Survival From Synchronous Bilateral Breast Cancer: The Experience of Surgeons Participating in the Breast Audit of the Society of Breast Surgeons of Australia and New Zealand

Abstract

Background: Previous studies generally indicate that synchronous bilateral breast cancers (SBBC) have an equivalent or moderately poorer survival compared with unilateral cases. The prognostic characteristics of SBBC would be relevant when planning adjuvant therapies and follow-up medical surveillance. The frequency of SBBC among early breast cancers in clinical settings in Australia and New Zealand was investigated, plus their prognostic significance, using the Breast Cancer Audit Database of the Society of Breast Surgeons of Australia and New Zealand, which covered an estimated 60% of early invasive lesions in those countries. Design: Rate ratios (95% confidence limits) of SBBC were investigated among 35,370 female breast cancer cases by age of woman, histology type, grade, tumour diameter, nodal status, lymphatic/vascular invasion and oestrogen receptor status. Univariate and multivariable disease-specific survival analyses were undertaken. Results: 2.3% of cases were found to be SBBC (i.e., diagnoses occurring within 3 months). The figure increased from 1.4% in women less than 40 years to 4.1% in those aged 80 years or more. Disease-specific survivals did not vary by SBBC status (p=0.206). After adjusting for age, histology type, diameter, grade, nodal status, lymphatic/vascular invasion, and oestrogen receptor status, the relative risk of breast cancer death for SBBC was 1.17 (95% CL: 0.91, 1.51). After adjusting for favourable prognostic factors more common in SBBC cases (i.e., histology type, grade, lymphatic/ vascular invasion, and oestrogen receptor status), the relative risk of breast cancer death for SBBC was 1.42 (95% CL: 1.10, 1.82). After adjusting for unfavourable prognostic factors more common in SBBC cases (i.e., older age and large tumour diameter), the relative risk of breast cancer death for SBBC was 0.98 (95% CL: 0.76, 1.26). Conclusions: Results confirm previous findings of an equivalent or moderately poorer survival for SBBC but indicate that SBBC status is likely to be an important prognostic indicator for some cases.

Influence of Mammographic Screening on Breast Cancer Incidence Trends in South Australia

“…While considerable emphasis has been place on evaluating breast cancer outcomes in Australia in recent publications (Roder et al, 2012;2013), less attention has been given to describing trends in breast cancer incidence in relation to screening and other associated risk factors. In this descriptive study we examine trends in BC incidence over the past three decades among SA women in the eligible age range for publicly funded mammography screening.…”

Synchronus Bilateral Breast Carcinoma (SBBC): A cytological diagnosis with review of literature

“…International evidence of the prognostic significance of SBBC is not consistent, although most studies suggest that these cancers have either an equiva lent or moderately poorer survival compared with unilateral cases. [5] Women diagnosed with unilateral cancer early in life and bilateral cancer within 5 years had a four times higher mortality rate than women with unilateral breast cancer. It is indeed notable that women with metachronous cancer diagnosed w ithin 5 years after unilateral cancer have a higher mortality rate than women with synchronous bilateral cancer.…”

“…In some reports a prevalence of lobular infiltrating breast carcinomas among bilateral cases is observed. 4 The increased proportion of SBBC among cases classified as lower grade and without lymphatic/vascular invasion may reflect le ss biologically aggressive tumour activity which may predispose to a longer pre-clinical phase, allowing more time for a second lesion to arise 5 . International evidence of the prognostic significance of SBBC is not consistent, although most studies suggest that these cancers have either an equiva lent or moderately poorer survival compared with unilateral cases.…”

“…It is indeed notable that women with metachronous cancer diagnosed w ithin 5 years after unilateral cancer have a higher mortality rate than women with synchronous bilateral cancer. [1,4,5] These differences may be attributed to variations in sample size, age, follow-up, and treatment regimes. Studies also found that comparision of women with unilateral disease, the prognostic outlook among women with metachronous disease deteriorated over time concomitantly with the decreasing incidence.…”

“…However, there are only limited data on incidence rates of synchronous and metachronous breast cancer, [2,3] results on temporal trends in incidence are conflicting, [4] and little is known about the prognostic outlook after treatment of a second primary cancer. [5,6] …”