Disciform Keratitis That Improves With Poly(Adenosine Diphosphate-Ribose) Polymerase Inhibitor Treatment for Ovarian Cancer but Recurs Upon Discontinuation of Treatment.

The patient was a 73-year-old woman. She underwent surgery for ovarian cancer but needed chemotherapy because tumor cells were observed at the resection margin. She was administered niraparib tosilate hydrate, a poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor, for five years; however, she developed severe malaise that made daily life difficult, rendering continued treatment impossible. Consequently, the PARP inhibitor was discontinued, and her physical condition improved. One year after discontinuation, she developed ocular herpes zoster, followed by disciform keratitis, leading to her presentation at our hospital. Examination of the right eye revealed disciform corneal edema and opacity, resulting in a diagnosis of disciform keratitis. Varicella-zoster virus (VZV) DNA was detected via PCR analysis of the aqueous humor; treatment with oral valacyclovir and topical betamethasone was initiated. Subsequently, the disciform keratitis resolved with continued topical betamethasone therapy. However, ovarian cancer recurrence was observed, and another PARP inhibitor, olaparib, was prescribed. She again experienced malaise, necessitating the discontinuation of the PARP inhibitor. One month after discontinuation, a recurrence of disciform keratitis was observed. Frequent topical betamethasone administration was initiated, resulting in the resolution of the disciform keratitis. These findings suggest the possibility that in patients with cancer who are immunocompromised due to treatment with PARP inhibitors, an immune response against VZV does not occur; however, when immune function recovers upon discontinuation of the PARP inhibitor, the immune response against VZV is reactivated, resulting in the recurrence of disciform keratitis. Thus, when managing patients with cancer, it is essential to monitor fluctuations in immune response while addressing ocular infections and inflammatory diseases.