## Retinoblastoma: Treatment Strategies and Classification ### Treatment Paradigm Shift **Key Point:** Modern retinoblastoma management prioritizes **globe salvage** over enucleation whenever possible, especially in unilateral disease with good visual potential and in all cases of bilateral disease. **High-Yield:** The treatment approach depends on: 1. **Unilateral vs. bilateral disease** 2. **Tumor size and location** 3. **Visual prognosis** 4. **Risk stratification using International Classification** ### Enucleation Indications **Key Point:** Enucleation is reserved for: - **Large tumors** (>8 mm in thickness OR >15 mm in base diameter) - **Poor visual prognosis** (vision <20/200 or rubeotic glaucoma) - **Neovascular glaucoma** - **Phthisical eye** - **Failed globe-salvaging therapy** - **Extraocular extension** **Clinical Pearl:** Even in unilateral disease, globe salvage is attempted if there is any potential for useful vision. ### Chemotherapy Approaches #### Systemic Chemotherapy - **Induction chemotherapy** (vincristine, etoposide, carboplatin) followed by focal therapy (laser, cryotherapy, brachytherapy) - Standard for bilateral disease and high-risk unilateral disease - Goal: reduce tumor burden and allow focal consolidation #### Intra-Arterial Chemotherapy (IAC) **High-Yield:** Intra-arterial chemotherapy is **NOT contraindicated** — it is an **established, effective globe-salvaging modality**. **Key Point:** IAC is indicated for: - **Chemotherapy-resistant tumors** - **Vitreous seeding** - **Recurrent or refractory disease** - **Unilateral tumors with good visual potential** **Clinical Pearl:** IAC delivers high drug concentration directly to the ophthalmic artery, minimizing systemic exposure compared to systemic IV chemotherapy. It has become a cornerstone of globe-salvaging therapy in specialized centers. ### International Classification of Retinoblastoma (Murphree) **Key Point:** The Murphree classification stratifies intraocular disease into five groups (A–E) based on tumor size, location, vitreous involvement, and other factors. | Group | Risk Profile | Treatment | | --- | --- | --- | | A | Smallest, best prognosis | Observation, focal therapy | | B | Small to medium | Systemic chemo + focal therapy | | C | Medium, vitreous seeding | Systemic chemo + focal therapy ± IAC | | D | Large, extensive seeding | Systemic chemo + IAC ± external beam | | E | Phthisical, pain, NVG | Enucleation | **High-Yield:** This classification guides treatment intensity and helps predict globe salvage rates and overall survival. ### Treatment Algorithm ```mermaid flowchart TD A[Retinoblastoma diagnosed]:::outcome --> B{Unilateral or Bilateral?}:::decision B -->|Unilateral| C{Group A-B or C-E?}:::decision B -->|Bilateral| D[Systemic chemotherapy induction]:::action C -->|A-B| E[Focal therapy ± systemic chemo]:::action C -->|C-E| F[Systemic chemotherapy]:::action D --> G[Assess response]:::decision F --> G G -->|Good response| H[Focal therapy: laser, cryo, brachytherapy]:::action G -->|Resistant| I[IAC or external beam]:::action H --> J{Globe salvaged?}:::decision I --> J J -->|Yes| K[Long-term surveillance]:::outcome J -->|No| L[Enucleation]:::action L --> M[Adjuvant therapy if high-risk pathology]:::action ``` [cite:Boyd 5e Ch 17]
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