The analysis of the National Cancer Institute's cancer registry, published in the journal Cancer, also shows this suboptimal care can lead to worse outcomes.

Dr. Heather Taffet Gold of Weill Cornell Medical College in New York and colleagues said that among a nationally representative sample of nearly 8,000 breast cancer registry patients age 65 and older, almost 1,300 women experienced delayed radiotherapy and about 270 had incomplete radiotherapy. Those with stage 1 breast cancer had worse health outcomes associated with this less-than-ideal therapy, while those with a precancerous lesion called ductal carcinoma in situ were not as affected.

"Timeliness of post-surgical radiotherapy is important in reducing the risk of subsequent recurrence or new breast malignancies in patients with early breast cancer. Delaying treatment by eight weeks or more significantly increased the odds for recurrence," Gold said in a statement. "One possible reason for the delays is that the coordination of care can be a challenge as treatment is usually delivered by multiple providers from different specialties, including surgeons, radiation oncologists and medical oncologists."