Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial after completion of 5 years' adjuvant treatment for breast cancer.
The standard adjuvant endocrine treatment for postmenopausal women with hormone-receptor-positive localised breast cancer is 5 years of tamoxifen, but recurrences and side-effects restrict its usefulness. The aromatase inhibitor anastrozole was compared with tamoxifen for 5 years in 9366 postmenopausal women with localised breast cancer. After a median follow-up of 68 months, anastrozole significantly prolonged disease-free survival (575 events with anastrozole vs 651 with tamoxifen, hazard ratio 0.87, 95% CI 0.78-0.97, p=0.01) and time-to-recurrence (402 vs 498, 0.79, 0.70-0.90, p=0.0005), and significantly reduced distant metastases (324 vs 375, 0.86, 0.74-0.99, p=0.04) and contralateral breast cancers (35 vs 59, 42% reduction, 12-62, p=0.01). Almost all patients have completed their scheduled treatment, and fewer withdrawals occurred with anastrozole than with tamoxifen. Anastrozole was also associated with fewer side-effects than tamoxifen, especially gynaecological problems and vascular events, but arthralgia and fractures were increased. Anastrozole should be the preferred initial treatment for postmenopausal women with localised hormone-receptor-positive breast cancer.
Howell
A
A
Christie Hospital, Manchester, UK. anthony.howell@christie-tr.nwest.nhs.uk
Cuzick
J
J
Baum
M
M
Buzdar
A
A
Dowsett
M
M
Forbes
J F
JF
Hoctin-Boes
G
G
Houghton
J
J
Locker
G Y
GY
Tobias
J S
JS
D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use; D047072:Aromatase Inhibitors / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D004965:Estrogen Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D009570:Nitriles / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D017698:Postmenopause; D016032:Randomized Controlled Trials as Topic; D015996:Survival Rate; D013629:Tamoxifen / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D014230:Triazoles / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*
D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D004965:Estrogen Antagonists; D009570:Nitriles; D014230:Triazoles; D013629:Tamoxifen; D000077384:Anastrozole