Nasolacrimal Duct Obstruction in the Patients Receiving Treatment for Cancer.

The lacrimal drainage system consists of the upper and lower puncta, canaliculi, lacrimal sac, and the nasolacrimal duct that opens into the inferior meatus. With nasolacrimal duct obstruction, constant tearing occurs, which may be accompanied by inflammation in the tear ducts and on the ocular surface. Classification of nasolacrimal duct obstruction implies their division into primary and secondary acquired.1 The latter may be a consequence of systemic cytostatic therapy, as well as radiation exposure in the treatment of patients with cancer, and patients seek medical attention after successful antitumor therapy.2,3 The frequency of chemotherapeutic and radiation agents in the management of patients with tumors has been increasing, and so is the reported frequency of secondary nasolacrimal duct obstruction.4,5 Although the mechanism is unclear, it is presumed to be associated with the contact of a toxic agent with the affected surface.6–9 This can be either through the drug secreted in the tears or reaching the tear ducts systemically from the blood.7,8,10 The tear fluid is a blood ultrafiltrate, where some components can be in higher concentrations than in blood. Once the drugs gain adequate access to the tear ducts, their toxicity on the mucous membranes results in undesirable effects.11,12