Recurrent and new tumours during conservative treatment of bilateral retinoblastoma.

Conservative treatment of retinoblastoma is a combination of different therapeutic modalities: radiotherapy, photocoagulation, cryocoagulation, chemotherapy. The choice of the most suitable treatment depends on the stage of the disease. The evaluation of the regression and quiescence of tumoral foci after radiotherapy, Xenon photocoagulation or cryocoagulation is based on a purely subjective examination of the ophthalmoscopic aspects which are common to various types of treatment. Frequently, degenerative changes of the tumour mass are difficult to differentiate from actual recurrence. Recurrences generally start at the edge of the scar or within the scar, while new retinal tumours are observed far from the original tumour, sometimes near the ora serrata. The authors discuss the regression patterns and the ophthalmoscopic and clinical aspects of recurrent and new tumours and report their personal experience on the therapeutic approach.