Monday, September 29, 2025
Contouring for Central Nervous System Cancer
Faculty:
- Michelle Kim, MD - University of Michigan
- Helen Shih, MD, MS, FASTRO, MPH, AM - Massachusetts General Hospital
Review the case description and images below and participate in the poll on how you would contour this case.
Case Description
A 45 year old right-handed male presented with headaches, nausea, double vision and word-finding difficulties. MRI reveals hydrocephalus and 1 cm of midline shift from a large, heterogeneous left frontal mass that is predominantly non-enhancing, with patchy areas of enhancement. The patient undergoes awake craniotomy and subtotal resection with pathology revealing Astrocytoma, IDH-mutant, CNS WHO grade 3 with MGMT promoter methylation and without CDKN2A/B homozygous deletion.
Which clinical target volume contour is the most appropriate? Please click on the poll to let us know how you would contour this case.
A. Surgical cavity + residual T1-post contrast enhancement and an anatomically constrained 1.5 cm CTV margin
B. Tumor bed + residual T1-post contrast enhancement + 2 cm CTV margin including ventriculostomy tract
C. Tumor bed + residual T1-post contrast enhancement + residual T2/FLAIR and an anatomically constrained 1.5 cm CTV margin
Check back tomorrow when Dr. Kim and Dr. Shih will weigh in on how they would contour.