Nick Mulcahy

December 11, 2010

December 11, 2010 (San Antonio, Texas) — A cohort of women who underwent either mastectomy or breast conservation therapy (BCT) an average of 25 years ago now have "equivalent" overall survival, according to the authors of new study from a long-term National Cancer Institute trial.

The study of 237 women with stage 1 or 2 breast cancer was presented as a poster here at the 33rd Annual San Antonio Breast Cancer Symposium.

There was no statistically significant difference in overall survival in either group of the study, with 45.7% of patients alive in the mastectomy group and 38.0% alive in the BCT group (P = .43), according to the authors, led by N.L. Simonen, MD, from the National Cancer Institute in Bethesda Maryland.

However, a breast cancer surgeon from the Mayo Clinic said that the difference in survival — despite its lack of statistical importance — was concerning.

"You have to wonder whether this difference would become significant with a larger patient group," said Judy Boughey, MD, who is an associate professor of surgery at the Mayo Clinic's Rochester, Minnesota, campus.

Dr. Boughey found some comfort in other findings that compare the 2 surgical approaches. "The lack of a statistically significant difference in overall survival is in keeping with multiple previous studies," Dr. Boughey told Medscape Medical News. She attended the meeting and was asked to comment on the poster.

The findings on local recurrence did indicate an important difference between mastectomy and BCT.

Disease-free survival was significantly worse in patients randomly assigned to receive BCT compared with mastectomy (57% vs 82%; P < .001).

The additional treatment failures in the BCT group were primarily isolated ipsilateral breast tumor recurrences, the authors point out. They also note that these recurrences were salvaged by mastectomy. In all, 22.3% of BCT patients experienced such a recurrence. However, "those patients had no significant decrease in overall survival," say the authors.

Talk About Local Recurrence Rate, Especially With Young Women

What is missing from this study is the rate of local recurrence for the mastectomy patients. "We know that it is not zero," said Dr. Boughey, "because some breast tissue remains after mastectomy."

The new study is a reminder of the importance and challenges of counseling women with early breast cancer.

"A lot of women struggle with the choice of surgery," said Dr. Boughey. She reminds women that the overall survival is roughly the same, but the local recurrence rate is significantly higher if they keep the breast. "The risk of local failure exists and needs to be discussed."

For most women, Dr. Boughey recites a set of figures in her local recurrence talk. "I say to patients, if you get a lumpectomy, the risk for local recurrence at 10 years is 8% to 10%, and if you get a mastectomy, the risk is 2% to 4%."

However, when counseling young woman — that is, women younger than 40 years — the discussion about local recurrence is a bit different, and is especially important, Dr. Boughey said.

Dr. Boughey presented a poster at the symposium that indicated the risks for recurrence by decade of life. In the new retrospective study, 6.9% of 3075 patients who underwent breast-conserving surgery at the Mayo Clinic had a local recurrence at a median of 3.4 years.

The frequency of local recurrence by age group was:

  • Younger than 40 years: 11.9%

  • Aged 40 to 49 years: 5.9%

  • Aged 50 to 59 years: 5.9%

  • Aged 60 to 69 years: 7.6%

  • Aged 70 years or older: 6.4%

The fact that the youngest women had the highest rate of recurrence is important in part, said Dr. Boughey, because they have more aggressive tumors.

Young women need to know that their risk for local recurrence is higher than other age groups, she said.

The authors have disclosed no relevant financial relationships.

33rd Annual San Antonio Breast Cancer Symposium: Abstracts P4-10-01 and P4-10-02. Presented December 11, 2010.


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