Abstract
We assessed the impact of including peritumoral edema in radiotherapy volumes on recurrence patterns among glioblastoma multiforme (GBM) patients treated with standard chemoradiotherapy (CRT). We analyzed 167 patients with histologically confirmed GBM who received temozolomide (TMZ)-based CRT between May 2006 and November 2012. The study cohort was divided into edema (+) (n = 130) and edema (−) (n = 37) groups, according to whether the entire peritumoral edema was included. At a median follow-up of 20 months (range, 2–99 months), 118 patients (71%) experienced progression/recurrence (infield: 69%; marginal: 26%; outfield: 16%; CSF seeding: 12%). The median overall survival and progression-free survival were 20 months and 15 months, respectively. The marginal failure rate was significantly greater in the edema (−) group (37% vs. 22%, p = 0.050). Among 33 patients who had a favorable prognosis (total resection and MGMT-methylation), the difference in the marginal failure rates was increased (40% vs. 14%, p = 0.138). Meanwhile, treatment of edema did not significantly increase the incidence of pseudoprogression/radiation necrosis (edema (−) 49% vs. (+) 37%, p = 0.253). Inclusion of peritumoral edema in the radiotherapy volume can reduce marginal failures following TMZ-based CRT without increasing pseudoprogression/radiation necrosis.
Highlights
Cells within the peritumoral edema[12], and a margin of 3 cm beyond the edema was proposed as an optimal margin to ensure complete coverage of all tumor cells[13]
Regarding the optimal radiotherapy volume, several retrospective studies suggested that a limited margin did not alter the failure patterns
In M.D Anderson Cancer Center, 48 patients were treated with a small field not intentionally including peritumoral edema
Summary
Cells within the peritumoral edema[12], and a margin of 3 cm beyond the edema was proposed as an optimal margin to ensure complete coverage of all tumor cells[13]. In the era of concurrent chemoradiotherapy with TMZ, many studies have reported that local recurrence is still a major failure pattern in limited-margin radiotherapy. Several studies reported improved local control but higher rates of distant failures in patients with favorable prognostic factors including O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation or extensive surgical resection[14,15,16,17,18]. With an increasing rate of gross total/subtotal resection and an empirical experience of frequent out-field recurrence without in-field recurrence, we have changed to larger-field radiotherapy including the peritumoral edema. We assessed the impact of including the peritumoral edema in radiotherapy volumes on recurrence patterns according to extent of surgical resection and MGMT promoter methylation status among GBM patients treated with the standard chemoradiotherapy in a single institution cohort
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
