Interim Tumor Progression and Volumetric Changes of Surgical Cavitiesduring the Surgery-to-Radiotherapy Interval in Anaplastic Gliomas:Implications for Additional Pre-radiotherapy Magnetic Resonance Imaging / Journal of the Korean Cancer Association, 대한암학회지

ABSTRACT

Purpose@#This study was designed to investigate the incidence of interim disease progression (IPD)and volumetric changes of the surgical cavity (SC) during the surgery-to-radiotherapy interval(SRI), and eventually assess the value of magnetic resonance imaging (MRI) at the time ofradiotherapy (RT) planning in newly diagnosed anaplastic gliomas. @*Materials and Methods@#Among 195 anaplastic glioma patients who underwent RT, 121 were evaluable with twoseparate MRIs during SRI. The presence of IPD was determined using the updatedResponse Assessment in Neuro-Oncology size criteria. In 84 patients who underwent surgicalresection, each SC was contoured by a radiation oncologist and the volumetric changesof the SCs were calculated between the two separate MRIs. Daily rate of change in the SCvolume was calculated assuming an exponential and linear change. @*Results@#Five of 121 patients (4.13%) demonstrated IPD during SRI, and the incidence was significantlyhigher in patients undergoing biopsy (vs. surgical resection, 12.9% vs. 1.1%, p=0.015)and in patients with remnant contrast-enhancing tumor after surgery (15.8 vs. 2.0%,p=0.027). The mean daily rate of absolute change in SC was 1.06% (95% confidence interval[CI], 0.89 to 1.23) and 0.89% (95% CI, 0.77 to 1.02) according to the exponential andlinear model, respectively. The expected mean volumetric change at 2 weeks were 16.64%(95% CI, 13.77 to 19.52) and 12.51% (95% CI, 10.77 to 14.26), respectively. @*Conclusion@#IPD during the SRI is rare in surgically resected anaplastic gliomas. However, pre-RT MRI isessential for accurate RT-target delineation and disease evaluation for patients initiatingRT beyond postoperative 2 weeks and undergoing biopsy, respectively.