Selecting a Treatment Regimen Duration, Timing and Sequencing of Therapy
ÎThe historical standard duration of tamoxifen therapy is 5 years, and is the standard comparator for all adjuvant trials of AIs.
ÎSafety and efficacy data from primary trials support up to 5 years of AI therapy as a primary adjuvant strategy.
ÎThe recommended limit on AI treatment is 5 years total across strategies.
> Regarding sequential and extended therapy; it is not known whether differences in duration of therapy are clinically significant, and optimal duration of therapy is unclear at this time.
ÎTherapy with an aromatase inhibitor should not extend beyond five years in either the primary or extended adjuvant settings outside of the clinical trials setting.
ÎPatients initially treated with an AI but discontinue treatment before 5 years should consider taking tamoxifen for a total of 5 years of adjuvant endocrine therapy.
Specific Patient Populations
ÎDirect evidence from randomized trials did not identify a specific marker or clinical subset that predicted which adjuvant treatment strategy–tamoxifen, or AI monotherapy or sequential therapy– would maximally improve outcomes for a given patient.
ÎThe Update Committee recommends AGAINST using CYP2D6 genotype to select adjuvant endocrine therapy.
ÎThe Committee encouraged caution with concurrent use of CYP2D6 inhibitors (such as bupropion, paroxetine, fluoxetine) and tamoxifen because of the known drug-drug interactions.
Male Breast Cancer
ÎOnly women were eligible for the adjuvant trials of postmenopausal endocrine therapy with AIs.
ÎThere is no evidence to evaluate the efficacy of adjuvant AI therapy in men.
ÎTamoxifen remains the standard adjuvant endocrine therapy for male breast cancer.
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