FDG-PET/CT Predicts Outcome in Oropharingeal Carcinoma Patients Undergoing Intensity Modulated Radiation Therapy with Dose Escalation to FDG-avid Tumour Volumes

Curr Radiopharm. 2017 Aug 24;10(2):102-110. doi: 10.2174/1874471010666170413151108.

Abstract

Objective: To evaluate the predictive value of FDG-PET/CT parameters on outcome of oropharyngeal squamocellular cancer (OSCC) patients undergoing helical tomotherapy (HTT), with dose escalation to FDG-PET/CT positive tumour volumes using the simultaneous integrated boost (SIB) technique.

Materials and methods: We analysed 41 patients studied by FDG-PET/CT and treated with radical intent between 2005 and 2014 for OSCC. HTT-SIB was delivered in 30 fractions concomitantly: 69 Gy, as SIB, to the PET-positive volume (biological target volume - BTV-PET), both to the primary tumour (T) and lymph nodes (N), 66 Gy to the T and positive N, 54 Gy to the laterocervical nodes at risk. Selected PET parameters were recovered: maximum and mean standardized uptake values (SUVmax and SUVmean, respectively), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) obtained with different thresholds (40-50-60% of the SUVmax) for T and N. The correlation between these parameters and the 3-year overall (OS), cancer specific (CSS), disease free (DFS), local relapse free for T and N (LRFS-T and LRFS-N) and distant metastasis free (DMFS) survivals was investigated.

Results: The median follow-up was 37 months (range: 3-125). The 3-year OS, CSS, DFS, LRFST, LRFS-N and DMFS were 86%, 88%, 76%, 83%, 88% and 91%, respectively. BTVT+ N>30.9cc and BTV-T>22.4cc were correlated with CSS (p=0.02) and OS (p=0.006) respectively; TLG-T-60>34.6cc was correlated with CSS (p=0.04) and OS (p=0.01). MTV-T-60>4.4cc could predict a higher risk of relapse/death (CSS: p=0.033; hazard ratio (HR) =10.92; OS: p=0.01; HR=16.4; LRFS-T: p=0.02; HR=13.90; LRFS-T+N: p=0.03; HR=6.50).

Conclusion: PET parameters predicted survival outcomes and may be considered in the future in the implementation of more personalized treatment schedules in patients affected by OSCC undergoing radiotherapy. FDG-PET/CT dose escalated HTT-SIB allowed very promising 3-year disease control rates in OSCC patients.

Keywords: FDG-PET/CT; MTV; SUV; TLG; oropharyngeal cancer; radiotherapy; survival outcomes..

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Squamous Cell / diagnostic imaging*
  • Carcinoma, Squamous Cell / pathology
  • Carcinoma, Squamous Cell / radiotherapy*
  • Dose Fractionation, Radiation
  • Female
  • Fluorodeoxyglucose F18 / metabolism*
  • Humans
  • Lymphatic Metastasis / diagnostic imaging
  • Lymphatic Metastasis / radiotherapy
  • Male
  • Middle Aged
  • Neoplasm Grading
  • Neoplasm Staging
  • Oropharyngeal Neoplasms / drug therapy*
  • Oropharyngeal Neoplasms / pathology
  • Oropharyngeal Neoplasms / radiotherapy*
  • Positron Emission Tomography Computed Tomography*
  • Predictive Value of Tests
  • Radiopharmaceuticals / metabolism*
  • Radiotherapy Dosage
  • Radiotherapy, Intensity-Modulated*
  • Retrospective Studies
  • Survival Rate
  • Treatment Outcome
  • Tumor Burden

Substances

  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18