Diagnostic accuracy of lymph node metastasis depends on metabolic activity of the primary lesion in thoracic squamous esophageal cancer

Completely Resectable (cT1-2) Esophageal Squamous Cell Carcinoma with Minimal Lymph Node Involvement (cN1): Is Neoadjuvant Chemoradiation Therapy the Only Viable Treatment Option?

BACKGROUND

Neoadjuvant chemoradiation therapy (nCRT) is recommended when lymph node metastasis is evident or strongly suspected on preoperative imaging studies, even for a completely resectable (cT1-2) tumor with minimal lymph node involvement (cN1). We evaluated the validity of upfront surgical approach in this patient group.

METHODS

We retrospectively reviewed data from 247 patients with cT1-2 esophageal squamous cell carcinoma (ESCC) who underwent upfront radical esophagectomy followed by the pathology-based adjuvant treatment. Oncologic outcomes of cN1 patients were compared with those of cN0 patients.

RESULTS

There were 203 cN0 and 44 cN1 patients. The lymph node yield was 62.0 (interquartile range [IQR], 51.0-76.0) in cN0 and 65.5 (IQR, 57.5-85.0) in cN1 patients (p = 0.033). The size of metastatic node was 0.6 cm (IQR, 0.4-0.9 cm) in cN0 and 0.8 cm (IQR, 0.5-1.3 cm) in cN1 patients (p = 0.001). Nodal upstaging was identified in 29.1% of cN0 and 40.9% of cN1 patients, whereas 18.2% of the cN1 had no actual lymph node metastasis (pN0). The 5-year disease-free survival rate was not significantly different between the groups (cN0, 74.4%; cN1, 71.8%; p = 0.529). Survival rates were closely correlated with pN stage, and a multivariate analysis revealed that pN2-3 stage was a risk factor for poor disease-free survival.

CONCLUSIONS

Upfront radical surgery provided accurate nodal staging information, potentially sparing some cN1 patients from unnecessary nCRT while demonstrating comparable survival rates. It might be a valid option for the treatment of cT1-2N1 ESCC.

Measuring distance from the incisors to the esophageal cancer by FDG PET/CT: endoscopy as the reference

BACKGROUND

Using endoscopy as the reference, this study evaluated the accuracy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in measuring distance from the incisors to the PET detectable esophageal cancer. If there is high concordance between endoscopic and PET measurements, our results may provide a basis to use FDG PET/CT in cooperation with endoscopic measurement to localize those PET/CT and CT undetectable esophageal tumors for radiotherapy planning.

MATERIALS

Esophageal cancer patients with pretreatment endoscopy and FDG PET/CT detectable esophageal tumors were recruited retrospectively. The distances from the incisors to the proximal esophageal tumor margins were determined by endoscopy and by the sagittal images of FDG PET/CT. The endoscopic measurement was used as the comparative reference. A nuclear medicine doctor and a radiation oncologist each performed the FDG PET/CT measurement twice for every patient. We analyzed the differences in these measurements, and assessed agreement and reproducibility of the results by the intraclass correlation coefficient (ICC).

RESULTS

Thirty-four patients, with 35 esophageal tumors, were included. By endoscopy and FDG PET/CT, the mean distances from the incisors to the proximal esophageal tumor margin were 27.3 ± 6.4 cm (range 17.1-40.0 cm) and 26.8 ± 6.3 cm (range 15.7-41.3 cm), respectively. The mean absolute differences between the endoscopic and four FDG PET/CT measurements ranged from 1.129 to 1.289 cm (SD: 0.98-1.19). The measurement agreement between FDG PET/CT and endoscopy by ICC was between 0.962 and 0.971. The intra- and interobserver reproducibilities of the two readers were excellent (intraobserver ICC: 0.985, 0.996; interobserver ICC: 0.976-0.984).

CONCLUSIONS

FDG PET/CT was in high agreement with endoscopy in measuring the distance from the incisors to the proximal esophageal tumor margin. For FDG PET/CT and CT undetectable esophageal cancer, incorporation of the endoscopic measurement with PET/CT might be a way for making radiotherapy plan.

Tumor SUVs on 18F-FDG PET/CT and Aggressive Pathological Features in Esophageal Squamous Cell Carcinoma

PURPOSE

Considerable discrepancies are observed between clinical staging and pathological staging after surgical resection in patients with esophageal squamous cell carcinoma (ESCC). In this study, we examined the relationships between tumor SUVs on FDG PET/CT and aggressive pathological features in resected ESCC patients.

METHODS

A total of 220 patients with surgically resected clinical stage I-II ESCC without neoadjuvant treatment were retrospectively analyzed. SUVmax of the primary tumor was measured on pretreatment FDG PET/CT. Pathological features included depth of tumor invasion, lymph node metastasis, tumor differentiation, lymphatic vessel tumor embolus, perineural invasion, Ki-67 index, and p53 protein expression. Receiver operating characteristic curve analysis was used to determine an optimal cutoff of SUVmax to predict pathologically advanced disease. Differences in pathological features associated with SUVmax were examined by t test or χ test.

RESULTS

The number of patients upstaged from clinical stage I-II to pathological stage III-IV was 43 (19.5%). Receiver operating characteristic curve analysis showed that the optimal cutoff SUVmax of 4.0 had good performance for predicting locally advanced disease (area under the receiver operating characteristic curve = 0.844, P < 0.001). Higher tumor SUVmax was significantly associated with advanced depth of tumor invasion (deeper than submucosa, P < 0.001), positive lymph node metastasis (P < 0.001), presence of lymphatic vessel tumor embolus (P < 0.001), presence of perineural invasion (P < 0.001), higher Ki-67 index (P = 0.025), and poor tumor differentiation (P = 0.039).

CONCLUSIONS

SUVmax measured on pretreatment FDG PET/CT is significantly associated with aggressive pathological features and may help clinicians identify patients at risk of advanced disease.

Does [18F] fluorodeoxyglucose-positron emission tomography/computed tomography have a role in cervical nodal staging for esophageal squamous cell carcinoma?

OBJECTIVE

Accurate nodal staging is crucial for esophageal cancer. A prospective study was performed to assess the value of [18F] fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) for diagnosing cervical lymph node metastasis (LNM) of esophageal squamous cell carcinoma.

METHODS

From June 2018 to November 2018, 110 patients with resectable esophageal cancer were prospectively enrolled. Esophagectomy with 3-field lymphadenectomy was performed after FDG-PET/CT scanning. The primary end point was cervical LNM determined via postoperative histologic examination. The sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and accuracy (AC) of FDG-PET/CT for the assessment of LNM were determined using histologic results as reference standards.

RESULTS

Positive lymph nodes as determined via FDG-PET/CT were detected in 61 patients (55.5%), of whom 13 (11.8%) had positive cervical lymph nodes. After surgery, 59 patients (53.6%) exhibited pathologic LNM, of whom 20 (18.2%) had cervical LNM. SE, SP, PPV, NPV, and AC were 65.6%, 61.2%, 67.8%, 58.8%, and 63.6%, respectively, with regards to diagnosing overall LNM, and were 45.0%, 95.6%, 69.2%, 88.7%, and 86.4%, respectively, for diagnosing cervical LNM. Of the 110 patients, 90 underwent both FDG-PET/CT scanning and ultrasonography in the neck, and there were no significant differences in SE, SP, PPV, NPV, or AC with respect to cervical LNM diagnosis between FDG-PET/CT and ultrasonography.

CONCLUSIONS

For cervical LNM of esophageal squamous cell carcinoma, FDG-PET/CT scanning exhibited high specificity but low sensitivity, suggesting that it is of limited value for this purpose.

Systematic review and meta-analysis of the accuracy of 18F-FDG PET/CT for detection of regional lymph node metastasis in esophageal squamous cell carcinoma

Background

We performed a systematic review and meta-analysis to assess the accuracy of 18F-fluorodeoxyglucose positron emission tomography with computer tomography (18F-FDG PET/CT) for detection of regional lymph node metastasis in esophageal squamous cell carcinoma in per-patient and per-nodal station basis.

Methods

Electronic databases were researched for studies assessing the sensitivity and specificity of PET/CT to detect the regional lymph node metastasis published between January 2006 and December 2017 on esophageal squamous cell carcinoma. STATA software was performed to assess the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odd ratio (DOR) and summary receiver operating characteristic (SROC) curve. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) and Deeks' Funnel Plot Asymmetry Test were performed to evaluate the study quality and publication bias of included studies.

Results

Nineteen studies were eligible for meta-analysis, comprising 1,089 patients with esophageal cancer who underwent 18F-FDG PET/CT before surgery. According to the content of the article, we divided the selected studies into per-patient basis group and per-nodal basis group (one of the articles was involved in both groups). For the per-nodal station basis group (12 studies, 5,681 stations), the pooled sensitivity and specificity estimates of 18F-FDG PET/CT for detecting regional lymph node metastasis were 66% [95% confidence interval (CI): 51-78%] and 96% (95% CI: 92-98%), respectively. The corresponding values on a per-patient basis group (8 studies; 506 patients) were 65% (95% CI: 49-78%) and 81% (95% CI: 69-89%) in sensitivity and specificity, respectively.

Conclusions

Overall, 18F-FDG PET/CT have a moderate to low sensitivity and a high to moderate specificity for detection of regional nodal metastasis in esophageal cancer. Therefore, since the false rate is considerable, extending the extent of lymph node dissection or radiotherapy target volume is necessary after diagnosis of regional nodal metastasis by 18F-FDG PET/CT.

Significance of Upper Mediastinal Lymph Node Dissection with Video-Assisted Thoracic Surgery in the Treatment of Middle Thoracic Esophageal Carcinoma

BACKGROUND

The aim of this study was to explore the significance of upper mediastinal lymph node dissection performed by video-assisted thoracic surgery in the treatment of middle thoracic esophageal carcinoma.

MATERIALS AND METHODS

The clinical and pathological data from 128 patients with middle thoracic esophageal carcinoma who underwent surgery from January 2013 to December 2015 using a right chest-abdomen-neck approach combined with thoracoscopy and laparoscopy in the Jieyang People's Hospital of Huangdong province were analyzed retrospectively.

RESULTS

The lymph node metastasis rates of the thoracic left para-recurrent laryngeal nerve (1, 2, and 4L zones) and right para-recurrent laryngeal nerve (1R zone) were 30.47% and 28.12% in 128 cases, respectively. The metastasis rates of the 2R, 4R, and 5 zones were 4.69%, 3.91%, and 5.47%, respectively.

CONCLUSIONS

The upper mediastinal region was the most common location for lymph node metastasis from middle thoracic esophageal carcinoma, and upper mediastinal lymph node dissection performed by video-assisted thoracic surgery was safe and complete. It also reduced the risk of para-recurrent laryngeal nerve injury, residual tumor, and the postoperative recurrence rate.

FDG PET using SUVmax for preoperative T-staging of esophageal squamous cell carcinoma with and without neoadjuvant chemoradiotherapy

BACKGROUND

Accurate T-staging is pivotal for predicting prognosis and selecting appropriate therapies for esophageal squamous cell carcinoma (ESCC). The diagnostic performance of fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for its T-staging is uncertain. We investigated use of FDG PET/CT for preoperative T-staging of patients with ESCC.

METHODS

Patients with ESCC given preoperative FDG PET/CT scans, either with (CRT[+] group) or without (CRT[-] group) neoadjuvant chemoradiotherapy, were retrospectively reviewed. Maximal standardized uptake value (SUVmax) of the primary tumors on FDG PET/CT scans were measured, and histopathological results were used as the reference standard. The associations between pathological T-stage and potential factors of age, tumor location, tumor grade, tumor size, and tumor SUVmax were analyzed. The cut-off levels of SUVmax for predicting different T-stages and for residual viable tumors after neoadjuvant chemoradiotherapy were determined using receiver operating characteristic analyses.

RESULTS

We enrolled 103 patients (45 in the CRT[-] group; 58 in the CRT[+] group). SUVmax, an independent predictive factor, positively correlated with the pathological T-stage in both groups (CRT[-] group: ρ = 0.736, p < 0.001; and CRT[+] group: ρ = 0.792, p < 0.001). The overall accuracy of the PET/CT with thresholded SUVmax for predicting the pathological T-stage was 73.3% in the CRT[-] group (SUVmax of T0: 0-1.9, T1: 2.0-4.4, T2: 4.5-6.5, T3: 6.6-13.0, T4: >13.0) and 67.2% in the CRT[+] group (SUVmax of T0: 0-3.4, T1: 3.5-3.9, T2: 4.0-5.5, T3: 5.6-6.2, T4: > 6.2). For CRT[-] group, the accuracy using an SUVmax cut-off of 4.4 to differentiate early (T0-1) from locally advanced disease (T2-4) was 82.2% (95% CI, 71.1-93.4%). For CRT[+] group, the accuracy using an SUVmax cut-off of 3.4 to predict residual viable tumors (non-T0) after completion of chemoradiotherapy was 82.8% (95% CI, 73.0-92.5%).

CONCLUSIONS

The FDG avidity of a primary esophageal tumor significantly positively correlated with the pathological T-stage. PET/CT with thresholded SUVmax was useful for predicting T-stage and differentiating residual viable tumors.

Distribution of FDG-avid nodes in esophageal cancer: implications for radiotherapy target delineation

PURPOSE

Clinical target volumes (CTV) for radiotherapy (RT) in esophageal cancer (EC) are based on standard expansions of primary tumor volume. Data is needed to define regions at highest risk for occult disease, based on histology and location of the primary tumor. We therefore reviewed PET scans in EC patients to characterize the location of FDG-avid lymph node metastases (LNM).

MATERIALS AND METHODS

We identified 473 EC patients with reviewable pre-treatment PET-CT scans. Tumors were classified by histology and location; 85% were distal or GE junction tumors and 71% were adenocarcinoma. FDG-avid LNM were classified using standard radiographic nodal atlases, and distances from primary tumor to paraesophageal LNM were also measured.

RESULTS

The most common LNM in upper EC were supraclavicular, retrotracheal and paratracheal. The most common LNM in lower EC were paraesophageal and in the gastrohepatic space. Overall, 55% of paraesophageal LNM were adjacent to primary tumor. Of upper esophageal tumors with paraesophageal LNM, 87% were adjacent to the tumor and none were >6 cm from tumor. However, 57% of lower esophageal tumors with paraesophageal LNM had non-adjacent paraesophageal nodes, 24% of which were >8 cm from the tumor.

CONCLUSION

A more data-driven and individualized approach to CTV delineation could improve the therapeutic ratio of RT in esophageal cancer. These results can guide CTV delineation by indicating the potential distribution of nodal involvement in esophageal cancer.

FDG-PET/CT lymph node staging after neoadjuvant chemotherapy in patients with adenocarcinoma of the esophageal-gastric junction

Objectives

The aim of the analysis was to assess the accuracy of various FDG-PET/CT parameters in staging lymph nodes after neoadjuvant chemotherapy.

Methods

In this prospective study, 74 patients with adenocarcinoma of the esophageal–gastric junction were examined by FDG-PET/CT in the course of their neoadjuvant chemotherapy given before surgical treatment. Data from the final FDG-PET/CT examinations were compared with the histology from the surgical specimens (gold standard). The accuracy was calculated for four FDG-PET/CT parameters: (1) hypermetabolic nodes, (2) large nodes, (3) large-and-medium large nodes, and (4) hypermetabolic or large nodes.

Results

In 74 patients, a total of 1540 lymph nodes were obtained by surgery, and these were grouped into 287 regions according to topographic origin. Five hundred and two nodes were imaged by FDG-PET/CT and were grouped into these same regions for comparison. In the analysis, (1) hypermetabolic nodes, (2) large nodes, (3) large-and-medium large nodes, and (4) hypermetabolic or large nodes identified metastases in particular regions with sensitivities of 11.6%, 2.9%, 21.7%, and 13.0%, respectively; specificity was 98.6%, 94.5%, 74.8%, and 93.6%, respectively. The best accuracy of 77.7% reached the parameter of hypermetabolic nodes. Accuracy decreased to 62.0% when also smaller nodes (medium-large) were taken for the parameter of metastases.

Conclusions

FDG-PET/CT proved low sensitivity and high specificity. Low sensitivity was based on low detection rate (32.6%) when compared nodes imaged by FDG-PET/CT to nodes found by surgery, and in inability to detect micrometastases. Sensitivity increased when also medium-large LNs were taken for positive, but specificity and accuracy decreased.

ypN0: Does It Matter How You Get There? Nodal Downstaging in Esophageal Cancer

BACKGROUND

ypN0 following induction treatment for advanced esophageal cancer improves survival. Importance of how ypN0 is achieved is unknown. This study evaluates survival in "natural" N0 (cN0/ypN0) and "downstaged" N0 (cN+/ypN0) patients.

METHODS

Among patients treated with induction treatment and surgery, 83 CT scans were retrieved in digital format and re-evaluated by a radiologist, blinded to pathological nodal status: 28 natural N0, 37 downstaged N0, and 18 ypN+. Impact of N0 classification on survival and associations with survival were identified.

RESULTS

Survival varied with ypN: 3-year survival was 84 % for natural N0 patients, 59 % for downstaged N0, and 20 % for ypN+ (p < .001). Compared with natural N0 patients, risk of cancer mortality was 3.8 for downstaged N0 and 7.6 for ypN+ (p = .01). Survival was also stratified by ypT: compared with ypT0 natural N0, who had the best survival, intermediate survival was seen in ypT+ natural N0 [hazard ratio (HR), 1.3] and ypT0 downstaged N0 (HR, 1.8), and poor survival in ypT+ downstaged N0 (HR, 9.5) and ypN+ (HR, 12.0) (p = .026).

CONCLUSIONS

Natural N0 and downstaged N0 patients are different clinical entities: downstaging cN+ with induction treatment producing downstaged N0 improves survival only if there is concomitant primary cancer downstaging to ypT0. Intermediate survival is seen in downstaged N0 patients with complete tumor response. Natural N0 patients experience intermediate survival with incomplete response (ypT+). Complete response in natural N0 patients produces the best survival. Means of obtaining ypN0 status matters and requires a complete response for downstaged N0 patients to benefit from induction treatment.

A study about different findings of PET-CT between neoadjuvant and non-neoadjuvant therapy: SUVmax is not a reliable predictor of lymphatic involvement after neoadjuvant therapy for esophageal cancer

BACKGROUND

No definitive findings or established guidelines have been published for the evaluation of esophageal tumors (tumor) and regional lymph nodes (LN) using positron emission tomography computed tomography (PET-CT) in patients with esophageal cancer. In addition, it remains unclear whether PET-CT findings vary between neoadjuvant (NT) and non-neoadjuvant (non-NT) therapy cases. Therefore, preoperative evaluation using PET-CT might provide unreliable information and influence the management plan for esophageal cancer. The purpose of the present study is to clarify the different findings of PET-CT between NT and non-NT in surgical esophageal cancer cases and to predict LN metastasis.

METHODS

We retrospectively reviewed the medical records of 192 consecutive cases that met this study's inclusion criteria from January 2009 to December 2014. All patients underwent curative and complete esophagectomy for intra-thoracic esophageal cancer at the department of thoracic and cardiovascular surgery in a single tertiary Korean hospital. We compiled and analyzed maximum standard uptake values (SUVmax) of tumor and LNs with other clinical information (chronic lung disease, history of previous other primary cancer, sex, pathological findings, NT, and other clinical data).

RESULTS

(I) In NT, a positive correlation between T stage and SUVmax was found (tumor SUVmax P<0.001, LN SUVmax P=0.010); however, no relationship between N stage and SUVmax was found. In non-NT, a positive correlation between pathological stage (T and N stage) and SUVmax was found (T stage, tumor SUVmax P<0.001, LN SUVmax P=0.001; N stage, tumor SUVmax P=0.003, LN SUVmax P=0.021); (II) In NT, the low SUVmax group had higher disease-free survival (DFS) and overall survival (OS) than the high SUVmax group (DFS, tumor SUVmax P<0.001, LN SUVmax P=0.142; OS, tumor SUVmax P<0.001, LN SUVmax P=0.002). In non-NT, the low SUVmax group also had higher DFS and OS than the high SUVmax group (DFS, tumor SUVmax P<0.001, LN SUVmax P=0.008; OS, tumor SUVmax P=0.029, LN SUVmax P=0.016). SUVmax values being equal, non-NT had significantly higher DFS and OS than NT (P=0.011, P=0.009, respectively), despite the absence of significant differences in pathological stage; (III) Tumor SUVmax had a positive correlation with LN SUVmax in both NT and non-NT (P=0.006, P<0.001, respectively); (IV) In NT, there were no diagnostic findings of LN metastases using SUVmax. However, in non-NT, significant cutoff values for diagnosis of LN metastases using both tumor and LN SUVmax were found (tumor SUVmax cutoff value 4.9, P=0.008; LN SUVmax cutoff value 2.5, P=0.045); (V) In NT, there was no significant difference in LN SUVmax between pathologically negative and positive LNs. However, in non-NT, the LN SUVmax of pathologically positive LNs was significantly higher than that of pathologically negative LNs (P=0.042); (VI) There were no significant differences in tumor and LN SUVmax according to various factors, including chronic lung disease (COPD, bronchiectasis), age, previous cancers, and sex, regardless of NT.

CONCLUSIONS

This study showed that there were some different findings of PET-CT using SUVmax between NT and non-NT. These findings should be clarified for further evaluation and management, especially of surgery, which should not be withheld out of ignorance of these different PET-CT findings and should be considered carefully in conjunction with other conditions. In addition, further studies about the effects of NT on PET-CT findings are required to improve the utility of PET-CT to evaluate the LNs in esophageal cancer.

A retrospective study of dual-energy CT for clinical detecting of metastatic cervical lymph nodes in laryngeal and hypopharyngeal squamous cell carcinoma

CONCLUSION

After the reconstruction of imaging in dual-energy CT gemstone spectral imaging, the ratio of the two slopes curves, the target lymph node and primary lesion, respectively, might contribute to the clinical diagnosis of cervical lymph nodes in laryngeal and hypopharyngeal squamous carcinoma.

OBJECTIVE

To investigate the value of the dual-energy CT gemstone spectral imaging for clinical detecting of metastatic cervical lymph nodes in laryngeal and hypopharyngeal squamous carcinoma.

METHODS

Forty-seven cases who were suffering from laryngeal or hypopharyngeal squamous carcinoma and had complete clinical and pathological data were included, and 79 cervical lymph nodes were studied retrospectively (including 31 metastatic nodes and 48 non-metastatic nodes). Contrast-enhanced energy spectral imaging and reconstruction were performed. After the reconstruction, the slope of the curve in the target lymph node and the lesion were calculated. The ratio of the two slopes was studied. The pathological data of cervical lymph node and primary lesion were also collected.

RESULTS

The ratios were 1.20 ± 0.09 and 0.82 ± 0.12 in metastatic and non-metastatic lymph nodes, respectively. The difference was statistically significant (p < 0.05). The ratio was positively correlated to the stasis of lymph nodes only, rather than their morphological appearance, the pathological classification, or the individual difference (p < 0.05).

Combination of FDG PET/CT and contrast-enhanced MSCT in detecting lymph node metastasis of esophageal cancer

BACKGROUND

Lymph node metastasis is believed to be a dependent negative prognostic factor of esophageal cancer. To explore detection methods with high sensitivity and accuracy for metastases to regional and distant lymph nodes in the clinic is of great significance. This study focused on clinical application of FDG PET/CT and contrast-enhanced multiple-slice helical computed tomography (MSCT) in lymph node staging of esophageal cancer.

MATERIALS AND METHODS

One hundred and fifteen cases were examined with enhanced 64-slice-MSCT scan, and FDG PET/CT imaging was conducted for neck, chest and upper abdomen within one week. The primary lesion, location and numbers of metastatic lymph nodes were observed. Surgery was performed within one week after FDG PET/CT detection. All resected lesions were confirmed histopathologically as the gold standard. Comparative analysis of the sensitivity, specificity, and accuracy based on FDG PET/CT and MSCT was conducted.

RESULTS

There were 946 lymph node groups resected during surgery from 115 patients, and 221 were confirmed to have metastasis pathologically. The sensitivity, specificity, accuracy of FDG PET/CT in detecting lymph node metastasis were 74.7%, 97.2% and 92.0%, while with MSCT they were 64.7%, 96.4%, and 89.0%, respectively. A significance difference was observed in sensitivity (p=0.030), but not the others (p>0.05). The accuracy of FDG PET/CT in detecting regional lymph node with or without metastasis were 91.9%, as compared to 89.4% for MSCT, while FDG PET/CT and MSCT values for detecting distant lymph node with or without metastasis were 94.4% and 94.7%. No significant difference was observed for either regional or distant lymph node metastasis. Additionally, for detecting para-esophageal lymph nodes metastasis, the sensitivity of FDG PET/CT was 72%, compared with 54.7% for MSCT (p=0.029).

CONCLUSIONS

FDG PET/CT is more sensitive than MSCT in detecting lymph node metastasis, especially for para-esophageal lymph nodes in esophageal cancer cases, although no significant difference was observed between FDG PET/CT and MSCT in detecting both regional and distant lymph node metastasis. However, enhanced MSCT was found to be of great value in distinguishing false negative metastatic lymph nodes from FDG PET/CT. The combination of FDG PET/CT with MSCT should improve the accuracy in lymph node metastasis staging of esophageal cancer.

Usefulness of positron emission tomography-computed tomography in pre-operative evaluation of intra-thoracic esophageal cancer

Background

The purpose of the study was to clarify the usefulness of positron emission tomography-computed tomography (PET-CT) for pre-operative evaluation of intra-thoracic esophageal cancer, especially in terms of regional lymph node status.

Methods

Medical records of 93 consecutive cases from July 2007 to October 2012 were retrospectively reviewed. All patients underwent curative and complete esophagectomies for intra-thoracic esophageal cancer. We compared pre-operative maximum standard uptake values (SUVmax) of esophageal tumors and regional lymph nodes (LN) with other variables (chronic obstructive pulmonary disease, history of previous other primary cancer, gender, differentiation, and neoadjuvant therapy). In addition, the SUVmax of tumors and LNs were analyzed with pathologic findings.

Results

There was no significant difference of each tumor and LN SUVmax according to factors including chronic lung disease, age, history of previous other cancer, differentiation, and gender. Pre-operative evaluations by PET-CT were not accurate (tumor sensitivity 76.4%, specificity 25%; LN sensitivity 45.2%, specificity 54.8%). Receiver operating characteristic analysis showed that LN metastasis could not be appropriately diagnosed with SUVmax (P = 0.871). There was no difference in SUVmax between pathologically positive and negative LN subgroups. Tumor SUVmax correlated with the progression of esophageal cancer in patients without neoadjuvant therapy (P < 0.001). However, LN SUVmax had no correlation with overall pathologic stage. After neoadjuvant therapy, there were significant decreases in SUVmax in both pathologically positive and negative LN subgroups (P = 0.043, P = 0.008).

Conclusion

 Surgery should not be withheld in N-stage according to PET-CT findings and carefully considered in conjunction with other conditions.

Positron Emission Tomography (PET) in Oncology

Since its introduction in the early nineties as a promising functional imaging technique in the management of neoplastic disorders, FDG-PET, and subsequently FDG-PET/CT, has become a cornerstone in several oncologic procedures such as tumor staging and restaging, treatment efficacy assessment during or after treatment end and radiotherapy planning. Moreover, the continuous technological progress of image generation and the introduction of sophisticated software to use PET scan as a biomarker paved the way to calculate new prognostic markers such as the metabolic tumor volume (MTV) and the total amount of tumor glycolysis (TLG). FDG-PET/CT proved more sensitive than contrast-enhanced CT scan in staging of several type of lymphoma or in detecting widespread tumor dissemination in several solid cancers, such as breast, lung, colon, ovary and head and neck carcinoma. As a consequence the stage of patients was upgraded, with a change of treatment in 10%-15% of them. One of the most evident advantages of FDG-PET was its ability to detect, very early during treatment, significant changes in glucose metabolism or even complete shutoff of the neoplastic cell metabolism as a surrogate of tumor chemosensitivity assessment. This could enable clinicians to detect much earlier the effectiveness of a given antineoplastic treatment, as compared to the traditional radiological detection of tumor shrinkage, which usually takes time and occurs much later.

Maximum standardized uptake value on PET/CT in preoperative assessment of lymph node metastasis from thoracic esophageal squamous cell carcinoma

The presence of lymph node metastasis is an important prognostic factor for patients with esophageal cancer. Accurate assessment of lymph nodes in thoracic esophageal carcinoma is essential for selecting appropriate treatment and forecasting disease progression. Positron emission tomography combined with computed tomography (PET/CT) is becoming an important tool in the workup of esophageal carcinoma. Here, we evaluated the effectiveness of the maximum standardized uptake value (SUVmax) in assessing lymph node metastasis in esophageal squamous cell carcinoma (ESCC) prior to surgery. Fifty-nine surgical patients with pathologically confirmed thoracic ESCC were retrospectively studied. These patients underwent radical esophagectomy with pathologic evaluation of lymph nodes. They all had ¹⁸F-FDG PET/CT scans in their preoperative staging procedures. None had a prior history of cancer. The pathologic status and PET/CT SUVmax of lymph nodes were collected to calculate the receiver operating characteristic (ROC) curve and to determine the best cutoff value of the PET/CT SUVmax to distinguish benign from malignant lymph nodes. Lymph node data from 27 others were used for the validation. A total of 323 lymph nodes including 39 metastatic lymph nodes were evaluated in the training cohort, and 117 lymph nodes including 32 metastatic lymph nodes were evaluated in the validation cohort. The cutoff point of the SUVmax for lymph nodes was 4.1, as calculated by ROC curve (sensitivity, 80%; specificity, 92%; accuracy, 90%). When this cutoff value was applied to the validation cohort, a sensitivity, a specificity, and an accuracy of 81%, 88%, and 86%, respectively, were obtained. These results suggest that the SUVmax of lymph nodes predicts malignancy. Indeed, when an SUVmax of 4.1 was used instead of 2.5, FDG-PET/CT was more accurate in assessing nodal metastasis.