FDG-PET parameters predict for recurrence in anal cancer – results from a prospective, multicentre clinical trial

Abstract

Background To investigate the prognostic significance of positron emission tomography (PET) parameters from F-18 fluorodeoxyglucose (FDG) PET scans performed pre- and post- chemo-radiotherapy (CRT) for squamous cell carcinoma of the anal canal (AC). Methods From January 2013 to January 2017, 19 patients with non-metastatic AC enrolled on a prospective trial underwent FDG-PET/CT imaging before and 12 weeks following CRT. A computer-generated volume of interest (VOI) was snapped around the primary tumour using six different standard uptake value (SUV) thresholds and the following parameters were extracted: SUV max, mean, median, standard deviation and peak as well as metabolic tumour volume (MTV) and total lesion glycolysis. Exact logistic regression and ROC AUC analyses were performed for each metric at each timepoint. Results With a median follow up of 15.8 months, 3/19 patients had a local recurrence and 5/19 had any recurrence. On post-CRT PET, the median SUV within a VOI bounded by an SUV of 3 correlated with local recurrence ( p < 0.01) and demonstrated excellent discrimination (ROC AUC 1.00, perfect separation was achieved at a median SUV of 3.38). The mean SUV at this threshold did not quite reach significance for prediction of local recurrence ( p = 0.06) but demonstrated excellent discrimination (ROC AUC 0.91). The MTV bounded by a threshold of 41% SUVmax on the pre-CRT PET predicted for any recurrence ( p = 0.03) and showed excellent discrimination (ROC AUC 0.89). Conclusions FDG-PET parameters are predictive of recurrence in AC. FDG-PET may represent a valuable tool for prognostication and response assessment in AC. Trial registration ANZCTR, ACTRN12614001219673 . Registered 19 November 2014 - Retrospectively registered.

Treatment outcome after radiochemotherapy in anal cancer patients staged with 18F-FDG-PET-CT

“…Another retrospective study including 75 patients found a correlation of the MTV of the primary tumor and OS with a cut off value of 7 cm [3]. There was no significant correlation of SUV max with OS or PFS of the patients [28]. Another study that included data of 19 patients derived from a prospective multi-center trial found a correlation between the MTV on pretreatment PET/CT and any tumor recurrence in anal cancer patients treated with radiochemotherapy.…”

Additional Value of 2-[18F]FDG PET/CT Comparing to MRI in Treatment Approach of Anal Cancer Patients

“…In one report, the higher pre-treatment SUVmax was associated with poorer DFS [ 29 ]. On the other hand, several other studies failed to demonstrate a relation between SUVmax of the tumor and survival parameters [ 26 , 27 , 30 , 40 ]. In line with their findings, our results showed that higher tumor SUVmax on the pre-treatment 2-[18F]FDG PET/CT did not predict worse DFS ( p = 0.127).…”

“…Gauthé et al revealed that MTV of the pre-treatment 2-[18F]FDG PET/CT is significantly correlated with OS [ 43 ]. Jones et al claimed that the only parameter predicting any recurrence was MTV of 41% maximum SUV on the pre-treatment 2-[18F]FDG PET/CT [ 40 ]. Also, Leccisotti et al documented that higher pre-treatment MTV and TLG are correlated with poorer different survival parameters [ 27 ].…”

Radiomics and Machine Learning in Anal Squamous Cell Carcinoma: A New Step for Personalized Medicine?

“…Exact logistic regression and ROC AUC analyses were completed. Two PET-CT parameters were found to be associated with recurrence: MTV bounded by a threshold of 41% maximum SUV on the pre-CRT PET-CT predicted for any recurrence (p = 0.03, ROC AUC 0.89), and median SUV within a VOI bounded by an SUV of three on post-CRT PET-CT correlated with local recurrence (p < 0.01, ROC AUC 1.00 with a median SUV threshold of 3.38) [34].…”