RESUMEN
PURPOSE: Progress of the novel carbon ion radiotherapy (CIRT) in the treatment of cancers has created the need for a method to accurately evaluate the response. We investigated whether L-[11C]methyl-methionine (11C-methionine) uptake at pre- and post-CIRT could be an early response predictor in patients with pelvic recurrence of rectal cancer. PROCEDURES: 11C-Methionine-positron emission tomography (PET) was performed prospectively in 53 patients with pelvic recurrence of rectal cancer before CIRT, and 48 patients were performed 11C-methionine PET at 1 month after CIRT. 11C-Methionine tumor uptake was measured by the tumor to muscle ratio (T/M ratio). The T/M ratios were evaluated in relation to clinical outcomes such as local re-recurrence, distant metastasis, and survival. The response to CIRT was also judged by computed tomography (CT) and magnetic resonance imaging (MRI). 11C-Methionine PET judgment was compared with CT/MRI judgment regarding the relevance to clinical outcome. RESULTS: Baseline T/M ratio was 5.27+/-1.90 (mean+/-SD) in patients without developing local re-recurrence and 7.66+/-3.17 in patients with local re-recurrence (p=0.023, Mann-Whitney U test). Post-CIRT T/M ratios were 3.10+/-1.28 in patients without local re-recurrence and 6.15+/-2.98 in patients with local re-recurrence (p=0.006, Mann-Whitney U test). By Kaplan-Meier analysis with log-rank test, patients with a baseline T/M ratio of Asunto(s)
Radioisótopos de Carbono/uso terapéutico
, Metionina
, Recurrencia Local de Neoplasia/diagnóstico por imagen
, Tomografía de Emisión de Positrones/métodos
, Neoplasias del Recto/diagnóstico por imagen
, Neoplasias del Recto/radioterapia
, Adenocarcinoma/diagnóstico por imagen
, Adenocarcinoma/radioterapia
, Adenocarcinoma/secundario
, Adulto
, Anciano
, Femenino
, Humanos
, Masculino
, Persona de Mediana Edad
, Neoplasias Pélvicas/diagnóstico por imagen
, Pronóstico
, Estudios Prospectivos
, Radiofármacos
RESUMEN
OBJECTIVE: Chordoma is a rare malignant bone tumor that arises from notochord remnants. This is the first trial to investigate the utility of (11)C-methionine (MET) positron emission tomography (PET) in the imaging of chordoma before and after carbon-ion radiotherapy (CIRT). DESIGN AND PATIENTS: Fifteen patients with chordoma were investigated with MET-PET before and after CIRT and the findings analyzed visually and quantitatively. Tumor MET uptake was evaluated by tumor-to-nontumor ratio (T/N ratio). RESULTS: In 12 (80%) patients chordoma was clearly visible in the baseline MET-PET study with a mean T/N ratio of 3.3+/-1.7. The MET uptake decreased significantly to 2.3+/-1.4 after CIRT ( P<0.05). A significant reduction in tumor MET uptake of 24% was observed after CIRT. Fourteen (93%) patients showed no local recurrence after CIRT with a median follow-up time of 20 months. CONCLUSION: This study has demonstrated that MET-PET is feasible for imaging of chordoma. MET-PET could provide important tumor metabolic information for the therapeutic monitoring of chordoma after CIRT.
Asunto(s)
Cordoma/diagnóstico por imagen , Tomografía de Emisión de Positrones , Sacro/diagnóstico por imagen , Neoplasias de la Columna Vertebral/diagnóstico por imagen , Anciano , Anciano de 80 o más Años , Radioisótopos de Carbono/uso terapéutico , Cordoma/radioterapia , Fraccionamiento de la Dosis de Radiación , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sacro/efectos de la radiación , Neoplasias de la Columna Vertebral/radioterapiaRESUMEN
PURPOSE: The development of the novel carbon ion radiotherapy (CIRT) in the treatment of refractory cancers has resulted in the need for a way to accurately evaluate patient prognosis. We evaluated whether L-[methyl-(11)C]-methionine (MET) uptake and its change after CIRT were the early survival predictors in patients with unresectable bone and soft tissue sarcomas. EXPERIMENTAL DESIGN: MET positron emission tomography was prospectively performed in 62 patients with unresectable bone and soft tissue sarcomas before and within 1 month after CIRT. Tumor MET uptake was measured with the semiquantitative tumor:nontumor ratio (T/N ratio). The MET uptake in the tumor and relevant clinical parameters were entered into univariate and multivariate survival analysis. RESULTS: The overall median survival time was 20 months. Patients with a baseline T/N ratio of