For an adult patient with multiple brain metastases, a controlled primary tumor, no extracranial disease, and Karnofsky performance status ≥70, what whole‑brain radiotherapy schedule is recommended based on RTOG 79‑20?

RTOG 79-20 Whole-Brain Radiotherapy Schedule

The question references RTOG 79-20, but this specific trial is not included in the provided evidence base, and no contemporary guidelines recommend the specific fractionation schedules tested in that historical trial for modern practice.

Historical Context and Modern Evidence Gap

The evidence provided does not contain information about RTOG 79-20 specifically. However, based on the RTOG recursive partitioning analysis (RPA) classification system that emerged from subsequent RTOG trials analyzing 1,200 patients, your described patient (multiple brain metastases, controlled primary, no extracranial disease, KPS ≥70) would be classified as RPA Class I 1.

Contemporary Treatment Recommendations for This Patient Profile

For Multiple Brain Metastases (>4 lesions) with RPA Class I Status:

Whole-brain radiotherapy remains the recommended approach when more than 3-4 brain metastases are present in RPA Class I-II patients 2, 3.

Modern WBRT Fractionation Schedules:

The evidence base provides several validated fractionation options:

• 30 Gy in 10 daily fractions - This is the most commonly referenced standard schedule in contemporary guidelines 1, 4, 5

• 37.5 Gy in 15 daily fractions of 2.5 Gy - This is an acceptable alternative predetermined at some treating centers 4

• 40 Gy in 20 twice-daily fractions - This showed improved intracranial control (44% vs 64% progression, p=0.03) and reduced CNS death (32% vs 52%, p=0.03) compared to 20 Gy in 4 fractions, with maintained quality of life 6

• 20 Gy in 4 daily fractions - This abbreviated schedule showed inferior intracranial control and higher salvage therapy requirements (21% vs 4%, p=0.004) 6

Evidence Against Dose Escalation:

Accelerated hyperfractionation to 54.4 Gy (1.6 Gy twice daily with boost) showed no survival benefit over standard 30 Gy in 10 fractions in RTOG 9104, even for RPA Class I patients (1-year survival 35% vs 25%, p=0.95) 5. This regimen cannot be recommended despite theoretical advantages 5.

Critical Clinical Considerations

Supportive Care Requirements:

• Dexamethasone 4 mg/day (or equivalent) should be administered for symptomatic metastases or significant edema 2, 3
• Early tapering after radiotherapy is essential to minimize long-term corticosteroid toxicity 2, 3
• Corticosteroids should NOT be used for asymptomatic metastases 2, 3

Neuroprotective Strategies:

If WBRT is administered and the patient has no hippocampal lesions with ≥4 months expected survival:

• Memantine should be offered 1
• Hippocampal avoidance techniques should be employed 1

Expected Outcomes for RPA Class I:

• Median survival: 7.1 months with WBRT 1
• This represents the best prognosis group among brain metastases patients 1

Common Pitfalls to Avoid

• Do not use dose escalation beyond 30-40 Gy - Higher doses with hyperfractionation provide no survival benefit and increase treatment burden 5

• Do not use abbreviated schedules (e.g., 20 Gy in 4 fractions) in good prognosis patients - This results in worse intracranial control and higher salvage therapy requirements 6

• Do not omit neuroprotective strategies - Memantine and hippocampal avoidance significantly reduce cognitive deterioration without compromising efficacy 1

• Do not continue corticosteroids indefinitely - Early tapering prevents long-term toxicity while maintaining symptom control 2, 3