LAUSR

e18008 Background: Chemo/radiotherapy for breast cancer patients does not require hospitalization in most cases. We investigated the relationship between the proportion of hospitalization for chemo/radiotherapy over total hospitalization among breast cancer cases (inpatient chemo/radiotherapy rate) and the number of hospital beds per capita using the national database in Japan. Methods: We conducted a retrospective observational study using Diagnosis Procedure Combination (DPC) database and National survey database from April 2012 to March 2016. We aggregated hospital-level data into prefecture-level data and classified the 47 prefectures into quintiles based on the number of hospital beds per capita (9-10 prefectures per quintile). Generalized estimating equations (GEE) were used for examining the relationship between the number of hospital beds and inpatient chemo/radiotherapy rate (discretionary setting) or the number of surgical operations (imperative setting). Results: Over the five-year study period, there were 561,165 records for hospitalization for breast cancer cases. The inpatient chemo/radiotherapy rate at each prefecture varied, ranging from 2.6% to 61.8% in 2016. The inpatient chemo/radiotherapy rate was significantly higher in the second highest and the highest quintile by 11.7% (95% CI 4.0-19.5%, P = 0.003) and 9.6% (95% CI 1.8-17.4%, P = 0.015), respectively, compared with the middle quintile. There was no significant difference between the lowest, second lowest and middle quintile. On the contrary, there was no significant difference in the number of surgical operations for breast cancer per capita between each quintile and middle quintile. Conclusions: We found that higher hospital beds associated with more chemo/radiotherapy in the inpatient setting. This study is a starting point for the discussion on the employment support for people with cancer and the economical utilization of the limited medical resource in the oncology field. The further studies evaluating the association between health resource and the other type of procedures are warranted.