PET-CT offers accurate assessment of tumour length in oesophageal malignancy. Eur J Radiol. 2015;84:195-200. [PMID: 25435270 DOI: 10.1016/j.ejrad.2014.10.014]

Efficacy evaluation and prognostic prediction of endoscopic ultrasound for neoadjuvant immunotherapy in esophageal cancer

BACKGROUND AND OBJECTIVES

Neoadjuvant immunotherapy combined with chemotherapy or chemoradiotherapy has emerged as a promising approach in the treatment of esophageal cancer. However, there is a lack of comprehensive understanding regarding the clinical factors that can predict patient response to this therapy. The aim of this study was to develop a predictive model for assessing the efficacy of neoadjuvant immunotherapy in patients undergoing surgical treatment.

METHODS

This study retrospectively enrolled 220 consecutive patients with preoperative immunotherapy combined chemotherapy or chemoradiotherapy. A logistic regression was used to evaluate the association between pathologic complete response (pCR) and endoscopic ultrasound parameters, constructing a predictive model for treatment response. Additional, overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method, and Cox regression analyses were introduced to explore the associations between EUS factors after neoadjuvant immunotherapy.

RESULTS

Logistic regression analysis identified that the significant predictors of pCR were treatment regimen, negative biopsy findings, RECIST assessment, endoscopic ultrasound responder, and downstaging in uN. A predictive model including above five variables was generated, and area under the curve was 0.840(95%CI 0.78-0.89), this nomogram was also adequately validated internally. In the cox regression analyses, EUS responder was found to be a significant predictor of overall survival with a hazard ratio (HR) of 0.38(95%CI 0.15-0.98), whereas only pCR status was a significant predictor of PFS (HR 0.80; 95%CI 0.01-0.60).

CONCLUSIONS

EUS responder can serve as a valuable predictor of the efficacy of adjuvant immunotherapy combined with chemotherapy or chemoradiotherapy, as well as of survival outcomes.

Pre- and postoperative prognostic factors for resectable esophageal adenocarcinoma

BACKGROUND

Prognostication for esophageal cancer has traditionally relied on postoperative tissue specimens. This study aimed to use a histologically homogenous cohort to investigate the relationship between clinical, pathological or radiological variables and overall survival in patients undergoing esophagectomy for adenocarcinoma.

METHODS

A single-centre study of patients who underwent esophagectomy for adenocarcinoma over 10 years in a tertiary centre was performed. By regression analysis, variables available preoperatively and postoperatively were studied for prognostication. The primary outcome was overall survival.

RESULTS

254 cases were analyzed. Over a median follow-up period of 31.8 months (IQR = 42.5), overall survival was 51.5 months (95% confidence interval: 33.0-69.9). According to hazard ratios (HR) for all-cause death, adverse prognostic factors included: a higher postoperative N-stage (HR ≥ 1.29; p ≤ 0.024), histopathological tumor length ≥25 mm (HR = 2.04; p = 0.03), poorer tumor differentiation (HR ≥ 2.86; p ≤ 0.042), and R1 status (HR = 2.33; p = 0.02). A lymph node yield ≥35 was a favorable prognostic factor (HR = 0.022; p < 0.001). Demographic and radiological variables, preoperative TNM stages, postoperative T-stage, and neoadjuvant/adjuvant treatment were not associated with overall survival.

CONCLUSIONS

This study identifies several postoperatively factors which are available for the prognostication and identifies factors that should not be used to exclude patients from curative surgery.

A comparative study of quantitative assessment with fluorine-18-fluorodeoxyglucose positron-emission tomography and endoscopic ultrasound in oesophageal cancer

OBJECTIVES

This study aims to assess the correlation between PET/CT and endoscopic ultrasound (EUS) parameters in patients with oesophageal cancer.

PATIENTS AND METHODS

All patients who had complete PET/CT and EUS staging performed for oesophageal cancer at our centre between 2010 and 2016 were included. Images were retrieved and analysed for a range of parameters including tumour length, volume and position relative to the aortic arch.

RESULTS

Seventy patients were included in the main analysis. A strong correlation was found between EUS and PET/CT in the tumour length, the volume and the position of the tumour relative to the aortic arch. Regression modelling showed a reasonable predictive value for PET/CT in calculating EUS parameters, with r higher than 0.585 in some cases.

CONCLUSION

Given the strong correlation between EUS and PET parameters, fluorine-18 fluorodeoxyglucose (F-FDG) PET can provide accurate information on the length and the volume of tumour in patients who either cannot tolerate EUS or have impassable strictures.

18-Fluorodeoxy-Glucose Positron Emission Tomography- Computed Tomography (18-FDG-PET/CT) for Gross Tumor Volume (GTV) Delineation in Gastric Cancer Radiotherapy

Purpose:

Evaluation of the 18-fluorodeoxy-glucose positron emission tomography-computed tomography (18-FDG-PET/_CT) for gross tumor volume (GTV) delineation in gastric cancer patients undergoing radiotherapy.

Methods:

In this study, 29 gastric cancer patients (17 unresectable and 7 inoperable) were initially enrolled for radical chemoradiotherapy (45Gy/25 fractions + chemotherapy based on 5 fluorouracil) or radiotherapy alone (45Gy/25 fractions) with planning based on the 18-FDG-PET/CT images. Five patients were excluded due to excess blood glucose levels (1), false-negative positron emission tomography (1) and distant metastases revealed by 18-FDG-PET/CT (3). The analysis involved measurement of metabolic tumor volumes (MTVs) performed on PET/CT workstations. Different threshold levels of the standardized uptake value (SUV) and liver uptake were set to obtain MTVs. Secondly, GTV_PET values were derived manually using the positron emission tomography (PET) dataset blinded to the computed tomography (CT) data. Subsequently, GTV_CT values were delineated using a radiotherapy planning system based on the CT scans blinded to the PET data. The referenced GTV_CT values were correlated with the GTV_PET and were compared with a conformality index (CI).

Results:

The mean CI was 0.52 (range, 0.12-0.85). In 13/24 patients (54%), the GTV_PET was larger than GTV_CT, and in the remainder, GTV_PET was smaller. Moreover, the cranio-caudal diameter of GTV_PET in 16 cases (64%) was larger than that of GTV_CT, smaller in 7 cases (29%), and unchanged in one case. Manual PET delineation (GTVPET) achieved the best correlation with GTV_CT (Pearson correlation = 0.76, p <0.0001). Among the analyzed MTVs, a statistically significant correlation with GTV_CT was revealed for MTV_10%SUVmax (r = 0.63; p = 0.0014), MTV_liv (r = 0.60; p = 0.0021), MTV_SUV2.5 (r = 0.54; p = 0.0063); MTV_20%SUVmax (r = 0.44; p = 0.0344); MTV_30%SUVmax (r = 0.44; p = 0.0373).

Conclusion:

18-FDG-PET/_CT in gastric cancer radiotherapy planning may affect the GTV delineation.

DVH- and NTCP-based dosimetric comparison of different longitudinal margins for VMAT-IMRT of esophageal cancer

Purpose

To cover the microscopic tumor spread in squamous cell carcinoma of the esophagus (SCC), longitudinal margins of 3–4 cm are used for radiotherapy (RT) protocols. However, smaller margins of 2–3 cm might be reasonable when advanced diagnostic imaging is integrated into target volume delineation. Purpose of this study was to compare the dose distribution and deposition to the organs at risk (OAR) for different longitudinal margins using a DVH- and NTCP-based approach.

Methods

Ten patients with SCC of the middle or lower third were retrospectively selected. Three planning target volumes (PTV) with longitudinal margins of 4 cm, 3 cm and 2 cm and an axial margin of 1.5 cm to the gross target volume (GTV) were defined for each patient. For each PTV two treatment plans with total doses of 41.4 Gy (neoadjuvant treatment) and 50.4 Gy (definite treatment) were calculated. Dose to the lungs, heart, myelon and liver were then evaluated and compared between different PTVs.

Results

When using a longitudinal margin of 3 cm instead of 4 cm, all dose parameters (Dmin, Dmean, Dmedian and V5-V35), except Dmax could be significantly reduced for the lungs. Regarding the heart, a significant reduction was seen for Dmean and V5, but not for Dmin, Dmax, Dmedian and V10-V35. When comparing a longitudinal margin of 4 cm to a longitudinal margin of 2 cm, a significant difference was calculated for Dmin, Dmean, Dmedian and V5-V35 of the lungs and for Dmax, Dmean and V5-V35 of the heart. Nevertheless, no difference was seen for median heart dose. An additional dose reduction for V10 of the heart was achieved for definite treatment plans when using a longitudinal margin of 3 cm. The NTCP-based risk of pneumonitis was significantly reduced by a margin reduction to 2 cm for neoadjuvant and definite treatment plans.

Conclusion

Reduction of longitudinal margins from 4 cm to 3 cm can significantly reduce the dose to lungs and Dmean of the heart. Despite clinical benefit and oncologic outcome remain unclear, reduction of the longitudinal margins might provide the opportunity to reduce side effects of chemoradiation (CRT) for SCC in upcoming studies.

Follow up results of a prospective study to evaluate the impact of FDG-PET on CT-based radiotherapy treatment planning for oesophageal cancer

Background

This prospective study aims to determine the impact of PET/CT on radiotherapy planning and outcomes in patients with oesophageal cancer.

Methods

All patients underwent PET/CT scanning in the radiotherapy treatment position, and received treatment planned using the PET/CT dataset. GTV was defined separately on PET/CT (GTV-PET) and CT (GTV-CT) datasets. A corresponding PTV was generated for each patient. Volumetric and spatial analysis quantified the proportion of FDG-avid disease not included in CT-based volumes. Clinical data was collected to determine locoregional control and overall survival rates.

Results

13 (24.1%) of 57 accrued patients had metastatic disease detected on PET. Median follow up was 4 years. FDG-avid disease would have been excluded from GTV-CT in 29 of 38 patients (76%). In 5 patients, FDG-avid disease would have been completely excluded from the PTV-CT. GTV-CT underestimated the cranial and caudal extent of FDG-avid tumour in 14 (36%) and 10 (26%) patients. 4-Year overall survival and locoregional failure free survival were 37% and 65%.

Conclusions

PET/CT altered the delineation of tumour volumes when compared to CT alone, and should be considered standard for treatment planning. Although clinical outcomes were not improved with PET/CT planning, it did allow the use of smaller radiotherapy volumes.

Is endoscopic ultrasound examination necessary in the management of esophageal cancer?

Despite substantial efforts at early diagnosis, accurate staging and advanced treatments, esophageal cancer (EC) continues to be an ominous disease worldwide. Risk factors for esophageal carcinomas include obesity, gastroesophageal reflux disease, hard-alcohol use and tobacco smoking. Five-year survival rates have improved from 5% to 20% since the 1970s, the result of advances in diagnostic staging and treatment. As the most sensitive test for locoregional staging of EC, endoscopic ultrasound (EUS) influences the development of an optimal oncologic treatment plan for a significant minority of patients with early cancers, which appropriately balances the risks and benefits of surgery, chemotherapy and radiation. EUS is costly, and may not be available at all centers. Thus, the yield of EUS needs to be thoughtfully considered for each patient. Localized intramucosal cancers occasionally require endoscopic resection (ER) for histologic staging or treatment; EUS evaluation may detect suspicious lymph nodes prior to exposing the patient to the risks of ER. Although positron emission tomography (PET) has been increasingly utilized in staging EC, it may be unnecessary for clinical staging of early, localized EC and carries the risk of false-positive metastasis (over staging). In EC patients with evidence of advanced disease, EUS or PET may be used to define the radiotherapy field. Multimodality staging with EUS, cross-sectional imaging and histopathologic analysis of ER, remains the standard-of-care in the evaluation of early esophageal cancers. Herein, published data regarding use of EUS for intramucosal, local, regional and metastatic esophageal cancers are reviewed. An algorithm to illustrate the current use of EUS at The University of Texas MD Anderson Cancer Center is presented.

Consensus and controversies on dose and target volume of three-dimensional conformal radiotherapy for esophageal carcinoma

Radiotherpay is the mainstay treatment for esophageal cancer. Three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy have been widely applied in routine clinical work, because they can raise the target dose and reduce the injury to normal tissue, and therefore raise the five-year survival rate to > 20%. In recent years, a number of studies on 3DCRT have been carried out with regard to radiation dose, target volume contour, and preventive lymph node irradiation, and this article will summarize these issues.