Abstract P5-12-03: Prevalence of bone loss among nonmetastatic breast cancer patients treated with aromatase inhibitors in the United States

Background: Adjuvant endocrine therapy compromises bone health in patients (pts) with breast cancer, leading to osteopenia, osteoporosis, and fractures (Forbes 2008). For postmenopausal women with estrogen receptor (ER) positive (+ve) breast cancer, aromatase inhibitors (AI) have emerged as the standard of care because of superior efficacy over selective ER modulators such as tamoxifen, shown in several large clinical trials. As rates of utilization and duration of AI therapy are expected to continue to increase, we report estimates of the prevalence of women with nonmetastatic breast cancer treated with AI in the United States and examine evidence of bone loss before and after AI exposure.

Methods: The Oncology Services Comprehensive Electronic Records (OSCER) database, an electronic medical record database on >500,000 cancer pts from oncology practices across the US, was used to identify women with breast cancer (ICD-9 174*), ≥1 clinic visit, and confirmed AI therapy (anastrozole, letrozole, or exemestane) in 2014, excluding pts with evidence of metastases (ICD-9 196-198, stage IV, or M1 disease). OSCER is projected nationally through methods of direct estimations utilizing claims data for 1-year period prevalence. Bone loss was defined by diagnosis of osteoporosis (ICD-9 733.0), osteopenia (ICD-9 733.90), or receipt of bone therapy in 2014. Bone therapies used as proxy for bone loss were intravenous (IV) (ibandronate, zoledronic acid), or oral bisphosphonates (BPs) (risedronate, ibandronate, etidronate, alendronate), or subcutaneous anti-RANK ligand antibody (denosumab [60 mg Q6M]).

Results: It is nationally estimated that 538,630 (95% CI 519,839 - 557,422) women with nonmetastatic breast cancer were treated with an AI in 2014, representing a median of 6 prescriptions (mean 6.8). Of these, most (94%) were treated with anastrozole or letrozole, 55% were ≥65 years, and 11% took tamoxifen prior to first AI. Among women taking AI in 2014, 39% started in 2014, 24% started in 2013, and 37% have been on AI therapy since 2012 or earlier. Overall, 285,543 (53%) pts on AI therapy had evidence of bone loss, 30% of whom developed bone loss after exposure to AI therapy. Among the 338,784 women with no evidence of pre-existing bone loss, 25% (85,697) developed bone loss after initiating AI therapy (table), with 21% treated with oral and 1% IV BPs, or 9% with denosumab.

2014 prevalenceN (%)Nonmetastatic pts on AI therapy538,630At least 2 AI prescriptions in lifetime468,608 (87)Bone loss before starting AI199,846 (37)No bone loss before AI, with bone loss after AI85,697 (16)

Conclusions: This study provides current estimates of the prevalence of nonmetastatic breast cancer treated with AI in the US using real-world data, indicating that more than 535,000 women were treated with AI in 2014. Considering that 37% of pts have been on endocrine therapy since 2012 or earlier, continued use of AI will likely lead to increased pts with bone loss. These women face an increased risk of fractures, highlighting the need for intervention with antiresorptive treatments (i.e., BPs have been studied, and denosumab has a labeled indication in this setting) that may help build bone mass and counteract detrimental effects on the bone.

Citation Format: Pirolli M, Hernandez RK, Reich A, Liede A. Prevalence of bone loss among nonmetastatic breast cancer patients treated with aromatase inhibitors in the United States. [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 P5-12-03.

Survival and clinical metastases among prostate cancer patients treated with androgen deprivation therapy in Sweden

OBJECTIVES

To examine the incidence of metastases and clinical course of prostate cancer patients who are without confirmed metastasis when initiating androgen deprivation therapy (ADT).

METHODS

Retrospective cohort study conducted using electronic medical records from Swedish outpatient urology clinics linked to national mandatory registries to capture medical and demographic data. Prostate cancer patients initiating ADT between 2000 and 2010 were followed from initiation of ADT to metastasis, death, and/or end of follow-up.

RESULTS

The 5-year cumulative incidence (CI) of metastasis was 18%. Survival was 60% after 5 years; results were similar for bone metastasis-free survival. The 5-year CI of castration-resistant prostate cancer (CRPC) was 50% and the median survival from CRPC development was 2.7 years. Serum prostate-specific antigen (PSA) levels and PSA doubling time were strong predictors of bone metastasis, any metastasis, and death.

CONCLUSION

This study provides understanding of the clinical course of prostate cancer patients without confirmed metastasis treated with ADT in Sweden. Greater PSA values and shorter PSA doubling time (particularly ≤ 6 months) were associated with increased risk of bone metastasis, any metastasis, and death.

Abstract P3-06-12: Estimating prevalence of stage II-III breast cancer in the United States by treatment and biologic subtypes using oncology clinic data

Background:

Breast cancer (BC) is the most common malignancy and the second most common cause of cancer death among women in the US, and the main cause of death in women ages 40 to 49 years. Stage II and III BC are diverse diseases represented by several biologic subtypes with distinct behaviors, which have not been quantified outside of clinical trials or SEER using observational data. Additionally, although guidelines address the use of adjuvant treatment (tx) based on tumor grade, lymph node involvement, tumor size, and whether the tumor expression pattern is consistent with estrogen receptor (ER), progesterone receptor (PR), or Her2 receptor over-expression, there is considerable heterogeneity in clinical practice with respect to the types of tx used for patients with early stage BC. The objective of this study was to estimate the number of women (prevalence) with Stage II and III BC in the US by year, as well as the proportion of patients treated with chemotherapy or biologic tx, stratified by subtype and age using electronic medical record (EMR) data from oncology clinics.

Methods:

The Oncology Services Comprehensive Electronic Records (OSCER) database was used to identify women with early stage BC and ≥1 visit to a clinic in each year, 2009-2012. OSCER captures EMR data on >500,000 cancer patients since 2004 from outpatient community and hospital-affiliated oncology practices across the US. Women with a diagnosis of BC (ICD-9 174) were identified using a 4-year look-back period. Women with stage I disease were excluded due to variability in the use of adjuvant tx. Treated patients were defined as receiving any chemotherapy or biologic tx during the year of interest. Raw counts from OSCER were projected nationally with 95% confidence intervals through direct estimation methods utilizing claims data.

Results: When projected to the US population, the prevalence of women with Stage II or III BC was estimated at 316,827 (311,040 - 322,614), 308,792 (303,267 - 314,317), 317,691 (311,543 - 323,839), and 321,281 (315,470 - 327,092) from 2009-2012, respectively. In 2012, 65% of these women had Stage II disease, 76% were over the age of 50, 30% were Her2 positive (+ve), and 63% were ER/PR +ve (17% were Her2/ER/PR +ve). Approximately 46% of Stage II-III BC patients received treatment in an outpatient oncology clinic (45% of Stage II and 48% of Stage III). The proportion of early-stage BC patients receiving tx was very similar across biologic subtypes. Women 65 years or older were least likely to receive tx (42%) of all strata examined.

 2012 Patients Prevalence% treatedBC Stage II-III32128146Stage II20932745Stage III11195448Her2 Status  Her2 +ve9677451Her2 -ve22450744ER, PR Status  ER, PR +ve20328644ER -ve, PR +ve498952ER +ve, PR -ve3339145ER, PR -ve7961552Age Group  <507608152≥5024520045<6521016948≥6511111242

Conclusions:

This is the first study to estimate diagnosed and treated prevalence of women with Stage II or III BC by hormonal and Her2 status in the US using real-world EMR data. These data suggest that adjuvant chemotherapy or biologic tx is used in approximately 46% of women after BC diagnosis, and women age 65 years or older are less likely to receive adjuvant tx.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-06-12.

Rosiglitazone use and post-discontinuation glycaemic control in two European countries, 2000-2010

OBJECTIVES

To evaluate the impact of risk minimisation policies on the use of rosiglitazone-containing products and on glycaemic control among patients in Denmark and the UK.

DESIGN, SETTING AND PARTICIPANTS

We used population-based data from the Aarhus University Prescription Database (AUPD) in northern Denmark and from the General Practice Research Database (GPRD) in the UK.

MAIN OUTCOME MEASURES

We examined the use of rosiglitazone during its entire period of availability on the European market (2000-2010) and evaluated changes in the glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) levels among patients discontinuing this drug.

RESULTS

During 2000-2010, 2321 patients with records in AUPD used rosiglitazone in northern Denmark and 25 428 patients with records in GPRD used it in the UK. The proportion of rosiglitazone users among all users of oral hypoglycaemic agents peaked at 4% in AUPD and at 15% in GPRD in May 2007, the month of publication of a meta-analysis showing increased cardiovascular morbidity associated with rosiglitazone use. 12 months after discontinuation of rosiglitazone-containing products, the mean change in HbA1c was -0.16% (95% CI -3.4% to 3.1%) in northern Denmark and -0.17% (95% CI -0.21% to 0.13%) in the UK. The corresponding mean changes in FPG were 0.01 mmol/L (95% CI -7.3 to 7.3 mmol/L) and 0.03 mmol/L (95% CI -0.22 to 0.28 mmol/L).

CONCLUSIONS

Publication of evidence concerning the potential cardiovascular risks of rosiglitazone was associated with an irreversible decline in the use of rosiglitazone-containing products in Denmark and the UK. The mean changes in HbA1c and FPG after drug discontinuation were slight.