Misinformation can be dangerous for patients and the general public. Studies with sensationalized headlines extracted from biased data analyses that draw conclusions slanted toward a particular viewpoint can not only lead newly diagnosed cancer patients down a false path but also harm landmark clinical trials that reveal the essence of critical scientific issues.
An MD Anderson study, presented at the San Antonio Breast Cancer Symposium on Dec. 7, 2011, compared five-year results from a national Medicare Claims database of older women with breast cancer who underwent partial breast irradiation (PBI). This is not a clinical trial, and therefore, lacks strict selection criteria for PBI that are built into well-designed, prospective clinical trials.
There were key features of these breast cancer patients unavailable to the MD Anderson authors, including known risk factors for local recurrence, such as surgical margin status, estrogen receptors, treatment details and other known prognostic factors. The study is simply a look backward at a large group of unselected U.S. women, treated by antiquated technology (single-channel balloon catheters) with no quality control.
The authors also did not have access to the actual recurrence rates, so they took a flawed leap of faith that subsequent mastectomies must be because of cancer recurrence. We know that mastectomy rates do not equate to recurrence rates, because women have mastectomies for many reasons after treatment, such as a positive BRCA test for genetic susceptibility, a false-positive MRI or fear resulting from poorly conducted, biased articles, such as this study.
Even with these scientific flaws and the power of a huge mixed bag of patients from diverse areas of the U.S., the authors could only “discover” a tiny 1.8 percent difference in mastectomy rates between PBI and conventional whole breast irradiation (WBI). Similarly, the difference in side effects and complications (3 to 8 percent) may be accounted for by other patient factors, such as a smoking history, obesity or the overall health of the patient.
Although none of my patients have been swayed away from PBI or participation in the randomized clinical trial by the small differences seen in this MD Anderson study, it would be tragic if incorrect and dangerous headlines, such as “Study faults quick, partial-breast radiation; more women lose breasts later when cancer recurs,” (Washington Post, Dec. 6, 2011) slows the entry rate into NSABP B-39/RTOG 0413. This ongoing NCI-sponsored, prospective clinical trial is a scientifically pure randomized comparison of PBI to WBI, with careful selection criteria and quality control of treatment delivery, unlike the MD Anderson study.
Patients across the U.S. and the world are seeking a shorter, more convenient alternative to six to seven weeks of WBI. They are attracted to treating only the affected portion of the breast, thereby minimizing radiation exposure to the heart, lung and other uninvolved tissues. Many heroic women are signing up for the randomized clinical trial, and others choose PBI because they are not candidates for the trial. The weight of evidence supports PBI as a viable option for many women, and we anxiously await the final results from NSABP B-39/RTOG 0413.
Unfortunately, flawed research and sensationalized headlines could impede clinical and scientific progress. HI
Dr. Kuske pioneered the use of accelerated partial breast irradiation (APBI), and is currently a co-principal investigator of the ongoing Phase III clinical trial NSABP B-39, a 4,300 patient randomized trial scheduled to be completed at the end of 2012. He co-founded Arizona Breast Cancer Specialists, the first breast-only radiation oncology practice in the U.S.