Comparison of radiological and clinical features of temporal lobe necrosis in nasopharyngeal carcinoma patients treated with 2D radiotherapy or intensity-modulated radiotherapy

BACKGROUND: To compare the imaging and clinical features of temporal lobe necrosis (TLN) in nasopharyngeal carcinoma (NPC) patients treated with two-dimensional radiotherapy (2D-RT) or those with intensity-modulated radiotherapy (IMRT). METHODS: We retrospectively analysed NPC patients who underwent 2D-RT (72 patients, 128 temporal lobes) or IMRT (36 patients, 50 lobes) and developed radiation-induced, MRI-confirmed TLN. RESULTS: White-matter lesions (WMLs), contrast-enhanced lesions, cysts and local mass effects were present in 128 out of 128 vs 48 out of 50 (P=0.078), 123 out of 128 vs 47 out of 50 (P=0.688), 10 out of 128 vs 1 out of 50 (P=0.185) and 57 out of 128 vs 13 out of 50 (P=0.023) temporal lobes, respectively, in the 2D-RT and IMRT groups. The WMLs were more extensive in the 2D-RT group (P<0.001). The maximum diameter of contrast-enhanced lesions was greater in the 2D-RT group (P<0.001), and these lesions tended to extend far away from the nasopharynx. The WMLs and enhancement had no impact on cyst development (both P=1). Local mass effects were always accompanied with contrast-enhanced lesions (P=0.024) but were not correlated with WMLs or cysts (P=0.523 and 0.341, respectively). There were no between-group differences in clinical features (all P-values>0.05), whereas the difference in the incidence of severe debility was of marginal significance (18.1% vs 5.6%, P=0.077). CONCLUSIONS: The IMRT-induced TLN was less extensive and milder than 2D-RT-induced TLN, but both had similar clinical features.