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Letter to the Editor. An extent of resection threshold for recurrent glioblastoma: why wait until recurrence?

TO THE EDITOR: We read with great interest the article by Oppenlander and colleagues,2 who have reported their experience with recurrent glioblastoma in a series of 170 patients treated first by reoperation (Oppenlander ME, Wolf AB, Snyder LA, et al: An extent of resection threshold for recurrent glioblastoma and its risk for neurological morbidity. J Neurosurg 120:846–853, April 2014). The authors have attempted to quantify the effect of the extent of resection (EOR) on survival in patients with recurrent glioblastoma, and to define a possible threshold for tumor cytoreduction. The authors should be complimented for reporting such a large and reliable group of data on reresection strategy, especially when we consider that repeat resection remains an increasingly common consideration for both patients and the neuro-oncological community. Nowadays, determining the best treatment of glioblastoma at recurrence represents a real clinical challenge. Reoperation is one of many other treatment possibilities.1 Reoperation for glioblastoma, especially when a gross-total resection seems feasible, remains increasingly of interest to our group at Tirana University Hospital. The actuarial literature has provided incomplete and controversial information on this issue. However, almost all authors agree that gross-total resection has real potential clinical and survival benefits. How can we increase the number of patients undergoing a larger EOR? Interestingly, despite the latter assumption, the second resection is always offered when new tumor growth is radiologically evident. If a gross-total resection is feasible at glioblastoma recurrence, it would surely be feasible at the time of maximal response just before tumor progression. Thus, why wait until recurrence? This was our working hypothesis. First, we performed a re-resection in 11 patients at the time of the best response after second-line bevacizumab-based chemotherapy. The median overall survival was 20.6 months. These encouraging results prompted us to propose maximal resection in 4 patients at the time of maximal response after concomitant radiochemotherapy. In all cases, a more than 90% EOR was achieved, correlating with an improved progression-free survival and a median overall survival of 24.8 months. Despite criticism for selection bias and the retrospective design of our study, our findings compared well with those of Oppenlander and colleagues in advocating an aggressive strategy whenever possible, regardless of the status of our patients, whether at recurrence or at greatest tumor shrinking. To conclude, we think that a second resection should always be considered when the response after first-line radiochemotherapy for glioblastoma may help optimize the extent of surgical removal, even for tumors initially considered unresectable. Why wait until recurrence to perform that operation? In our opinion, the timing of re-resection could considerably modify the natural course of the disease as well as patient survival. Certainly, a prospective study with a long-term follow-up and larger population is required to better define the impact of reoperation at the right moment.