Información sobre riesgo, prevención, detección, síntomas, diagnosis, tratamiento y apoyo para el cáncer.
Información sobre el tratamiento del cáncer incluyendo quirúrgica, quimioterapia, radioterapia, estudios clínicos, terapia con protón, medicina complementaria avanzadas.
OncoLink se complace en ofrecer una amplia lista de lista completa de los agentes quimioterapéuticos más comúnmente usados??. Esta guía de referencia incluye información sobre la forma en que cada fármaco se administra, cómo funcionan, y los pacientes los efectos secundarios comunes pueden experimentar.
Maneras que los pacientes de cáncer y las personas que le cuidan puedan enfrentar el cáncer, los efectos secundarios, nutrición, cuestiones en general sobre el apoyo para el cáncer, duelo/decisiones sobre el termino de vida, y experiencias compartidas por sobrevivientes.
Tipos de C�ncer / Cáncer del Seno / Recursos de NCI
National Cancer Institute
Last Modified: January 4, 2013
General Information About Breast Cancer
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This summary discusses only primary epithelial breast cancers. Rarely, the breast may be involved by other tumors such as lymphomas, sarcomas, or melanomas. (Refer to the PDQ® summaries on Adult Hodgkin Lymphoma Treatment, Adult Soft Tissue Sarcoma Treatment, and Melanoma Treatment for more information.)
Estimated new cases and deaths from breast cancer (women only) in the United States in 2012: 1
Genetic Characteristics and Risk Factors
Several well-established factors have been associated with an increased risk of breast cancer, including family history, nulliparity, early menarche, advanced age, and a personal history of breast cancer (in situ or invasive).
Age-specific risk estimates are available to help counsel and design screening strategies for women with a family history of breast cancer. 2 3 Of all women with breast cancer, 5% to 10% may have a germ-line mutation of the genes BRCA1 and BRCA2. 4 Specific mutations of BRCA1 and BRCA2 are more common in women of Jewish ancestry. 5 The estimated lifetime risk of developing breast cancer for women with BRCA1 and BRCA2 mutations is 40% to 85%. Carriers with a history of breast cancer have an increased risk of contralateral disease that may be as great as 5% per year. 6 Ma le carriers of BRCA2 mutations are also at increased risk for breast cancer. 7
Mutations in either the BRCA1 or BRCA2 gene also confer an increased risk of ovarian cancer. 7 8 9 In addition, mutation carriers may be at increased risk of other primary cancers. 7 9 Genetic testing is available to detect mutations in members of high-risk families. 10 11 12 13 14 Such individuals should first be referred for counseling. 15 (Refer to the PDQ® summaries on Genetics of Breast and Ovarian Cancer; Breast Cancer Prevention; and Breast Cancer Screening for more information.)
Clinical trials have established that screening with mammography, with or without clinical breast examination, may decrease breast cancer mortality. (Refer to the PDQ® summary on Breast Cancer Screening for more information.)
Patient management following initial suspicion of breast cancer generally includes confirmation of the diagnosis, evaluation of stage of disease, and selection of therapy. At the time the tumor tissue is surgically removed, estrogen receptor (ER) and progesterone receptor (PR) status should be determined.
Prognostic and Predictive Factors
Breast cancer is commonly treated by various combinations of surgery, radiation therapy, chemotherapy, and hormone therapy. Prognosis and selection of therapy may be influenced by the following clinical and pathology features (based on conventional histology and immunohistochemistry): 16
Molecular profiling has led to classification of breast cancer into the following five distinct subtypes: 17 18
The use of molecular profiling in breast cancer includes the following: 17 18
Although certain rare inherited mutations, such as those of BRCA1 and BRCA2, predispose women to develop breast cancer, prognostic data on BRCA1/BRCA2 mutation carriers who have developed breast cancer are conflicting; these women are at greater risk of developing contralateral breast cancer. Since criteria for menopausal status vary widely, some studies have substituted age older than 50 years as a surrogate for the postmenopausal state. Breast cancer is classified into a variety of histologic types, some of which have prognostic importance. For example, favorable histologic types include mucinous, medullary, and tubular carcinoma. 19 20 21
Pathologically, breast cancer can be a multicentric and bilateral disease. Bilateral disease is somewhat more common in patients with infiltrating lobular carcinoma. Patients who have breast cancer should have bilateral mammography at the time of diagnosis to rule out synchronous disease. The role of magnetic resonance imaging (MRI) in screening and follow-up continues to evolve. Having demonstrated an increased detection rate of mammographically occult disease, the selective use of MRI for additional screening is being used with increased frequency despite the absence of randomized, controlled data. Because only 25% of MRI-positive findings represent malignancy, pathologic confirmation prior to treatment action is recommended. Whether this increased detection rate will translate into improved treatment outcome is unknown. 22 23 24 When BRCA1/BRCA2 mutation carriers were diagnosed at a young age, the risk of a contralateral breast cancer reached nearly 50% in the ensuing 25 years. 25 26
Patients should continue to have regular breast physical examinations and mammography to detect either recurrence in the ipsilateral breast in those patients treated with breast-conserving surgery or a second primary cancer in the contralateral breast. 27 The risk of a primary breast cancer in the contralateral breast is approximately 1% per year. 28 29 Patient age younger than 55 years at the time of diagnosis or lobular tumor histology appear to increase this risk to 1.5%. 30 The development of a contralateral breast cancer is associated with an increased risk of distant recurrence. 31 32
The use of hormone replacement therapy (HRT) poses a dilemma for the rising numbers of breast cancer survivors, many of whom enter menopause prematurely as a result of therapy. HRT has generally not been used for women with a history of breast cancer because estrogen is a growth factor for most breast cancer cells in the laboratory; however, empiric data on the safety of HRT after breast cancer are limited. 33 34
Two randomized trials (including Regional Oncologic Center-Hormonal Replacement Therapy After Breast Cancer--Is It Safe [ROC-HABITS]) comparing HRT with no hormonal supplementation have been reported. 35 36 The first trial included 345 evaluable breast cancer patients with menopausal symptoms and was terminated early because of an increased incidence of recurrences and new primaries in the HRT group (hazard ratio [HR], 3.5; 95% confidence interval [CI], 1.57.4). 35[Level of evidence: 1iiDii] In total, 26 women in the HRT group and 7 in the non-HRT group developed recurrences or new primaries. This study, however, was not double blinded, and it is possible that patients on HRT were monitored more closely. Because of the results of the first trial, the second trial, which was conducted under a joint steering committee with the first, closed prematurely after the enrollment of 378 patients. 36 With a median follow-up of 4.1 years, there were 11 recurrences in the hormone replacement group and 13 recurrences in the patients assigned to no hormone replacement (HR, 0.82; 95% CI, 0.351.9). 36[Level of evidence: 1iiDii] The trials differed in several ways; 37 however, until further data become available, decisions concerning the use of HRT in patients with breast cancer will have to be based on the results of these studies and on inferences from the impact of HRT use on breast cancer risk in other settings. 37 A comprehensive intervention, including education, counseling, and nonhormonal drug therapy, has been shown to reduce menopausal symptoms and to improve sexual functioning in breast cancer survivors. 38[Level of evidence: 1iiC] (Refer to the PDQ® summaries on Fever, Sweats, and Hot Flashes and Sexuality and Reproductive Issues for more information.)
For patients who opt for a total mastectomy, reconstructive surgery may be used at the time of the mastectomy (immediate reconstruction) or at some subsequent time (delayed reconstruction). 39 40 41 42 Breast contour can be restored by the submuscular insertion of an artificial implant (saline-filled) or a rectus muscle or other flap. If a saline implant is used, a tissue expander can be inserted beneath the pectoral muscle. Saline is injected into the expander to stretch the tissues for a period of weeks or months until the desired volume is obtained. The tissue expander is replaced by a permanent implant. (Visit the FDA's Web site for more information on breast implants.) Rectus muscle flaps require a considerably more complicated and prolonged operative procedure, and blood transfusions may be required.
Following breast reconstruction, radiation therapy can be delivered to the chest wall and regional nodes either in the adjuvant setting or if local disease recurs. Radiation therapy following reconstruction with a breast prosthesis may affect cosmesis, and the incidence of capsular fibrosis, pain, or the need for implant removal may be increased. 43
Evidence from randomized trials indicates that periodic follow-up with bone scans, liver sonography, chest x-rays, and blood tests of liver function does not improve survival or quality of life when compared to routine physical examinations. 44 45 46 Even when these tests permit earlier detection of recurrent disease, patient survival is unaffected. 45 Based on these data, some investigators recommend that acceptable follow-up be limited to physical examination and annual mammography for asymptomatic patients who complete treatment for stage I to stage III breast cancer. The frequency of follow-up and the appropriateness of screening tests after the completion of primary treatment for stage I to breast cancer remain controversial.
Other PDQ® summaries containing information related to breast cancer include the following:
Cellular Classification of Breast Cancer
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The following is a list of breast cancer histologic classifications. 1 Infiltrating or invasive ductal cancer is the most common breast cancer histologic type and comprises 70% to 80% of all cases.
The following are tumor subtypes that occur in the breast but are not considered to be typical breast cancers:
Stage Information for Breast Cancer
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The American Joint Committee on Cancer (AJCC) staging system provides a strategy for grouping patients with respect to prognosis. Therapeutic decisions are formulated in part according to staging categories but primarily according to tumor size, lymph node status, estrogen-receptor and progesterone-receptor levels in the tumor tissue, human epidermal growth factor receptor 2 (HER2/neu) status, menopausal status, and the general health of the patient.
The AJCC has designated staging by TNM classification to define breast cancer. 1 When this system was modified in 2002, some nodal categories that were previously considered stage II were reclassified as stage III. 2 As a result of the stage migration phenomenon, survival by stage for case series classified by the new system will appear superior to those using the old system. 3
| TX | Primary tumor cannot be assessed. |
| T0 | No evidence of primary tumor. |
| Tis | Carcinoma in situ. |
| Tis (DCIS) | DCIS. |
| Tis (LCIS) | LCIS. |
| Tis (Paget) | Paget disease of the nipple NOT associated with invasive carcinoma and/or carcinoma in situ (DCIS and/or LCIS) in the underlying breast parenchyma. Carcinomas in the breast parenchyma associated with Paget disease are categorized based on the size and characteristics of the parenchymal disease, although the presence of Paget disease should still be noted. |
| T1 | Tumor 20 mm in greatest dimension. |
| T1mi | Tumor 1 mm in greatest dimension. |
| T1a | Tumor >1 mm but 5 mm in greatest dimension. |
| T1b | Tumor >5 mm but 10 mm in greatest dimension. |
| T1c | Tumor >10 mm but 20 mm in greatest dimension. |
| T2 | Tumor >20 mm but 50 mm in greatest dimension. |
| T3 | Tumor >50 mm in greatest dimension. |
| T4 | Tumor of any size with direct extension to the chest wall and/or to the skin (ulceration or skin nodules).c |
| T4a | Extension to the chest wall, not including only pectoralis muscle adherence/invasion. |
| T4b | Ulceration and/or ipsilateral satellite nodules and/or edema (including peau d'orange) of the skin, which do not meet the criteria for inflammatory carcinoma. |
| T4c | Both T4a and T4b. |
| T4d | Inflammatory carcinoma. |
| DCIS = ductal carcinoma | |
| Clinical | |
| NX | Regional lymph nodes cannot be assessed (e.g., previously removed). |
| N0 | No regional lymph node metastases. |
| N1 | Metastases to movable ipsilateral level I, II axillary lymph node(s). |
| N2 | Metastases in ipsilateral level I, II axillary lymph nodes that are clinically fixed or matted. |
| OR | |
| Metastases in clinically detectedb ipsilateral internal mammary nodes in the absence of clinically evident axillary lymph node metastases. | |
| N2a | Metastases in ipsilateral level I, II axillary lymph nodes fixed to one another (matted) or to other structures. |
| N2b | Metastases only in clinically detectedb ipsilateral internal mammary nodes and in the absence of clinically evident level I, II axillary lymph node metastases. |
| N3 | Metastases in ipsilateral infraclavicular (level III axillary) lymph node(s) with or without level I, II axillary lymph node involvement. |
| OR | |
| Metastases in clinically detectedb ipsilateral internal mammary lymph node(s) with clinically evident level I, II axillary lymph node metastases. | |
| OR | |
| Metastases in ipsilateral supraclavicular lymph node(s) with or without axillary or internal mammary lymph node involvement. | |
| N3a | Metastases in ipsilateral infraclavicular lymph node(s). |
| N3b | Metastases in ipsilateral internal mammary lymph node(s) and axillary lymph node(s). |
| N3c | Metastases in ipsilateral supraclavicular lymph node(s). |
| pNX | Regional lymph nodes cannot be assessed (e.g., previously removed or not removed for pathologic study). |
| pN0 | No regional lymph node metastasis identified histologically. |
| Note: ITCs are defined as small clusters of cells 0.2 mm, or single tumor cells, or a cluster of <200 cells in a single histologic cross-section. ITCs may be detected by routine histology or by IHC methods. Nodes containing only ITCs are excluded from the total positive node count for purposes of N classification but should be included in the total number of nodes evaluated. | |
| pN0(i) | No regional lymph node metastases histologically, negative IHC. |
| pN0(i+) | Malignant cells in regional lymph node(s) 0.2 mm (detected by H&E or IHC including ITC). |
| pN0(mol) | No regional lymph node metastases histologically, negative molecular findings (RT-PCR). |
| pN0(mol+) | Positive molecular findings (RT-PCR), but no regional lymph node metastases detected by histology or IHC. |
| pN1 | Micrometastases. |
| OR | |
| Metastases in 13 axillary lymph nodes. | |
| AND/OR | |
| Metastases in internal mammary nodes with metastases detected by sentinel lymph node biopsy but not clinically detected.c | |
| pN1mi | Micrometastases (>0.2 mm and/or >200 cells but none >2.0 mm). |
| pN1a | Metastases in 13 axillary lymph nodes, at least one metastasis >2.0 mm. |
| pN1b | Metastases in internal mammary nodes with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected.c |
| pN1c | Metastases in 13 axillary lymph nodes and in internal mammary lymph nodes with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected. |
| pN2 | Metastases in 49 axillary lymph nodes. |
| OR | |
| Metastases in clinically detectedd internal mammary lymph nodes in the absence of axillary lymph node metastases. | |
| pN2a | Metastases in 49 axillary lymph nodes (at least 1 tumor deposit >2 mm). |
| pN2b | Metastases in clinically detectedd internal mammary lymph nodes in the absence of axillary lymph node metastases. |
| pN3 | Metastases in 10 axillary lymph nodes. |
| OR | |
| Metastases in infraclavicular (level III axillary) lymph nodes. | |
| OR | |
| Metastases in clinically detectedc ipsilateral internal mammary lymph nodes in the presence of one or more positive level I, II axillary lymph nodes. | |
| OR | |
| Metastases in >3 axillary lymph nodes and in internal mammary lymph nodes with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected.c | |
| OR | |
| Metastases in ipsilateral supraclavicular lymph nodes. | |
| pN3a | Metastases in 10 axillary lymph nodes (at least 1 tumor deposit >2.0 mm). |
| OR | |
| Metastases to the infraclavicular (level III axillary lymph) nodes. | |
| pN3b | Metastases in clinically detectedd ipsilateral internal mammary lymph nodes in the presence of one or more positive axillary lymph nodes; |
| OR | |
| Metastases in >3 axillary lymph nodes and in internal mammary lymph nodes with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected.c | |
| pN3c | Metastases in ipsilateral supraclavicular lymph nodes. |
| Posttreatment ypN | |
| Posttreatment yp "N" should be evaluated as for clinical (pretreatment) "N" methods above. The modifier "SN" is used only if a sentinel node evaluation was performed after treatment. If no subscript is attached, it is assumed that the axillary nodal evaluation was by AND. | |
| The X classification will be used (ypNX) if no yp posttreatment SN or AND was performed. | |
| N categories are the same as those used for pN. | |
| AND = axillary node dissection; H&E = hematoxylin and eosin stain; IHC = immunohistochemical; ITC = isolated tumor cells; RT-PCR = reverse transcriptase/polymerase chain reaction. | |
| M0 | No clinical or radiographic evidence of distant metastases. |
| cM0(i+) | No clinical or radiographic evidence of distant metastases, but deposits of molecularly or microscopically detected tumor cells in circulating blood, bone marrow, or other nonregional nodal tissue that are 0.2 mm in a patient without symptoms or signs of metastases. |
| M1 | Distant detectable metastases as determined by classic clinical and radiographic means and/or histologically proven >0.2 mm. |
Posttreatment yp M classification. The M category for patients treated with neoadjuvant therapy is the category assigned in the clinical stage, prior to initiation of neoadjuvant therapy. Identification of distant metastases after the start of therapy in cases where pretherapy evaluation showed no metastases is considered progression of disease. If a patient was designated to have detectable distant metastases (M1) before chemotherapy, the patient will be designated as M1 throughout. 1

