What is the recommended monitoring protocol for secondary tumours in patients with a history of retinoblastoma (cancer of the retina)?

Monitoring Protocol for Secondary Tumours in Retinoblastoma Survivors

Annual comprehensive history and physical examination with patient education about warning signs is recommended, but routine imaging surveillance with whole-body MRI, head/neck MRI, or CNS imaging is NOT recommended for asymptomatic heritable retinoblastoma survivors. 1

Core Surveillance Strategy

The monitoring approach differs fundamentally from what many institutions practice, as imaging-based surveillance has not demonstrated survival benefit and carries significant harms 1:

Annual Clinical Surveillance (Recommended)

• Annual comprehensive history and physical examination focusing on signs and symptoms of secondary malignancies 1, 2
• Patient and family education about concerning symptoms requiring prompt evaluation (new bone pain, masses, neurological symptoms, skin changes) 1
• Prompt medical evaluation for any new concerns between scheduled visits 1

Specific Cancer Surveillance by Type

Bone and Soft Tissue Sarcomas

• No routine imaging surveillance despite extremely high risk (SIR 360 for bone, SIR 122 for soft tissue) 1
• No whole-body MRI - lacks evidence of benefit and causes harm through false positives, gadolinium exposure, and psychological distress 1
• No head/neck regional MRI - no studies demonstrate benefit of this common institutional practice 1
• Risk is highest with prior radiotherapy, especially if irradiated in first year of life, but also elevated without radiation exposure 1

CNS Tumors

• No routine CNS surveillance imaging regardless of prior radiation exposure 1
• Despite increased risk (SIR 3.96 in irradiated patients), no study demonstrates surveillance benefit 1
• No CNS tumors observed in non-irradiated heritable retinoblastoma survivors in large cohorts 1

Melanoma

• Annual dermatologic examination is the only imaging-based surveillance recommended 2
• This represents a specific, evidence-supported exception to the no-imaging rule 2

Breast Cancer

• Surveillance per local guidelines (typically starting age 40) 1, 2
• Increased risk with SIR 3.0-4.5, but no evidence supports earlier or more intensive screening than general population 1
• Prioritize non-radiation imaging modalities (MRI over mammography when possible) due to theoretical radiation sensitivity 1

Uterine Leiomyosarcoma

• Gynecologic awareness of risk, but no effective screening available 2
• High case-fatality rate with inadequate detection methods 1

Colorectal Cancer

• No specific surveillance beyond general population recommendations 1
• Small number of cases at older ages (30-71 years) without clear increased risk 1

Hematologic Malignancies

• No specific surveillance - no increased risk demonstrated 1

Critical Pitfalls to Avoid

Common Practice vs. Evidence-Based Care

Many institutions routinely perform head/neck or whole-body MRI surveillance, but this practice lacks any evidence of benefit 1. One retrospective series of 25 patients undergoing whole-body MRI detected 2 osteosarcomas, but both patients died, and another sarcoma developed 3 months after a normal scan, demonstrating no survival advantage 1.

Harms of Imaging Surveillance

The recommendation against routine imaging is based on 1:

• False positive findings requiring additional invasive testing
• Potential gadolinium deposition (though often performed without contrast)
• Increased anxiety and psychosocial distress
• No demonstrated mortality benefit

Radiation Exposure Considerations

Minimize all ionizing radiation exposure in heritable retinoblastoma survivors 1:

• Avoid CT scans when alternatives exist
• Prefer MRI over mammography for breast screening when feasible
• Radiotherapy significantly increases secondary malignancy risk, particularly in those irradiated before age 1 year 1

Rationale for This Approach

This surveillance strategy aligns with American Association for Cancer Research (AACR) Childhood Cancer Predisposition Workshop consensus guidelines 1. The approach prioritizes quality of life by avoiding surveillance harms while maintaining vigilance through clinical monitoring, recognizing that no surveillance modality has been shown to extend life in this population 1.

The need for prospective international surveillance trials remains clear, potentially incorporating whole-body MRI, circulating cell-free DNA, or other novel modalities 1. Until such evidence emerges, clinical surveillance with prompt symptom evaluation represents the evidence-based standard 1, 2.