Prognostic evaluation of re-resection for recurrent glioblastoma using the novel RANO classification for extent of resection: A report of the RANO resect group

Background The value of re-resection in recurrent glioblastoma remains controversial as a randomized trial that specifies intentional incomplete resection cannot be justified ethically. Here, we aimed to (1) explore the prognostic role of extent of re-resection using the previously proposed Response Assessment in Neuro-Oncology (RANO) classification (based upon residual contrast-enhancing (CE) and non-CE tumor), and to (2) define factors consolidating the surgical effects on outcome. Methods The RANO resect group retrospectively compiled an 8-center cohort of patients with first recurrence from previously resected glioblastomas. The associations of re-resection and other clinical factors with outcome were analyzed. Propensity score-matched analyses were constructed to minimize confounding effects when comparing the different RANO classes. Results We studied 681 patients with first recurrence of Isocitrate Dehydrogenase (IDH) wild-type glioblastomas, including 310 patients who underwent re-resection. Re-resection was associated with prolonged survival even when stratifying for molecular and clinical confounders on multivariate analysis; <= 1 cm(3) residual CE tumor was associated with longer survival than non-surgical management. Accordingly, maximal resection (class 2) had superior survival compared to submaximal resection (class 3). Administration of (radio-)chemotherapy in the absence of postoperative deficits augmented the survival associations of smaller residual CE tumors. Conversely, supramaximal resection of non-CE tumor (class 1) was not associated with prolonged survival but was frequently accompanied by postoperative deficits. The prognostic role of residual CE tumor was confirmed in propensity score analyses. Conclusions The RANO resect classification serves to stratify patients with re-resection of glioblastoma. Complete resection according to RANO resect classes 1 and 2 is prognostic.

Automated summary

This study retrospectively analyzed 681 patients with first recurrence of IDH wild-type glioblastomas. It found that re-resection could prolong the survival time of patients, and residual contrast-enhancing tumor of 1 cm³ or less had longer survival than non-surgical management. Complete resection according to the RANO resect classification had a better prognosis. Patients without postoperative deficits who received (radio-)chemotherapy had enhanced survival associations with smaller residual contrast-enhancing tumors. However, resection of non-contrast-enhancing tumor did not prolong survival.