Nearly two-thirds of women 70 years or older with early-stage breast cancer continue to receive radiation treatment, even though a large, randomized clinical trial from 2004 showed that it did not reduce recurrence or prolong survival, a study found.
Researchers analyzed information from the Surveillance, Epidemiology and End Results database and reviewed changes in practice patterns before and after the 2004 publication of the Cancer and Leukemia Group B (CALGB) 9343 study, which was a randomized, controlled trial comparing lumpectomy with tamoxifen to lumpectomy, whole breast radiotherapy, and tamoxifen in women 70 years of age and older with early-stage, estrogen receptor-positive breast cancer.
Their findings were published early online Dec. 8 by CANCER.
The study included 40,583 women older than age 70 who were treated with lumpectomy from 2000 to 2009. From 2000 to 2004, before CALGB 9343 results appeared, 12,881 (68.6%) of patients received some form of radiation therapy. From 2005 to 2009, 13,440 (61.7%) of patients received radiation (P<0.001).
Researchers noted a change in the type of radiation therapy used. Beam radiotherapy declined from 66% in 2000 through 2004 to 54.2% in 2005 through 2009 (P<0.001). Concurrently, implant radiotherapy increased from 1.4% in 2000 through 2004 to 6.2% in 2005 through 2009 (P<0.001).
Radiotherapy declined across all age groups, tumor sizes, and tumor grades, and regardless of laterality (P<0.001 for all). Radiotherapy was administered less frequently in the older age groups, with approximately 30% of patients age 85 years or older receiving adjuvant radiotherapy compared with 75% of those patients aged 70 years to 74 years, but use decreased across all age groups after publication of the CALGB 9343 results.
There was a consistent decline in radiotherapy use across all tumor sizes. Use of radiotherapy also declined regardless of tumor grade when comparing patients treated during 2000 through 2004 compared with 2005 through 2009.
Publication of the CALGB 9343 trial results had only a very small impact on practice patterns, the researchers concluded, noting that there could be many reasons for this. The medical community may be concerned about the trial's relatively short duration of follow-up of 5 years, may react differently to withholding treatment compared with adding a new treatment, or may be incentivized to favor treatment over no treatment, particularly when either option is considered appropriate.
The authors wrote, “As physicians, the onus is on us to critically analyze data to shape our treatment recommendations for patients who seek our expert opinions, weighing the potential toxicities of treatment against clinical benefit.”