Grace Lee1, Luke Besse2, Nayan Lamba3, Cindy Hancox4, Iquan Usta5, Fred Hacker6, Paul Catalano7, Paul D Brown8, Shyam Tanguturi9, Itai Pashtan10, John Phillips11, Daphne Haas-Kogan12, Brian Alexander13, Daniel Cagney14, Ayal Aizer15. 1. Harvard Medical School, Boston, MA 02115, USA; Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: grace0691@gmail.com. 2. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA; Broad Institute, Cambridge, MA 02142, USA. Electronic address: lbesse@broadinstitute.org. 3. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: nlamba@partners.org. 4. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: chancox@bwh.harvard.edu. 5. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: iusta@bwh.harvard.edu. 6. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: fhacker@bwh.harvard.edu. 7. Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA. Electronic address: catalano@hsph.harvard.edu. 8. Department of Radiation Oncology, Mayo Clinic, Rochester, MN 55905, USA. Electronic address: brown.paul@mayo.edu. 9. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: stanguturi@partners.org. 10. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. 11. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: ipashtan@partners.org. 12. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: jphillips@bwh.harvard.edu. 13. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: dhaas-kogan@bwh.harvard.edu. 14. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: dcagney@bwh.harvard.edu. 15. Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA, 02115, USA. Electronic address: ayal_aizer@dfci.harvard.edu.
Abstract
PURPOSE: Among patients with brain metastases, hippocampal avoidance whole brain radiation (HA-WBRT) preserves neurocognitive function relative to conventional WBRT but the feasibility of hippocampal sparing in patients with metastases in/near the hippocampus is unknown. We identified the incidence of hippocampal/perihippocampal metastases and evaluated the feasibility of HA-WBRT in such patients. MATERIALS/ METHODS: Dosimetric data from 34 patients randomized to HA-WBRT (30 Gy/10 fractions) in a phase III trial (NCT03075072) comparing HA-WBRT to stereotactic radiation in patients with 5 to 20 brain metastases were analyzed. Patients with metastases in/near the hippocampi received HA-WBRT with prioritization of tumor coverage over hippocampal avoidance. Target coverage and hippocampal sparing metrics were compared between patients with targets in/near the hippocampus versus not. RESULTS: In total, 9 of 34 (26%) patients had targets in the hippocampus and an additional 5 of 34 (15%) patients had targets in the hippocampal avoidance zone (HAZ, hippocampus plus 5 mm expansion) but outside the hippocampus. Patients with targets within the hippocampus and those with targets in the HAZ but outside the hippocampus were spared 34% and 73% of the ipsilateral mean biologically equivalent prescription dose, respectively. Of the latter cohort, 88% and 25% met conventional hippocampal sparing metrics of Dmin ≤ 9 Gy and Dmax ≤ 16 Gy, respectively. Among 11 patients with unilateral hippocampal/perihippocampal involvement, the uninvolved/contralateral hippocampus was limited to Dmin ≤ 9 Gy and Dmax ≤ 17 Gy in all cases. CONCLUSIONS: In this study, a substantial percentage of patients with 5 to 20 brain metastases harbored metastases in/near the hippocampus. In such cases, minimizing hippocampal dose while providing tumor coverage was feasible and may translate to neurocognitive protection. Published by Elsevier Inc.
PURPOSE: Among patients with brain metastases, hippocampal avoidance whole brain radiation (HA-WBRT) preserves neurocognitive function relative to conventional WBRT but the feasibility of hippocampal sparing in patients with metastases in/near the hippocampus is unknown. We identified the incidence of hippocampal/perihippocampal metastases and evaluated the feasibility of HA-WBRT in such patients. MATERIALS/ METHODS: Dosimetric data from 34 patients randomized to HA-WBRT (30 Gy/10 fractions) in a phase III trial (NCT03075072) comparing HA-WBRT to stereotactic radiation in patients with 5 to 20 brain metastases were analyzed. Patients with metastases in/near the hippocampi received HA-WBRT with prioritization of tumor coverage over hippocampal avoidance. Target coverage and hippocampal sparing metrics were compared between patients with targets in/near the hippocampus versus not. RESULTS: In total, 9 of 34 (26%) patients had targets in the hippocampus and an additional 5 of 34 (15%) patients had targets in the hippocampal avoidance zone (HAZ, hippocampus plus 5 mm expansion) but outside the hippocampus. Patients with targets within the hippocampus and those with targets in the HAZ but outside the hippocampus were spared 34% and 73% of the ipsilateral mean biologically equivalent prescription dose, respectively. Of the latter cohort, 88% and 25% met conventional hippocampal sparing metrics of Dmin ≤ 9 Gy and Dmax ≤ 16 Gy, respectively. Among 11 patients with unilateral hippocampal/perihippocampal involvement, the uninvolved/contralateral hippocampus was limited to Dmin ≤ 9 Gy and Dmax ≤ 17 Gy in all cases. CONCLUSIONS: In this study, a substantial percentage of patients with 5 to 20 brain metastases harbored metastases in/near the hippocampus. In such cases, minimizing hippocampal dose while providing tumor coverage was feasible and may translate to neurocognitive protection. Published by Elsevier Inc.
Authors: Jasmine A Graham; Gage Redler; Kirby B Delozier; Hsiang-Hsuan Michael Yu; Daniel E Oliver; Stephen A Rosenberg Journal: J Appl Clin Med Phys Date: 2022-03-28 Impact factor: 2.243