Phase 2 LATTICE radiotherapy spatially fractionated SBRT vs dose-escalated palliative RT.

Stanford University is running an unblinded, randomized Phase 2 study testing whether LATTICE radiotherapy—a spatially fractionated stereotactic technique that delivers a lower “background” dose to the full metastasis with a simultaneous integrated boost (SIB) to small lattice sub-volumes—can improve palliation and local control versus a more conventional hypofractionated palliative regimen. Patients with metastatic solid tumors are randomized to either 20 Gy in 5 fractions with an SIB to 66.7 Gy in 5 fractions (LATTICE) or 25 Gy in 5 fractions of moderately dose-escalated palliative radiation. The key scientific angle is whether concentrating very high biologic dose into “peaks” inside bulky tumors can drive better tumor kill while keeping surrounding normal-tissue dose closer to standard palliative plans, building on early prospective/technical experience with Lattice SBRT schedules like 20 Gy/5 with a 66.7 Gy SIB. Today’s care for symptomatic metastases is palliative external-beam radiation (often 8 Gy ×1, 20 Gy ×5, or 30 Gy ×10 depending on site/urgency), with systemic therapy chosen by tumor type; this trial asks if a novel radiation geometry can outperform a straightforward 5-fraction dose escalation.