Prognostic value of subclassification using MRI in the t4 classification nasopharyngeal carcinoma intensity-modulated radiotherapy treatment.
OBJECTIVE
To subclassify patients with the T4 classification nasopharyngeal carcinoma (NPC), according to the seventh edition of the American Joint Committee on Cancer staging system, using magnetic resonance imaging (MRI), and to evaluate the prognostic value of subclassification after intensity-modulated radiotherapy (IMRT).


METHODS
A total of 140 patients who underwent MRI and were subsequently histologically diagnosed with nondisseminated classification T4 NPC received IMRT as their primary treatment and were included in this retrospective study. T4 patients were subclassified into two grades: T4a was defined as a primary nasopharyngeal tumor with involvement of the masticator space only; and T4b was defined as involvement of the intracranial region, cranial nerves, and/or orbit.


RESULTS
The 5-year overall survival (OS) rate and distant metastasis-free survival (DMFS) rate for T4a patients (82.5% and 87.0%, respectively), were significantly higher than for T4b patients (62.6% and 66.8%; p = 0.033 and p = 0.036, respectively). The T4a/b subclassification was an independent prognostic factor for OS (hazard ratio = 2.331, p = 0.032) and DMFS (hazard ratio = 2.602, p = 0.034), and had no significant effect on local relapse-free survival.


CONCLUSIONS
Subclassification of T4 patients, as T4a or T4b, using MRI according to the site of invasion, has prognostic value for the outcomes of IMRT treatment in NPC.
State Key Laboratory of Oncology in South China, Department of Radiation Oncology, Sun Yat-sen University Cancer Center, Guangzhou, People's Republic of China.
Lei
L
Chen
Li-Zhi
LZ
Liu
Mo
M
Chen
Wen-Fei
WF
Li
Wen-Jing
WJ
Yin
Ai-Hua
AH
Lin
Ying
Y
Sun
Li
L
Li
Jun
J
Ma
D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D059248:Chemoradiotherapy / Q000379:methods; D017024:Chemotherapy, Adjuvant / Q000379:methods; D005260:Female; D006801:Humans; D017567:Karnofsky Performance Status; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000145:classification / Q000188:drug therapy / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D050397:Radiotherapy, Intensity-Modulated; D055815:Young Adult