The government in principle bans combining medical treatments that are covered by public health insurance with treatments that are not. Patients usually pay 30 percent of medical fees for treatments covered by public insurance. But if they receive different treatments concurrently, they must pay the full amount for all drugs and therapies.

In November 2007, the Tokyo District Court ruled in favor of a kidney cancer patient who filed a lawsuit against the state after he had to pay the full amount for his treatments — which involved an insured interferon treatment and a noninsured treatment using his own lymphocytes. But the Tokyo High Court on Sept. 29 reversed the earlier decision, thus upholding the ban.

The health ministry and the Japan Medical Association oppose mixed treatment on the grounds that doctors may see it as an opportunity to test new treatments whose safety has not been proven or whose efficacy has not been established; that patients will bear a large financial burden since new treatments tend to be expensive; that inequality will arise in medical services since low-income individuals will not be able to afford these additional expenses; and that the public health insurance system could collapse if many people who want to receive new treatments buy private health insurance policies.