(RxWiki News) Cancer patients may assume that the less radiation they need, the better. But that might not be the case for some.
A new study from Canada found that, for some breast cancer patients, additional radiation treatment in surrounding areas may reduce the risk of cancer recurrence.
"Additional radiation to the surrounding lymph nodes reduced the risk of subsequent recurrence of breast cancer both locally, such as under the arm, and at sites distant from the breast, such as the bone, liver and lung," said lead study author Timothy J. Whelan, BM, of the Juravinski Cancer Centre in Ontario, in a press release. "The treatment did not increase survival, but follow-up is still relatively early."
According to Dr. Whelan and team, for most breast cancer patients, the typical treatment involves breast-conserving surgery (a procedure that removes only a part of the breast) and radiation to the whole breast.
These researchers explored whether additional radiation to surrounding areas — including the chest wall and lymph nodes in the underarm, collar bone and breast bone — could better help these patients.
Dr. Whelan and team looked at 1,832 US, Canadian and Australian women with breast cancers that were either present in the lymph nodes or that were determined to be at a high risk of spreading. These women were followed for an average of 9.5 years.
The lymph nodes are often the first place breast cancer spreads.
Half of these women received whole-breast radiation, while the other half received whole-breast radiation plus additional radiation to the surrounding areas.
Dr. Whelan and team found that 82 percent of the additional radiation group did not have any cancer recurrence.
These results were slightly better than the traditional treatment group, of whom 77 percent did not have any cancer recurrence.
When it came to overall survival, however, no significant differences were seen between the two treatment methods.
The women who received additional radiation were also more likely to experience certain side effects, including lung inflammation and lymphedema (swelling after lymph node damage).
In a related editorial, Harold J. Burstein, MD, PhD, of the Dana–Farber Cancer Institute in Boston, MA, and Monica Morrow, MD, of the Memorial Sloan Kettering Cancer Center in New York, wrote that a big issue is deciding which patients need these additional treatments.
"At the extremes, there is relatively little controversy," Drs. Burstein and Morrow wrote.
According to Drs. Burnstein and Morrow, it's fairly easy for doctors to identify patients who are at very high risk or very low risk of their cancers spreading.
However, it's more complicated for patients who fall in the middle.
Drs. Burnstein and Morrow recommended that doctors consider this additional lymph node radiation for patients who have one to three tumors in the lymph nodes along with additional signs of a cancer that is likely to spread.
This study was published online July 22 in The New England Journal of Medicine.
The Canadian Cancer Society Research Institute and the US National Cancer Institute funded this research.
Several study authors disclosed funding from pharmaceutical and medical technology companies, including Genomic Health, AstraZeneca and Novartis.