Selective Ophthalmic Artery Chemotherapy with Melphalan in the Management of Unilateral Retinoblastoma: A Prospective Study

Efficacy of a prolonged stability melphalan formulation for intra-arterial treatment of retinoblastoma

BACKGROUND

Melphalan, which is poorly soluble at room temperature, is widely used for the treatment of retinoblastoma by selective ophthalmic artery infusion. Evomela, a propylene glycol-free formulation of melphalan with improved solubility and stability, has recently been used as an alternative.To compare the safety and efficacy of Evomela with standard-formulation melphalan (SFM) in the treatment of retinoblastoma by selective ophthalmic artery infusion.

METHODS

We performed a retrospective case-control study of patients with retinoblastoma undergoing selective ophthalmic artery infusion with SFM or Evomela at a single institution. Cycle-specific percent tumor regression (CSPTR) was estimated by comparing photos obtained during pretreatment examination under anesthesia (EUA) with those obtained during post-treatment EUA 3-4 weeks later. CSPTR, ocular salvage rates, complication rates, operation times (unadjusted and adjusted for difficulty of ophthalmic artery catheterization), and intraprocedural dose expiration rates were compared between Evomela- and SFM-treated groups. Univariate and multivariate analyses were performed.

RESULTS

Ninety-seven operations (melphalan: 45; Evomela: 52) for 23 patients with 27 retinoblastomas were studied. The ocular salvage rate was 79% in the SFM-treated group and 69% in the Evomela-treated group. Multivariate regression controlling for tumor grade, patient age, and treatment history revealed no significant differences in ocular salvage rate, CSPTR, complication rates, or operation times. Although the dose expiration rate was higher for the SFM-treated group, the difference was not statistically significant. Notably, there were no ocular or cerebral ischemic complications.

CONCLUSION

Evomela has non-inferior safety and efficacy relative to SFM when used for the treatment of retinoblastoma by selective ophthalmic artery infusion.

Retinoblastoma: From genes to patient care

Retinoblastoma is the most common paediatric neoplasm of the retina, and one of the earliest model of cancer genetics since the identification of the master tumour suppressor gene RB1. Tumorigenesis has been shown to be driven by pathogenic variants of the RB1 locus, but also genomic and epigenomic alterations outside the locus. The increasing knowledge on this "mutational landscape" is used in current practice for precise genetic testing and counselling. Novel methods provide access to pre-therapeutic tumour DNA, by isolating cell-free DNA from aqueous humour or plasma. This is expected to facilitate assessment of the constitutional status of RB1, to provide an early risk stratification using molecular prognostic markers, to follow the response to the treatment in longitudinal studies, and to predict the response to targeted therapies. The aim of this review is to show how molecular genetics of retinoblastoma drives diagnosis, treatment, monitoring of the disease and surveillance of the patients and relatives. We first recap the current knowledge on retinoblastoma genetics and its use in every-day practice. We then focus on retinoblastoma subgrouping at the era of molecular biology, and the expected input of cell-free DNA in the field.