Key Points
➤ In 2017 an American Society of Clinical Oncology (ASCO)-Ontario Health
(Cancer Care Ontario) meta-analysis noted significant benefit from
bisphosphonates in all postmenopausal breast cancer patients for bone
recurrence (6.6% vs. 8.8%), fracture rates (9.1% vs. 10.3%), breast
cancer mortality (14.7% vs. 18.0%), overall survival (OS) (any death 21.1%
vs. 23.5%), and outcomes that included bone recurrence (i.e., distant
recurrence, any recurrence) and made treatment recommendations based
on those findings.
➤ This update concerns the choice and dose of bisphosphonates, the use
of denosumab and a revision of patient selection based on three recently
published studies.
Treatment
Table 1. Complete List of Recommendations
a
New Recommendations from 2021 ASCO-OH Focused Guideline Update
Recommendation Evidence rating
Adjuvant bisphosphonate therapy should be discussed with all
postmenopausal patients (natural or therapy-induced) with primary
breast cancer, irrespective of hormone receptor status and Human
Epidermal Growth Factor Receptor 2 (HER2) status, who are candidates
to receive adjuvant systemic therapy. Adjuvant bisphosphonates, if used,
are not substitutes for standard anticancer modalities.
e benefit of adjuvant bisphosphonate therapy will vary depending
on the underlying risk of recurrence and is associated with a modest
improvement in overall survival. e NHS PREDICT tool (https://
breast.predict.nhs.uk/) provides estimates of benefit of adjuvant
bisphosphonate therapy and may aid in shared decision-making.
Factors influencing the decision to recommend adjuvant bisphosphonate
use that should be weighed in the discussion with patients include the
patient's risk of recurrence, the risk of side effects, financial toxicity, drug
availability, patient preferences, comorbidities, and life expectancy.
Moderate
recommendation;
IC-I
e Panel supports starting bisphosphonate therapy early, consistent with
the points outlined in the parent CCO-ASCO guideline. Many studies
initiated bisphosphonate within 3 months of definitive surgery or within
2 months of completion of adjuvant chemotherapy; this is a consensus
recommendation. e therapeutic options, listed alphabetically, with the
strongest supporting data include:
• oral clodronate (1,600 mg daily for 2 to 3 years)
• oral ibandronate (50 mg daily for 3 years)
• zoledronic acid; dosing regimens as per the protocols of the clinical
trials (including the option of 4 mg every 6 months for 3 years or 4 mg
every 3 months for 2 years)
Patient preference should be factored into the choice of adjuvant
bisphosphonate therapy. Access to adjuvant bisphosphonate therapy may
currently limit choice of agent depending on jurisdiction.
Moderate
recommendation;
EB-I
