Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology

1135 - Early prediction of histopathological response by PET/CT after two weeks of neoadjuvant chemoradiotherapy for rectal cancer: Wishful thinking or reality?

Date

21 Oct 2018

Session

Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology

Presenters

Yulia Kundel

Citation

Annals of Oncology (2018) 29 (suppl_8): viii150-viii204. 10.1093/annonc/mdy281

Authors

Y. Kundel1, G. Natalia2, H. Berenshtain2, J. Prus3, B. Brenner3

Author affiliations

  • 1 Radiation oncology, Rabin Medical Center Davidoff Cancer Centre, Beilinson Campus, 49100 - Petah Tikva/IL
  • 2 Radiology, Rabin Medical Center Beilinson Campus, 49100 - Petah Tikva/IL
  • 3 Oncology, Institute of Oncology, Davidoff Cancer Center, Rabin Medical Center, Beilinson Hospital, 49100 - Petach Tiqva/IL
More

Resources

Abstract 1135

Background

Neoadjuvant chemoradiotherapy (CRT) is standard in locally advanced rectal cancer (LARC). Current data on the predictive value of early PET/CT, i.e. the correlation between the tumor’s early metabolic response, manifested by the reduction of its 18F-FDG uptake after two weeks of CRT compared with baseline, and histopathological response, are conflicting.

Methods

Patients (pts) with histologically confirmed LARC who were planned to receive standard CRT regimen of 50.4 Gray radiotherapy with concurrent fluoropyrimidine–based chemotherapy followed by radical surgery were eligible for the study. Baseline PET/CT was done within 4 weeks prior to CRT and the investigational scan was done two weeks+/-two days after its initiation. Maximum standardized uptake value (SUV-MAX) and the changes in FDG uptake between the two scans (ΔSUV-MAX) were compared with the histopathological response at surgery. Response was classified by tumor regression grade (TRG) and presence of pathological complete response (pCR).

Results

Twenty pts were included in the study, 65% with clinical stage II and 35% with stage III. Ninety percents of tumors were located at least 5 cm from the anal verge. Pts underwent surgery within a median of 8.6 weeks (4.5-12.8) after the completion of CRT. Six pts (30%) achieved pCR and 7 (35%) had TRG I-II. Absolute SUV-MAX values at both time points did not correlate with pCR (p = 0.099) nor with TRG (p = 0.670). Histopathological response also did not correlate with ΔSUV-MAX: pts who achieved pCR had median ΔSUV-MAX of -45%, while those who did not had median ΔSUV-MAX of -41% (p = 0.617). Similarly, pts with TRG I-II and those with TRG III-IV had the same median ΔSUV-MAX of -42% (p = 0.882). In addition, using ROC analysis we did not find any cutoff of any the PET-CT parameters that will predict pCR or TRG I-II.

Conclusions

In the current study, early PET/CT done after two weeks of neoadjuvant CRT for LARC, failed to predict histopathological response to treatment.

Clinical trial identification

Legal entity responsible for the study

Rabin Medical Center.

Funding

Has not received any funding.

Editorial Acknowledgement

Disclosure

All authors have declared no conflicts of interest.

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.