Early FDG PET response assessment of preoperative radiochemotherapy in locally advanced rectal cancer: Correlation with long-term outcome

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Abstract

Purpose: The aim of the present study is to prospectively evaluate the prognostic value of previously defined [18F]2-fluoro-2-deoxy-D- glucose positron emission tomography (FDG PET) criteria of early metabolic response in patients with locally advanced rectal cancer (LARC) after long-term follow-up. Methods: Forty-two patients with poor prognosis LARC underwent three biweekly courses of chemotherapy with oxaliplatin, raltitrexed and 5-fluorouracil modulated by levofolinic acid during pelvic radiotherapy. FDG PET studies were performed before and 12 days after the beginning of the chemoradiotherapy (CRT) treatment. Total mesorectal excision (TME) was carried out 8 weeks after completion of CRT. A previously identified cutoff value of ≥52 % reduction of the baseline mean FDG standardized uptake value (SUV mean) was applied to differentiate metabolic responders from non-responders and correlated to tumour regression grade (TRG) and survival. Results: Twenty-two metabolic responders showed complete (TRG1) or subtotal tumour regression (TRG2) and demonstrated a statistically significantly higher 5-year relapse-free survival (RFS) compared with the 20 nonresponders (86 vs 55 %, p0.014) who showed TRG3 and TRG4 pathologic responses. A multivariate analysis demonstrated that early δSUVmean was the only presurgical parameter correlated to the likelihood of recurrence (p0.05). Conclusion: This study is the first prospective long-term evaluation demonstrating that FDG PET is not only an early predictor of pathologic response but is also a valuable prognostic tool. Our results indicate the potential of FDG PET for optimizing multidisciplinary management of patients with LARC.

Original languageEnglish
Pages (from-to)1848-1857
Number of pages10
JournalEuropean Journal of Nuclear Medicine and Molecular Imaging
Volume39
Issue number12
DOIs
Publication statusPublished - Dec 2012

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Keywords

  • FDG PET
  • Locally advanced rectal cancer
  • Long-term outcome
  • Preoperative radiochemotherapy
  • Response assessment

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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