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Breast Cancer · Medical · Adjuvant Endocrine Therapy

DBCG 77C

In high-risk postmenopausal breast cancer, does adjuvant tamoxifen improve recurrence-free and overall survival?

Tumour site
Breast Cancer
Discipline
Medical
Clinical setting
Adjuvant Endocrine Therapy
Evidence type
Comparative clinical evidence

Absolute Effect

DBCG 77C randomized postmenopausal high-risk patients after mastectomy and radiotherapy to tamoxifen for one year or no further therapy. Ten-year recurrence-free survival was 31% versus 28%, and survival was 38% versus 34%.

NNT / NNH: Calculated only when a defensible fixed-time absolute event difference is available. Hazard ratios alone are not converted into NNT.

Clinical interpretation

The historical tamoxifen result should be interpreted through today's longer, risk-adapted endocrine strategies rather than treated as a template for treatment duration.

Limitations

The trial predates aromatase inhibitors and current endocrine sequencing; toxicity, menopausal status and recurrence risk change the modern choice.

Primary / authoritative source

Primary evidence source

Current-practice context · reviewed 14 October 2026

DBCG 77C is historical evidence for adjuvant tamoxifen in postmenopausal high-risk breast cancer. Contemporary endocrine treatment is individualized by ER status, menopausal status, recurrence risk and tolerance, with aromatase inhibitors and sequential endocrine strategies now commonly used; one year of tamoxifen from this trial should not be treated as a contemporary default duration.

DBCG 77C primary/registry source ↗ · Current guideline guidance ↗