The role of dual-time combined 18-fluorodeoxyglucose positron emission tomography and computed tomography in the staging and restaging workup of locally advanced rectal cancer, treated with preoperative chemoradiation therapy and radical surgery.

Abstract

PURPOSE:

In patients with locally advanced rectal cancer (LARC) staging and, after preoperative chemo-radiation therapy (CRT), restaging workup could be useful to tailor therapeutic approaches. Fluorine-18-fluorodeoxyglucose positron emission tomography ([(18)F]FDG-PET) is a promising tool for monitoring the effect of antitumor therapy. This study was aimed to evaluate the possible role of dual time sequential FDG-PET scans in the staging and restaging workup of LARC.

METHODS AND MATERIALS:

Eighty-seven consecutive patients with LARC were enrolled. CRT consisted of external-beam intensified radiotherapy (concurrent boost), with concomitant chemotherapy PVI 5-FU (300 mg/m(2)/day) followed 8-10 weeks later by surgery. All patients underwent [(18)F]FDG-PET/CT before and 5-6 weeks later after the completion of CRT. Measurements of FDG uptake (SUV(max)), and percentage of SUV(max) difference (Response Index = RI) between pre- and post-CRT [(18)F]FDG-PET scans were evaluated.

RESULTS:

Six of 87 patients were excluded due to protocol deviation. Following CRT, 40/81 patients (49%) were classified as responders according to Mandard's criteria (TRG1-2). The mean pre-CRT SUV(max) was significantly higher than post-CRT (15.8, vs 5.9; p < 0.001). The mean RI was significantly higher in responders than in nonresponder patients (71.3% vs 38%; p = 0.0038). Using a RI cut-off of 65% for defining response to therapy, the following parameters have been obtained: 84.5% sensitivity, 80% specificity, 81.4% positive predictive value, 84.2% negative predictive value, and 81% overall accuracy.

CONCLUSION:

These results suggest the potential role of [(18)F]FDG-PET in the restaging workup after preoperative CRT in LARC. RI seems the best predictor to identify CRT response.

• Authors: Carlo Capirci, Domenico Rubello, Felice Pasini, Fabrizio Galeotti, Enzo Bianchini, Giuseppe Del Favero, Riccardo Panzavolta, Giorgio Crepaldi, Lucia Rampin, Enzo Facci, Marcello Gava, Elena Banti, Gianfranco Marano
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 74 Issue 5 Pg. 1461-9 (Aug 01 2009) ISSN: 1879-355X [Electronic] United States
• PMID: 19419820 (Publication Type: Evaluation Study, Journal Article)

Chemical References

• Antimetabolites, Antineoplastic
• Radiopharmaceuticals
• Fluorodeoxyglucose F18
• Fluorouracil

Topics

• Adult
• Aged
• Aged, 80 and over
• Antimetabolites, Antineoplastic (administration & dosage)
• Female
• Fluorodeoxyglucose F18
• Fluorouracil (administration & dosage)
• Humans
• Male
• Middle Aged
• Neoadjuvant Therapy (methods)
• Neoplasm Staging (methods)
• Positron-Emission Tomography (methods)
• Prospective Studies
• Radiopharmaceuticals
• Rectal Neoplasms (diagnostic imaging, pathology, therapy)
• Remission Induction (methods)
• Sensitivity and Specificity
• Statistics, Nonparametric
• Tomography, X-Ray Computed (methods)