[Clinical preliminary observation of RET inhibitors on tear fluid]

Objective: To investigate the changes in ocular surface damage signs in patients with non-small cell lung cancer (NSCLC) after treatment with rearrangement during transfection (RET) inhibitors. Methods: This was a retrospective case series study. Clinical data were collected from 7 NSCLC patients (14 eyes) who developed dry eye symptoms after receiving RET inhibitor chemotherapy at the Second Affiliated Hospital of Zunyi Medical University from October 2023 to December 2024. All patients presented to the ophthalmology department due to dry eye symptoms occurring at different time points after RET inhibitor treatment. Corneal fluorescein staining scores, tear film breakup time (BUT), and Schirmer Ⅱ test results were recorded at different time periods post-treatment. Patients were treated with artificial tears, meibomian gland massage, and eyelid heat compress, and some patients were additionally prescribed cyclosporine A eye drops. Follow-up was conducted to observe the improvement of dry eye symptoms and ocular surface damage. Results: A total of 7 patients were included, consisting of 5 males and 2 females, with an average age of (50.6±5.0) years. The time from initiation of treatment to the onset of ocular symptoms was (87.7±54.3) days. All patients had corneal fluorescein staining scores>1, BUT<5 seconds, and Schirmer Ⅱ test results<5 mm. No abnormalities were detected in corneal endothelial cell count, macular optical coherence tomography, ultra-wide field fundus imaging, or fundus autofluorescence. During the treatment period, 3 patients (42.9%) developed simultaneous peeling of palm skin and nails. After treatment, symptoms improved in 4 patients, and the remaining 3 patients showed improvement after adding cyclosporine A eye drops. One patient discontinued the RET inhibitor due to severe dry eye symptoms, with subsequent improvement; however, symptoms recurred and worsened upon resumption of the medication. Conclusions: NSCLC patients receiving RET inhibitor treatment may develop ocular surface damage characterized by corneal epithelial injury, reduced tear film stability, and decreased tear secretion. Clinicians should pay close attention to the ocular adverse reactions and associated mucocutaneous manifestations of these drugs.