In women with breast cancers up to 5 cm across, the rates of long-term survival and metastasis-free survival are similar for mastectomy and breast-conserving treatment, according to a new study.
Previous studies have shown both approaches to be similar for women with tumors 2 cm or less across, for which breast-conserving treatment is widely used. But this is the first study to show equally good long-term results even when the width of a tumor is as much as 5 cm.
The results suggest that breast-conserving treatments, instead of mastectomy, could now be offered to most women with breast cancer, according to the researchers (J Natl Cancer Inst 2000;92:1143-1150).
Women who have tumors less than 2 cm across often undergo lumpectomy. For women with larger tumors, however, there was previously little evidence that breast-conserving surgery offered long-term benefits, according to the team of researchers led by Dr Harry Bartelink of the Netherlands Cancer Institute in Amsterdam. For these women, the recommended treatment is often modified radical mastectomy.
In the new study, researchers compared the survival of 868 women who were randomly assigned to undergo either lumpectomy or modified radical mastectomy to see whether women with tumors as wide as 5 cm could be treated effectively with breast-conserving surgery. Of these women, 696 had a tumor that measured 2.1 to 5 cm.
Ten years after surgery, no significant difference in survival was found in women with larger tumors, regardless of the type of surgery. Almost two thirds of the women in each group were still alive after 10 years. In addition, the cancer was no more likely to metastasize in women who had had a lumpectomy than in women who had had a mastectomy.
“This international trial has now shown that breast-conserving therapy results in a similar survival rate as mastectomy, even for patients with larger tumors,” Dr Bartelink said. “Breast-conserving therapy instead of mastectomy can, therefore, now be offered to the large majority of the breast cancer population as the majority of patients in the western world nowadays present with tumors smaller than 5 cm.”
Researchers, however, did find that about 20% of women in the lumpectomy group had a recurrence within 10 years, compared with about 12% in the mastectomy group, even if the recurrence did not affect 10-year survival. Researchers said that it was important for further studies to establish which subgroup of women is at greatest risk of recurrence.