Patterns of care study of breast-conserving therapy in Japan: comparison of the treatment process among 1995-1997, 1999-2001 and 2003-2005 surveys.

Abstract

Abstract Abstract #5142 Background and Purpose: The number of the patients with breast cancer who undergo breast-conserving therapy (BCT) has been rapidly growing in Japan. The Japanese Breast Cancer Society (JBCS) published its treatment guideline for BCT in 1999. The Japan Patterns of Care Study (JPCS) conducted three national surveys to identify changes associated with the treatment process of care for the patients undergoing BCT. The purpose of the study is to compare the results from the three national surveys, and evaluate the impact of the treatment guideline published meanwhile.
 Materials and Methods: The first national survey (JPCS1)on the process of BCT collected the data of 865 patients from 72 institutions who were treated between 1995 and 1997, and the second survey (JPCS1) collected the data of 746 patients from 66 institutions who were treated between 1999 and 2001 (JPCS2).The third survey (JPCS3) is on going and collected the data of 362 patients underwent BCT between 2003-2005 by now. The data was collected by external audit in which the patients' clinical records were retrospectively reviewed by visiting radiation oncologists. The patient characteristic,the extent of surgery, prescription and technique of radiation therapy were compared among three surveys.
 Results: The median patient age was significantly increased among three surveys and the median age was 49.2, 52.4 and 53.9 in JPCS1, JPCS2 and JPCS3, respectively (p<0.0001). Although there was a significant reduction in the extent of breast surgery and more patients received wide excision in JPCS2 compared with JPCS1, there was not significant change in JPCS3 compared with JPCS2. Sentinel lymph node biopsy (SLNB) was performed for 12.2% of the patients in the JPCS-2 and 29.8% in JPCS3. As concern with radiation planning, fixation system such as cast or shell was used on 74.9% of the patients in JPCS3 and the rate was significantly higher than those of the JPCS1(32.6%) and the JPCS2(52.9%). CT simulation was increasingly used for 67.3% of the JPCS3, although it was used for only 22.2% of the JPCS1 cases and 26.7% of the JPCS2. Breast irradiation was given predominantly with photons of ≤6MV in the JPCS-2 (91.3%) and the JPCS3 (97.2%) compared to JPCS-1( 73.3%) (p<0.001). Photon of ≥ 10MV without bolus, which is inappropriate for small breast, was used on up to 4.4% of the patients in the JPCS-1 , 2.0% in the JPCS-2.and 1.2% in the JPCS3. Matching of the dorsal margin of tangential fields was performed for 96.0% of the JPCS3 cases, although it was performed for only 78.8% of the JPCS 1 cases and 85.0% of the JPCS-2 cases.
 Conclusions: The three surveys demonstrated the rapid change of trend in the treatment process of BCT in Japan. The JBCS guideline for BCT seem to have great impact on the patterns of care in Japan, considering the rapid change in this interval. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5142.