Cancer is the leading cause of death worldwide, with approximately 10 million deaths by 2022 [1]. Lung cancer is the most common form of cancer, followed by breast, colorectal, and prostate cancers. In Japan, approximately 380,000 people died in 2021 [2], mostly from lung, colorectal, and gastric cancers, and disease progression due to distant metastasis will be the main cause of death [3]. Hereditary cancer predisposition syndromes also account for 5–10% of all cancers [4].
The main treatments for cancer include surgery and radiation therapy, forms of local therapies, along with drug therapy, a form of systemic therapy. Depending on the stage of the disease, these treatments may be administered alone or in combination with the help of a multidisciplinary team. However, in cases of advanced recurrence and where the disease has spread throughout the body, drug therapy is the mainstay treatment used. Drug therapy for metastatic, recurrent, and advanced solid tumors rarely cure the disease; hence, improving treatment outcomes is one of the major challenges in cancer treatment. One approach to overcome this challenge is the development of molecular targeted therapy based on the molecular biology of cancer. Trastuzumab [5] and imatinib [6] were developed as specific inhibitors of tumor cell-causing driver mutations in early 2000s. Many driver mutations have been identified and molecular targeted drugs been developed since then. Furthermore, it has become clear that driver mutations, which were initially identified in each organ, are commonly found across organs [7]. This gave rise to a new treatment approach based on genetic mutations, or tumor-agnostic therapy, which led to the development of various therapeutic methods. However, to determine the indication for such molecularly targeted agents, it is necessary to perform a comprehensive analysis of gene mutation profiling extracted from tumor specimens of individual patients.
Given this background, in November 2017, comprehensive genome profiling (CGP) was adopted in the United States as a method to comprehensively collect mutation profiles in tumor cells of patients with advanced recurrent solid tumors [8]. American Society of Health-System Pharmacists has published a statement on the Pharmacist’s Role in Clinical Pharmacogenomics [9]. The statement recommends the choice of drug treatment based on the results of pharmacogenomic testing. In addition, it mentions the need for information provision and empowering patients to help them performing pharmacogenomic testing and understanding the results. However, these are views on genetic discrimination by health insurers or employers [10], it is unclear the association between patient health literacy and decision making. Furthermore, the role of pharmacists in the precision oncology, as a member of a multidisciplinary team, has reported [11], on the other hand, there are little involvement for patients who consider undergoing CGP.
Subsequently, in June 2019, CGP was covered by insurance in Japan. As of 2024, cancer genome medicine is available in 268 institutions, designated by the Ministry of Health, Labour, and Welfare; with their roles divided into core cancer genome hospitals, hub hospitals, and cooperative hospitals [12]. Facilities not designated by Ministry cannot provide cancer genomic medicine. Therefore, cancer genome medicine is not yet widely known in Japan. Since CGP is intended for patients with completed standard treatment and those with rare cancers, patients have high expectations of curing from the test. However, even if a genetic mutation is found, an effective drug may not be found. Furthermore, even if a candidate drug is found, it may not be approved and administered in Japan. Drugs under development, such as investigational drugs, may also act as candidate drugs. It takes several weeks from the time of application for the test until the availability of results. Considering the general condition of patients with completed standard treatment, it is highly unlikely that treatment will be available. Currently, it is estimated that 10–15% of patients who undergo CGP actually receive treatment [13]. Some patients may be hesitant to perform CGP for financial reasons as expensive cost at 560,000 yen (about 3,700 USD). In addition, the timing of CGP is important since insurance reimbursement allows only one CGP per cancer.
Information on precautions for such tests is provided on patient-oriented websites and other sources. However, it is unclear whether patients have access to this information or correctly understand it. In a public opinion survey on cancer control conducted by the Cabinet Office in 2019, most respondents (66.4%) cited doctors and nurses at hospitals and clinics as their source of information on treatment and hospitals when diagnosed with cancer, followed by the internet (36.9%) and family, friends, and acquaintances (33.8%) [14]. The most recent survey, conducted in 2023, had a different survey methodology due to the COVID-19 pandemic, and thus, it is difficult to compare it with past reports. Nevertheless, the latest report still had majority citing doctors and nurses at hospitals and clinics (56.2%), followed again by the internet (26.2%) and by family, friends, and acquaintances (36.7%) [14]. In Japan, medical institutions have established consultation support centers and other contact points. However, it is expected that many patients will not use such contact points, but rather, rely on the doctors and nurses involved in their visit as their source of information.
In Japan, pharmacists have many opportunities to work directly with cancer patients. Both inpatients and outpatients can have their chemotherapy explained by a pharmacist. There are also many opportunities for patients and pharmacists to get involved in community pharmacies. Some pharmacies have pharmacists with cancer-related training at the hospital. They can also serve as a resource in various places when patients want to learn about CGP. However, the timing and patient population that would benefit the most from their assistance remains unclear. Considering the time required for CGP and the patient's general condition, it is desirable to inform the patient about CGP at an early stage, then the patient fully understands the contents of CGP and decides promptly to undergo it. It is anticipated that being better informed about CGP before deciding to take the test can improve patient health literacy and empowering them to participate in decisions about their own treatment. Therefore, we decided to examine the impact on patient decision making if pharmacists provide information about CGP earlier than the end of standard treatment.
A known measure of patient decisional conflict is the Decisional Conflict Scale (DCS) developed by O'Connor et al [15]–[29]. The DCS consists of 16 items and is calculated on a score of 0–100, with smaller numbers indicating less conflict. In this study, DCS scores were measured before and after information was provided by the pharmacist in order to quantitatively evaluate changes in patient awareness. A secondary search was also conducted for factors that influence changes in attitudes.