Aromatase inhibitor-induced carpal tunnel syndrome: results from the ATAC trial.
OBJECTIVE
Carpal tunnel syndrome (CTS) is a condition in which the median nerve is compressed, leading to pain and muscle weakness in the fingers and hand. Aromatase inhibitors lead to profound estrogen suppression and may be expected to increase the risk of CTS in postmenopausal women receiving adjuvant therapy for early breast cancer.


METHODS
The current analyses were based on the 100-month median follow-up data in postmenopausal women in the two monotherapy arms (anastrozole, n = 3,092; tamoxifen, n = 3,094). Here, we investigate the natural history of patients who presented with CTS during adjuvant treatment for breast cancer and the relative importance of a range of known risk factors for CTS.


RESULTS
After 100 months of follow-up, 80 cases (2.6%) of CTS were reported in the anastrozole arm, compared with 23 cases (0.7%) in the tamoxifen arm (P < .0001). The majority of CTS cases were reported as mild to moderate intensity and occurred early. None of the women stopped treatment medication as a result of CTS. CTS was significantly increased for women who used prior hormone replacement therapy (P = .007) or received prior chemotherapy (P = .01). Those who were 60 years of age or older at entry were at lower risk of CTS compared with their counterparts (P = .002).


CONCLUSIONS
Although the use of anastrozole is associated with a greater incidence of CTS, it is rare, and most cases were of mild to moderate intensity and short duration. CTS has little impact on the overall risk-to-benefit ratio for the use of anastrozole in postmenopausal women with early breast cancer.
Sestak
Ivana
I
Cancer Research UK, Centre for Epidemiology, Mathematics and Statistics, Wolfson Institute of Preventive Medicine, London, UK. ivana.sestak@cancer.org.uk
Sapunar
Francisco
F
Cuzick
Jack
J
D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal / Q000009:adverse effects*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000009:adverse effects*; D047072:Aromatase Inhibitors / Q000009:adverse effects*; D001943:Breast Neoplasms / Q000188:drug therapy; D002349:Carpal Tunnel Syndrome / Q000139:chemically induced*; D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008875:Middle Aged; D009570:Nitriles / Q000009:adverse effects; D017698:Postmenopause; D012307:Risk Factors; D013629:Tamoxifen / Q000009:adverse effects; D014230:Triazoles / Q000009:adverse effects
D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D009570:Nitriles; D014230:Triazoles; D013629:Tamoxifen; D000077384:Anastrozole