ASOURCE Navi

New technologies are being introduced one after another in the medical field to deliver optimal treatment to each individual patient. One such technology that has rapidly gained attention in recent years is genetic testing. It is commonly referred to as "genetic testing," and many people have likely heard of it. By analyzing genetic information obtained from blood and tissues at the molecular level, the causes of disease and predisposition can be clarified, leading directly to diagnosis and treatment decisions. The range of applications is constantly expanding, including improving the accuracy of cancer treatment, prenatal diagnosis, and pharmacogenetic testing to predict drug efficacy and side effects. In this first installment, we will discuss the current state of genetic testing in medical institutions.

In the fields of cancer treatment and prenatal diagnosis, genetic testing is positioned as a test that directly links to diagnosis and treatment decisions, and is dramatically changing the quality of medical care. Such technology is essential to modern medicine as the foundation of personalized medicine, which enables treatment tailored to the characteristics of each patient.

Genetic testing performed at medical institutions has three main purposes. First, to diagnose hereditary diseases. Identifying the causes of familial and congenital diseases enables early diagnosis and preventative measures. Muscular dystrophy and hereditary breast and ovarian cancer syndromes have been linked to specific genetic mutations, and testing to confirm their presence or absence can provide important information to patients and their families. Second, to confirm the diagnosis of cancer and determine treatment options. Even cancers that originate in the same organ can vary significantly depending on the type of genetic mutation. Identifying the molecular profile of a tumor can optimize the selection of anticancer drugs and molecularly targeted drugs, maximizing treatment efficacy. Third, to optimize drug therapy through pharmacogenetic testing. Because drug metabolism varies depending on a patient's genetic background, pharmacogenetic testing can predict which drugs are most likely to be effective and which drugs are most likely to cause side effects, enabling safe and effective drug therapy.

One of the most common tests is cancer genome testing, which analyzes DNA from tumor tissue or blood to identify genetic mutations that cause cancer. Cancer genome testing includes "companion diagnostics," which examine a small number of genes to predict the effectiveness of specific therapeutic drugs, and "cancer gene panel testing," which analyzes dozens to hundreds of genes at once. Companion diagnostics are generally covered by insurance only once, and the cost varies depending on the number of diagnostic items and the testing method, but is generally around 25,000 to 180,000 yen (with a 10-30% co-payment from the patient). Cancer gene panel testing is available to patients who have completed standard treatment, is also covered by insurance only once, and costs approximately 560,000 yen (with a 10-30% co-payment from the patient). Based on these results, it may be possible to recommend the optimal treatment for each patient.

Non-invasive prenatal genetic testing (NIPT), used for prenatal diagnosis, is also an important test. It analyzes fetal DNA fragments from the pregnant woman's blood to detect numerical chromosomal abnormalities. It can be performed from the 10th week of pregnancy and is generally limited to pregnant women aged 35 or older. The test is limited to three conditions: trisomy 13 (Patau syndrome), trisomy 18 (Edwards syndrome), and trisomy 21 (Down syndrome). While the accuracy rate is extremely high at approximately 99%, a positive result requires a definitive diagnosis, such as an amniocentesis. Costs vary depending on the medical institution and the test, but are generally expected to be around 100,000 to 200,000 yen.

Another example is pharmacogenetic testing, which examines differences in genes that affect the effectiveness and side effects of drugs, with the aim of selecting the optimal drug and administration method for each patient, maximizing efficacy while minimizing the risk of side effects. Insurance coverage for some drugs, such as certain anticancer drugs, is increasing, and their use in clinical settings is becoming more widespread.

Genetic testing performed at medical institutions has several clear advantages. First, because it is performed under strict quality control, it is characterized by its high accuracy and reliability as a test that directly links to diagnosis and treatment. Second, some cancer genome tests and tests for hereditary diseases are covered by public health insurance if certain conditions are met, which may reduce the financial burden on patients. Furthermore, there is a system in place where test results are carefully explained by specialists and genetic counselors, which gives patients and their families peace of mind as they can choose a treatment plan with a full understanding.

At the same time, there are said to be many issues that need to be resolved. While the spread of personalized medicine has made it possible to select different treatments for each patient, the current medical system and human resource development have not kept up. The shortage of specialists is particularly serious given the increasing demand for genetic counseling. Furthermore, ethical issues such as the appropriateness of "choosing life" in prenatal testing and the protection of privacy regarding the handling of genetic information are important themes that require discussion throughout society. In addition, the high cost of testing and limited scope of insurance coverage are also problems, and creating an environment in which all patients can receive the necessary testing is a major challenge for the future.

Genetic testing conducted at medical institutions is used in a wide range of fields, from cancer treatment to prenatal diagnosis and drug therapy optimization. It has dramatically improved the quality of medical care and is becoming established as a highly accurate and reliable test. Genetic testing is an important technology that will shape the future of medicine and is essential for realizing medical care that is tailored to each individual patient. As testing becomes more widespread, it is expected that specialized personnel will be trained and ethical frameworks will be established, and genetic testing will become established as a new standard in medical care.