Prognosis, treatment, and recurrence of breast cancer for women attending or not attending the Screening Mammography Program of British Columbia

Abstract

Breast cancer screening programs have been initiated in many countries in the past decade. To determine the impact of the Screening Mammography Program of British Columbia (SMPBC), disease and treatment outcomes for women with breast cancer diagnosed in BC between 1989 and 1996 were compared on the basis of attendance at the SMPBC. An SMPBC attender was a women diagnosed with breast cancer within three years of an SMPBC screen, regardless whether the cancer was detected as a result of that screen. Of the 13,636 women aged 40-89 years diagnosed with breast cancer in BC during the study period, 2,647 (19.4%) were SMPBC attenders. 73.5% of SMPBC attenders (N = 1,946) and 74.2% of non-attenders (N = 8,149) were referred to the BC Cancer Agency and had pathology, staging, treatment, and outcome information available. SMPBC attenders compared with non-attenders were more likely to have in situ disease alone, and those with invasive cancers had smaller tumors which were less likely to have grade III histology and less likely to have spread to axillary lymph nodes (all P < 0.001). SMPBC attenders were more likely to be treated with breast conservation and less likely to receive adjuvant chemotherapy or tamoxifen (P < 0.001). Log-rank tests showed local (P = 0.017), distant (P < 0.001), and overall (P < 0.001) disease-free survival were better for SMPBC attenders. These favorable surrogate endpoints suggest that the benefits of breast screening as demonstrated by randomized trials can be translated into community practice by an organized breast screening program.

Ten years of breast screening in the Screening Mammography Program of British Columbia, 1988–97

“…17 In addition, SMPBC attendees were more likely to have been treated with breast conserving surgery and less likely to have required chemotherapy or tamoxifen. 17 British Columbia has one of the highest incidence rates for breast cancer in Canada and yet it enjoys one of the lowest breast cancer mortality rates in the country.…”

Receipt of adjuvant systemic therapy among patients with high-risk breast cancer detected by mammography screening

“…In some North American studies [8][9][10], they were less likely to receive chemo/hormone therapy than symptomatic patients, although adjustment for prognostic factors was incomplete. In Europe, some papers reported the frequency of adjuvant systemic therapy in consecutive series of SD patients without symptomatic controls [11,12].…”

Proliferation marker securin identifies favourable outcome in invasive ductal breast cancer

“…The prognostic power of mitotic activity and traditional proliferation markers, such as standardised mitotic counts and Ki-67, is established in pathological practice. To benefit individual breast cancer patients, the potential of the traditional prognostic features could still be intensified by additional methods (Olivotto et al, 1999;Michels et al, 2003;Oestreicher et al, 2004;Warwick et al, 2004;Jalava et al, 2006).…”