Table 3 Regrading of meningiomas would change recommendations for postoperative radiotherapy/radiosurgery.

	After complete resection		After incomplete resection
	WHO grade I → II (n = 56)	WHO grade II → III (n = 55)	WHO grade I → II (n = 58)	WHO grade II → III (n = 56)
No change	47 (83.9%)	20 (36.4%)	28 (48.3%)	22 (39.3%)
No radiotherapy → EBR	2 (3.6%)	20 (36.4%)	10 (17.2%)	16 (28.6%)
No radiotherapy → radiosurgery/conformal radiotherapy	3 (5.4%)	16 (29.1%)	12 (20.7%)	9 (16.1%)
No radiotherapy → radiotherapy	9 (16.1%)	31 (56.4%)	18 (31.0%)	21 (37.5%)
Other changes*	0	5 (9.1%)	6 (10.3%)	16 (28.6%)

The table details how changing the histological grade (for example, by applying a different grading system) would result in significantly different recommendations for postoperative radiation therapy. Numbers exclude centres recommending radiotherapy only for progressive/recurrent disease or specific tumour locations (for example, cavernous sinus).

*Includes recommending EBR instead of conformal radiotherapy/radiosurgery and vice versa, and applying radiotherapy in selected cases v recommending it to all patients.

EBR, external beam radiotherapy; WHO, World Health Organisation.