Editorials

Genetic tests for cancer therapy

Genetic tests to help cancer patients search for the best drugs and therapies for their treatment are now covered by the public health insurance system. The tests analyze the tumor tissues of the patients to detect gene mutations linked to cancer. With the health insurance coverage beginning this month, the cancer genome profiling systems — already introduced in the United States and Europe — are expected to take off in Japan, raising hopes for patients who have not responded to conventional cancer therapies and for those with conditions that have no effective treatment.

The systems, whose marketing in this country was approved by the Health, Labor and Welfare Ministry last December, are based on research showing that the same drugs and therapies may work in treating cancers that developed in different organs if the genes linked to the cancers have undergone the same types of mutation. The two systems — one developed by the National Cancer Center and health instrument-maker Sysmex Corp., and another developed by a U.S. firm and sold by Chugai Pharmaceutical Co. — are said to be capable of profiling over 100 types of cancer-related genes in one test.

With the health insurance coverage and a system capping patients’ share of the monthly medical bills in proportion to their income, the amount that the patients pay out of their pockets for the tests — each costing ¥560,000 — will be significantly reduced. The tests are expected to cover some 10,000 to 20,000 of the roughly 1 million people who are diagnosed with cancer in Japan annually.

Patients can provide tumor tissue specimens for testing at 11 hospitals that play a key role in cancer genomic medicine and 156 other hospitals across the country. Experts will assess drugs that can be effective in the treatment of patients, and each patient will be informed of the findings through the doctors in charge.

However, officials and experts call for caution against investing too much hope in the new tests. Currently it is said that the tests will be able to identify drugs and therapies that can possibly treat the cancer of only about 10 to 20 percent of the patients taking them. Some of the potential drugs found through the tests may not be covered by the health insurance or even approved for use in this country. Sufficient care needs to be taken to adequately inform the patients about the nature of the tests so they will not place excessive hope in them.

Meanwhile, the government, as a condition for public health insurance coverage of the tests, has created a plan to collect the genetic information and history of treatment of the cancer patients who take the tests in a National Cancer Center database with the patients’ consent in an effort to improve the accuracy of the tests and the effectiveness of the treatment. The anonymized data of genetic profiling of the patients will be made available to businesses and research institutions to promote the development of new cancer drugs and therapies.

That will mark a new phase in cancer treatment in which massive volumes of genetic information of individual patients — extremely private information — will be collected and analyzed not only for treating the patients themselves but for the research and development of new treatments. That should indeed be promoted on the condition that an environment will be established in which individual patients can provide their information without privacy concerns. Along with strict control of the patients’ genetic data, experts who support the choice of patients to consent to supplying their information or not need to be trained and adequately placed in relevant institutions.

Also among the key challenges in promoting cancer genetic medicine is how information that pertains to hereditary tumors should be handled. In addition to genetic mutations that relate to treatment of patients’ cancer, the genome profiling tests can detect abnormal genes linked to inherited cancers. Since the patients blood relatives may share the same genes, there is concern that such information could cause discrimination against family members.

According to a survey last year led by a professor at the University of Tokyo’s Institute of Medical Science, roughly half of the cancer patients and their family members polled expressed concern on whether the test results registered on the National Cancer Center database would be properly used, and 30 percent of the patients and 40 percent of their relatives expressed worry that test results finding genes linked to hereditary tumors could be used to their disadvantage.

The volume of genetic information to be used in medical treatments will no doubt increase not just in treating cancer but also other diseases — and not only in treating patients but also for the research and development of medical technologies. Along with measures to promote public understanding about genetic information, the introduction of rules to ensure the confidentiality of patients and prohibit all forms of unfair treatment based on genetic information need to be considered.