The timing of systemic chemotherapy in patients with breast cancer does not affect patient survival or disease progression, say researchers reporting in the Feb. 2 issue of the Journal of the National Cancer Institute.

However, the study did find that breast cancer patients who receive systemic therapy and radiation therapy without surgery may be more likely to suffer cancer recurrence than women treated with chemotherapy after surgery.

The findings may be important, since a growing number of breast cancer patients are undergoing what's called '"neoadjuvant" chemotherapy -- drug therapy given in the weeks before surgery to help shrink tumor size and reduce the amount of tissue removed.

Researchers at the Ioannina School of Medicine, in Greece, analyzed data from nine studies of almost 4,000 breast cancer patients who'd received systemic therapy either before or after surgery and/or radiation treatment.

They found no difference between neoadjuvant and adjuvant (post-surgical) systemic therapy in terms of death, disease progression or distant recurrence of cancer. But the researchers did find that neoadjuvant therapy was associated with a 22 percent increased risk of local cancer recurrence compared with adjuvant therapy. The risk of recurrence was 53 percent greater when radiation therapy was used without surgery.

The study "demonstrates the equivalence of neoadjuvant and adjuvant treatments for breast cancer in terms of survival, disease progression," the study authors write in a prepared statement.

They add that neoadjuvant treatment may be associated with an increased risk of local tumor recurrence, however, "especially when primary systemic treatment is not accompanied by any surgical intervention."

"Consequently, we recommend avoiding the use of radiotherapy without any surgical treatment, even in the presence of an apparently good clinical response to neoadjuvant chemotherapy," the researchers conclude.

The U.S. National Cancer Institute has more about breast cancer treatment .