Survival and ocular preservation in a long-term cohort of Japanese patients with retinoblastoma

Background: Retinoblastoma is an ocular tumor in infants with cancer predisposition. Treatment of the rare tumor needs to be optimized for ocular preserved survival without second primary malignancy (SPM). Methods: We studied the outcomes of all patients with retinoblastoma at a tertiary center in 1984-2016, when preservation method changed from radiotherapy (1984-2001) to systemic chemotherapy (2002-2016). Results: One-hundred sixteen infants developed unilateral- (n = 77), bilateral- (n = 38), or trilateral-onset (n = 1) tumor. Ten (8.6%) had a positive family history, despite a few studies on RB1 gene. Contralateral disease occurred in one unilateral-onset case. One-hundred eight of 155 eyes (70%) were enucleated. Nine binocular survivors were from 5 bilateral- and 4 unilateral-onset cases. Two survivors received bilateral enucleation. Six deaths occurred; brain involvement (including 3 trilateral diseases) in 4 bilateral-onset, systemic invasion in a unilateral-onset, and SPM (osteosarcoma) in a bilateral-onset case(s). Two others survived SPM of osteosarcoma or lymphoma. The 10-year overall survival (OS: 98.5% vs. 91.3%, p = 0.068) and binocular survivors (13.2% vs. 5.2%, p = 0.154) between bilateral- and unilateral-onsets did not differ statistically. The 10-year OS and cancer (retinoblastoma/SPM)-free survival (CFS) rates of all patients were 94.9 and 88.5%, respectively. The proportion of preserved eyes did not differ between radiotherapy and chemotherapy eras. The CFS rate of bilateral-onset cases in systemic chemotherapy era was higher than that in radiotherapy era (p = 0.042). The CFS rates of bilateral-onset patients with neoadjuvant chemotherapy (upfront systemic therapy for preservation) was higher than those without it (p = 0.030). Conclusions: Systemic chemotherapy and local therapy raised OS and binocular survival rates of bilateral-onset patients similarly to those of unilateral-onset patients. All but one death was associated with a probable germline defect of the RB1 gene. Neoadjuvant stratified chemotherapy may support the long-term binocular life with minimized risk of SPM.