Guidelines for Complications of Cancer Treatment Vol VIII Part B

which mirrors the increased incidence of CVA. The possiblerisk factors include hypopituitarism, radiotherapy and extentof surgery but none are at present proven causes. Theevaluation of new treatment strategies should not only assessintermediate end-points of tumour and endocrine control butshould concentrate on long-term survival with particularemphasis on CVA incidence and mortality.D. Radiation induced necrosis1. Pseudoprogression (PsPr) after concurrentradiotherapy (RT) and temozolomide (TMZ) fornewly diagnosed glioblastoma multiforme (GBM).Clarke JL, Abrey LE, Karimi S, Lassman AB. J ClinOncol 26: 2008 (May 20 suppl; abstr 2025)Background: Increased contrast enhancement on brain imagingfollowing chemoradiotherapy is often interpreted asprogression of disease (PD). However, there is growingevidence that radiographic and even clinical worsening mayresult from effects of therapy, i.e. PsPr, rather than from truePD. Methods: 80 patients (pts) with GBM were treated in anIRB-approved phase 2 clinical trial with concurrent RT andTMZ followed by adjuvant TMZ. MRI was performed post-RT. PsPr was defined as increased contrast enhancement onthe initial post-RT MRI scan that improved without changingchemotherapy, or as histologically documented necrosis. TruePD was defined as continued progression on subsequent scans,or histologically documented viable tumor. MR perfusionimaging with relative cerebral blood volume (rCBV) and FDGPET imaging were collected in subsets of patients. Results:There were 33 pts with increased enhancement on the initialpost-RT MRI; 8 (24%) had PsPr, 17 (52%) had true PD, and8 (24%) discontinued TMZ (PsPr vs. true PD unknown). Ofthe 8 pts with PsPr, 2 had MR perfusion scans; bothdemonstrated increased rather than decreased rCBV. Twoothers had FDG PET scans; both showed hyper- rather than366