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Ocular toxicity after adjuvant chemo-endocrine treatment for early breast cancer
Recent
clinical trials of adjuvant endocrine therapy for early postmenopausal
breast cancer have shown superiority of third generation aromatase
inhibitors over tamoxifen, with a favorable pattern of side effects.
Attention has been concentrated on the principal side effects such as
thromboembolic events, endometrial disease and bone alterations with minor
attention to other side effects such as ocular toxicity. International
Breast Cancer Study Group (IBCSG) recently conducted a retrospective study
to review the incidence and timing of ocular toxicity after adjuvant
chemo-endocrine treatment for early breast cancer in a large number of
patients from seven IBCSG trials conducted from 1978 to 1989. Among 4948
patients randomized to receive endocrine therapy with a selective estrogen
receptor modulator (SERM: tamoxifen or toremifene for one or five years)
alone or with chemotherapy, ocular toxicity was reported by 10,9% of
patients, mainly during chemotherapy. Forty-five (0,9%) patients had
ocular toxicity during tamoxifen or toremifene therapy alone; impaired
visual acuity, ocular irritation and cataract were the most frequent side
effects while no cases of confirmed retinopathy were reported. Despite its
limitations (retrospective analysis and limited number of patient with
opthalmic evaluation), our study has a pragmatic significance.
Ocular toxicity after chemotherapy is not infrequent and is sometimes
disturbing, but it is rare or possibly asymptomatic after low dose SERMs
alone. Nurses and physician should pay attention and inform patients about
possible side effects for a prompt ocular evaluation in case of ocular
complaints. The
current scientific discussion is most relevant if Tamoxifen still has a
role in adjuvant treatment of postmenopausal breast cancer. Evidence from
clinical trials seems to support the choice of
an aromatase inhibitors, but pending further information from
ongoing trials, we believe that tamoxifen should still be considered
particularly in patients at low risk of recurrence, and after considering
the risk of side effects related to different drugs. The
fear of ocular toxicity should not influence this decision in most cases,
but for patients with pre-existing ocular disease the use of an aromatase
inhibitor rather than tamoxifen may be appropriate, keeping in mind that
aromatase inhibitors have not been as fully evaluated as tamoxifen for
ocular and other adverse events.
Bibliographical reference: Lorenzo Gianni Division of Oncology and Hematology, Hospital degli Infermi, Rimini, Italy
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