Aromatase inhibitors versus tamoxifen in premenopausal women with oestrogen receptor-positive early-stage breast cancer treated with ovarian suppression: a patient-level meta-analysis of 7030 women from four randomised trials

BACKGROUND: For women with early-stage oestrogen receptor (ER)-positive breast cancer, adjuvant tamoxifen reduces 15-year breast cancer mortality by a third. Aromatase inhibitors are more effective than tamoxifen in postmenopausal women but are ineffective in premenopausal women when used without ovarian suppression. We aimed to investigate whether premenopausal women treated with ovarian suppression benefit from aromatase inhibitors. METHODS: We did a meta-analysis of individual patient data from randomised trials comparing aromatase inhibitors (anastrozole, exemestane, or letrozole) versus tamoxifen for 3 or 5 years in premenopausal women with ER-positive breast cancer receiving ovarian suppression (goserelin or triptorelin) or ablation. We collected data on baseline characteristics, dates and sites of any breast cancer recurrence or second primary cancer, and dates and causes of death. Primary outcomes were breast cancer recurrence (distant, locoregional, or contralateral), breast cancer mortality, death without recurrence, and all-cause mortality. As distant recurrence invariably results in death from breast cancer several years after the occurrence, whereas locoregional recurrence and new contralateral breast cancer are not usually fatal, the distant recurrence analysis is shown separately. Standard intention-to-treat log-rank analyses estimated first-event rate ratios (RR) and their confidence intervals (CIs). FINDINGS: We obtained data from all four identified trials (ABCSG XII, SOFT, TEXT, and HOBOE trials), which included 7030 women with ER-positive tumours enrolled between June 17, 1999, and Aug 4, 2015. Median follow-up was 8·0 years (IQR 6·1-9·3). The rate of breast cancer recurrence was lower for women allocated to an aromatase inhibitor than for women assigned to tamoxifen (RR 0·79, 95% CI 0·69-0·90, p=0·0005). The main benefit was seen in years 0-4 (RR 0·68, 99% CI 0·55-0·85; p<0·0001), the period when treatments differed, with a 3·2% (95% CI 1·8-4·5) absolute reduction in 5-year recurrence risk (6·9% vs 10·1%). There was no further benefit, or loss of benefit, in years 5-9 (RR 0·98, 99% CI 0·73-1·33, p=0·89) or beyond year 10. Distant recurrence was reduced with aromatase inhibitor (RR 0·83, 95% CI 0·71-0·97; p=0·018). No significant differences were observed between treatments for breast cancer mortality (RR 1·01, 95% CI 0·82-1·24; p=0·94), death without recurrence (1·30, 0·75-2·25; p=0·34), or all-cause mortality (1·04, 0·86-1·27; p=0·68). There were more bone fractures with aromatase inhibitor than with tamoxifen (227 [6·4%] of 3528 women allocated to an aromatase inhibitor vs 180 [5·1%] of 3502 women allocated to tamoxifen; RR 1·27 [95% CI 1·04-1·54]; p=0·017). Non-breast cancer deaths (30 [0·9%] vs 24 [0·7%]; 1·30 [0·75-2·25]; p=0·36) and endometrial cancer (seven [0·2%] vs 15 [0·3%]; 0·52 [0·22-1·23]; p=0·14) were rare. INTERPRETATION: Using an aromatase inhibitor rather than tamoxifen in premenopausal women receiving ovarian suppression reduces the risk of breast cancer recurrence. Longer follow-up is needed to assess any impact on breast cancer mortality. FUNDING: Cancer Research UK, UK Medical Research Council

Current misconception 3: that subgroup-specific trial mortality results often provide a good basis for individualising patient care

Misconceptions and ill-founded theories can arise in all areas of science. However, the apparent accessibility of many epidemiology findings and popular interest in the subject can lead to additional misunderstandings. The article below is the third in an occasional series of short editorials highlighting some current misinterpretations of epidemiological findings. Invited authors will be given wide scope in judging the prevalence of the misconception under discussion. We hope that this series will prove instructive to cancer researchers in other disciplines as well as to students of epidemiology. Adrian L Harris and Leo Kinle

Horizon scanning implanted biosensors in personalising breast cancer management:First pilot study of breast cancer patients views

Aims: This study aimed to explore breast cancer patients' understanding and acceptability of implanted biosensors (BS) within the primary tumour to personalise adjuvant radiotherapy, and to determine optimal design and number of BS, and evaluate potential clinical benefits as well as concerns about tolerance, toxicity, dwell time, and confidentiality of data. Patients and methods: A total of 32 patients treated by surgery (29 breast conserving, 3 mastectomy), postoperative radiotherapy and systemic therapy for early breast cancer, were recruited from a posttreatment radiotherapy clinic at a cancer centre. Patients participated in semistructured interviews. Interview transcripts were analysed using qualitative methods. Results: Participants were aged 39 to 87 years, with a median age of 62 years. Most (N = 23[72%]) were unfamiliar with biosensors. The majority (N = 29[90.6%]) were supportive of the technology's potential use in future breast cancer treatment and were willing to accept biosensors (N = 28[88%]) if they were endorsed by their breast cancer consultant. Only 3 patients expressed concerns, predominantly about uncertainties on their role in the diagnostic and treatment pathway. Patients were flexible about the size and shape of BS, but had a preference for small size (N = 28 [87.5%]). Most (N = 22[69%]) would accept implantation of more than 5 BS and were flexible (N = 22[69%]) about indefinite dwell time. Patients had a strong preference for wireless powering of the BS (N = 28[87.5%]). Few had concerns about loss of confidentiality of data collected. All patients considered biosensors to be potentially of important clinical benefit. Conclusions: While knowledge of biosensors was limited, patients were generally supportive of biosensors implanted within the primary tumour to collect data that might personalise and improve breast cancer radiotherapy in future

Radiotherapy after mastectomy for screen-detected ductal carcinoma in situ

Background. A role for radiotherapy after mastectomy for ductal carcinoma in situ (DCIS) is unclear. Using a prospective audit of DCIS detected through the NHS Breast Screening Programme we sought to determine a rationale for the use of postmastectomy radiotherapy for DCIS. Methods. Over a nine year period, from 9,972 patients with screen-detected DCIS and complete surgical, pathology, radiotherapy and follow up data, 2,944 women underwent mastectomy for DCIS of whom 33 (1.12%) received radiotherapy. Results. Use of post mastectomy radiotherapy was significantly associated with a close (<1mm) pathology margin, particularly (χ2(1) 95.81; p<0.00001), DCIS size (χ2 (3) 16.96; p<0.001) and the presence of microinvasion (χ2(1) 3.92; p<0.05). At median follow up 61 months, no woman who received radiotherapy had an ipsilateral further event, and only 1/33 women (3.0%) had a contralateral event. Of the women known not to have had radiotherapy post mastectomy, 45/2,894 (1.6%) had an ipsilateral further event and 83 (2.9%) had a contralateral event. Conclusion: For DCIS treated by mastectomy, a close (<1mm) margin, large tumour size and microinvasion, may merit radiotherapy to reduce ipsilateral recurrence