Paget’s Carcinoma

The basic lesion is usually an infiltrating ductal carcinoma, usually well differentiated, or a ductal carcinoma in situ (DCIS). The ducts of the nipple epithelium are infiltrated, but gross nipple changes are often minimal, and a tumor mass may not be palpable. The first symptom is often itching or burning of the nipple, with superficial erosion or ulceration. The diagnosis is established by biopsy of the erosion.

Paget’s carcinoma is not common (about 1% of all breast cancers), but it is important because the nipple changes appear innocuous. These are frequently diagnosed and treated as dermatitis or bacterial infection, leading to delay in detection. When the lesion consists of nipple changes only, the incidence of axillary metastases is less than 5%, and the prognosis is excellent. When a breast mass is also present, the incidence of axillary metastases rises, with an associated marked decrease in prospects for cure by surgical or other treatment.

Inflammatory Carcinoma

This is the most malignant form of breast cancer and constitutes less than 3% of all cases. The clinical findings consist of a rapidly growing, sometimes painful mass that enlarges the breast. The overlying skin becomes erythematous, edematous, and warm. Often there is no distinct mass, since the tumor infiltrates the involved breast diffusely. The diagnosis should be made when the redness involves more than one-third of the skin over the breast and biopsy shows infiltrating carcinoma with invasion of the subdermal lymphatics. The inflammatory changes, often mistaken for an infection, are caused by carcinomatous invasion of the subdermal lymphatics, with resulting edema and hyperemia. If the physician suspects infection but the lesion does not respond rapidly (1-2 weeks) to antibiotics, biopsy is performed. Metastases tend to occur early and widely, and for this reason inflammatory carcinoma is rarely curable. Mastectomy is seldom indicated unless chemotherapy and radiation have resulted in clinical remission with no evidence of distant metastases. In these cases, residual disease in the breast may be eradicated. Radiation, hormone therapy, and chemotherapy are the measures most likely to be of value, rather than operation.

Breast Cancer Occurring during Pregnancy or Lactation

Breast cancer complicates approximately 1 in 3000 pregnancies. The diagnosis is frequently delayed, because physiologic changes in the breast may obscure the lesion. This results in a tendency of both patients and physicians to misinterpret findings and to delay biopsy. When the cancer is confined to the breast, the 5-year survival rate after mastectomy is about 70%. Axillary metastases are already present in 60-70% of patients, and for them the 5-year survival rate after mastectomy is only 30-40%. Pregnancy (or lactation) is not a contraindication to operation, and treatment should be based on the stage of the disease as in the nonpregnant (or nonlactating) woman. Overall survival rates have improved, since cancers are now diagnosed in pregnant women earlier than in the past. Breast-conserving surgery may be performed - and radiation and chemotherapy given - even during the pregnancy.

Bilateral Breast Cancer

Clinically evident simultaneous bilateral breast cancer occurs in less than 1% of cases, but there is a 5-8% incidence of later occurrence of cancer in the second breast. Bilaterality occurs more often in familial breast cancer, in women under age 50 years, and when the tumor in the primary breast is lobular. The incidence of second breast cancers increases directly with the length of time the patient is alive after her first cancer - about 1% per year.

In patients with breast cancer, mammography should be performed before primary treatment and at regular intervals thereafter, to search for occult cancer in the opposite breast. Routine biopsy of the opposite breast is usually not warranted even for lobular cancer.

Noninvasive Cancer

Noninvasive cancer can occur within the ducts (ductal carcinoma in situ, DCIS) or lobules (lobular carcinoma in situ, LCIS). LCIS, although thought to be a premalignant lesion or a risk factor for breast cancer, in fact behaves like other carcinomas in situ. In a recent study, patients with LCIS not only went on to develop invasive lobular breast cancer, but also some developed it in the same breast and indexed location of the original LCIS. Although more research needs to be done in this area, the invasive potential of LCIS is being reconsidered. DCIS tends to be unilateral and most often progresses to invasive cancer if untreated. Approximately 40-60% of women who have DCIS treated with biopsy alone develop invasive cancer within the same breast.

The treatment of intraductal lesions is controversial. DCIS can be treated with total mastectomy or by wide excision with or without radiation therapy. Conservative management, excision only, is advised in this patient population until further data are developed. Although research is defining the malignant potential of LCIS, it may be well managed with observation, but patients unwilling to accept the increased risk of breast cancer may be offered surgical excision of the area in question or even bilateral total mastectomy. Currently, accepted standards of care offer the alternative of chemoprevention, using agents such as tamoxifen, which is effective in preventing invasive breast cancer from developing in both LCIS and intraductal carcinoma in situ. Axillary metastases from in situ cancers should not occur unless there is an occult invasive cancer.

_{Anderson WF et al: Inflammatory breast carcinoma and noninflammatory locally advanced breast carcinoma: distinct clinicopathologic entities? J Clin Oncol 2003;21:2254. Pubmed: 12805323}

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