Phase I Trial of MRI-Guided Prostate Cancer Lattice Extreme Ablative Dose (LEAD) Boost Radiation Therapy

Alan Pollack, Felix M. Chinea, Elizabeth Bossart, Deukwoo Kwon, Matthew C. Abramowitz, Charles Lynne, Merce Jorda, Brian Marples, Vivek N. Patel, Xiaodong Wu, Isildinha Reis, Matthew T. Studenski, Javier Casillas, Radka Stoyanova

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Purpose: A phase I clinical trial was designed to test the feasibility and toxicity of administering high-dose spatially fractionated radiation therapy to magnetic resonance imaging (MRI)–defined prostate tumor volumes, in addition to standard treatment. Methods and Materials: We enrolled 25 men with favorable to high-risk prostate cancer and 1 to 3 suspicious multiparametric MRI (mpMRI) gross tumor volumes (GTVs). The mpMRI-GTVs were treated on day 1 with 12 to 14 Gy via dose cylinders using a lattice extreme ablative dose technique. The entire prostate, along with the proximal seminal vesicles, was then treated to 76 Gy at 2 Gy/fraction. For some high-risk patients, the distal seminal vesicles and pelvic lymph nodes received 56 Gy at 1.47 Gy/fraction concurrently in 38 fractions. The total dose to the lattice extreme ablative dose cylinder volume(s) was 88 to 90 Gy (112-123 Gy in 2.0 Gy equivalents, assuming an α-to-β ratio of 3). Results: Dosimetric parameters were satisfactorily met. Median follow-up was 66 months. There were no grade 3 acute/subacute genitourinary or gastrointestinal adverse events. Maximum late genitourinary toxicity was grade 1 in 15 (60%), grade 2 in 4 (16%), and grade 4 in 1 (4%; sepsis after a posttreatment transurethral resection). Maximum late gastrointestinal toxicity was grade 1 in 11 (44%) and grade 2 in 4 (16%). Two patients experienced biochemical failure. Conclusions: External beam radiation therapy delivered with an upfront spatially fractionated, stereotactic high-dose mpMRI-GTV boost is feasible and was not associated with any unexpected events. The technique is now part of a follow-up phase II randomized trial.

Original languageEnglish (US)
Pages (from-to)305-315
Number of pages11
JournalInternational Journal of Radiation Oncology Biology Physics
Issue number2
StatePublished - Jun 1 2020

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research


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