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Recommendation
Endocrine therapy with tamoxifen – Duration of therapy
Consider extending the duration of tamoxifen therapy beyond 5 years for premenopausal or postmenopausal women with ER-positive breast cancer.
Consider extending the duration of tamoxifen therapy for longer than 5 years for both premenopausal and postmenopausal women with ER-positive invasive breast cancer
Tamoxifen for 10 years should be considered in high-risk patients, if tolerated (Level of evidence – I)
A “strong” rating was assigned when the observed consensus agreement was between 90% and 100%
Strong evidence for efficacy with a substantial clinical benefit, strongly recommended
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How this guidance was developed
This recommendation was adopted from the NICE 2018 guidelines (UK). The source recommendation was based on a systematic review of the evidence conducted to September 2017 and used wording (‘Consider’) indicative of a conditional recommendation (using GRADE methods) by the source guideline authors. Consideration of extending the duration of extended therapy to 10 years for premenopausal women at higher risk of recurrence is noted in the ESO-ESMO 2017/2020 guidelines for young women with breast cancer recommendation graded 'A' (using ACCP methods), as well as the ASCO 2018 updated guidelines.
NICE (2018) note that the low quality of evidence for extended duration (longer than 5 years versus fewer than 5 years) of tamoxifen therapy among postmenopausal women meant that the committee were only able to make a weak recommendation. Further, in Table 2 in the NICE (2018) guidelines, “in postmenopausal women who have taken tamoxifen for 5 years, switching to an aromatase inhibitor (AI) may be more effective at reducing recurrence than continuing with tamoxifen”. The supporting evidence review indicated that there was good evidence that switching to an AI after 5 years of tamoxifen improved disease-free survival compared with postmenopausal women who had only received tamoxifen for 5 years, with the benefits being greater in those women who had a greater risk of disease recurrence. Similarly, in the systematic evidence review by ASCO (2018) for the guideline update on use of AIs, a survival benefit for extended therapy for women who received 10 years of tamoxifen compared with 5 years, and for women who receive 5 years of AI therapy after 5 years of tamoxifen, was noted. The recently released ASCO 2020 guideline on the management of male breast cancer is noted. This guideline, based on a systematic review of the evidence to 20 September 2019, indicates that ‘Men who have completed five years of tamoxifen, have tolerated therapy, and still have a high risk of recurrence, may be offered an additional five years of tamoxifen therapy’ (Type: formal consensus; Evidence quality: low; Strength of recommendation: strong).
Related guidance by topic
Endocrine therapy with tamoxifen – Duration of therapy
Recommendation
Consider extending the duration of tamoxifen therapy beyond 5 years for premenopausal or postmenopausal women with ER-positive breast cancer.
Principles in action
Patient-centred care
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Safe and quality care
Useful Links
This recommendation was adopted from the NICE 2018 guidelines (UK). The source recommendation was based on a systematic review of the evidence conducted to September 2017 and used wording (‘Consider’) indicative of a conditional recommendation (using GRADE methods) by the source guideline authors. Consideration of extending the duration of extended therapy to 10 years for premenopausal women at higher risk of recurrence is noted in the ESO-ESMO 2017/2020 guidelines for young women with breast cancer recommendation graded 'A' (using ACCP methods), as well as the ASCO 2018 updated guidelines.
NICE (2018) note that the low quality of evidence for extended duration (longer than 5 years versus fewer than 5 years) of tamoxifen therapy among postmenopausal women meant that the committee were only able to make a weak recommendation. Further, in Table 2 in the NICE (2018) guidelines, “in postmenopausal women who have taken tamoxifen for 5 years, switching to an aromatase inhibitor (AI) may be more effective at reducing recurrence than continuing with tamoxifen”. The supporting evidence review indicated that there was good evidence that switching to an AI after 5 years of tamoxifen improved disease-free survival compared with postmenopausal women who had only received tamoxifen for 5 years, with the benefits being greater in those women who had a greater risk of disease recurrence. Similarly, in the systematic evidence review by ASCO (2018) for the guideline update on use of AIs, a survival benefit for extended therapy for women who received 10 years of tamoxifen compared with 5 years, and for women who receive 5 years of AI therapy after 5 years of tamoxifen, was noted. The recently released ASCO 2020 guideline on the management of male breast cancer is noted. This guideline, based on a systematic review of the evidence to 20 September 2019, indicates that ‘Men who have completed five years of tamoxifen, have tolerated therapy, and still have a high risk of recurrence, may be offered an additional five years of tamoxifen therapy’ (Type: formal consensus; Evidence quality: low; Strength of recommendation: strong).
Related guidance by topic
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