Access to breast‐conserving treatment: are surgeons responsible?

Patterns of Surgical Treatment for Women Diagnosed with Early Breast Cancer in Queensland

BACKGROUND

Australian women with early breast cancer should be given the choice between breast-conserving surgery (BCS) or mastectomy. This is the first Australian study to report on patterns of surgical care specifically for early breast cancer at a population level.

METHODS

Two population-based routine data collections were linked to obtain surgical treatment information for breast cancer cases diagnosed in 2004 in Queensland, from which we identified 1274 cases of early female breast cancer. Logistic regression was used to assess the likelihood of female breast cancer patients having mastectomy, BCS, and axillary node dissection, after adjusting for patient and hospital demographics, tumor size, and comorbidities.

RESULTS

Three-quarters (77%) of women had BCS, 29% had a mastectomy, and 86% had dissection of the axillary lymph nodes. The likelihood of women having mastectomy was higher among women living in rural areas, those treated in public hospitals, and women who had comorbidities of anemia or heart failure. In contrast, BCS was more likely for women treated in private hospitals or hospitals with high surgical caseload. Heart failure decreased the likelihood of BCS. Having an axillary node dissection was more likely among younger women and those treated in high caseload hospitals.

CONCLUSION

The observed differentials in surgical treatment for early breast cancer patients suggest that access issues may have contributed to the decision-making process. Understanding the reasons why women with early breast cancer choose a certain treatment strategy should be a focus of future research.

URBAN?RURAL DIFFERENCES IN THE MANAGEMENT OF SCREEN-DETECTED INVASIVE BREAST CANCER AND DUCTAL CARCINOMA IN SITU IN VICTORIA

BACKGROUND

At least one-third of primary breast cancers in Australia are discovered by population-based mammographic screening. The aim of this study was to determine whether there were any differences in the surgical treatment of women diagnosed with breast cancer by BreastScreen Victoria between urban and rural populations and to investigate temporal changes in their pattern of care.

METHODS

An analysis of women diagnosed with breast cancer (invasive and non-invasive) by BreastScreen Victoria from 1993 to 2000 was conducted. Descriptive analyses of the proportion of women undergoing each surgical treatment type over time were carried out. Logistic regression was used to assess the effect of urban-rural residence on each treatment outcome while accounting for possible confounding factors.

RESULTS

Rural women with invasive breast cancer were less likely to undergo breast-conserving surgery (BCS) compared with urban women (odds ratio, 0.42; 95% confidence interval, 0.35-0.50). The same was also true for rural women with ductal carcinoma in situ (odds ratio, 0.53; 95% confidence interval, 0.29-0.96). This difference was independent of patient and tumour characteristics, including tumour size, surgeon caseload, patient's age and socioeconomic status. It also persisted over time despite a steady overall increase in use of BCS for both invasive and non-invasive cancers over the study period.

CONCLUSIONS

Among Victorian women with screen-detected breast cancer, urban women consistently had higher rates of BCS compared with rural women despite increased overall adoption of BCS. Reasons for this disparity are still unclear and warrant further investigation.

Breast-Conserving Surgery Versus Mastectomy for Survival from Breast Cancer: the Western Australian Experience

BACKGROUND

The focus of this study was the relative survival rates of breast cancer patients whose treatment was breast-conserving surgery compared with that of mastectomy, adjusting for tumor size and nodal status because these factors may be intrinsically associated with mastectomy being the treatment of choice. Patient age was also accounted for in the model. By adjusting for these factors, we mitigate them as confounders of treatment choice in assessing effects on survival rates.

METHODS

Data were sourced from linked administrative data from the Western Australian Department of Health Record Linkage Unit. The data consisted of linked records containing the diagnosis, subsequent hospital admission, and death records of about 3000 women diagnosed with cancer in Western Australia between 1 January 1995 and 31 December 1999. Cox proportional hazards regression was used to investigate survival outcomes of breast-conserving surgery compared with that of mastectomy, adjusting for tumor size, nodal status, and subject age.

RESULTS

The hazard of death is reduced by a factor of about one half for subjects whose treatment was breast-conserving surgery over treatment by mastectomy. Furthermore, the hazard of death increases substantially for subjects with nodal involvement over subjects for whom there has been no identified spread to regional lymph nodes. Hazard of death increases as both age and tumor size increase.

CONCLUSIONS

Western Australian breast cancer patients treated with breast-conserving surgery have improved survival outcomes over those treated with mastectomy, after allowing for tumor size, patient age, and lymph node involvement.

Mastectomy or breast conserving surgery? Factors affecting type of surgical treatment for breast cancer--a classification tree approach

BACKGROUND

A critical choice facing breast cancer patients is which surgical treatment--mastectomy or breast conserving surgery (BCS)--is most appropriate. Several studies have investigated factors that impact the type of surgery chosen, identifying features such as place of residence, age at diagnosis, tumor size, socio-economic and racial/ethnic elements as relevant. Such assessment of "propensity" is important in understanding issues such as a reported under-utilisation of BCS among women for whom such treatment was not contraindicated. Using Western Australian (WA) data, we further examine the factors associated with the type of surgical treatment for breast cancer using a classification tree approach. This approach deals naturally with complicated interactions between factors, and so allows flexible and interpretable models for treatment choice to be built that add to the current understanding of this complex decision process.

METHODS

Data was extracted from the WA Cancer Registry on women diagnosed with breast cancer in WA from 1990 to 2000. Subjects' treatment preferences were predicted from covariates using both classification trees and logistic regression.

RESULTS

Tumor size was the primary determinant of patient choice, subjects with tumors smaller than 20 mm in diameter preferring BCS. For subjects with tumors greater than 20 mm in diameter factors such as patient age, nodal status, and tumor histology become relevant as predictors of patient choice.

CONCLUSION

Classification trees perform as well as logistic regression for predicting patient choice, but are much easier to interpret for clinical use. The selected tree can inform clinicians' advice to patients.