Prognostic significance of endoluminal ultrasound-defined disease length and tumor volume (EDTV) for patients with the diagnosis of esophageal cancer

A computed tomography-based nomogram for neoadjuvant chemotherapy plus immunotherapy response prediction in patients with advanced esophageal squamous cell carcinoma

OBJECTIVE

To develop a CT-based nomogram to predict the response of advanced esophageal squamous cell carcinoma (ESCC) to neoadjuvant chemotherapy plus immunotherapy.

METHODS

In this retrospective study, 158 consecutive patients with advanced ESCC receiving contrast-enhanced CT before neoadjuvant chemotherapy plus immunotherapy were randomized to a training cohort (TC, n = 121) and a validation cohort (VC, n = 37). Response to treatment was assessed with response evaluation criteria in solid tumors. Patients in the TC were divided into the responder (n = 69) and non-responder (n = 52) groups. For the TC, univariate analyses were performed to confirm factors associated with response prediction, and binary analyses were performed to identify independent variables to develop a nomogram. In both the TC and VC, the nomogram performance was assessed by area under the receiver operating characteristic curve (AUC), calibration slope, and decision curve analysis (DCA).

RESULTS

In the TC, univariate analysis showed that cT stage, cN stage, gross tumor volume, gross volume of all enlarged lymph nodes, and tumor length were associated with the response (all P < 0.05). Binary analysis demonstrated that cT stage, cN stage, and tumor length were independent predictors. The independent factors were imported into the R software to construct a nomogram, showing the discriminatory ability with an AUC of 0.813 (95% confidence interval: 0.735-0.890), and the calibration curve and DCA showed that the predictive ability of the nomogram was in good agreement with the actual observation.

CONCLUSION

This study provides an accurate nomogram to predict the response of advanced ESCC to neoadjuvant chemotherapy plus immunotherapy.

Tumour volume of resectable oesophageal squamous cell carcinoma measured with MRI correlates well with T category and lymphatic metastasis

OBJECTIVES

To determine association of gross tumour volume (GTV) of resectable oesophageal squamous cell carcinoma (SCC) measured on T2-weighted imaging (T2WI), contrast-enhanced T1-weighted imaging (CE-T1WI) and diffusion-weighted imaging (DWI) with T category and lymphatic metastasis (LM).

METHODS

Sixty oesophageal SCC patients underwent fat-suppressed T2WI, CE-T1WI and DWI with b values of 0, 500 and 800 s/mm2. GTV was measured on three sequences. Statistical analyses were performed to determine association of GTV with T category and LM.

RESULTS

Spearman's rank correlation analysis showed positive association of GTV with T category and LM (all p values < 0.01). Differences in GTV were found between T1 and T2 or T3 categories shown by Kruskal-Wallis H and one-way ANOVA tests, and between T1/T2 and T3 and between tumours with and without LM by Mann-Whitney U tests (all p values < 0.05). Receiver operating characteristic analyses showed cut-off GTVs of 5.795, 5.276 and 10.11 cm3 on CE-T1WI could better differentiate T1 from T2 categories, T1 from T3, and T1-2 from T3 than those of 7.066, 7.045 and 8.504 cm3 on T2WI, of 5.793, 6.609 and 6.989 cm3 on DWI with b value of 500 s/mm2, and of 4.156, 4.519 and 4.985 cm3 with b value of 800 s/mm2, respectively. Cut-off of 10.462 cm3 on DWI with b value of 500 s/mm2 could better identify LM than of 12.38, 8.793 and 9.600 cm3 on T2WI, CE-T1WI and DWI with b value of 800 s/mm2, respectively.

CONCLUSIONS

GTVs on T2WI, CE-T1WI and DWI are associated with T category of and LM of oesophageal SCC.

KEY POINTS

• GTV is associated with T category and lymphatic metastasis of oesophageal SCC • GTV measured on contrast-enhanced T 1 -weighted imaging better identifies T category • GTV measured on DWI with b value of 500 s/mm 2 better identifies lymphatic metastasis.

Esophageal luminal stenosis is an independent prognostic factor in esophageal squamous cell carcinoma

BACKGROUND

Predictive value of preoperative endoscopic characteristic of esophageal tumor has not been fully evaluated. The aim of this study is to investigate the impact of esophageal luminal stenosis on survival for patients with resectable esophageal squamous cell carcinoma (ESCC).

METHODS

The clinicopathologic characteristics of 623 ESCC patients who underwent curative resection as the primary treatment between January 2005 and April 2009 were retrospectively reviewed. The esophageal luminal stenosis measured by endoscopy was defined as a uniform measurement preoperatively. The impact of esophageal luminal stenosis on patients' overall survival (OS) and relation with other clinicopathological features were assessed. A Cox regression model was used to identify prognostic factors.

RESULTS

The results showed that OS significantly decreased in patients with manifest stenotic tumor compared with patients without luminal obstruction (P<0.05). Considerable esophageal luminal stenosis was associated with a higher T stage, longer tumor length, and poorer differentiation (all P<0.05). In multivariate survival analysis, esophageal luminal stenosis remained as an independent prognostic factor for OS (P= 0.036).

CONCLUSIONS

Esophageal luminal stenosis could have a significant impact on the OS in patients with resected ESCC and may provide additional prognostic value to the current staging system before any cancer-specific treatment.

Prognostic relevance of serial endoscopic ultrasound after chemoradiation in esophageal cancer

The objective of this study is the feasibility of sequential endoscopic and endosonographic measurement of locoregional tumor load for the prediction of tumor recurrence in patients after neoadjuvant or definitive chemoradiotherapy, treated in curative intent for locally advanced esophageal carcinoma. In 67 patients with esophageal cancer, serial endoscopic ultrasound was performed before and after neoadjuvant (25) or definitive (42) chemoradiotherapy. Rate of complete endoscopic and endosonographic tumor response, reduction in tumor length or circumferential tumorous extension, maximal tumor thickness, lymph node size, and endosonographic uT- and uN-stage shift was measured. Results were correlated with tumor recurrence rate. After chemoradiotherapy, endosonography revealed a complete response of the primary tumor in 27 patients, and complete resolution of suspicious lymph nodes in 24 patients. According to uTN-stage, 43 patients showed a therapeutic response, with stage shift to a lower tumor stage. In patients with macroscopic residual disease, mean tumor thickness decreased from 13 to 9 mm, with nine patients presenting with a decrease of >50%. Mean tumor length decreased from 5.6 to 4.6 cm, with 10 patients showing a decrease of >50%. Mean lymph node size decreased from 14.5 to 12 mm, with four patients having a reduction in size of >50%. Tumor response was generally more pronounced after definitive than after neoadjuvant chemoradiotherapy. During follow-up, 33 patients developed a tumor recurrence. None of the endoscopic and endosonographic parameter analyzed was predictive for patient's prognosis, irrespective of the kind of chemoradiotherapy (neoadjuvant or definitive). Sequential measurement of locoregional tumor load with endoscopic ultrasound before and after chemoradiotherapy is not suitable for the prediction of tumor recurrence risk.

Metabolic tumor volume provides complementary prognostic information to EUS staging in esophageal and junctional cancer

To determine the correlation between 18F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) derived esophageal tumor parameters [maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV)] and endoscopic ultrasound (EUS) derived tumor parameters (T stage, N stage) and their prognostic implications. 150 consecutive patients with cancer of the esophagus or esophagogastric junction underwent staging PET-CT and staging EUS. PET-CT derived SUVmax and MTV of the primary tumor was recorded. EUS evaluated T and N stage. Relationships between parameters were investigated using the Mann-Whitney U tests, survival analysis performed using Kaplan-Meier and independent prognostic factors determined using Cox regression multivariate analysis. A significant difference in MTV was noted between EUS T1/T2 tumors (median 6.7 cm3) and EUS T3/T4 tumors (median 35.7 cm3; P < 0.0001). An MTV of <23.4 cm3 (P = 0.0001), SUVmax < 4.1 (P = 0014), EUS T stage (P < 0.0001), EUS N stage (P < 0.0001), and clinical stage (P < 0.0001) were all significantly associated with survival, with MTV <23.4 cm3 (P = 0.004), EUS T stage (P = 0.01), and EUS N stage (P = 0.01) significant in multivariate analysis. MTV, a volumetric parameter of PET-CT, has more prognostic importance than SUVmax and provides valuable prognostic information in esophageal and junctional cancer, along with EUS T and N stage. MTV provides complementary information to EUS and should be included in the staging of esophageal and junctional cancer.

Prediction of survival by tumor area on endosonography after definitive chemoradiotherapy for locally advanced squamous cell carcinoma of the esophagus

BACKGROUND

Definitive chemoradiotherapy (CRT) is a reasonable approach for patients with locally advanced esophageal cancer who are not surgical candidates. This study was performed to investigate whether endosonography (EUS) assessment of tumor area response is a useful prognostic marker in patients with squamous cell carcinoma (SCC) of the esophagus who receive definitive CRT.

METHODS

A total of 33 patients who received definitive CRT for locally advanced esophageal SCC were enrolled. The maximal transverse cross-sectional area of the tumor was measured before and after definitive therapy. EUS response was defined as a ≥50% reduction of the tumor area after definitive CRT.

RESULTS

Based on EUS evaluation, there were 20 nonresponders (60.6%) and 13 responders (39.4%). The median progression-free survival (PFS) was significantly longer in EUS responders than EUS nonresponders (p = 0.005). However, there was no statistical significance in overall survival according to EUS response (p = 0.120). During multivariate analysis, EUS response to definitive CRT was the only significant factor associated with PFS (p = 0.045), whereas EUS response to definitive CRT was not associated with overall survival (p = 0.221).

CONCLUSIONS

A reduction of the maximal cross-sectional tumor area measured by EUS correlates with a superior prognosis in patients with locally advanced SCC of the esophagus after definitive CRT.

Prognostic significance of novel ¹⁸F-FDG PET/CT defined tumour variables in patients with oesophageal cancer

PURPOSE

(18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) combined with computed tomography (PET/CT) is now established as a routine staging investigation of oesophageal cancer (OC). The aim of the study was to determine the prognostic significance of PET/CT defined tumour variables including maximum standardised uptake value (SUVmax), tumour length (TL), metastatic length of disease (MLoD), metabolic tumour volume (MTV), total lesion glycolysis (TLG) and total local nodal metastasis count (PET/CT LNMC).

MATERIALS AND METHODS

103 pre-treatment OC patients (76 adenocarcinoma, 25 squamous cell carcinoma, 1 poorly differentiated and 1 neuroendocrine tumour) were staged using PET/CT. The prognostic value of the measured tumour variables were tested using log-rank analysis of the Kaplan-Meier method and Cox's proportional hazards method. Primary outcome measure was survival from diagnosis.

RESULTS

Univariate analysis showed all variables to have strong statistical significance in relation to survival. Multivariate analysis demonstrated three variables that were significantly and independently associated with survival; MLoD (HR 1.035, 95% CI 1.008-1.064, p=0.011), TLG (HR 1.002, 95% CI 1.000-1.003, p=0.018) and PET/CT LNMC (HR 0.048-0.633, 95% CI 0.005-2.725, p=0.015).

CONCLUSION

MLoD, TLG, and PET/CT LNMC are important prognostic indicators in OC. This is the first study to demonstrate an independent statistical association between TLG, MLoD and survival by multivariable analysis, and highlights the value of staging OC patients with PET/CT using functional tumour variables.

Computed tomography scan as a tool to predict tumor T category in resectable esophageal squamous cell carcinoma

BACKGROUND

The purpose of this study was to determine whether the degree of esophageal circumferential tumor involvement and tumor size of resectable esophageal squamous cell carcinoma (ESCC) assessed on computed tomography could predict T category.

METHODS

One hundred eighty-five consecutive patients with ESCC underwent radical esophagectomy less than 3 weeks after contrast-enhanced computed tomography. The degree of esophageal circumferential tumor involvement and tumor size of ESCC expressed as tumor length, maximal thickness, and gross tumor volume were evaluated on computed tomography. Statistical analyses were performed to identify whether degree of esophageal circumferential tumor involvement and tumor size could predict T category.

RESULTS

Esophageal squamous cell carcinoma with whole esophageal circumferential tumor involvement was more likely to be at T3 category, whereas tumor without this involvement was more likely to be at T1 or T2 category (p < 0.001). Degree of esophageal circumferential tumor involvement could distinguish ESCC at T1/T2 from ESCC at T3 category with a sensitivity of 77.4% and specificity of 74.8%. Tumor length, maximal thickness, and gross tumor volume increased with advancing T category (p < 0.001). Mann-Whitney tests showed that tumor size could distinguish T category (p < 0.001). Compared with degree of esophageal circumferential tumor involvement, tumor length, and maximal thickness, gross tumor volume could be a better differentiating indicator between T1 and T2 categories (cutoff, 5.15 cm(3)), between T1 and T3 categories (cutoff, 11.1 cm(3)), between T2 and T3 categories (cutoff, 17.75 cm(3)), and between T1/T2 and T3 categories (cutoff, 15.9 cm(3)), with sensitivity of 81.3%, 88.8%, 68.8%, and 78.8%, and specificity of 76%, 88%, 67.5%, and 75.4%, respectively.

CONCLUSIONS

Gross tumor volume of resectable ESCC measured with computed tomography could be a recommended indicator for predicting T category.

Tumour size of resectable oesophageal squamous cell carcinoma measured with multidetector computed tomography for predicting regional lymph node metastasis and N stage

OBJECTIVES

To determine whether and how tumour size of resectable oesophageal squamous cell carcinoma (ESCC) measured with multidetector CT could predict regional lymph node metastasis (LNM) and N stage.

METHODS

Two hundred five patients with ESCC underwent radical oesophagectomy with three-field lymphadenectomy less than 3 weeks after contrast-enhanced CT. Tumour size of the ESCC (tumour length, maximal thickness and gross tumour volume, GTV) was measured on CT. Statistical analyses were performed to identify whether tumour size could predict regional LNM and N stage, and to determine how to use the size of ESCC to predict N stage.

RESULTS

Univariate analysis showed that tumour size could predict regional LNM (all P < 0.05). Logistic regression analysis revealed that GTV could independently predict regional LNM (P = 0.021, odds ratio = 1.813). Mann-Whitney tests showed that tumour size could distinguish grouped N stages (all P < 0.05). GTV might be a differentiating indicator between N0 and N1-3 stages (cutoff, 14.4 cm(3)), between N0-1 and N2-3 (cutoff, 15.9 cm(3)), and between N0-2 and N3 (cutoff, 26.1 cm(3)), with sensitivity of 76%, 63% or 75%, and specificity of 75%, 61% and 81%, respectively.

CONCLUSIONS

The GTV of ESCC measured with CT could be an indicator for predicting regional LNM and grouped N stages.

KEY POINTS

• Multidetector computed tomography (MDCT) allows accurate assessment of oesophageal tumour size • For resectable squamous cell tumours, size helped predict regional lymph node involvement • Gross tumour volume may predict the N stage of oesophageal squamous cell carcinoma.

Prognostic significance of 18-FDG PET/CT and EUS-defined tumour characteristics in patients with oesophageal cancer

AIM

To determine the correlation between 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) defined maximum standardized uptake value (SUVmax) and endoluminal ultrasound-defined tumour volume (EDTV) in patients with oesophageal cancer (OC) and their relative prognostic significance.

MATERIALS AND METHODS

One hundred and eighty-five consecutive patients with OC were staged using CT, endoscopic ultrasound (EUS), and PET/CT. The maximum potential EDTV was calculated (πr(2)L, where r = tumour thickness and L = total length of disease including proximal and distal lymph node metastases). Primary outcome measure was survival from diagnosis.

RESULTS

Ninety-one percent of patients (168/185) had FDG-avid tumours on PET/CT. SUVmax correlated positively and significantly with EDTV (Spearman's rho = 0.339, p = 0.001). On univariate analysis, survival was inversely related to the PET/CT lymph node metastasis count (LNMC, p = 0.015), EUS N stage (p = 0.002), EDTV (<48 cm(3), p = 0.001), EUS total length of disease (p = 0.001), SUVmax (p = 0.002), PET/CT N stage (p < 0.0001), and EUS LNMC (p < 0.0001). On multivariate analysis two factors were significantly and independently associated with survival: EDTV (HR, 3.118; 95% CI: 1.357-7.167; p = 0.007), and PET/CT N stage (HR, 0.496; 95% CI: 0.084-1.577; p = 0.022).

CONCLUSION

EDTV and PET/CT N stage were important predictors of survival and further research is needed to identify critical prognostic values.

Prognostic significance of total disease length in esophageal cancer

BACKGROUND

This study tested the hypothesis that endoluminal ultrasound (EUS) defined total length of disease (including both the primary tumor and the position and number of proximal and distal lymph nodes-ELoD) and the associated EUS lymph node metastasis count (ELNMC) are better predictors of outcome than endoscopic esophageal cancer (OC) length and radiological tumor node metastasis stage in patients who undergo potentially curative treatment with surgery or definitive chemoradiotherapy (dCRT).

METHODS

A total of 645 consecutive patients diagnosed with OC and managed by a multidisciplinary team were staged by CT and EUS. The primary outcome measure was survival from date of diagnosis.

RESULTS

A total of 323 patients received surgery (208 neoadjuvant chemotherapy), and 322 who were deemed unsuitable for surgery received dCRT. Univariable analysis revealed that survival was related to EUS T (p < 0.0001), N (p < 0.0001), EUS primary tumor length (p = 0.037), ELoD (p = 0.011), ELNMC (p < 0.0001), and treatment type (p = 0.001). Multivariable analysis revealed two factors: ELoD (hazard ratio (HR), 0.961; 95 % confidence interval (CI), 0.925-0.998; p = 0.041) and ELNMC (HR, 1.08; 95 % CI, 1.015-1.15; p = 0.016) were independently associated with survival.

CONCLUSIONS

ELoD and ELNMC should become part of routine OC radiological staging to optimize stage-directed therapeutic outcomes.

Endoscopic tumor length is an independent prognostic factor in esophageal squamous cell carcinoma

PURPOSE

To investigate the impact of endoscopic esophageal tumor length on survival for patients with resected esophageal squamous cell carcinoma (ESCC).

METHODS

We retrospectively reviewed the clinicopathologic characteristics of 244 ESCC patients who underwent curative resection as the primary treatment at Taipei Veterans General Hospital between January 2000 and November 2010. The endoscopic tumor length was defined as a uniform measurement before completion of the esophagectomy. The impact of endoscopic tumor length on a patient's overall survival (OS) and disease-free survival (DFS) were assessed. A Cox regression model was used to identify prognostic factors.

RESULTS

The 1-, 3-, and 5-year OS rates were 81.2, 48.2, and 39.6%, respectively, with a median survival time of 18.0 months. The 1-, 3-, and 5-year DFS rates were 66.2, 34.7, and 32.4%, respectively, with a median DFS of 15.0 months. Endoscopic tumor length correlated with pathologic tumor length [Pearson correction (r)=0.621; P<0.001] Regression trees analyses suggested an optimum cutoff point of >4 cm to identify patients with decreased long-term survival. In multivariate survival analysis, endoscopic tumor length (more or less than 4 cm) remained an independent prognostic factor for both OS (P=0.006) and DFS (P=0.002).

CONCLUSIONS

Endoscopic tumor length could have a significant impact on both the OS and DFS of patients with resected ESCC and may provide additional prognostic value to the current tumor, node, and metastasis staging system before patients receive any cancer-specific treatment.

The role of endoscopic ultrasound in assessing tumor response and staging after neoadjuvant chemotherapy for esophageal cancer

BACKGROUND

Although the role of endoscopic ultrasound (EUS) in the initial staging of esophageal cancer is well established, its role in assessing tumor response and staging esophageal cancers after neoadjuvant chemotherapy (NAC) is controversial, and this study aimed to investigate this role.

METHODS

This study retrospectively analyzed 110 patients with esophageal cancer who underwent EUS by single surgeon before and after NAC. Tumor response was assessed before and after NAC. Patients with more than a 50% reduction in tumor size based on EUS evaluation were classified as having a significant response to chemotherapy, and those with less than a 50% reduction were categorized as having a partial response. Disease stage was established by tumor node metastasis (TNM) classification. Initial staging was performed using EUS and computed tomography (CT) scans of the chest and abdomen. The EUS-determined stage was compared with the postsurgical pathologic stage. χ(2) analysis and Fisher's exact testing were performed.

RESULTS

A response to NAC was shown by 96 patients (87.3%) and no response by 14 patients (12.7%). Of the 96 responding patients, 37 (38.5%) showed a significant response, whereas 43 (61.5%) of 69 patients showed a partial response. The EUS staging correlated well with the pathologic staging for 9 (64.3%) of the 14 nonresponders and for 34 (35.4%) of the 96 responders to NAC (P = 0.04). The EUS accurately predicted both the T and N status for 26 (23.6%) of the 110 patients. Prediction of N status was significantly more accurate than prediction of the T stage for the post-NAC patients. Of the 110 patients, 43 (39.1%) patients had an accurate T-stage prediction, and 64 (58.2%) had an accurate N stage match (P = 0.02). The T stage was overstaged for 60 (54.5%) of the patients and understaged for 7 of the patients (6.4%).The study found overstaging of the T stage to be more common among the patients who responded to chemotherapy. The N stage was overstaged for 25 (22.7%) and understaged for 21 (19.1%) of the 110 patients.

CONCLUSION

The findings showed EUS to be a useful tool for assessing response to chemotherapy and for evaluating the extent of disease, thus facilitating surgical decision making. However, EUS is an unreliable tool for staging esophageal cancer after NAC. Overstaging of the T stage is significantly more common and could be related to the inflammatory effect or fibrosis after NAC.

Prognostic significance of the endoscopic ultrasound defined lymph node metastasis count in esophageal cancer

The key prognostic factor which predicts outcome after esophagectomy for cancer is the number of malignant lymph node metastases, but data regarding the accuracy of endoscopic ultrasound (EUS) in determining and predicting the metastatic lymph node count preoperatively are limited. The aim of this study was to assess the prognostic significance of EUS defined lymph node metastasis count (eLNMC) in patients diagnosed with esophageal cancer. Two hundred and sixty-seven consecutive patients (median age 63 years, 187 months) underwent specialist EUS followed by stage directed multidisciplinary treatment (183 esophagectomy [64 neoadjuvant chemotherapy, 19 neoadjuvant chemoradiotherapy], 79 definitive chemoradiotherapy, and 5 palliative therapy). The eLNMC was subdivided into four groups (0, 1, 2 to 4, >4) and the primary measure of outcome was survival. Survival was related to EUS tumor (T) stage (P < 0.0001), EUS node (N) stage (P < 0.0001), EUS tumor length (p < 0.0001), and eLNMC (P < 0.0001). Multivariable analysis revealed EUS tumor length (hazard ratio [HR] 1.071, 95% CI 1.008-1.138, P= 0.027) and eLNMC (HR 1.302, 95% CI 1.133-1.496, P= 0.0001) to be significantly and independently associated with survival. Median and 2-year survival for patients with 0, 1, 2-4, and >4 lymph node metastases were: 44 months and 71%, 36 months and 59%, 24 months and 50%, and 17 months and 32%, respectively. The total number of EUS defined lymph node metastases was an important and significant prognostic indicator.

Computed tomography overestimation of esophageal tumor length: Implications for radiotherapy planning

AIM: To assess the relationship between preoperative computed tomography (CT) and postoperative pathological measurements of esophageal tumor length and the prognostic significance of CT tumor length data.

METHODS: A retrospective study was carried out in 56 patients who underwent curative esophagogastrectomy. Tumor lengths were measured on the immediate preoperative CT and on the post-operative resection specimens. Inter- and intra-observer variations in CT measurements were assessed. Survival data were collected.

RESULTS: There was a weak correlation between CT and pathological tumor length (r = 0.30, P = 0.025). CT lengths were longer than pathological lengths in 68% (38/56) of patients with a mean difference of 1.67 cm (95% CI: 1.18-2.97). The mean difference in measurements by two radiologists was 0.39 cm (95% CI: -0.59-1.44). The mean difference between repeat CT measured tumor length (intra-observer variation) were 0.04 cm (95% CI: -0.59-0.66) and 0.47 cm (95% CI: -0.53-1.47). When stratified, patients not receiving neoadjuvant chemotherapy showed a strong correlation between CT and pathological tumor length (r = 0.69, P = 0.0014, n = 37) than patients that did (r = 0.13, P = 0.43, n = 19). Median survival with CT tumor length > 5.6 cm was poorer than with smaller tumors, but the difference was not statistically significant.

CONCLUSION: Esophageal tumor length assessed using CT does not reflect pathological tumor extent and should not be the only modality used for management decisions, particularly for planning radiotherapy.