Abstract P2-09-03: Long-term comparison of anastrozole versus tamoxifen: Results from LATTE/ATAC

Background: Previous reports from the Anastrozole Tamoxifen Alone or in Combination (ATAC) trial have shown significantly prolonged disease-free survival, lower rates of recurrence and distant recurrence, and reduced contralateral breast cancer in patients treated with anastrozole compared to tamoxifen (Cuzick et al., Lancet, 2010). Here, we compare the long-term effects of anastrozole versus tamoxifen in patients randomised to either monotherapy arm in the ATAC trial.

Methods: Postmenopausal women with hormone receptor positive breast cancer randomised to anastrozole or tamoxifen in the main ATAC trial were eligible for the LATTE observational study. The primary objective was to compare the long-term effects of tamoxifen and anastrozole on time to recurrence and death beyond 10 years after randomisation. Secondary objectives included time to distant recurrence, cancer-specific survival, new breast primaries, other cancers, fractures, and cardiac/cerebrovascular events. Cox proportional hazard methods were used to compute hazard ratios (95% CI) for recurrence from the time of last publication (10 years median follow-up).

Results: 2452 women from 11 countries were entered into the LATTE study. 40 women withdrew consent and 759 women died or had a recurrence within 10 years, which left 1653 women for analysis (838 anastrozole vs. 815 tamoxifen). A total of 118 breast events (69 anastrozole (8.2%) vs. 49 tamoxifen (6.0%)) were reported. No significant difference between the two treatment arms were observed (HR=1.36 (0.94-1.97), P=0.098). 57 women had a distant recurrence (33 (3.9%) vs. 24 (2.9%)), 41 reported a loco-regional recurrence (23 (2.7%) vs. 18 (2.2%)), and 26 contra-lateral breast cancer were recorded (17 (2.0%) vs. 9 (1.1%)). None of the treatment comparisons were statistically significant. 305 deaths were recorded (147 (17.5%) vs. 158 (19.4%)), of which 31 were due to breast cancer. Significantly fewer gynaecological cancers were recorded with anastrozole (7 vs. 16; OR=0.42 (0.15-1.09), P=0.05), but overall the effect on other cancers was not significant (54 (6.4%) vs. 64 (7.9%). Fractures, cardiovascular, and cerebrovascular events were evenly distributed between the treatment arms.

Conclusions: Although anastrozole was associated with significant fewer recurrences compared to tamoxifen in the first 10 years of follow-up, in this analysis, with limited number of patients, we could not find a significant difference between the two treatment arms.

Citation Format: Cuzick J, Sestak I, Bianco A, Strobbe L, Bergh J, Hanusch C, Neven P, Dowsett M, Forbes JF, Buzdar A, Smith R, Howell A. Long-term comparison of anastrozole versus tamoxifen: Results from LATTE/ATAC [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-09-03.

Abstract S5-03: Menopausal symptoms as predictors of long-term adherence in the International breast cancer intervention study (IBIS-1)

Tamoxifen reduces the risk of breast cancer among women at increased risk of the disease. The effectiveness of the drug is dependent on its appropriate use for the duration of therapy. Adherence for the full course of preventive therapy ranges from 60-80%. Early discontinuation is largely attributed to side-effects, but no studies have validated this using 5-year follow-up data. We assessed the role of menopausal side-effects on long-term adherence in the UK arm of the International Breast Cancer Intervention Study (IBIS-1).

In the IBIS-1 trial, 4279 women in the UK were randomised to placebo vs. tamoxifen (20mg/day). A total of 292 were excluded (breast cancer, death, or other cancer), leaving 3987 to be included in the analysis (2000 placebo arm, 1987 tamoxifen arm). Adherence was calculated using data from six monthly clinical visits during the trial. Adherence (<4.5 years, ≥4.5 years) was calculated using the Kaplan-Meier estimator. Our main objective was to investigate the effect of menopausal side effects experienced during the first six months on adherence overall and by treatment arm. All analyses were adjusted for age, Tyrer-Cuzick risk, smoking, hormone replacement therapy use, menopausal status, baseline symptoms, and treatment.

Overall, 66.8% of women were adherent for at least 4.5 years (placebo: 71.5% vs. tamoxifen: 62.1%, p<0.001). Highest drop-out rates were found within the first 12 months of follow-up, and a significant difference in adherence between treatment arms was observed thereafter (p<0.05). A low number of women experienced nausea/vomiting (5.0%) and headaches (7.0%), while higher proportions reported gynaecological symptoms (irregular bleeding/vaginal dryness/vaginal discharge, 13.8%) and hot flushes (31.5%). Women reporting nausea/vomiting (OR=1.82 [95% CI, 1.35-2.47], p<0.001) and headaches (OR=1.41 [1.08-1.84], p=0.01) were significantly more likely to be non-adherent at 4.5 years. Long-term adherence was not significantly affected for those who reported hot flushes (OR=1.10 [0.94-1.30], p=0.2) or gynaecological symptoms (OR=1.18 [0.99-1.41], p=0.07) compared with their counterparts. Nausea/vomiting was significantly associated with non-adherence in both the placebo (OR=1.82 [1.16-2.87], p=0.009) and tamoxifen (OR=1.84 [1.22-2.76], p=0.004) arms. Headaches were associated with non-adherence in the placebo arm (OR=1.70 [1.16-2.50], p=0.006), while gynaecological symptoms were only significant in the tamoxifen arm (OR=1.30 [1.05-1.63], p=0.02). The majority of side effects were of mild or moderate severity and we observed significant trends for lower adherence with increasing severity for all symptoms (p<0.05 to <0.001).

In the IBIS-I trial, we observed a significant effect of common menopausal symptoms on long-term adherence. These effects were largely similar between tamoxifen and placebo arms, suggesting women are attributing age-related menopausal symptoms to preventive therapy. To ensure women experience the full benefit of preventive therapy, interventions are required to support the management of menopausal symptoms and to promote adherence. The higher rate of drop-out in the early months of the trial suggests early intervention may be an effective way to promote long-term adherence.

Citation Format: Smith SG, Sestak I, Forbes J, Howell A, Cuzick JJ. Menopausal symptoms as predictors of long-term adherence in the International breast cancer intervention study (IBIS-1) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr S5-03.

Risk algorithms that include pathology adjustment for HER2 amplification need to make further downward adjustments in likelihood scores

To assess the need for adjustment in the likelihood of germline BRCA1/2 mutations in women with HER2+ breast cancers. We analysed primary mutation screens on women with breast cancer with unequivocal HER2 overexpression and assessed the likelihood of BRCA1/BRCA2 mutations by age, oestrogen receptor status and Manchester score. Of 1111 primary BRCA screens with confirmed HER2 status only 4/161 (2.5%) of women with HER2 amplification had a BRCA1 mutation identified and 5/161 (3.1%) a BRCA2 mutation. The pathology adjusted Manchester score between 10 and 19% and 20%+ thresholds resulted in a detection rate of only 6.5 and 15% respectively. BOADICEA examples appeared to make even less downward adjustment. There is a very low detection rate of BRCA1 and BRCA2 mutations in women with HER2 amplified breast cancers. The Manchester score and BOADICEA do not make sufficient downward adjustment for HER2 amplification. For unaffected women, assessment of breast cancer risk and BRCA1/2 probability should take into account the pathology of the most relevant close relative. Unaffected women undergoing mutation testing for BRCA1/2 should be advised that there is limited reassurance from a negative test result if their close relative had a HER2+ breast cancer.

The burden of bone, native joint and soft tissue infections on orthopaedic emergency referrals in a city hospital

Introduction Bone, native joint and soft tissue infections are frequently referred to orthopaedic units although their volume as a proportion of the total emergency workload has not been reported previously. Geographic and socioeconomic variation may influence their presentation. The aim of this study was to quantify the burden of such infections on the orthopaedic department in an inner city hospital, determine patient demographics and associated risk factors, and review our current utilisation of specialist services. Methods All cases involving bone, native joint and soft tissue infections admitted under or referred to the orthopaedic team throughout 2012 were reviewed retrospectively. Prosthetic joint infections were excluded. Results Almost 15% of emergency admissions and referrals were associated with bone, native joint or soft tissue infection or suspected infection. The cohort consisted of 169 patients with a mean age of 43 years (range: 1-91 years). The most common diagnosis was cellulitis/other soft tissue infection and the mean length of stay was 13 days. Two-thirds of patients (n=112, 66%) underwent an operation. Fifteen per cent of patients were carrying at least one blood borne virus, eleven per cent were alcohol dependent, fifteen per cent were using or had been using intravenous drugs and nine per cent were homeless or vulnerably housed. Conclusions This study has shown that a significant number of patients are admitted for orthopaedic care as a result of infection. These patients are relatively young, with multiple complex medical and social co-morbidities, and a long length of stay.

Intensive breast screening in BRCA2 mutation carriers is associated with reduced breast cancer specific and all cause mortality

Background

The addition of annual MRI screening to mammography has heightened optimism that intensive screening along with improved treatments may substantially improve life expectancy of women at high risk of breast cancer. However, survival data from BRCA2 mutation carriers undergoing intensive combined breast screening are scarce.

Methods

We have collated the results of screening with either annual mammography or mammography with MRI in female BRCA2 mutation carriers in Manchester and Oslo and use a Manchester control group of BRCA2 mutation carriers who had their first breast cancer diagnosed without intensive screening.

Results

Eighty-seven BRCA2 mutation carriers had undergone combined (n = 34) or mammography (n = 53) screening compared to 274 without such intensive screening. Ten year breast cancer specific survival was 100 % in the combined group (95 % CI 82.5–100 %) and 85.5 % (95 % CI 72.6–98.4 %) in the mammography group compared to 74.6 % (95 % CI 66.6–82.6 %) in the control group. Better survival was driven by lymph node status (negative in 67 % of screened vs 39 % of unscreened women; p < 0.001) and a significantly greater proportion of intensively screened women had invasive breast cancers <2 cm at diagnosis (74.6 % vs 50.4 %; p = 0.002).

Conclusion

Intensive combined breast cancer screening with annual MRI and mammography appears to improve survival from breast cancer in BRCA2 mutation carriers. Data from larger groups are required to confirm the effectiveness of combined screening in BRCA2 carriers.

Abstract S6-03: Anastrozole versus tamoxifen for the prevention of loco-regional and contralateral breast cancer in postmenopausal women with locally excised ductal carcinoma in-situ (IBIS-II DCIS)

Background: Third generation aromatase inhibitors are a more effective treatment option than tamoxifen for hormone receptor positive invasive breast cancer in postmenopausal women. However, it is not known whether anastrozole is more effective than tamoxifen in preventing the recurrence of breast cancer in women with hormone receptor (HR) positive ductal carcinoma in situ (DCIS). Here, we compare the efficacy of anastrozole versus tamoxifen in postmenopausal women with HR positive DCIS.

Methods: A multi-centre randomised placebo-controlled trial of 1mg/day anastrozole (oral) vs. 20mg/day tamoxifen (oral) for five years was conducted in 2980 postmenopausal women with locally excised HR positive DCIS. The primary endpoint was to determine if anastrozole is at least as effective as tamoxifen in loco-regional control and prevention of contralateral disease. Secondary endpoints included breast cancer mortality, other cancers, cardiovascular disease, fractures, adverse events and non-breast cancer deaths. All analyses were done on an intention-to-treat basis and Cox proportional hazard were used to compute hazard ratios and corresponding confidence intervals for recurrence.

Results: Between 2003 and 2012, a total of 2980 postmenopausal women were recruited into the IBIS-II DCIS trial. 1471 women were randomly assigned to receive anastrozole and 1509 women tamoxifen. Median follow-up for this first analysis is 6.8 years and 131 breast cancer recurrences have been recorded. Median age was 60.3 years (56.1-64.6), median BMI was 26.7 (23.6-30.7), and 45.6% of women had used hormone replacement therapy (HRT) before joining the trial. Of the 131 women with recurrent disease, 77 had a loco-regional recurrence and 51 reported contralateral disease. A total of 61 deaths were recorded. We will present a comprehensive analysis of the efficacy of anastrozole and tamoxifen for preventing loco-regional/contralateral breast cancer and major adverse events by intention to treat (ITT).

Conclusions: To follow.

Citation Format: Cuzick J, Forbes JF, Sestak I, Howell A, Bonanni B, Bundred N, Levy C, von Minckwitz G, Eiermann W, Neven P, Stierer M, Holcombe C, Coleman RE, Jones LJ, Ellis I. Anastrozole versus tamoxifen for the prevention of loco-regional and contralateral breast cancer in postmenopausal women with locally excised ductal carcinoma in-situ (IBIS-II DCIS). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S6-03.

A phase II trial of low-dose estradiol in postmenopausal women with advanced breast cancer and acquired resistance to aromatase inhibition

BACKGROUND

High-dose oestrogen (HDE) is effective but toxic in postmenopausal women with advanced breast cancer (ABC). Prolonged oestrogen deprivation sensitises BC cell lines to estrogen and we hypothesised that third-generation aromatase inhibitors (AIs) would sensitise BCs to low-dose estradiol (LDE).

METHODS

A single-arm phase II study of LDE (2 mg estradiol valerate daily) in postmenopausal women with estrogen receptor-positive (ER+) ABC. The primary end-point was clinical benefit (CB) rate. If LDE was ineffective, HDE was offered. If LDE was effective, retreatment with the pre-LDE AI was offered on progression.

RESULTS

Twenty-one patients were recruited before the trial was closed early due to slow accrual; 19 were assessable for efficacy and toxicity. CB was seen in 5 in 19 patients (26%; 95% confidence interval 9.1-51.2%), all with prolonged SD (median duration 16.8 months; range 11.0-29.6). Treatment was discontinued for toxicity in 4 in 19 patients (21%) and 8 in 11 women without hysterectomy experienced vaginal bleeding (VB). After primary LDE failure, three patients received HDE and one achieved a partial response (PR). Following CB on LDE, four patients restarted pre-LDE AI and three achieved CB including one PR. Those with CB to LDE had a significantly longer duration of first-line endocrine therapy for ABC than those without (54.9 versus 16.8 months; p < 0.01) CONCLUSION: LDE is an effective endocrine option in women with evidence of prolonged sensitivity to AI therapy. LDE is reasonably well tolerated although VB is an issue. Re-challenge with the pre-LDE AI following progression confirms re-sensitisation as a true phenomenon.

Mammographic surveillance in women aged 35-39 at enhanced familial risk of breast cancer (FH02)

Although there have been encouraging recent studies showing a potential benefit from annual mammography in women aged 40-49 years of age with an elevated breast cancer risk due to family history there is little evidence of efficacy in women aged <40 years of age. A prospective study (FH02) has been developed to assess the efficacy of mammography screening in women aged 35-39 years of age with a lifetime breast cancer risk of ≥ 17 % who are not receiving MRI screening. Retrospective analyses from five centres with robust recall systems identified 47 breast cancers (n = 12 in situ) with an interval cancer rate of 15/47 (32%). Invasive tumour size, lymph node status and current vital status were all significantly better than in two control groups of unscreened women (including those with a family history) recruited to the POSH study. Further evaluation of the prospective arm of FH02 is required to assess the potential added value of digital mammography and the cancer incidence rates in moderate and high risk women in order to inform cost effectiveness analyses.

Uptake of tamoxifen in consecutive premenopausal women under surveillance in a high-risk breast cancer clinic

BACKGROUND

Randomised trials of tamoxifen versus placebo indicate that tamoxifen reduces breast cancer risk by approximately 33%, yet uptake is low. Approximately 10% of women in our clinic entered the IBIS-I prevention trial. We assess the uptake of tamoxifen in a consecutive series of premenopausal women not in a trial and explore the reasons for uptake through interviews.

METHODS

All eligible women between 33 and 46 years at ≥17% lifetime risk of breast cancer and undergoing annual mammography in our service were invited to take a 5-year course of tamoxifen. Reasons for accepting (n=15) or declining (n=15) were explored using semi-structured interviews.

RESULTS

Of 1279 eligible women, 136 (10.6%) decided to take tamoxifen. Women >40 years (74 out of 553 (13.4%)) and those at higher non-BRCA-associated risk were more likely to accept tamoxifen (129 out of 1109 (11.6%)). Interviews highlighted four themes surrounding decision making: perceived impact of side effects, the impact of others' experience on beliefs about tamoxifen, tamoxifen as a 'cancer drug', and daily reminder of cancer risk.

CONCLUSIONS

Tamoxifen uptake was similar to previously ascertained uptake in a randomised controlled trial (IBIS-I). Concerns were similar in women who did or did not accept tamoxifen. Decision making appeared to be embedded in the experience of significant others.

Abstract S3-01: Breast cancer prevention using anastrozole in postmenopausal women at high risk

Background: Third generation aromatase inhibitors are the most effective endocrine treatment for hormone receptor positive breast cancer in postmenopausal women. Here, we assess the efficacy of anastrozole in postmenopausal women who do not have breast cancer, but are at high risk of developing the disease.

Methods: A multi-centre randomised placebo-controlled trial of 1mg/day oral anastrozole vs. matching placebo for five years was conducted in 3864 postmenopausal women at increased risk of breast cancer. The primary endpoint was the incidence of breast cancer (including ductal carcinoma in-situ (DCIS) and differences were assessed by the proportional hazards model. Detailed information on adverse events was collected.

Results: After a median follow up of 5.03 years, 125 breast cancers were recorded. A 53% reduction (95% CI (32-68%), P&lt;0.0001) was seen in the anastrozole arm. Significant reductions were seen for all invasive (50%), oestrogen receptor positive invasive (58%) and in situ tumours (70%). Fractures were non-significantly higher (8.5% vs. 7.7%, P = 0.3) and musculoskeletal events were significantly higher in the anastrozole arm (1226 vs. 1124, RR = 1.10 (1.05-1.16)) but were very common in both arms (63.9% vs. 57.8%). Vasomotor symptoms were also increased with anastrozole (RR = 1.15 (1.08-1.22)). Cancers at other sites were significantly decreased (40 vs. 70, RR = 0.58 (0.39-0.85)). Deaths from breast cancer and other causes were similar in both arms.

Conclusions: Anastrozole is an effective agent for reducing breast cancer incidence in postmenopausal women at high risk. Anastrozole was well tolerated and side effects associated with oestrogen deprivation were only slightly higher than for placebo.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S3-01.