as distinct as risk factors for lung cancer and cervical cancer. Other malignancies are associated with breast cancer, and multiple primary tumors of the ovary and uterus.
Family History
The family history is an important factor in assessing an individual's risk of a heritable predisposition to breast cancer. One should attempt to distinguish women carrying mutations in breast cancer susceptibility genes, in whom the risk of disease is very high, from women in those same families.
Reproductive History
Certain reproductive characteristics--nulliparity, early age of menarche, older age at menopause, and older age at first full-term pregnancy--have been associated with increased risk of breast cancer. Oophorectomy at an early age has been considered protective in reducing the risk of breast cancer.
Estrogen Replacement Therapy
Physicians should understand the rationale for estrogen replacement therapy, especially in terms of the prevention of cardiovascular disease.
Use of Oral Contraceptives
Soon after the approval of oral contraceptives, a number of epidemiologic studies reported on the risk of breast cancer associated with them. Oral contraceptives are widely used, and any effect on the risk of breast cancer will have important public health implications. Studies suggest that, overall, there has been no increase in the risk of breast cancer for women who had ever used oral contraceptives.
Dietary Fat Intake
International differences in rates of breast cancer and the striking increase among populations migrating from low-to high-incidence areas has suggested that environmental factors, possibly dietary, influence the occurrence of breast cancer.
Alcohol Consumption
A number of epidemiologic studies have shown a possible relationship between moderate drinking and breast cancer. However, the benefit of decreasing alcohol consumption, if any, needs to be evaluated by considering all the potential effects of alcohol on a woman's overall risk profile.
Other Factors
Approximately 10% of patients with breast cancer have a history of trauma to the breast. This trauma probably results in increased attention to the breast and the discovery of a tumor or other changes that initiate breast self-examination.
Virus-like particles have been identified in human breast milk. There is no evidence, however, that viruses are involved in breast cancer risk.
A number of histologic changes have been noted in benign fibrocystic breasts, and some have been associated with the later development of breast cancer. The College of American Pathologists has published a consensus statement indicating that there is no increased risk for breast cancer in patients with conditions such as macrocysts or microcysts, duct ectasia, fibroadenoma, mild hyperplasia, mastitis, or squamous metaplasia. There is a slight increase in risk in patients with sclerosing adenosis; biopsy-proven hyperplasia that is moderate or florid, solid or papillary; and those who had papillomas with a fibrovascular core. Finally, risk increases substantially--fourfold to fivefold--in women with biopsy-proven atypical hyperplasia.
Staging
Appropriate staging includes a pretreatment chest X-ray, routine blood studies, and liver function tests. For invasive lesions, a bone scan is recommended, although the yield is low for T1 lesions. It is helpful to have the results as a baseline for later comparison during the follow-up evaluations. Clinical staging by the tumor, nodes, and metastases (TNM) system is recommended (see the box).
Treatment Options
Untreated breast cancer has a surprisingly predictable 5-year survival rate. In one series, 20% of patients were still alive at 5 years and 5% survived 10 years. Thus, in discussing treatment, the surgeon should be aware of the natural history of the disease and the necessity for long-term (15-25 years) follow-up to determine the efficacy.
A number of factors influence the definitive surgical treatment of breast cancer. Important considerations include the size and histology of the lesion, the skill and experience of the multidisciplinary team, and the wishes of the patient. There have been a number of published reports, both from retrospective studies and from prospective randomized clinical trials, that have concluded that segmental mastectomy or wide local excision followed by axillary dissection and radiation therapy is appropriate therapy for stage I and stage II breast cancers less than 4 cm, provided the margins of the
The use of conservative surgery with axillary lymphadenectomy and radiation therapy requires consideration of four important criteria: patient selection, surgery of the primary tumor, radiotherapy of the primary tumor, and surgery of the axilla. The principal advantage of conservative treatment is cosmetic. There are no data to indicate that the conservative approach provides improved survival compared with the radical or modified radical
Radiotherapy is begun as soon as the wounds are healed. It is generally agreed that the breast should be treated with 180-200 cGy/d for a total of 4,500--5,000 cGy. Total doses in excess of 5,000 cGy result in fibrosis, retraction, and an unacceptable cosmetic result. For patients treated with
The conservative approach appeals to many patients, but statistics clearly indicate that most patients in the United States are still treated with the modified radical mastectomy. In some cases, the conservative approach is not appropriate, and some patients request removal of the breast. The modified radical mastectomy should be performed in a cosmetic manner, preferably with a transverse incision to permit later reconstruction.
There are advantages and disadvantages to the conservative and radical approaches. Obviously, the main advantage of the
Although some surgeons are performing reconstruction at the time of the modified radical mastectomy, many patients elect reconstructive procedures at a later date. The patient should see the plastic surgeon before the mastectomy. Occasionally, a support group will be available to discuss the reconstructive techniques and results. Immediate reconstruction, although appealing, has drawbacks.