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Lumpectomy With Radiation Does Not Increase Chances of Second Cancer In Early-Stage Breast Cancer Patients (dateline June 21, 2000)

Women with early- stage breast cancer who have had breast conserving surgery ( lumpectomy)   followed by radiation therapy are no more likely to develop a second cancer than women who have had a mastectomy (breast removal), according to a large study published in the Journal of Clinical Oncology.  This study confirms previous findings and should help eliminate worries that radiation therapy may increase the chances of developing a second cancer later in life.   

In the study, Yale researchers analyzed data from over 2000 breast cancer patients who underwent breast cancer treatment between 1970 and 1990.  They found that the risk of developing another breast tumor was approximately the same for all women (about 10% after 15 years), regardless of whether they had a mastectomy without radiation or a lumpectomy followed by radiation.  The risk of developing cancerous tumors elsewhere in the body (such as the lungs) was also the same among the two groups of women.  

The researchers did see an increased risk for a second cancer (most often, lung cancer) in women who continued to smoke during treatment.  The study also found a slight decrease in the risk for breast cancer in women who also used hormone therapy (such as the drug, tamoxifen), although the researchers say the difference observed in their study was not large enough to be statistically significant.  However, other large studies from the National Surgical Adjuvant Breast and Bowel Project (NSABP) have shown that tamoxifen does reduce the chances of breast cancer recurrence . Interestingly, researchers also found that chemotherapy after a lumpectomy did not increase the risk for a second cancer either, compared with mastectomy.

Common Surgical Options for Early Stage Breast Cancer
  • Mastectomy
  • Lumpectomy followed by six weeks of radiation therapy

Note: Each of these options may include lymph node removal (with either axillary node dissection or sentinel node biopsy).

Some earlier studies had shown that radiation therapy might increase the chances of developing breast cancer again years later, causing some women to choose to have a mastectomy rather than a lumpectomy followed by radiation.  However, researchers say that those studies involved women who had received an early form of radiation therapy after lumpectomy.  According to Marc Lippman, MD of Georgetown University’s Lombardi Cancer Center in Washington, DC, it is possible that lower-dose radiation and larger surgical margins (amount of cancer-free tissue a surgeon also removes along with a cancerous breast lump) that are now standard have reduced the chances of developing a second cancer in women who undergo radiation.

“With nearly 15 years median follow-up periods, these data should be reassuring to women who are considering lumpectomy and radiation therapy as a treatment option,” the researchers wrote in their report.  Several studies have already found that the survival rate for women who have a lumpectomy followed by radiation is equal to the survival rate after a mastectomy.

Often, women diagnosed with early-stage breast cancer have the option of having a lumpectomy followed by radiation therapy or a mastectomy.   Though one option may be more favorable than the other depending on a woman’s situation, this study confirms previous research that shows a lumpectomy with radiation therapy does not typically increase the chances for cancer later in life.  However, the researchers plan to continue monitoring the women in the study, warning that a 15 year observation period after breast cancer treatment may not be a long enough period to conclusively say that radiation therapy does not increase cancer risk during a lifetime.

Additional Resources and References