## First-Line Chemotherapy for Retinoblastoma **Key Point:** The standard chemotherapy regimen for intraocular retinoblastoma is the **VEC regimen** (Vincristine + Etoposide + Carboplatin), which has become the gold standard for globe-salvaging chemotherapy in most cases of retinoblastoma. ### Mechanism of VEC Regimen **Vincristine** — Microtubule destabilizer; arrests cells in metaphase. **Etoposide** — Topoisomerase II inhibitor; induces DNA breaks. **Carboplatin** — Platinum alkylating agent; cross-links DNA. This three-drug combination provides synergistic cytotoxicity with manageable toxicity profiles when delivered via systemic chemotherapy or intra-arterial chemotherapy (IAC). ### Treatment Approach by Stage | Classification | Treatment Strategy | | --- | --- | | Group A–B (small, favourable) | Chemotherapy (VEC) ± focal therapy (laser/cryotherapy) | | Group C (medium, intermediate) | VEC chemotherapy ± focal therapy; consider IAC | | Group D (large, unfavourable) | VEC ± IAC; may require external beam radiotherapy or enucleation | | Group E (very large, advanced) | Enucleation ± adjuvant chemotherapy | **High-Yield:** In the current era, **intra-arterial chemotherapy (IAC)** with carboplatin is increasingly preferred over systemic chemotherapy for intraocular disease because it delivers higher drug concentrations directly to the tumour with lower systemic toxicity. **Clinical Pearl:** Systemic VEC chemotherapy is still the standard for: - Bilateral retinoblastoma (to treat both eyes) - Extraocular disease - Metastatic retinoblastoma - Neoadjuvant therapy before focal treatment or IAC ### Why VEC? The VEC regimen achieves globe salvage rates of 60–70% in Group C tumours when combined with focal therapy. Single-agent chemotherapy (vincristine or carboplatin alone) is insufficient and has been superseded by combination regimens. [cite:Boyd & Murphree, Retinoblastoma; American Academy of Ophthalmology]
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