Intraductal carcinoma

Intraductal carcinoma, also called ductal carcinoma in situ (DCIS), is a noninvasive condition in which abnormal cells are found in the lining of a breast duct. The abnormal cells have not spread outside the duct to other tissues in the breast. In some cases, intraductal carcinoma may become invasive cancer and spread to other tissues, although it is not known at this time how to predict which lesions will become invasive.

Symptoms
Most of the women who develop intraductal carcinoma do not experience symptoms at all. The first signs and symptoms may however appear once the cancer advances. In few cases, intraductal carcinoma may cause: Because of the lack of early symptoms, most women who develop this condition are detected with it as a result of breast screening. Intraductal cancer can be easily seen on mammograms.
 * A lump or thickening in or near the breast or under the arm
 * A change in the size or shape of the breast
 * Nipple discharge or nipple tenderness; the nipple may also be inverted, or pulled back into the breast
 * Ridges or pitting of the breast; the skin may look like the skin of an orange
 * A change in the way the skin of the breast, areola, or nipple looks or feels such as warmth, swelling, redness or scaliness.

Causes
The specific causes of intraductal carcinoma are still unknown. The risk factors for developing this condition are similar to those for invasive breast cancer.

Some women are however more prone than others to developing intraductal carcinoma. Women considered at higher risks are those who have a family history of breast cancer, those who have had their periods at an early age or who have had a late menopause. Also, women who have never had children or had them late in life are also more likely to get this condition.

Long-term use of estrogen-progestin hormone replacement therapy (HRT) for more than five years after menopause, genetic mutations (BRCA1 or BRCA2 genes), atypical hyperplasia, as well as radiation exposure or exposure to certain chemicals may also contribute in the development of the condition. Nonetheless, the risk of developing noninvasive cancer increases with age and it is higher in women older than 45 years.

Treatment
The main treatment for intraductal carcinoma used to be mastectomy. This treatment therapy consists in the removal of the affected breast and until recently it was the only way in which this condition was treated. The rationale for mastectomy includes a 30% incidence of multicentric disease, a 40% prevalence of residual tumor at mastectomy following wide excision alone, and a 25% to 50% incidence of breast recurrence following limited surgery for palpable tumor, with 50% of those recurrences being invasive carcinoma.

Another treatment option consists of breast-conserving surgery along with radiation therapy. This type of treatment is usually considered in patients with non-palpable lesions and microcalcifications that may be seen on a mammography. Breast-conserving surgery, also referred to as lumpectomy, is considered nowadays a reasonable approach in the treatment of intraductal carcinoma. A lumpectomy consists in the removal of the tumor and a part of the surrounding tissues of the breast. Sometimes, lumpectomies are also referred to as partial mastectomies because they mainly consist in the removal of a part of the breast tissue. The National Surgical Adjuvant Breast and Bowel Project (NSABP) and the European Organization for Research and Treatment of Cancer (EORTC) have carried out clinical trials in order to establish whether lumpectomies and radiation therapy are more efficient in the management of intraductal carcinoma when comparing to the conservative method, mastectomies. Lumpectomies are commonly performed with radiation therapy to avoid noninvasive cancer from recurring or from developing into invasive cancers.

The clinical trials completed by the first organization (NSABP-B-17) concluded that radiation therapy given at the same time with breast-conservative surgery may decrease the recurrence rate with nearly a half, from 31% to 15%. Also, this type of treatment may reduce the occurrence of invasive cancer to nearly 8% from nearly 17% and recurrence rate of intraductal carcinoma to 8% from nearly 15%.

According to the results of the trials carried out by EORTC (EORTC-10853), radiation therapy has a consistent efficiency in treating intraductal carcinoma. This clinical trial showed that the recurrence rate of breast carcinoma may be reduced with 10%, from which invasive cancer recurrence was reduced with 5% and noninvasive cancer recurrence with 7%. This study also concluded that the risks of recurrence are greatly dependent on the age of the patient, the type of carcinoma (intermediate or poorly differentiated), the indeterminate margins of the tumor and the growth pattern.

Mastectomies however remain the main treatment option in patients with persistent microscopic involvement of margins after local excision or with a diagnosis of intraductal carcinoma and evidence of suspicious, diffuse microcalcifications.

A clinical study carried out by NSABP revealed that Taximofen may reduce the incidence of contralateral breast neoplasms (invasive and noninvasive) from 0.8% per year to 0.4% per year and the ipsilateral invasive breast cancer with 2% at 5 years.

Chemotherapy is thought to be inefficient in treating this type of noninvasive breast cancer and the role of hormonal therapy in this matter is currently being researched.

Epidemiology
Intraductal carcinoma can be easily detected with mammographies but is rarely palpable, so it can not generally be found during manual examination by patients or medical professionals. With the increasing use of screening mammography, noninvasive cancers are more frequently diagnosed and now constitute 15% to 20% of all breast cancers. By the time screening had become an important part in diagnosing early breast cancer, only in the United States there were 53,000 women diagnosed with this condition, in 2009. In the prescreening era, only 4,900 women were diagnosed with the same condition.

Because intraductal carcinoma is normally found early and it is treated or managed, it is difficult to say what occurs if left untreated. It appears that nearly 2% of the women who were diagnosed with this condition and treated between 1984 and 1989, died within 10 years.

The development of the condition varies greatly based on the treatment that is received. Radiation appears to play an important role in the further development of the condition and the complications likelihood. According to several studies, in 4% of the women treated with both lumpectomy and radiation therapy the condition may complicate into invasive cancer whereas invasive cancer is likely to occur in 14% of those who do not receive radiation.