Management of Anastrozole-Related Adverse Events

Introduction to Management

• The European Society for Medical Oncology recommends maintaining corticosteroids at a dose of 40 mg/day until complete resolution of symptoms in patients experiencing anastrozole-related adverse events 1

Treatment Alternatives

• The American Society of Clinical Oncology and the National Comprehensive Cancer Network suggest considering tamoxifen 20 mg/day as a therapeutic alternative in postmenopausal women with hormone receptor-positive breast cancer, which presents a different adverse effect profile compared to aromatase inhibitors 2, 3, 4
• For premenopausal patients, the European Society for Medical Oncology recommends considering tamoxifen with ovarian ablation as a treatment option 3
• For postmenopausal patients, the European Society for Medical Oncology recommends considering tamoxifen as first-line instead of AIs, and AIs should only be considered if benefits clearly outweigh risks and other options are contraindicated 3
• Letrozole or exemestane may also be considered as alternative aromatase inhibitors for patients with severe reactions to anastrozole 5

Monitoring and Follow-up

• Regular clinical evaluation is necessary until complete resolution of symptoms, followed by gradual reduction of corticosteroids and periodic assessment of tumor response to the new hormonal treatment 1, 2
• The European Respiratory Society recommends monitoring for potential adverse effects of tamoxifen, including thromboembolic risk and endometrial hyperplasia 2
• Patients with mast cell disease should avoid aromatase inhibitors due to the risk of triggering mast cell activation, and regular monitoring of symptoms and prompt intervention for any signs of mast cell activation is essential in patients with mast cell disease taking AIs, although the strength of evidence for this is based on expert opinion due to the lack of specific clinical trials 3, 6

Side Effect Management

• Aromatase inhibitors increase the risk of vasomotor symptoms and musculoskeletal symptoms, impacting quality of life, and side effects may lead to decreased adherence to therapy 5
• Reducing anastrozole from 0.25mg to 0.125mg twice weekly is a reasonable approach for managing side effects while maintaining some therapeutic benefit in postmenopausal women with breast cancer 5
• Common side effects of anastrozole include joint stiffness, arthralgias, vasomotor symptoms, hypertension, dry eyes, and vaginal dryness, and patients should be monitored for these side effects and instructed to report any symptoms to their healthcare provider 5
• Consider treatment options such as topical corticosteroids for mild to moderate skin reactions, and for severe reactions, consider a short course of oral corticosteroids or alternative therapy, such as switching to a different aromatase inhibitor (letrozole or exemestane), or tamoxifen as an alternative in postmenopausal women with severe reactions to aromatase inhibitors 5

Bone Health Management

• Aromatase inhibitors increase the risk of osteoporosis and fractures in postmenopausal women with hormone receptor-positive breast cancer, highlighting the need for bone health monitoring and management 7, 5, 8
• The American College of Oncology, the National Comprehensive Cancer Network, and other organizations recommend vitamin D and calcium supplements to counteract the increased risk of osteoporosis associated with aromatase inhibitors 7, 9, 5, 10
• Consider bisphosphonate therapy for patients with additional risk factors for bone loss, although there is no clear evidence for routine use of bisphosphonates concomitantly with aromatase inhibitors 7
• The following table summarizes the risk factors for osteoporosis and fractures in patients on anastrozole:

Perioperative Management

• Anastrozole can be safely continued during the perioperative period, as it does not pose significant perioperative risks, such as bleeding or wound healing impairment, according to the American College of Surgeons and oncology organizations 11, 12
• Interrupting anastrozole therapy unnecessarily could potentially compromise treatment efficacy and allow cancer cell proliferation, highlighting the importance of maintaining continuous therapy 7, 9