Objective: Identification of incidence and risk factors for recurrence of de novo retinoblastomas after chemotherapy treatment in patients with hereditary retinoblastoma.
Methods: A retrospective, case-control study of 32 patients (50 eyes) with sporadic or familial bilateral retinoblastomas was conducted. Patients received a systemic chemotherapy regimen applying three courses of a combination of three drugs (including vincristine, etoposide, carboplatin, or cyclophosphamide) followed by additional local therapy. The primary outcome analyzed was the development of retinoblastomas, probably arising as the cause of a new mutational event (de novo) after completion of chemotherapy treatment.
Results: Patients were treated with an average of 5.8 +/- 1.8 chemotherapy courses (4.6 +/- 2.4-year follow-up time). Development of de novo tumors occurred in 48% of the treated eyes. These tumors occurred during chemotherapy treatment or within 7 months of chemotherapy completion. No de novo tumors developed in patients older than 3.2 years. Children who developed de novo tumors were significantly younger at the time of diagnosis (6.7 +/- 6.3 months vs 14.4 +/- 11.4 months, P < 0.001), and had a significantly lower number of tumors per eye at treatment begin (2.6 +/- 2.3 tumors vs 4.3 +/- 6.4 tumors, P < 0.001). The difference of the total numbers of retinoblastomas that developed per eye between the patients that developed de novo retinoblastomas during or after chemotherapy and patients who did not was not statistically significant (4.9 +/- 2.7 and 4.3 +/- 6.4, respectively, P = 0.8). No eye was lost because of de novo retinoblastoma development, and 92% of the eyes were preserved.
Conclusions: De novo retinoblastomas developed both during and after completion of chemotherapy treatment. Younger children were at a significantly higher risk for developing de novo intraocular retinoblastomas. Good tumor control and eye preservation rates were achieved with regular and frequent control examinations in addition to the immediate treatment of de novo retinoblastomas.