Adverse events and bone health during anastrozole therapy in postmenopausal Japanese breast cancer patients

Current and future advances in practice: aromatase inhibitor-induced arthralgia

Aromatase inhibitors (AIs) have shown great success as adjuvant therapy for post-menopausal women with hormone receptor-positive breast cancers. AI-induced arthralgia (AIA) is a frequent AI toxicity contributing to non-adherence and discontinuation. This review aims to understand current knowledge of AIA. The mean incidence of AIA was 39.1% and the mean discontinuation of AI therapy due to AIA was 9.3%. Most of the AIAs were non-inflammatory. A shorter time since the last menstrual period and pre-existing joint pain were risk factors. Vitamin D3 supplementation may be a preventative measure and treatment with duloxetine, acupuncture and/or exercise is supported by large randomized controlled trials. There was consistent improvement in AIAs with switching to an alternate AI, and this could additionally allow continuation of cancer treatment with AI. Further research is needed to identify predictive biomarkers, better characterize AIA subcategories and study more reliable therapeutic options.

Symptom Map of Endocrine Therapy for Breast Cancer: A Scoping Review

BACKGROUND

Multiple symptoms associated with endocrine therapy have a detrimental impact on medication adherence and quality of life.

OBJECTIVE

The purpose of this scoping review is to map the symptoms during endocrine therapy for breast cancer to provide implications for current practice and suggestions for future research.

METHODS

The PubMed, CINAHL, and China Science Periodical Databases were searched to identify related studies published in English and Chinese languages. References of included articles were reviewed for additional eligible studies. Of the 2551 articles identified, 57 articles met inclusion criteria and were included in this scoping review.

RESULTS

Evidence for the 16 most studied symptoms and 15 most prevalent symptoms were synthesized. Five key symptoms associated with endocrine therapy were identified, including joint/muscle pain, hot flashes, low sexual interest/desire, joint/muscle stiffness, and fatigue/lack of energy. Rarely studied but highly prevalent symptoms and other gaps in the symptom science during endocrine therapy for breast cancer were identified.

CONCLUSION

Nurses caring for women receiving endocrine therapy for breast cancer should assess the 5 key symptoms identified. There remain substantial gaps in the science related to the symptom experience during endocrine therapy for breast cancer. Future studies should focus on the domains of symptom intensity and distress, specific understudied symptoms, symptom clusters, and development of symptom assessment instruments specific to symptoms associated with endocrine therapy.

IMPLICATIONS FOR PRACTICE

This scoping review identified 5 well-studied and highly prevalent symptoms that should be assessed in women with breast cancer receiving endocrine therapy.

Bioequivalence of Oral Formulations of Anastrozole in Healthy Chinese Male Volunteers: A Randomized, Single-Dose, Two-Period, Two-Sequence Crossover Study

Anastrozole is currently used as first-line treatment in locally advanced or metastatic breast cancer. A generic anastrozole tablet was developed to offer an alternative to the marketed tablet formulation. The aim of the current study was to evaluate the bioequivalence between the test and reference formulations of anastrozole in a single-dose, 2-period, 2-sequence crossover study with a 14-day washout interval. A total of 20 healthy male Chinese volunteers were enrolled and completed the study, after oral administration of a single dose of 1.0-mg test and reference formulations of anastrozole. The blood samples were collected at different times and were determined by a fully validated high-pressure liquid chromatography-tandem mass spectrometry method. The evaluated pharmacokinetic parameters, including C_max , AUC_0-t , and AUC_0-∞ , were assessed for bioequivalence based on current guidelines. The observed pharmacokinetic parameters of anastrozole of the test drug were similar to those of the reference formulation. The 90% confidence intervals of test/reference ratios for C_max , AUC_0-t , and AUC_0-∞ were within the bioequivalence acceptance range of 80%-125%. The results obtained from these healthy Chinese subjects in this study suggest that the test formulation of anastrozole 1.0-mg tablet is bioequivalent to the reference formulation (Arimidex 1.0-mg tablet).

Aromatase inhibitors associated musculoskeletal disorders and bone fractures in postmenopausal breast cancer patients: a result from Chinese population

As the prognosis of early breast cancer patients improves, the long-term safety of aromatase inhibitors (AIs) is increasingly important. In the present study, we retrospectively investigated the incidences of musculoskeletal disorders (MSDs) and bone fractures in a cohort of Chinese postmenopausal patients with breast cancer. Data of postmenopausal patients with breast cancer were collected. Among which, 70 patients received AIs therapy (median follow-up of 32.5 months), 52 patients received tamoxifen (TAM), and 89 patients received no endocrine therapy (NE). Baseline characteristics, incidence of MSDs and bone fractures were analyzed and compared. When compared with NE group (40.4 %, 36/89), more patients in AIs group developed MSDs (72.9 %, 51/70, adjusted odds ratio (AOR) = 3.30, 95 % confidence interval (CI) = 1.59-6.88, P = 0.001). But no difference was found between TAM group (36.5 %, 19/52, AOR = 0.70, 95 % CI = 0.32-1.52, P = 0.372) and NE group. About 39.7 months after initial AIs therapy, nine patients in AI group developed bone fractures in different sites, and the bone fracture rate was significantly increased (12.9 %, 9/70, adjusted hazard ratio (AHR) = 20.08, 95 % CI = 1.72-234.08, P = 0.017) in comparison with NE group (1.1 %, 1/89). Moreover, the bone fracture rate of TAM group was not different from NE group (1.9 %, 1/52, AHR = 2.64, 95 % CI = 0.14-48.73, P = 0.513). AIs therapy may induce increased rates of MSDs and bone fractures in Chinese population of postmenopausal breast cancer patients, whereas TAM therapy did not help reduce the incidences of MSDs and bone fractures.

A multicenter prospective study to evaluate bone fracture related to adjuvant anastrozole in Japanese postmenopausal women with breast cancer: two-year interim analysis of Saitama Breast Cancer Clinical Study Group (SBCCSG-06)

BACKGROUND

Because of its superior efficacy to tamoxifen, anastrozole has been widely used in Japan as an adjuvant treatment for postmenopausal, hormone-responsive breast cancer patients. However, anastrozole may affect bone in Japanese patients similar to its effects in Western patients. The aim of this study is to evaluate the rate of bone fracture and bone mineral density (BMD) during anastrozole treatment in Japanese patients.

PATIENTS AND METHODS

In this study, 350 postmenopausal women with hormone-responsive, stage I to IIIA breast cancer were enrolled and scheduled to receive adjuvant anastrozole treatment for up to 5 years. Patients underwent clinical examination for bone fractures and annual measurement of BMD during treatment.

RESULTS

After a median follow-up of 33.0 months, bone fractures occurred in 1.8 %. Annual fracture rates were 0.3 and 1.2 % during the first and second year, respectively. The overall median BMD significantly decreased, measuring 87.5, 84.3, and 83.5 % at baseline and after 1 and 2 years, respectively. Musculoskeletal disorders were the most common (26.1 %), and hot flashes were the second most common adverse event (7.9 %). Severe adverse events occurred in 5.5 % of all the cases.

CONCLUSIONS

In this interim analysis, the bone fracture rate was lower than that in the Western population despite a significant reduction of BMD after 2 years of treatment with anastrozole. Adjuvant anastrozole treatment was well tolerated in Japanese postmenopausal women with breast cancer. Long-term follow-up data is necessary to elucidate the racial disparities of the safety profile of anastrozole.

Putting the cardiovascular safety of aromatase inhibitors in patients with early breast cancer into perspective: a systematic review of the literature

In the adjuvant setting, the third-generation aromatase inhibitors (AIs) anastrozole, letrozole and exemestane are recommended at some point during treatment, either in the upfront, switch after tamoxifen or extended treatment setting after tamoxifen in postmenopausal patients with hormone receptor-positive early breast cancer. AIs have demonstrated superior disease-free survival and overall benefit-to-risk profiles compared with tamoxifen. Potential adverse events, including cardiovascular (CV) side effects, should be considered in the long-term management of patients undergoing treatment with AIs. AIs reduce estrogen levels by inhibiting the aromatase enzyme, thus reducing the levels of circulating estrogen. This further reduction in estrogen levels may potentially increase the risk of developing CV disease. This systematic review evaluated published clinical data for changes in plasma lipoproteins and ischaemic CV events during adjuvant therapy with AIs in patients with hormone receptor-positive early breast cancer. The electronic databases MEDLINE, EMBASE, Derwent Drug File and BIOSIS were searched to identify English-language articles published from January 1998 to 15 April 2011 that reported data on AIs and plasma lipoproteins and/or ischaemic CV events. Overall, available data did not show any definitive patterns or suggest an unfavourable effect of AIs on plasma lipoproteins from baseline to follow-up assessment in patients with hormone receptor-positive early breast cancer. Changes that occurred in plasma lipoproteins were observed soon after initiation of AI therapy and generally remained stable throughout the studies. Available data do not support a substantial risk of ischaemic CV events associated with adjuvant AI therapy; however, studies with longer follow-up are required to better characterize the CV profile of AIs.