TITLE:
Is 18F-FDG-PET/CT a Valid Non-Invasive Predictor for Regression Grade after Neoadjuvant Treatment in Patients with NSCLC Stage III?
AUTHORS:
Natalie Desiree Klass, Richard P. Baum, Michael Schmuecking, Norbert Presselt, Klaus-Michael Mueller, Thomas G. Wendt, Reiner Bonnet
KEYWORDS:
NSCLC, 1818F-FDG-PET, Neoadjuvant Treatment, Non-Invasive Predictor
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.5 No.6,
May
16,
2014
ABSTRACT: Introduction: CT alone cannot provide sufficient information
referring to response after neoadjuvant therapy in a timely manner. To evaluate
the role of 18F-FDG-PET after neoadjuvant chemoradiation as a valid,
non-invasive predictor for early therapy response and its effect on survival as
compared to histopathologic tumor response, data of 32 of 210 randomized
patients with NSCLC stage IIIA/IIIB, who were treated in aprospective randomized controlled multicenter trial (LUCAS- MD), were
re-evaluated. Material and Methods: For 32 patients with NSCLC stage IIIA (44%)
IIIB (56%) neoadjuvant treatment consisted of two to three cycles of
chemotherapy (225 mg/m2 paclitaxel and carboplatin AUC 6 d1q22) and concomitant chemoradiation (50
mg/m2 paclitaxel and carboplatin AUC 2 d1, d8, d15; 1.5 Gy b.i.d.
up to 45 Gy). Documentation of involved lymph node stations as detected by 18F-FDG-PET/CT and lymph node sampling during surgery according to the IASLC
lymph node mapping (2009). Evaluation of histological regression grade (RG)
according to Junker et al. (2001) and correlation with18F-FDG-PET/CT for primary tumor
and each lymph node station. Calculation of disease free survival using
Kaplan-Meier estimates and log rank tests. Results: Actuarial tumor specific
survival for the 32 patients with concomitant chemoradiation pluschemotherapy: complete vs. incomplete metabolic remission prior to surgery
after 60 months:40% vs. 24% (p= 0.018). RG III/IIb (no/less than 10% of vital tumor cells)
vs. RG IIa/I (more than 10% vital tumor cells) after 60 months: 46% vs. 15% (p= 0.006). 18/32 (56%) patients had RG III/IIb, 8/32 (25%)
patients had regression grade III. 1/8 pts. with RG III were in the 18F-FDG- PET/CT false positive, 10 pts. with RG IIb (i.e. all pts. with RG IIb) were
in the 18F-FDG-PET/CT false negative. One patient with RG IIa was in
the 18F-FDG-PET/CT false negative. Hence, the cut-off level in
detecting vital tumor cells by 18F-FDG-PET/CT after neoadjuvant chemoradiation for NSCLC is
about 10%. Conclusion: Histological regression grading correlates well with
metabolic remission as detected by 18F-FDG-PET. Thus, 18F-FDG-PET precedes CT in measuring the tumor response and may
predict long-term therapeutic outcome in patients with stage III NSCLC.
Invasive staging procedures may be avoided and patients who will not profit
from resection due to insufficient downstaging after neoadjuvant treatment will
be easily detected by using 18F-FDG-PET as standard imaging in workup and evaluation of
treatment response.