324P - Radiation response assessment by hybrid positron emission tomography/magnetic resonance imaging for cervical cancer treatment

Date 18 December 2016
Event ESMO Asia 2016 Congress
Session Poster lunch
Topics Cervical Cancer
Imaging, Diagnosis and Staging
Surgery and/or Radiotherapy of Cancer
Presenter Bok Ai Choo
Citation Annals of Oncology (2016) 27 (suppl_9): ix94-ix103. 10.1093/annonc/mdw585
Authors B.A. Choo1, V. Koh1, J. Tang1, J. Low1, M.C. Stephenson2, D.L. Cheong2, E. Laurens2, J.J. Totman2, J.S. Ng1, S. Roy2
  • 1Radiation Oncology, National University Cancer Institute, Singapore, 119228 - Singapore/SG
  • 2A*star-nus, Clinical Imaging Research Centre, Singapore/SG

Abstract

Background

Treatment response after radiation therapy (RT) in locally advanced cervical cancer is commonly 2-3 months post-therapy. We aim to investigate the ability of hybrid PET-MRI to visualize tumour changes during the initial radiation phase, to optimise and personalised radiation dosage.

Methods

All patients received four or five insertions of ring (Vienna) or ovoid (Utrecht) MRI compatible based brachytherapy in addition to five and half weeks of daily external RT. With the mandatory written informed consent, four multi-parametric PET/MRI scans comprising of dynamic contrast-enhance imaging and diffusion weighted imaging were performed on each patient. The patients were examined first with 6mCi 18F-FDG scan at baseline. Prior to the first and third brachytherapy insertions, the patients were examined with the second and third 3mCi 18F-FDG scans respectively. The last scan was performed 3 months post-treatment with 6mCi 18F-FDG as this will act as a prognosticator tool to assess whether a complete response has been achieved.

Results

We report results of our pilot study. Aging between 46-55 years, all patients had histopathologically confirmed cervical cancer. On PET, metabolic target volume was 15.5-22.6 cm3 at baseline, with SUVmax 6.0-7.5 and SUVmean 4.3-5.4. MRI region of interest volume at baseline was 12.3-114.7 cm3. Good radiological treatment response was shown by all patients on both PET and MRI, with observations typically reflecting largest variation between the baseline and second scan (post external RT). A mid-treatment increase in SUV occurred to one patient due to additional interstitial needle insertion during brachytherapy. At 3 months post-treatment, all patients attained complete radiological response. To date, there are no clinical locoregional recurrences.

Conclusions

Significant treatment response to RT can be detected early using PET/MRI, typically by end of external beam RT. The intention is to establish this finding through patient accrual. Personalized treatment concordant to tumour response may be developed. This will help to enhance cure rate and reduce potential side effects by giving a personalised radiation dose to the tumour rather than a standard protocolised dose.

Clinical trial indentification

National University Hospital Singapore Institutional Review Board approved protocol number 2013/00052

Legal entity responsible for the study

National University Hospital Singapore

Funding

National Cancer Institute Singapore

Disclosure

All authors have declared no conflicts of interest.