Malignant mucosal melanoma treated with carbon ion radiotherapy with concurrent chemotherapy: prognostic value of pretreatment apparent diffusion coefficient (ADC).
OBJECTIVE
To evaluate the potential of apparent diffusion coefficient (ADC) value before carbon ion radiotherapy (C-ion RT) for malignant mucosal melanoma (MMM) to predict prognosis.


METHODS
We recruited 37 patients with MMM in the head and neck treated by C-ion RT with concomitant chemotherapy. Univariate and multivariate analyses of minimum ADC, mean ADC, tumor volume, age, PS, and gender were performed to identify prognostic factors.


RESULTS
The 3-year local control rate, distant metastasis-free survival rate and overall survival rate of all patients were 81.1%, 37.6% and 65.3%, respectively, with a median follow-up period of 19.0 months. In univariate analyses, lower minimum ADC (≤0.6380 × 10(-3) mm(2)/s) and lower mean ADC (≤1.1523 × 10(-3) mm(2)/s) were unfavorable prognostic factors for distant metastasis (p=0.029 and p=0.014, respectively), and lower minimum ADC was an unfavorable prognostic factor for overall survival (p=0.019). However, there was no significant prognostic factor of local control including ADC value. In multivariate analyses, only minimum ADC was selected as a prognostic factor of distant metastasis-free survival and overall survival (p=0.015 and p=0.006, respectively).


CONCLUSIONS
Minimum ADC can be a prognostic factor of MMM in the head and neck after C-ion RT.
Jingu
Keiichi
K
Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Japan. kjingu@nirs.go.jp
Kishimoto
Riwa
R
Mizoe
Jun-Etsu
JE
Hasegawa
Azusa
A
Bessho
Hiroki
H
Tsuji
Hiroshi
H
Kamada
Tadashi
T
Yamada
Shogo
S
Tsujii
Hirohiko
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002244:Carbon / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D063193:Heavy Ion Radiotherapy; D006801:Humans; D008297:Male; D008545:Melanoma / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D008875:Middle Aged; D011379:Prognosis; D015996:Survival Rate
D002244:Carbon