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Key Words

Breast cancer, ductal carcinoma in situ (DCIS). (Definitions of many terms related to cancer can be found in the Cancer.gov Dictionary ³.)

Summary

Researchers from Harvard Medical School examined whether some women with ductal carcinoma in situ (DCIS), a precancerous condition of the breast, can safely be treated with surgery alone. They found that, in the absence of radiation therapy, the rate of local recurrence was unacceptably high.

Source

Journal of Clinical Oncology, published online Feb. 6, 2006; in print March 1, 2006 (see the journal abstract).
(J Clin Oncol. 2006 Feb 6; [Epub ahead of print])

Background

Ductal carcinoma in situ is a noninvasive, precancerous condition in which abnormal cells are found in the lining of a breast’s milk duct. In some cases, DCIS may become invasive cancer and spread outside the duct to other tissues, although it is not known how to predict which lesions will become invasive.

The combination of breast-conserving surgery and radiation therapy has become a widely accepted treatment for early-stage breast cancer and precancerous masses. However, because radiation therapy has toxic side effects and has not been shown to increase survival for women with DCIS, doctors would like to know whether some women with the condition can safely be treated with surgery alone.

Retrospective studies (which look at past data, such as medical records) have suggested that women with small, low-grade DCIS or who undergo surgery for DCIS that removes at least 1 centimeter of tissue around the tumor have low rates of local recurrence without adjuvant (additional) radiation therapy. The study from Harvard was a prospective clinical trial designed to more reliably test this treatment approach.

The Study

Women with low-grade DCIS whose tumors were no larger than 2.5 centimeters were eligible for the study. All patients had surgery to remove the tumor as well as 1 centimeter of normal tissue around the tumor site.

No patients in the study received radiation therapy, chemotherapy, or tamoxifen. All patients were scheduled to return for follow-up physical examinations and mammograms of the affected breast every six months for five years, then once a year after that. In additional, mammograms of the opposite breast were performed once a year.

The study’s lead author is Julia Wong, M.D., from the Dana-Farber Cancer Institute Department of Radiation Oncology in Boston, Mass.

Results

The researchers enrolled 158 women into the trial between May 1995 and July 2002. They intended to enroll more, but in July 2002 the trial was stopped because the rate of local recurrence exceeded the limit that had been deemed acceptable before the start of the trial. At the time the trial closed, the women had been followed for a median of 3.6 years.

Thirteen women experienced recurrence in the same breast; nine recurrences were DCIS and four were invasive cancer. This amounted to a cumulative five-year ipsilateral (same breast) recurrence rate of 12 percent.

In addition, eight women developed cancer in the opposite breast. No patients had metastatic disease at recurrence and, at last follow-up, all were free of further recurrence after additional treatment including surgery as well as radiation therapy, tamoxifen, or both..

Limitations

The authors mention several limitations to their study. First, the trial looked only at one group - patients who underwent surgery without radiation therapy. There was no way to compare these women to women who followed their surgery with radiation treatment.

In addition, because the trial was stopped early, the number of patients was too small to perform statistical analyses of subgroups, such as different age groups.

Comments

“Our prospective data suggest that a margin of 1 centimeter or greater, without radiation therapy, is not sufficient to provide low recurrence rates for small-, low- or intermediate-grade DCIS,” state the authors.

An accompanying editorial by Lawrence Solin, M.D., from the University of Pennsylvania, puts these results in historical context. “The importance of this study is that it is one of the first reported attempts to identify prospectively a low-risk subgroup of patients with DCIS who could be adequately treated with excision alone,” he writes.

Unfortunately, he continues, “For now and the near future, there is no well-defined, low-risk subgroup of patients with DCIS after excision who can reasonably forego adjuvant therapy.”

This view is shared by Jennifer Eng-Wong, M.D., a breast cancer specialist from the National Cancer Institute’s Center for Cancer Research, who states that, for patients with DCIS, there “is no population that we can identify up front to exclude radiation therapy at this point.”

Glossary Terms

An operation to remove the breast cancer but not the breast itself. Types of breast-conserving surgery include lumpectomy (removal of the lump), quadrantectomy (removal of one quarter, or quadrant, of the breast), and segmental mastectomy (removal of the cancer as well as some of the breast tissue around the tumor and the lining over the chest muscles below the tumor). Also called breast-sparing surgery.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.

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, DCIS 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. Also called ductal carcinoma in situ and intraductal carcinoma.

An x-ray of the breast.

A statistics term. The middle value in a set of measurements.

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-tuh-SEEZ).

In medicine, a study or clinical trial in which participants are identified and then followed forward in time.

A drug used to treat certain types of breast cancer in women and men. It is also used to prevent breast cancer in women who have had ductal carcinoma in situ (abnormal cells in the ducts of the breast) and in women who are at a high risk of developing breast cancer. Tamoxifen is also being studied in the treatment of other types of cancer. It blocks the effects of the hormone estrogen in the breast. Tamoxifen is a type of antiestrogen. Also called tamoxifen citrate.