In general, variations of the health care system in different countries have derived a variety of scenarios leading to delay or refusal of therapy [11]. Medical treatments of breast cancer include surgery, chemotherapy, radiotherapy and hormone therapy. In addition to classical therapies, alternative or complementary therapies are also available for cancer patients. Previous fpsyg.2017.00209 studies have shown that patients may need to face many physical and psychological adaption after diagnosed with cancer, including uncertainty of disease progression and fear of death [12?4], change of body image [15, 16], lack of effective doctor-patient communication and information [17, 18], intolerable adverse effects of chemotherapy such as emesis and nausea, and SKF-96365 (hydrochloride) clinical trials deterioration in quality of life [19, 20]. These physical and psychological challenges and patients’ assessment of effectiveness and risk for cancer therapy [21, 22] may result in delay of medical treatment. The National Health Insurance (NHI) has been implemented since 1995 in Taiwan, and the coverage rate has reached 99 by the end of 2004[23]. Exemption from copayment on cancer therapy reduced the financial burden and increased the accessibility of healthcare for cancer patients [24?8]. Although the healthcare models for cancer treatment and financial burdens of cancer patients are varied in different countries, there are still breast cancer patients delaying or refusing therapy when cancer care is almost 100 accessible for patients in Taiwan. The aim of this study is to explore the characteristics of breast cancer patients who delayed or refused treatment in Taiwan. Our finding might point out some problems for cancer therapy in different health care systems, and could serve as a reference to Leupeptin (hemisulfate) supplement reduce the number of patients delaying or refusing treatments and to increase survival rate.PLOS ONE | DOI:10.1371/journal.pone.0131305 June 26,2 /Delayed or Refusal Therapy in Breast Cancer PatientsMethods Data sourceWe conducted a retrospective national population-based study from 2004 to 2010. This databases including the National Health Insurance Research Database (NHIRD), Taiwan Cancer Registry Database (CRD) and the Cause of Death Database. This study protocol was approved by the institutional review board of the China Medical University and wcs.1183 Hospital, Taiwan (IRB No: CMUH102-REC3-076). All patient identification information has been deleted prior to analysis, and personal privacy was under protection from using these data.Study populationThere were 45,911 patients of newly diagnosed breast cancer in Taiwan from 2004 to 2010 [29]. This study included 35,095 patients with cancer new diagnosis code C500-C509 (ICD9 code: 174?75, 217) from Taiwan Cancer Registry Database, thus the sampling has covered over 76.4 of the national breast cancer population. The patients were followed-up till December 31, 2012.Study variables and measurementsThe Cancer Registry Database in the Health Promotion Administration defines the aggressive treatment as treatment within 120 days of diagnosis. Since the staging might be different after 120 days after diagnosis, treatment of cancer with different stages does not belong to aggressive treatment anymore. Another study analyzing the cumulative treatment rate in one year showed that there was only slight increase in the proportion of patients who started treatment after four months of new diagnosis [30]. Consequently, this study defined “delay or refuse therapy” as no classical t.In general, variations of the health care system in different countries have derived a variety of scenarios leading to delay or refusal of therapy [11]. Medical treatments of breast cancer include surgery, chemotherapy, radiotherapy and hormone therapy. In addition to classical therapies, alternative or complementary therapies are also available for cancer patients. Previous fpsyg.2017.00209 studies have shown that patients may need to face many physical and psychological adaption after diagnosed with cancer, including uncertainty of disease progression and fear of death [12?4], change of body image [15, 16], lack of effective doctor-patient communication and information [17, 18], intolerable adverse effects of chemotherapy such as emesis and nausea, and deterioration in quality of life [19, 20]. These physical and psychological challenges and patients’ assessment of effectiveness and risk for cancer therapy [21, 22] may result in delay of medical treatment. The National Health Insurance (NHI) has been implemented since 1995 in Taiwan, and the coverage rate has reached 99 by the end of 2004[23]. Exemption from copayment on cancer therapy reduced the financial burden and increased the accessibility of healthcare for cancer patients [24?8]. Although the healthcare models for cancer treatment and financial burdens of cancer patients are varied in different countries, there are still breast cancer patients delaying or refusing therapy when cancer care is almost 100 accessible for patients in Taiwan. The aim of this study is to explore the characteristics of breast cancer patients who delayed or refused treatment in Taiwan. Our finding might point out some problems for cancer therapy in different health care systems, and could serve as a reference to reduce the number of patients delaying or refusing treatments and to increase survival rate.PLOS ONE | DOI:10.1371/journal.pone.0131305 June 26,2 /Delayed or Refusal Therapy in Breast Cancer PatientsMethods Data sourceWe conducted a retrospective national population-based study from 2004 to 2010. This databases including the National Health Insurance Research Database (NHIRD), Taiwan Cancer Registry Database (CRD) and the Cause of Death Database. This study protocol was approved by the institutional review board of the China Medical University and wcs.1183 Hospital, Taiwan (IRB No: CMUH102-REC3-076). All patient identification information has been deleted prior to analysis, and personal privacy was under protection from using these data.Study populationThere were 45,911 patients of newly diagnosed breast cancer in Taiwan from 2004 to 2010 [29]. This study included 35,095 patients with cancer new diagnosis code C500-C509 (ICD9 code: 174?75, 217) from Taiwan Cancer Registry Database, thus the sampling has covered over 76.4 of the national breast cancer population. The patients were followed-up till December 31, 2012.Study variables and measurementsThe Cancer Registry Database in the Health Promotion Administration defines the aggressive treatment as treatment within 120 days of diagnosis. Since the staging might be different after 120 days after diagnosis, treatment of cancer with different stages does not belong to aggressive treatment anymore. Another study analyzing the cumulative treatment rate in one year showed that there was only slight increase in the proportion of patients who started treatment after four months of new diagnosis [30]. Consequently, this study defined “delay or refuse therapy” as no classical t.