Endocrine therapy with aromatase inhibitors – Duration of therapy #3

Recommendation

Endocrine therapy with aromatase inhibitors – Duration of therapy #3

Be aware that alternative strategies for extending aromatase inhibitor therapy beyond 5 years, depending on risk of recurrence and tolerance of therapy, include: continuous therapy to 7.5 years, therapy up to 10 years with a 3-month break each year, and continuous therapy for up to 10 years.

How this guidance was developed

This practice point was developed using an expert consensus process. It is informed by the ASCO 2018 guidelines recommendation (based on a systematic review of the evidence) to not exceed 10 years of total adjuvant endocrine therapy treatment, and by the findings from two trials (ABCSG 16 (no difference in disease-free survival of 10 vs. 7 years of extended therapy with AIs) and the SOLE trial of intermittent vs. continuous extended AI therapy up to a total of 10 years). It is noted that in the evidence reviews by ASCO 2018 and NICE 2018, none of the studies to date has noted a survival benefit of extended AI therapy.

Further, in the ASCO (2018) evidence review, at least 5 of the 6 included trials examining extended AI duration, participants had received prior adjuvant tamoxifen therapy.

Overall, the guideline panel for ASCO (2018) highlighted three ‘preferred options’ for extended duration endocrine therapy for postmenopausal patients:

  • 10 years with an AI

  • 2-3 years of tamoxifen followed by 7-8 years with an AI

  • 5 years of tamoxifen followed by 5 years with an AI.

Postmenopausal patients may also continue tamoxifen for 10 years if they cannot tolerate an AI or prefer tamoxifen over an AI.

ASCO (2018) considered that the data supporting these different regimes should provide reassurance to patients and clinicians that minor degrees of non-adherence during the course of extended therapy likely does not impact on clinical outcomes among average-risk patients. 

Endocrine therapy with aromatase inhibitors – Duration of therapy #3

Recommendation

Be aware that alternative strategies for extending aromatase inhibitor therapy beyond 5 years, depending on risk of recurrence and tolerance of therapy, include: continuous therapy to 7.5 years, therapy up to 10 years with a 3-month break each year, and continuous therapy for up to 10 years.

Principles in action
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Safe and quality care
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Multidisciplinary care
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Care coordination

This practice point was developed using an expert consensus process. It is informed by the ASCO 2018 guidelines recommendation (based on a systematic review of the evidence) to not exceed 10 years of total adjuvant endocrine therapy treatment, and by the findings from two trials (ABCSG 16 (no difference in disease-free survival of 10 vs. 7 years of extended therapy with AIs) and the SOLE trial of intermittent vs. continuous extended AI therapy up to a total of 10 years). It is noted that in the evidence reviews by ASCO 2018 and NICE 2018, none of the studies to date has noted a survival benefit of extended AI therapy.

Further, in the ASCO (2018) evidence review, at least 5 of the 6 included trials examining extended AI duration, participants had received prior adjuvant tamoxifen therapy.

Overall, the guideline panel for ASCO (2018) highlighted three ‘preferred options’ for extended duration endocrine therapy for postmenopausal patients:

  • 10 years with an AI

  • 2-3 years of tamoxifen followed by 7-8 years with an AI

  • 5 years of tamoxifen followed by 5 years with an AI.

Postmenopausal patients may also continue tamoxifen for 10 years if they cannot tolerate an AI or prefer tamoxifen over an AI.

ASCO (2018) considered that the data supporting these different regimes should provide reassurance to patients and clinicians that minor degrees of non-adherence during the course of extended therapy likely does not impact on clinical outcomes among average-risk patients.