LAUSR

PURPOSE To evaluate the ability of the 8th edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual to estimate metastatic and mortality rates for children with retinoblastoma(RB). DESIGN International, multicenter, registry-based retrospective case series PARTICIPANTS: 2190 patients from 18 ophthalmic oncology centers from 13 countries over 6 continents. METHODS Patient-specific data fields for RB were designed by participating eye cancer specialists. All RB patients with adequate records to allow tumor staging by the AJCC criteria and follow-up for metastatic disease were studied. MAIN OUTCOME MEASURES Metastasis-related 5- and 10-year survival data after initial tumor staging were estimated with the Kaplan-Meier method depending on AJCC clinical (cTNM) and pathological (pTNM) tumor, node, metastasis category and age, tumor laterality, and presence of heritable trait. RESULTS Of the 2190 patients, the records of 2085 patients(95.2%) with 2905 eyes were complete. The median age at diagnosis was 17.0 months. 1260 (65.4%) had unilateral RB. Amongst the 2085 patients, tumor categories were cT1a in 55 (2.6%), cT1b 168 (8.1%), cT2a 197 (9.4%), cT2b 812 (38.9%), cT3 835 (40.0%) and cT4 in 18 (0.9%) patients. Of these, 1397 eyes in 1353 patients(48.1%) were treated with enucleation. One hundred and nine patients (5.2%) developed metastases and died. The median time(n=92) from diagnosis to metastasis was 9.50 months. The 5- year Kaplan-Meier cumulative survival estimates by clinical tumor categories were 100% for category cT1a, 98% (95% confidence interval[CI], 97-99) for cT1b and cT2a, 96% (95% CI, 95-97) for cT2b, 89%(95% CI, 88-90) for cT3 tumors, and 45%(95% CI, 31-59) for cT4 tumors, respectively. Risk of metastasis increased with increasing cT (and pT) category(p < .001). Cox proportional hazards regression analysis confirmed a higher risk of metastasis in category cT3 (hazard rate [HR], 8.09; 95% CI, 2.55-25.70; p<0.001) and cT4 (HR, 48.55; 95% CI, 12.86-183.27; p< 0.001) compared to category cT1. Age, tumor laterality and presence of heritable trait did not influence the incidence of metastatic disease. CONCLUSION Multicenter, international, internet-based data sharing facilitated analysis of the 8th edition AJCC RB Staging System for metastasis-related mortality and offered a proof of concept yielding quantitative, predictive estimates per category in a large, real life, heterogenous RB patient population.