Incomplete retinoblastoma regression after chemotherapy: is follow-up without adjuvant treatment a possible option?

Purpose. To evaluate the safety of dynamic follow-up without adjuvant treatment in patients with incomplete retinoblastoma regression and to determine predictors of tumor progression by univariate statistical analysis. Material and methods. We analyzed medical history and data of 80 patients (84 eyes, 89 tumors) with incomplete retinoblastoma regression, treated by systemic and/or local chemotherapy, which underwent dynamic follow-up without adjuvant treatment. The obligate criterion was translucent, avascular tumor without signs of continued tumor growth. Patients’ age varied from 1 to 62 months (Me 14 mo.). 46 patients (58%) were male, 34 – female (42%). 51 patients (64%) presented with bilateral retinoblastoma, 29 patients (36%) – with monocular. In 9 cases (11%) the only eye was present. Eye distribution according to tumor stages was the following: T1b, group В – 20 eyes (24%), Т2а, group С – 18 eyes (21%), Т2b, group D – 42 eyes (50%), T2c, group E – 4 eyes (5%). Most of the tumor had central localization (n=60, 67%), 22 tumors (25%) – postequatorial, 7 tumors (8%) – preequatorial. 29 tumors (33%) had signs of 2nd regression type, 60 tumors (67%) – of 3rd type. Results. In 55% of cases (n=49) we observed continuous tumor regression in time. Nineteen tumors (21%) were stable without change of size in the mean follow-up of 20 months (range, 8–105 mo.). In almost quarter of tumors (n=21, 24%) we noted tumor progression within 2 to 23 months (Me 6 mo.). Analysis by Kaplan – Meier estimates showed tumor progression peak in first year of follow-up. Complications of adjuvant treatment had been observed in 5 of treated eyes (23%). Overall, 96% of eyes were preserved. The only significant variable identified by univariate analysis was 3rd regression type (p=0.01). Conclusion. Dynamic follow-up is a possible option for patients with chemoresistant retinoblastoma, especially for central tumor localization. Tumors with type 2 regression significantly less often demonstrate tumor progression in time. Tumor progression occurs in first 2 years of follow-up. Key words: retinoblastoma, incomplete regression, follow-up, local treatment, chemotherapy