Complexity, Conflicts of Interest, and Cancer Doctors' Decisions About Chemotherapy

The New York Times recently reported on research suggesting the susceptibility of physicians to financial incentives. The research, and how it was reported, illustrate the complexity of untangling issues of conflict of interest affecting physicians and other health care decision makers.

To summarize, the Times reported on a study just published in Health Affairs that found "providers who were more generously reimbursed prescribed more costly chemotherapy regimens to metastatic breast, colorectal, and lung cancer patients." The Times noted that "unlike other physicians, cancer doctors can profit from the sale of chemotherapy drugs in a practice known as the chemotherapy concession." So, "while critics say this creates a potential conflict of interst among oncologists advising patients on treatment, the doctors have said that the profit is needed to pay the high cost of running their practices." The Times then quoted opposition to the notion that physicians' decisions were ruled by conflict of interest from an "executive" [actually, Interim Executive Vice President and CEO] of the American Society of Clinical Oncology, Dr Joseph S Bailes, who said words to the effect that "cancer doctor select treatments only on the basic of clinical evidence." The Times then interviewed the study's senior author, Professor Joseph P Newhouse of Harvard, who argued that "there is little evidence that one chemotherapy drug works better than another, [so] 'the physicians have more control over the agents chosen.'" Bailes countered that "there was clear clinical evidence about which drugs should be used even in advanced stages of the disease and that doctors recommend the most appropriate treatments." But Dr Craig C Earle, another study author, had the last word, arguing that "doctors, despite their insistence that their treatment decisions are based solely on what is best for the patient, are affected by payment policies and other financial influences, including gifts from drug companies...."

So what really is the message, that physicians make appropriate decisions based on the evidence, or that they are influenced by financial incentives, including gifts from drug companies? The Times reported the research results in the context of a tit-for-tat among the articles' authors and the ASCO CEO. By giving the authors more air time and the last word, the Times seemed to slightly favor their point of view.

To try to get a clearer fix on this, I did a quick review of the study itself. [Jacobson M et al. Does reimbursement influence chemotherapy treatment for cancer patients? Health Aff 2006; 25: 437-443. The link is here.]

This was a retrospective cohort study, apparently using physicians as units of analysis. Data was obtained from the Surveillance, Epidemiology and End Results (SEER) cancer registry, and Medicare administrative data. The costs of chemotherapy drugs physicians prescribed for patients with lung, breast, or gastrointestinal metastatic cancer were compared across physicians to the average chemotherapy reimbursements per drug received by the physicians, controlling for some characteristics of the patients seen by them in a fiendishly complex statistical analysis. Reimbursement was not correlated with the rate physicians employed chemotherapy, but was correlated with the Medicare spending per physician on chemotherapy.

So this was not an easy study for rapid critical review. My main concern is that the observational study design was susceptible to study biases. In particular, physicians who received higher reimbursement rates may also have had patient populations who differed, especially in terms of disease severity or patient preferences, from those who received lower rates. These differences, rather than differences in reimbursment rates, could have been the main reason they selected different treatments. The complexity of the analyses makes it harder to assess the study, especially given that their results were presented only in brief summary form.

Do cancer physicians make decisions about specific chemotherapy drugs for patients with metastatic disease based on the evidence and patient preferences, or on financial incentives? I am not sure that the study gives a clear answer (and was not designed to give an either or answer).

For what it's worth, my gut feeling is that most physicians try to make decisions based on evidence, on patients' characteristics and their preferences, but that it is hard not to be influenced by other factors, including financial incentives.

I should also note that the only financial incentives the study analyzed were Medicare reimbursement rates. Conflicts of interest, such as gifts by pharmaceutical firms to physicians, may affect their decisions, but this study was not designed to assess such conflicts. Hence Dr Earle's last comment may reflect his beliefs, and may be true, but does not follow from this single study's results.

Furthermore, just to further confuse the issues, it appears the study and its reporting may also have been affected by different kinds of conflicts of interest. The Health Affairs article does not mention any relevant conflicts of interests affecting the authors of the study. But Professor Newhouse, the senior author, has disclosed in other articles (for example, here) that he has a financial interest in Aetna, Inc, the large, for-profit managed care company (which, in turn, is likely interested in reducing physicians' utilization of expensive drugs). In fact, he is a member of Aetna's Board of Directors. (See Newhouse's most detailed biography on the Harvard web-site, confirmed on the Aetna web-site here.) Thus, he has a particularly strong conflict, since he has a fiduciary responsibility to protect the financial interests of Aetna Inc and its share-holders.

So maybe this is all another argument for what I have said before about conflicts of interest: I suggest developing a broad set of principles about conflicts of interest, and generally about business ethics in health care, focused on all transactions with outside organizations with their own vested interests or agendas. These principles should apply to all who make decisions in health care, physicians, other health care professionals, and leaders of health care organizations. The details of the implementation of these principles could vary, so as to apply to the setting and role of each individual.