Artimis - Feature Article : July 2000

Feature Article

Understanding Breast Cancer at its Earliest Stages: LCIS and DCIS

About 15% to 20% of breast cancers are considered pre-cancerous conditions or very early cancers. They are sometimes called "carcinoma in situ." There are two types of breast cancer in situ: lobular carcinoma in situ (LCIS), and ductal carcinoma in situ (DCIS), also known as intraductal carcinoma.

Each breast has 15 to 20 overlapping sections called lobes. Within each lobe are many smaller lobules, which end in dozens of tiny bulbs that can produce milk. Lobular carcinoma arises in these lobules.

The lobes, lobules, and bulbs within the breast are all linked by thin tubes called ducts. These ducts lead to the nipple in the center of a dark area of skin called the areola. Ductal carcinoma begins in the lining of these ducts.

LCIS and DCIS have not yet broken through these lobules and ducts to invade the surrounding tissue of the breast and become a true invasive breast cancer.

Lobular Carcinoma In Situ (LCIS)

Lobular carcinoma in situ (LCIS) is usually discovered by a biopsy done for another breast lump and is rarely seen on a woman's mammogram. LCIS is not cancer. It is a precancerous condition. A woman with LCIS is generally believed to have a 25% chance of developing breast cancer in either breast in the next 25 years.

Lobular carcinoma in situ is less common than DCIS, accounting for 13% of in situ breast cancers diagnosed in recent years. Between 1982 and 1988, increases in LCIS incidence rates were smaller than increases for DCIS, and since 1988, incidence rates of LCIS have remained level.

The treatment options for LCIS extend from mild to aggressive, and this broad range is a source of controversy. The options range from close monitoring with regular physical exams and annual mammograms (which are generally recommended), to total mastectomy-removal of both breasts. The use of tamoxifen, a hormone therapy that blocks the growth of some breast cancer cells, is a new option being explored for treating LCIS.

Ductal Carcinoma In Situ (DCIS)

Ductal carcinoma in-situ or DCIS, is a pre-cancerous condition in which abnormal cells are confined to the duct in the breast. These tumors have no evidence of microscopic invasion to the surrounding breast tissues. DCIS is usually indicated by tiny specks of calcium on a mammogram. Since DCIS is a pre-cancerous condition, it can become an invasive cancer if left untreated.

Most cases of DCIS are detectable only by mammography, and the large increases in DCIS incidence rates since 1982 are a direct result of better mammography screening practices. Although invasive breast cancer incidence rates have remained level since 1988, DCIS incidence rates have continued to increase. This, however, reflects a shift in the stage of the disease at diagnosis toward earlier, more curable cancers rather than a true increase in occurrence.

It is sometimes difficult to distinguish between DCIS and atypical hyperplasia, a benign breast condition consisting of more breast cells than is normal, some with atypical features. A second-opinion of the biopsy may therefore be appropriate. Accurate diagnosis is important because of the significant differences in treatment options.

Treatment for DCIS may be:

Surgery to remove the whole breast;
Surgery to remove only the tumor (lumpectomy) followed by radiation therapy;
Participation in a clinical trial of lumpectomy followed by radiation therapy and, perhaps, also treatment with the anti-estrogen drug tamoxifen.

There is disagreement among breast cancer experts about whether mastectomy is an appropriate treatment for DCIS that is localized to one area of the breast and that could be removed by a lumpectomy. Some feel breast removal is not justified for a diagnosis that may never lead to breast cancer. One study (National Surgical Breast and Bowel Project study B-17) showed that lumpectomy plus radiation was an acceptable alternative to mastectomy.

An ongoing national study being conducted by the National Cancer Institute is seeking to learn whether lumpectomy followed by radiation therapy and tamoxifen is more effective than lumpectomy followed only by radiation. Results are not yet available.

In the News

A number of promising studies are resulting in a better understanding of ductal carcinoma in situ and how best to treat the disease. For example:

An international consensus conference on ductal carcinoma in situ (DCIS) recently concluded that breast-conserving lumpectomy should be the first line of treatment for DCIS. The gathering of breast cancer experts, hosted by Dr. Gordon Schwarz of Jefferson Medical College in Philadelphia, said that many DCIS cases do not require mastectomy, and lumpectomy alone or lumpectomy in combination with radiation therapy may be preferred options. But he added that there is not uniform agreement whether women should receive radiation along with lumpectomy.
A similar finding was presented at the 17th annual Miami Breast Cancer Conference in March. Dr. Richard Margolese from the Jewish General Hospital in Montreal reviewed two DCIS treatment trials. The first (B-17) compared lumpectomy alone with lumpectomy and radiation, while the other (B-24) compared lumpectomy and radiation with a combination of lumpectomy, radiation and tamoxifen.
In the B-17 trial, 3.9 percent of the patients undergoing lumpectomy and radiation developed recurrent invasive breast cancer. In the B-24 trial, patients receiving lumpectomy, radiation and tamoxifen had a further reduction in the rate of recurrent invasive breast cancer to about 2 percent. Margolese suggested that these results indicate that some women may be receiving mastectomies when there are other, less invasive alternatives that provide similar outcomes.
In another study emphasizing the importance of tumor-free surgical margins, researchers from the University of California, Los Angeles, concluded that localized surgery with tumor-free margins plus radiation is equivalent to mastectomy in preventing local recurrence of DCIS.
According to an article by Dr. Elaine Weng and colleagues appearing in the journal Cancer, recurrence rates for 88 patients diagnosed with DCIS between 1985 and 1992 were 4 percent for those undergoing mastectomy, 25 percent for patients undergoing localized surgery, and 13 percent for patients undergoing localized surgery plus radiation. However, the recurrence rate for localized surgery plus radiation therapy was only 3.4 percent among patients whose surgical margins were tumor free.
An article appearing in the Journal of Clinical Oncology suggested that women younger than 45 years of age whose DCIS is treated with breast-conserving lumpectomy face higher rates of recurrence than older women. One reason for this, according to Dr. Frank Vicini and colleagues from William Beaumont Hospital in Royal Oak, Michigan, could be that surgical margins may not be wide enough to take out surrounding tissue that may contain cancerous cells. He added that in younger women, the cancer might be spread over a slightly larger area in the breast because the tissue is denser and has more ducts.

Sources:
The National Cancer Institute (www.nci.nih.gov)
The American Cancer Society (www.cancer.org)
The Susan G. Komen Breast Cancer Foundation (www.komen.org)
Reuters Medical News, Feb. 18, 2000
Journal of Clinical Oncology, January 2000; 18:296-306
Cancer, April 1, 2000; 88:1643-1649
Abstracts from the 17th annual Miami Breast Cancer Conference

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