When is chemotherapy indicated for patients with retinoblastoma?

Chemotherapy is indicated for patients with retinoblastoma primarily for intraocular groups C and D because these classifications indicate a more advanced disease state where the tumors are large or have spread within the eye. In these cases, chemotherapy can help reduce the size of the tumors or facilitate other treatment options, such as laser therapy or cryotherapy, ultimately aiming to preserve vision and control the disease.

Intraocular groups C and D indicate that treatment is necessary to effectively manage the disease, as lump sizes and potential invasion of surrounding tissues increase the risk of complications. Chemotherapy works by targeting rapidly dividing cancer cells, making it a useful modality to shrink tumors before other interventions or to treat aggressive disease.

Other potential treatment options, such as surgical removal of the tumor, might not be directly applicable in the earlier stages represented by intraocular groups, or surgeries might not achieve the same outcomes when lesions are still present or when there is a significant risk of metastasis. The other options either suggest interventions inappropriate for the disease stage or imply a lack of treatment when chemotherapy could be beneficial. Thus, for groups C and D, utilizing chemotherapy is essential to optimize patient care and outcomes in retinoblastoma.