Purpose: No standard therapies are available for the elderly with breast cancer and they tend to refuse to undergo treatment because of complications and shorter-life expectancy. In this study, feasible therapies were examined by evaluating cases we had experienced in our hospital.Methods: We report the results of a study on 12 seniors with breast cancer at age 80 and over in regard to preoperative examinations, operative procedures, histopathological examinations and adjuvant therapies.Results: Preoperative examinations were performed before mammography, ultrasonography (US), computed tomography, enhanced MRI of breast and fine-needle aspiration cytology. Though it was necessary to get their consent for biopsy under local anesthesia, we could perform US-guided core needle biopsy without their objections resistance. The first half of patients underwent mastectomy with lymph node dissection, whereas the second half had less invasive surgeries, such as partial resection of the breast and sentinel lymph node biopsy (SLNB). Histological checks revealed invasive carcinoma in 11 cases and the hormone receptor positive in 11 cases. Adjuvant therapy was performed with endocrine and fluoropyrimidine drugs orally administered. Irradiation to the remaining breast after partial resection was omitted by administering endocrine drugs.Conclusions: Elderly cases were apt to shun undergoing surgery, chemotherapy and radiation therapy, but they were treated with curative therapy by proposing less invasive partial resection, SLNB and adjuvant therapy. We should not omit lymph node dissection and adjuvant therapy just because the patients are elderly. However, less invasive and curative treatment based on the guideline should also be taken into full account.

PMDA, the Japanese regulatory agency, has worked for reinforcing and enhancing its post-marketing safety measures as stated in the second mid-term (FY 2009-2013) plan. MIHARI Project-Medical Information for Risk Assessment Initiative was started in FY 2009 to develop a new safety assessment system for post-marketing drugs using Japanese electronic healthcare data in PMDA. In the second mid-term, we examined characteristics of some electronic healthcare data available in Japan including, claims data, hospital information system data and Diagnosis Procedure Combination (DPC) data in order to make efficient use of those databases for the purpose of drug safety assessment. In addition, some pilot pharmacoepidemiological studies for risk assessment and drug utilization were conducted by use of these electronic healthcare data. Based on the accumulated findings, knowledge, and experiences from the pilot studies, we established the framework by FY 2013 to implement pharmacoepidemiology-based safety assessment in PMDA. In the third mid-term (FY 2014-2018), one of the important mission is to apply this framework into the current risk management process of drug safety. For that purpose, cooperation with other divisions of PMDA such as Office of Safety and Office of New Drug is a key. Simultaneously, we will work to establish an access to another database and novel pharmacoepidemiological methods using electronic healthcare data. A large-scale electronic health record database (MID-NET) as well as national claims database are expected to be an important database in the future activities of MIHARI Project. Furthermore, in April 2015, PMDA established new office focusing on Medical Informatics and Epidemiology for further promotion of electronic healthcare data utilization in Japan. In this article, we describe history and past activities of MIHARI Project followed by future challenges.

In these days, Japanese regulatory reform toward Real World Data (RWD) utilization in Pharmacovigilance (PV) has been carried out. One of the major changes is the amendment of “Ministerial Ordinance on Good Post-marketing Study Practice for Drugs” (No. 171, Ministry of Health, Labour and Welfare, dated December 20, 2004) implemented in April 2018. In this amendment, it clearly defines “Post-marketing database study” as one of post-marketing studies conducted by pharmaceutical companies. However, it does not mean that conventional post-marketing studies (e.g.；enrolling a few thousands patients in a single cohort study with primary data collection), can be simply replaced by the “Post-marketing database study” . The RWD utilization could be a trigger to accelerate efforts on pharmacovigilance in Japan for selecting the best method based on the issue to be addressed.

Objectives：MID-NET® has contributed to post-marketing drug safety assessment through various pharmacoepidemiological studies. To further promote an appropriate use of MID-NET®, this paper describes points to consider in conducting studies utilizing MID-NET® based on results from the two MID-NET® studies.Study design：Cohort study based on the secondary utilization of medical information databaseMethods：In the first study, the incidence of decreased liver function in patients prescribed drugs for pulmonary arterial hypertension was compared with the results from all-case surveillance (primary data collection). In the second study, real world utilization of biosimilar (hereinafter referred to as “BS”) was investigated to understand characteristics of BS prescription in clinical practice. Results：Although the incidence of decreased liver function varied depending on outcome definitions, the proportion on the definition identifying severe cases was similar to that in the all-case surveillance. It suggests that use of multiple outcomes including a definition taking into consideration a degree of severity is important to evaluate study results with robustness appropriately. In the second study, increased trends of BS prescriptions and various patterns of switching (from original biopharmaceutical to BS or from BS to original biopharmaceutical) depending on age and other factors were confirmed. It indicates that considerations about real world utilization of original biopharmaceutical and BS are necessary for future studies targeting BS.Conclusion：These studies further expanded an understanding and knowledge about data characteristics of MID-NET® and provide useful points to consider for promoting appropriate data utilization in future MID-NET® studies.