This multicenter study examined 503 patients with recurrent glioblastomas who underwent surgical resection. It found that aggressive surgical resection of recurrent glioblastomas, when followed by adjuvant therapy, was associated with increased overall survival. Specifically, survival was longer for patients who were younger, had a higher Karnofsky performance status, underwent a more extensive resection, and had a longer time between initial diagnosis and recurrence. However, the study had limitations as a retrospective analysis subject to selection bias. Repeat resection improved survival, but its benefits compared to nonsurgical therapy require further prospective evaluation.

1. MACQUARIE NEUROSURGERY JOURNAL CLUB
Ahmad M. Badran
10 November 2016

2. Clinical benefit from resection of recurrent glioblastomas:
results of a multicenter study including 503 patients with
recurrent glioblastomas undergoing surgical resection

3. Institution metrics/ Authors/ Journal
20 participating neurosurgical departments in Germany, Switzerland,
and Austria.
• Department of Neurosurgery, Klinikum Rechts der Isar, Technische Universita¨ t Mu¨ nchen,
Munich, Germany (F.R., H.P., B.M.); Department of Neurosurgery, Heinrich Heine Universita¨ t Du¨
sseldorf, Du¨ sseldorf, Germany (M.S.); Department of Neurosurgery, Universita¨ tsklinikum Carl
Gustav Carus, Dresden, Germany (D.K.); Department of Neurosurgery, Universita¨ tsmedizin
Go¨ ttingen, Go¨ ttingen, Germany (H.C.B.); Department of Neurosurgery, Charite´
Universita¨ tsmedizin, Berlin, Germany (M.M.); Department of Neurosurgery, Universita¨ tsklinikum
Freiburg, Freiburg, Germany (A.W.); Department of Neurosurgery, Universita¨ tsklinikum
Wu¨ rzburg, Wu¨ rzburg, Germany (T.W.); Department of Neurosurgery, Goethe Universita¨ t
Frankfurt, Frankfurt, Germany (C.S.); Department of Neurosurgery, Inselspital, Universita¨ tsklinikum
Bern, Bern, Switzerland (P.S.); Department of Neurosurgery, Universita¨ tskliniken Bonn,
Rheinische Friedrich Wilhelms Universita¨ t, Bonn, Germany (M.S.)

4. Institution metrics/ Authors/ Journal
• Florian Ringel, Haiko Pape, Michael Sabel, Dietmar Krex, Hans
Christoph Bock, Martin Misch, Astrid Weyerbrock, Thomas
Westermaier, Christian Senft, Philippe Schucht, Bernhard Meyer,
Matthias Simon, and the SN1 study group.
• Neuro-Oncology 18(1), 96–104, 2016.

5. Study Relevance and Originality
• Both relevant and important.
• The role of a surgical resection of recurrent glioblastomas remains
largely unclear at present.
• This study aimed to assess the effect of repeated resection of
recurrent glioblastomas on patient survival.

6. Study Relevance and Originality

7. Research hypothesis
Aggressive surgical resection of recurrent/ progressive glioblastomas,
followed by adjuvant therapy, could contribute to increased overall
survival.
A beneficial influence of repeat surgery on survival is also suggested
by the correlation between the extent of resection and survival.

8. Study Design
• Retrospective cohort study.
• Database (2006-2010).
• Multicenter study (20 participating neurosurgical departments in
Germany, Switzerland, and Austria).
• 503 patients with primary glioblastomas undergoing repeat resections
for recurrent tumours were evaluated for factors affecting survival.
• Age, Karnofsky performance status (KPS), extent of resection (EOR),
tumour location, and complications were assessed.

9. Internal Validity
This is a retrospective analysis and is, therefore, inherently subject to
bias. Patient’s selection bias may have resulted from the treating
surgeons leading a group of patients towards redo surgery.
This is a multi-center analysis and thereby doesn’t reflect the treatment
bias of one institution.
The number of patients and longitudinal nature of follow-up was good
compared to other reports in the literature.
Statistical analysis was reasonable.

10. External Validity
• Inclusion criteria:
(i) De novo glioblastoma (WHO IV) upon initial tumour diagnosis.
(ii) Initial diagnosis between January 2006 and June 2010.
(iii) Surgical tumour resection following initial diagnosis.
(iv) Surgical resection of a recurrent tumour or progressive tumour
remnant.

11. External Validity
• Exclusion criteria:
(i) Secondary glioblastomas.
(ii) If the initially diagnosed tumour was not resected (biopsy only).
(iii) If the patient received a nonsurgical treatment for first tumour
recurrence.

12. External Validity
• For each patient, the following parameters were recorded: sex, date of
first (second, third, etc.) surgery, age at the respective surgeries, and
extent of resection.
• The extent of the surgical resection (EOR) was categorized as
(i)complete, (ii) resection above 90% but incomplete, (iii) resection
between 50% and 90%, and (iv) resection of less than 50%.
• EOR was assessed at the respective centres, which all used
postoperative imaging during the period of patient inclusion as a
routine procedure.

13. Results

14. Results

15. Results

16. Results

17. Results

18. Results

19. Results

20. Discussion / conclusions
Repeat surgery was believed to be associated with a higher
incidence of new neurological deficits, and the oncological
benefit of a second resection remained obscure.
When comparing repeat surgery with nonsurgical therapy from
retrospective and prospective data, studies so far have failed to
reveal a benefit from repeat resection.

21. Discussion / conclusions
Selection of patients for repeat resections was at the discretion of the
respective centres, and not all patients undergoing surgery in the study
period might have been reported.
Surprisingly, the duration between initial surgery and re-resection did
not influence survival after re-resection. However, this might be due to
a selection bias since patients with early progression/recurrence were
probably not chosen for a re-resection by the contributing centres.
Standardized information on tumour size, location, and extent of
resection are not available. This could change the results if only
small-sized recurrent tumours would have been included.

22. Presentation and style
The paper was clear and organized.
The number of words were acceptable.
The tables and figures were good.

23. Conclusion
Repeat resection of a recurrent/progressive glioblastoma should be
considered whenever safely possible, especially in young age
group patients, high KPS, and longer time of recurrence.
The surgery should aim at a maximum safe resection and should
be followed by adjuvant chemotherapy.

24. Conclusion
Is the study believable (internally valid)?
Is the study relevant (externally valid)?
Will the study change my practice?

25. Thank You