The effect of mammographic screening on invasive breast cancer in Western Australia

Abstract

Objective To determine whether mammographic screening has affected the presentation of invasive breast cancer in Western Australia. Design Population‐based reviews of the presentation of all invasive breast cancers diagnosed in Western Australia in 1989 and 1994. Setting Western Australia (population 1.8 million). Active recruitment of women aged 50‐69 years for mammographie screening began in 1989. Main outcome measures Size and stage of invasive breast cancers at diagnosis. Results From 1989 to 1994, the age‐standardised incidence rose from 109 to 123 per 100000 woman‐years, based on 584 and 750 cases, respectively. The proportion of all invasive breast cancers detected as a result of a mammogram increased from 9.2% in 1989 to 34.5% in 1994. Among the cases where relevant information was recorded, the proportion of “impalpable” tumours increased from 7.7% in 1989 to 27.6% in 1994, and the average size of palpable tumours fell. There was an unexpected increase in the proportion of tumours that were negative on assays for oestrogen and progesterone receptors. Conclusions A relatively simple and inexpensive clinical review has boosted confidence that the outlay of public monies required to establish and conduct screening in Australia appears likely to yield the reductions in mortality from breast cancer that would be predicted on the basis of the earlier controlled trials of mammography.

Assessing the effectiveness of a mammography screening service

“…Our results indicate that BSWA detects tumours at an earlier stage. This extends the earlier work of Jamrozik et al 10 who compared the characteristics of all breast cancers who presented in WA in 1989 and 1994, and inferred that the introduction of BSWA resulted in earlier detection of invasive tumours. According to Klemi et al 11 and Ernst et al 12 if mammographically detected cases were simply at an earlier stage of tumour progression, the significant differences in prognostic factors would disappear after adjusting for tumour size.…”

Unequal Access To Breast‐Conserving Surgery In Western Australia 1982–;2000

“…Conservation of breast structures has led to less mental and physical health problems postsurgery, with less depression, improved body image and less concern with sexuality. These outcomes have been achieved with no reduction in cancer survival 3–;7 . Not all breast cancers are suitable for such limited surgery, and mastectomy is still appropriate in women with tumours that are extensive, have poorly defined histological margins, or in women who select mastectomy for personal reasons 3 .…”

Provider case volume and outcome in the evaluation and treatment of patients with mammogram‐detected breast carcinoma

“…The impact of surgery and emotional stress associated with the possibility of a diagnosis of breast carcinoma may undermine support for mammography screening 35. Assuming that 40% of breast carcinomas in the United States are diagnosed by mammography, positive biopsy rates of 15% versus 25% nationally would increase the annual number of benign breast biopsies by 187,000 (from 280,000 benign breast biopsies to 467,000 benign breast biopsies) 10, 36–38. There are few efforts to address this quality issue.…”