There are two putative mechanisms for canalicular damage: First, bathing of the puncta and canaliculi in 5-FU secreted into the tears may lead to chronic mucosal inflammation per se. Second, 5-FU may damage rapidly

4proliferating canalicular epithelium, causing chronic inflammation and fibrosis within the underlying substantia propria. These theories are similar to those proposed for the canalicular stenosis associated with docetaxel (Taxotere , v.i.), discussed below.

and syringing (followed by a short course of topical steroids) appear adequate to prevent problems in most patients on a ie every 3 weeks dosing schedule. Docetaxel is, however, an increasingly used chemotherapy, and with a trend toward weekly dosing to reduce systemic complications, lacrimal complications are set to increase. Treating physicians should counsel patients about the risk of lacrimal problems and seek appropriate early referral if symptoms arise.

Docetaxel is a semisynthetic taxane used in the treatment of advanced solid malignancies, especially those of breast, prostate, and non-small cell lung cancers. It is secreted into the tears [13] and may lead to canalicular stenosis or occlusion, with this troublesome side effect related to both the dosing frequency and total cumulative dose. Histological studies have shown fibrosis within the mucosal lining of the lacrimal drainage apparatus [11].

Clinical features of docetaxel toxicity include symptomatic punctal and canalicular stenosis or occlusion in up to a half of patients while on a weekly dosing schedule [12, 32]. Temporary canalicular intubation has been recommended for patients on weekly therapy, but probing

Due to their propensity to invade the medial orbit, tumors at the medial canthus carry a relatively worse prognosis, and Mohs surgery is now the preferred approach in managing such basal or squamous cell carcinomas. Historically, radiotherapy has often been used in this location, with almost universal canalicular occlusion (Fig. 4.4a). In 1981, Call and Welham described 13 patients with severe epiphora following radiotherapy for medial basal cell carcinomas, all of whom had complete obstruction of both upper and lower canaliculi; 12 were successfully managed by DCR and insertion of a Jones tube, and 1 settled with canaliculo-DCR for a common canalicular block [6].