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