| ductal carcinoma | |
|---|---|
| Classification and external resources | |
 Histopathologic image from ductal cell carcinoma in situ (DCIS) of breast. Hematoxylin-eosin stain. |
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| ICD-10 | C50., D05. |
| ICD-9 | 174-175, 233.0 |
| ICD-O: | M8500/2-M8500/3 |
| MeSH | D018270 |
Mammary ductal carcinoma is the most common type of breast cancer in women. It comes in two forms: invasive ductal carcinoma (IDC), an infiltrating, malignant and abnormal proliferation of neoplastic cells in the breast tissue, or ductal carcinoma in situ (DCIS), a noninvasive, possibly malignant, neoplasm that is still confined to the lactiferous ducts, where breast cancer most often originates.
Contents |
Ductal Carcinoma In Situ, DCIS (aka Intraductal Carcinoma) is the most common type of noninvasive breast cancer in women. "Ductal carcinoma" refers to the development of cancer cells within the milk ducts of the breast. In situ means "in place" and refers to the fact that the cancer has not moved out of the duct and into any surrounding tissue.
As screening mammography has become more widespread, DCIS has become one of the most commonly diagnosed breast conditions, now accounting for 20% of screening detected breast cancer.[1] It is often referred to as "stage zero breast cancer" and experts disagree on whether it should even be called "cancer." In countries where screening mammography is uncommon, DCIS is sometimes diagnosed at a later stage, but in countries where screening mammography is widespread, it is usually diagnosed on a mammogram when it is so small that it has not yet formed a palpable lump. DCIS is not traditionally regarded as being harmful in itself, however there is evidence of metastases in up 2% of cases of DCIS.[2]
DCIS is usually discovered through a mammogram as very small specks of calcium known as microcalcifications. However, not all microcalcifications indicate the presence of DCIS, which must be confirmed by biopsy. DCIS may be multifocal, and treatment is aimed at excising all of the abnormal duct elements, leaving "clear margins", an area of much debate. After excision treatment often includes local radiation therapy. With appropriate treatment, DCIS is unlikely to develop into invasive cancer. Surgical excision with radiation lowers the risk that the DCIS will recur or that invasive breast cancer will develop.
DCIS patients have two surgery strategy choices. They are lumpectomy (most commonly followed by radiation therapy) or mastectomy. The survival rate is equally high for both treatments, 95 percent or higher, according to a 2009 Consensus Conference at the National Institutes of Health in the United States.
Lumpectomy is surgery that removes only the cancer and a rim of normal breast tissue around it. For women with only one area of cancer in their breast, and a tumor under 4 centimeters that was removed with clear margins, lumpectomy followed by radiation is often equivalent to mastectomy for mortality related to their cancer, albeit at the higher risk of local disease recurrence on the breast/chest wall. The addition of radiation therapy to lumpectomy in DCIS reduces the risk of local recurrence by about 58% as compared to excision alone. Lumpectomy with radiation is estimated to carry between a 12-19% chance at 15 years for local recurrence of breast cancer (approximately a 0.5% to 1.0% risk per year), which would require a "salvage mastectomy".
Patients with family history of breast cancer and those presenting with breast cancer who are less than 40 years old face higher risks of local recurrence of DCIS or breast cancer with breast conservation techniques. However, approximately 80 percent of women treated with breast conservation (lumpectomy) with radiation will not have a recurrence of either DCIS or breast cancer. Extensive DCIS of high grade, large size, and resected with minimal surgical margins, even with radiotherapy, results in recurrence rates of at least 50% and would be better served with a mastectomy procedure.
Mastectomy may also be the preferred treatment in certain instances:
The system for analysing the suitability of DCIS patients for the options of breast conservation without radiation, breast conservation with radiation, or mastectomy is called the VanNuys Prognostic Scoring Index (VNPI). This VNPI analyzes DCIS features in terms of size, grade, surgical margins, and patient age and assigns "scores" to favourable features.
Tamoxifen or another hormonal therapy is recommended for some women with DCIS to help prevent breast cancer. Hormonal therapy further decreases the risk of recurrence of DCIS or the development of invasive breast cancer. However, they have potentially dangerous side effects, such as increased risk of endometrial cancer, severe circulatory problems, or stroke. In addition, hot flashes, vaginal dryness, abnormal vaginal bleeding, and a possibility of premature menopause are common for women who were not yet menopausal when they started treatment.
Unlike women with invasive breast cancer, women with DCIS do not undergo chemotherapy and have traditionally not been advised to have their lymph nodes tested or removed. Some institutional series reporting significant rates of recurrent invasive cancers after mastectomy for DCIS, have recently endorsed routine sentinel node biopsy (SNB) in these patients,[3] while other have concluded it be reserved for selected patients. Most agree that SNB should be considered with tissue diagnosis of high risk DCIS (grade III with palpable mass or larger size on imaging) as well as in patients undergoing mastectomy after a core or excisional biopsy diagnosis of DCIS. [4][5] Experts are not sure whether all women with DCIS would eventually develop invasive breast cancer if they live for a long time and are not treated.
Research has indicated that the absence of caveolin-1 in adjacent stromal cells can be an indicator of likely progression of DCIS into invasive cancer.[6]
If DCIS is allowed to go untreated, the natural course or natural history of the disease is as follows. "The natural history of DCIS varies according to the grade of the DCIS detected. The natural history of low grade DCIS is that approximately 60% of lesions will become invasive at 40 years follow-up. The natural history of high grade DCIS derived from local recurrence rates within high grade DCIS lesions, which have been inadequately resected and not given radiotherapy, suggests an invasive risk of at least 50% at 7 years follow-up. Given the average life expectancy of women with screen-detected DCIS is 25 years, this suggests high grade DCIS is an obligate precursor of invasive disease. There is a strong correlation between the grading of invasive cancer and the grade of DCIS from which it arose. This suggests that approximately 50% of low grade DCIS detected at screening will represent overdiagnosis while overdiagnosis of high grade DCIS would be rare. The natural history of intermediate grade DCIS is as yet unknown. Only 15% of screen-detected DCIS is low grade, suggesting that overdiagnosis is uncommon. Approximately 60% of screen-detected DCIS is high grade and in the vast majority of these patients adequate treatment will be preventing the occurrence of high grade invasive breast cancer. Approximately one-third of malignant calcification clusters detected at screening mammography already has an invasive focus." [1]
Invasive Ductal Carcinoma (IDC) is the most common form of invasive breast cancer. It accounts for 80% of all types of breast cancer. On a mammogram, it is usually visualized as a mass with fine spikes radiating from the edges. On physical examination, this lump usually feels much harder or firmer than benign breast lesions such as fibroadenoma. On microscopic examination, the cancerous cells invade and replace the surrounding normal tissues. IDC is divided in several histological subtypes.
The prognosis of IDC depends, in part, on its histological subtype. Mucinous, papillary, cribriform, and tubular carcinomas have longer survival, and lower recurrence, rates. The prognosis of the most common form of IDC, called "IDC Not Otherwise Specified", is intermediate. Finally, some rare forms of breast cancer (e.g. sarcomatoid carcinoma, inflammatory carcinoma) have a poor prognosis.
Regardless of the histological subtype, the prognosis of IDC depends also on its staging, histological grade, expression of hormone receptors and of oncogenes like HER2/neu.
Treatment of IDC depends on the size of the mass: a. <4cm mass: surgery to remove the main tumor mass and to sample the lymph nodes in the axilla. The stage of the tumor is ascertained after this first surgery. Adjuvant therapy (i.e. treatment after surgery) usually includes chemotherapy, radiotherapy, hormonal therapy (e.g. Tamoxifen) and targeted therapy (e.g. Trastuzumab). More surgery is occasionally needed to complete the removal of the initial tumor or to remove recurrences. b. 4cm or larger mass: modified (a less aggressive form of radical mastectomy) radical mastectomy (because any malignant mass in excess of 4cm in size exceeds the criteria for a lumpectomy) along with sampling of the lymph nodes in the axilla.
The treatment options offered to an individual patient are determined by the form, stage and location of the cancer, and also by the age, history of prior disease and general health of the patient. Not all patients are treated the same way.
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  | Stromal caveolin-1 levels predict early DCIS progression to invasive breast cancer - Landes Bioscience Journals: Cancer Biology & Therapy |
| | DCIS, LCIS, and Other Stage 0 Breast Cancer, National Research Center for Women & Families - DCIS, LCIS, and other Pre-cancers |
| | Axillary lymph node metastases in patients with a final diagnosis of ductal carcinoma in situ - Elsevier: Article Locator |
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