Role of Pre-therapeutic (18)F-FDG PET/CT in Guiding the Treatment Strategy and Predicting Prognosis in Patients with Esophageal Carcinoma

Contribution of FDG-PET/CT to the management of esophageal cancer patients at multidisciplinary tumor board conferences

Background

A multidisciplinary team approach to the management of esophageal cancer patients leads to better clinical decisions.

Purpose

The contribution of CT, endoscopic and laparoscopic ultrasound to clinical staging and treatment selection by multidisciplinary tumor boards (MTB) in patients with esophageal cancer is well documented. However, there is a paucity of data addressing the role that FDG-PET/CT (PET/CT) plays to inform the clinical decision-making process at MTB conferences. The aim of this study was to assess the impact and contribution of PET/CT to clinical management decisions and to the plan of care for esophageal cancer patients at the MTB conferences held at our institution.

Materials and methods

This IRB approved study included all the cases discussed in the esophageal MTB meetings over a year period. The information contributed by PET/CT to MTB decision making was grouped into four categories. Category I, no additional information provided for clinical management; category II, equivocal and misguiding information; category III, complementary information to other imaging modalities, and category IV, information that directly changed clinical management. The overall impact on management was assessed retrospectively from prospectively discussed clinical histories, imaging, histopathology, and the official minutes of the MTB conferences.

Results

79 patients (61 males and 18 females; median age, 61 years, range, 33–86) with esophageal cancer (53 adenocarcinomas and 26 squamous cell carcinomas) were included. The contribution of PET/CT-derived information was as follows: category I in 50 patients (63%); category II in 3 patients (4%); category III in 8 patients (10%), and category IV information in 18 patients (23%). Forty-five patients (57%) had systemic disease, and in 5 (11%) of these, metastatic disease was only detected by PET/CT. In addition, PET/CT detected previously unknown recurrence in 4 (9%) of 43 patients. In summary, PET/CT provided clinically useful information to guide management in 26 of 79 esophageal cancer patients (33%) discussed at the MTB.

Conclusion

The study showed that PET/CT provided additional information and changed clinical management in 1 out of 3 (33%) esophageal cancer cases discussed at MTB conferences. These results support the inclusion whenever available, of FDG-PET/CT imaging information to augment and improve the patient management decision process in MTB conferences.

Staging and Response Evaluation to Neo-Adjuvant Chemoradiation in Esophageal Cancers Using 18FDG PET/ CT with Standardized Protocol

Background:

Precise staging of esophageal cancer (EC) is important for selection of optimal treatment option and prognostication. Aim of this study was to assess the role of ¹⁸FDG PET/CT in staging and response evaluation to neoadjuvant chemoradiation (nCR) in EC patients using standardized imaging protocol.

Material and methods:

This prospective study was conducted at PET/CT Section of Department of Radiology, Aga Khan University Hospital Karachi, Pakistan from July 2017 till February 2018. We included 34 biopsy proven EC patients who had ¹⁸FDG PET/CT and CT of neck, chest and abdomen as part of initial staging. Eleven patients had post-nCR ¹⁸FDG PET/CT using standardized imaging protocol as per EANM guidelines. CT and PET/CT based staging was compared. Based on PERCIST criteria, response evaluation was assessed using change in highest SUVmax (%∆SUVmax) in baseline and follow-up scans (primary lesion, node or extra-nodal metastases).

Results:

Mean age of cohort was 57 ± 14 years (23 males and 11 females) having adenocarcinoma (AC) in 23 and squamous cell cancer (SCC) in 11 patients. Mean ¹⁸FDG dose, uptake time and hepatic SUVmean for baseline scans were 169 ±54 MBq, 65 ±10 minute and 1.91 ± 0.49 which were within ± 10%, ± 15% and ± 20% for follow-up scans in 11 patients respectively. Mean size (craniocaudal dimension in mm) and SUVmax of primary tumor was 56 ±27 mm and 13.4 ± 4.7. Based on ¹⁸FDG PET/CT findings, patients were categorized into N0 (10/34), N1 (09/34), N2 (11/34) and N3 (04/34) while 11/32 had stage IV disease. No significant difference was seen in AC and SCC groups. CT found stage IV disease in 3/34 (09%) while PET/CT found in 11/34 (32%; p value: 0.019) cases. PET/CT showed concordance with CT in 41% while discordance (all with upstaging) seen in 59%. On follow-up PET/CT, complete metabolic response was seen in 5/11 (45%) and partial metabolic response was noted in 6/11 (55% - p value non-significant) patients. Median %∆SUVmax over primary lesions was 49.84% (-32.69 -100%) while over nodal sites it was 41.18% (-82.60 -100%).

Conclusion:

We conclude that ¹⁸FDG PET/CT was found a sensitive tool in initial staging of EC. Compared with CT, it had higher diagnostic accuracy for distant nodal and extra-nodal metastasis. %∆SUVmax between baseline and post-nCR studies acquired with standardized protocol had changed management in more than half of our patients. For response evaluation in EC more studies with standardized ¹⁸FDG PET/CT imaging protocols are warranted.