A study on the prognostic evaluation of carbon ion radiotherapy for head and neck adenocarcinoma with C-11 methionine PET.
OBJECTIVE
Carbon ion radiotherapy (CIRT) has been developed, and a phase I/II CIRT trial has been conducted in patients with adenocarcinoma in the head and neck region. We evaluated whether the L-methyl [11C]-methionine (MET) uptake could be an early predictor for local recurrence, metastasis, and the prognosis in patients with adenocarcinoma in the head and neck region.


METHODS
Twenty-six patients were prospectively studied by MET-positron emission tomography (PET) before and about 1 month after CIRT. The tumor MET uptake was measured with the semiquantitative tumor to normal tissue ratio (TNR). The tumor TNR and relevant clinical parameters were then evaluated by both univariate and multivariate analyses.


RESULTS
The average TNRs before and after the treatment were 6.2 (± 2.2) and 3.9 (± 1.7), respectively, and significant differences were observed between them. In a univariate analysis, both local recurrence and metastasis were observed more frequently in the group with a higher TNR before and after the treatment than a lower TNR, and the prognosis was also poor. The cut-off values were 9.3, 4.9, and 5.1 before the treatment and 4.9, 4.2, and 4.3 after the treatment, respectively. In the rate of TNR changes before and after the treatment, metastasis was observed more frequently in the group with lower rates of change, and the prognosis was poor. The cut-off values for metastasis and prognosis determination were 18.0% and 16.9%, respectively. In a multivariate analysis, significant differences were observed for all relationships except for the relationship between the TNR before the treatment and local recurrence. Significant differences were observed for metastasis and prognosis in the rate of TNR changes before and after the treatment.


CONCLUSIONS
The determination of treatment effectiveness using TNR in CIRT for head and neck adenocarcinoma is an independent factor for predicting local recurrence, the incidence of metastasis, and the prognosis. MET-PET is therefore considered to be useful for determining the treatment effectiveness in patients with head and neck adenocarcinoma undergoing CIRT.
Hasebe
Mitsuhiko
M
Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage-ku, Chiba-shi, Chiba, Japan. m_hasebe@nirs.go.jp
Yoshikawa
Kyosan
K
Ohashi
Seiya
S
Toubaru
Sachiko
S
Kawaguchi
Koji
K
Sato
Junichi
J
Mizoe
Junetsu
J
Tsujii
Hirohiko
H
D000230:Adenocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002250:Carbon Radioisotopes; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008715:Methionine; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011379:Prognosis
D002250:Carbon Radioisotopes; D008715:Methionine