Women With Hereditary Breast Cancer Can Safely Have Radiation
Contralateral cancer -- which is when the disease occurs in the other breast -- was seen more frequently in the group with the BRCA breast cancer susceptibility gene. At their five-year follow-up, the researchers found that contralateral cancer had occurred in 15 of the women with BRCA genes, and only four without it.
The study does not address the question of whether contralateral breast cancer rates are higher because of the radiation therapy, says John Daniels, MD, who commented on the study for WebMD. "The authors discuss this and give their opinion, but it is just that," says Daniels, an associate professor of medicine/oncology at the University of Southern California School of Medicine, in Los Angeles.
Gaffney believes that the higher rate of contralateral breast cancer is not due to the radiation the women received, but because of the BRCA genes themselves. "Near as we know," he says, "It has nothing to do with the radiation."
But Daniels points out that this study also does not tell us what may happen further down the road. The patients were only followed for five years, and that may not be long enough to evaluate the potential consequences. "The study does not answer the question because of the brief follow-up," he says. "Most radiation-induced cancers do not [show up] ? clinically for 7-15 years in [children,] and likely later in adults."
Gaffney agrees, and says studies with longer follow-ups, using larger numbers of patients, are needed. But he points out that the researchers have followed many of the individual women who were involved in the study for longer than five years. "So as far as we know it at this point in time, there doesn't seem to be an increased rate of cancers," he says.
The researchers believe their finding can help early-stage breast cancer patients with these gene mutations and their doctors discuss treatment options. The study also provides some reassurance that radiation therapy is safe and appropriate for these women.
"We need better therapies to prevent cancer in the opposite breast," Gaffney says. "But I think that we can have some cautious optimism to proceed with breast conservation therapy in selected patients."