Role of the FDG PET CT Scan in Pretreatment Evaluation of Oral Carcinomas.

Abstract

Pre-treatment role of FDG PET CT scan to evaluate- the extent of the primary lesion, nodal staging and distant metastasis in oral carcinoma in various TNM stages. Additionally, our study investigated the Correlation between SUVmax values on FDG-PET CT scans and histopathological proven positive nodes in patients undergoing surgery. In this study, all suspected cases of oral carcinoma in adults who visited the ENT clinic were examined and evaluated using various methods, including clinical examination, cytology, histopathology, and imaging tests like CECT scans, ultrasound, and CEMRI. Based on the results of these evaluations, the patients were staged. The patients were then given FDG-PET CT scans (done within 2 weeks of CECT/MRI scans), for restaging and treatment plans, such as surgery, chemotherapy, radiotherapy, or a combination of these methods, were developed. After surgery, the patients were restaged based on the histopathology report, and the results of the FDG-PET CT scans were compared to the histopathological findings and the histopathological positive nodes were compared to the SUV max value on the FDG PET CT scan and were correlated. In our study, the mean age of patients was found to be 50 years with a male: female ratio of 3.5:1. Maximum tumors presented at the buccal mucosa region. 92% of patients gave a history of tobacco addiction, and 18% were smokers. As per initial biopsy reports, maximum (62%) tumors were detected to be WDSCC, 2% were MDSCC and 6% were PDSCC. All 50 patients had normal findings on the chest x-ray and USG abdomen. 41 patients underwent CECT scans and 9 patients got CEMRI scans done. Staging after FDG PET CT scan was compared with that of radiological staging. It was found that in T staging there was upstaging in 36% of cases and downstaging in 14% of cases following the FDG PET CT scan. Likewise, N staging showed upstaging in 36% of cases and downstaging in 16% of cases after the FDG PET CT scan. In M staging, there was upstaging in 10% of cases after the FDG PET CT scan. In our study 15 cases got operated on. All 8 (53.3%) cases of postoperative histopathological positive lymph nodes had SUV max values greater than their reference value (> 2.5), and all negative histopathological lymph nodes had a low SUV max (< 2.5) value in the PET CT scan. The FDG PET CT scan is a highly effective tool for accurately diagnosing, staging, and predicting the outcome of oral cancers at all stages of the disease. The SUV max value (> 2.5) of the PET CT scan is positively correlated with the likelihood of nodal metastasis, as higher values were found to correspond with histopathological evidence of positive neck nodes.