“Behind a cancer-treatment firm’s rosy survival claims”

In a recent post on the blog, Statistical Modeling, Causal Inference, and Social Science, the following was reported:

Brett Keller points to a recent news article by Sharon Begley and Robin Respaut:

A lot of doctors, hospitals and other healthcare providers in the United States decline to treat people who can’t pay, or have inadequate insurance, among other reasons. What sets CTCA [Cancer Treatment Centers of America] apart is that rejecting certain patients and, even more, culling some of its patients from its survival data lets the company tout in ads and post on its website patient outcomes that look dramatically better than they would if the company treated all comers. These are the rosy survival numbers . . .

Details:

CTCA reports on its website that the percentage of its patients who are alive after six months, a year, 18 months and longer regularly tops national figures. For instance, 60 percent of its non-small-cell lung cancer patients are alive at six months, CTCA says, compared to 38 percent nationally. And 64 percent of its prostate cancer patients are alive at three years, versus 38 percent nationally.

Such claims are misleading, according to nine experts in cancer and medical statistics whom Reuters asked to review CTCA’s survival numbers and its statistical methodology.

The experts were unanimous that CTCA’s patients are different from the patients the company compares them to, in a way that skews their survival data. It has relatively few elderly patients, even though cancer is a disease of the aged. It has almost none who are uninsured or covered by Medicaid – patients who tend to die sooner if they develop cancer and who are comparatively numerous in national statistics. . . . Accepting only selected patients and calculating survival outcomes from only some of them “is a huge bias and gives an enormous advantage to CTCA,” said biostatistician Donald Berry . . .

What I really like about this article is how it combines quantitative information with qualitative interviews:

Carolyn Holmes, a former CTCA oncology information specialist in Tulsa, Oklahoma, said she and others routinely tried to turn away people who “were the wrong demographic” because they were less likely to have an insurance policy that CTCA preferred. Holmes said she would try to “let those people down easy.” . . .

The ads also challenge viewers to “compare our treatment results to national averages.” Doing so, on the company’s website, shows that CTCA’s reported survival outcomes regularly beat those averages.

Experts in medical data who reviewed CTCA’s claims for Reuters say those claims are suspect because of what they called deviations from best practices in statistics – in particular, comparing its carefully selected patients to those nationwide.

“It makes their data look better than it is,” said Robert Strawderman, professor and chairman of biostatistics at the University of Rochester. “So the comparisons used to suggest that CTCA has better survival rates are pretty meaningless.”