Superficial Esophageal Carcinoma: Evaluation by Endoscopic Ultrasonography

Objectives: The aim of this study was to evaluate the usefulness of endoscopic ultrasonography (EUS) in the staging of superficial esophageal carcinoma (SEC). Methods: We examined the histopathologic findings of 28 patients with SEC which was confirmed in the postoperative histologic evaluation. The EUS results preoperatively estimated were compared with them. Results: There were nine patients with mucosal carcinoma (two intraepithelial carcinomas and seven carcinomas limited to the mucosal layer) and 19 patients with submucosal carcinoma. The mucosal carcinomas revealed no lymph node metastasis or vessel permeation, whereas the submucosal carcinomas revealed lymph node metastasis (71%) and vessel permeation (lymphatic, 58%, vascular, 21%). The accuracy rates of depth of invasion by EUS were mucosa, 67% (6/9); submucosa, 79% (15/19); and total, 75% (21/28). EUS could not detect microinvasion to the submucosa. The overall accuracy rate of EUS in the evaluation of periesophagogastric lymph node metastasis was 72%: sensitivity 58% and specificity 85%. Conclusions: It has been clinically proved important to differentiate mucosal carcinoma from submucosal carcinoma in the staging of SEC, and EUS is recommended in differentiating between them.     

Long-term outcome after endoscopic mucosal resection in patients with esophageal squamous cell carcinoma invading the muscularis mucosae or deeper

BACKGROUND: Endoscopic mucosal resection is recommended for squamous cell carcinoma of the esophagus confined to the lamina propria. However, endoscopic mucosal resection is often performed in patients with tumors that invade the muscularis mucosa or upper submucosa to minimize surgical invasiveness, despite the increased risk of lymph node metastasis. This study prospectively evaluated long-term outcome in such patients. METHODS: Twenty-six consecutive patients with squamous cell esophageal carcinoma invading the muscularis mucosa or submucosa who underwent endoscopic mucosal resection from June 1992 through March 2000 (extended endoscopic mucosal resection group) were studied. As control group, 44 consecutive patients with esophageal carcinoma invading the muscularis mucosae or upper third of the submucosa and no preoperative evidence of lymph node metastasis who underwent esophagectomy during the same period (surgical resection group) were studied. RESULTS: Overall survival rates at 5 years in the extended endoscopic mucosal resection group and surgical resection group were, respectively, 77.4% and 84.5%. There was no significant difference between survival distributions. Cause-specific survival rates at 5 years in extended endoscopic mucosal resection and surgical resection groups were, respectively, 95.0% and 93.5%. Survival curves for the groups were similar. CONCLUSION: Although patients were not randomized to extended endoscopic mucosal resection or surgical resection in this study, the results suggest that endoscopic mucosal resection may be safe and effective for management of squamous cell esophageal carcinoma invading the muscularis mucosae or upper submucosa.     

Independent histological risk factors for lymph node metastasis of superficial esophageal squamous cell carcinoma; implication of claudin‐5 immunohistochemistry for expanding the indications of endoscopic resection

Endoscopic resection is curative for superficial esophageal squamous cell carcinoma (ESCC) limited to the lamina propria. Endoscopic resection is not recommended for superficial ESCC invading muscularis mucosa or submucosa, however, because of the high frequency of lymph node metastasis (LNM) in such patients. Methods to more accurately predict LNM by analysis of endoscopically resected specimens are needed. Patients with superficial ESCC who underwent surgery without prior chemoradiotherapy (n= 110) were retrospectively examined to determine whether LNM correlated with immunohistochemical parameters and conventional histological parameters, including depth of invasion and vascular permeation. Cancer cell expression of claudins‐1, 5, and 7, E‐cadherin, β‐catenin, and matrix metalloproteinase 7 was evaluated. Univariate analysis revealed that LNM correlated with claudin‐5 expression, but not any other immunohistochemical parameter examined. Multivariate analysis revealed three independent risk factors for LNM: aberrant claudin‐5 expression in cancer cells (odds ratio; OR [95% confidence interval]= 4.61[1.44–14.77]), depth of submucosal invasion greater than 200 µm (3.55 [1.02–13.17]), and positive lymphatic permeation (3.34 [1.22–9.15]). LNM was found in one of 29 (3.4%) patients with none of these three risk factors, and in 32 of 81 (39.5%) patients with one or more of these risk factors. In superficial ESCC, routine analysis of claudin‐5 expression in cancer cells together with depth of invasion and lymphatic permeation may be useful for predicting LNM and thereby reducing the number of patients undergoing additional surgery after successful endoscopic resection.     

Clinical Usefulness of D2-40 in Non-Small Cell Lung Cancer

D2-40 is a recently developed monoclonal antibody that reacts with a 40 kDa O-linked sialoglycoprotein and has been used for the assessment of lymphatic invasion in tumor specimens. We have evaluated the diagnostic usefulness of D2-40 and association of its immunopositivity with clinicopathological parameters in adenocarcinoma and squamous cell carcinoma of the lung. We investigated 97 cases of surgically resected adenocarcinoma or squamous cell carcinoma of the lung for the determination of D2-40 positivity in tumor cells and peritumoral lymphatic vessel density (LVD) using an immunostaining method. D2-40 immunoreactivity in tumor cells was invariably negative in adenocarcinoma but 47% of squamous cell carcinomas were positive. D2-40 positivity in the tumor was significantly associated with high LVD in squamous cell carcinoma (P < 0.006). There was no significant association between peritumoral LVD and clinicopathologic parameters, including lymphatic vessel invasion, lymph node metastasis, and survival in adenocarcinoma and squamous cell carcinoma. These results suggest that D2-40 immunoreactivity in tumor cells can be used for distinguishing between adenocarcinoma and squamous cell carcinoma and that the reactivity of tumor cells with D2-40 is positively correlated with LVD in squamous cell carcinoma but not with lymph node metastasis in adenocarcinoma and squamous cell carcinoma.     

Tumor cell dissociation score highly correlates with lymph node metastasis in superficial esophageal carcinoma

BACKGROUND: It is still not clear which parameters are important for predicting the metastatic potential of superficial esophageal squamous cell carcinoma (SESCC). The purpose of the present paper was thus to investigate tumor cell dissociation (TCD) in SESCC as a predictive factor of lymph node metastasis. METHODS: Thirty-three SESCC were classified into four groups based on the depth of tumor invasion. Carcinomas not invading as far as the muscularis mucosa were classified as group A; carcinomas invading to the muscularis mucosa or less than one-third of the upper submucosa were classified as group B; those invading to the middle layer of the submucosa were classified as group C; and those invading one-third of the lower submucosa were classified as group D. The TCD score was calculated by dividing the length of the TCD region by the maximal longitudinal length of the area of invasion into or beyond the lamina propria, and multiplying by 100. E-cadherin expression of the carcinomas was investigated in the TCD area and the successive area of mucosal invasive carcinoma (SAM). RESULTS: The incidence of lymph node metastasis was 0% in group A, 10% in group B, 36.4% in group C and 57.1% in group D. The mean TCD scores (+/-SEM) of SESCC with lymph node metastasis were higher than that without (85.3 +/- 5.7, 16.3 +/- 3.9, respectively; P < 0.001). In group C, the TCD score of cases with lymph node metastases was higher than in those without lymph node metastasis (P < 0.001). E-cadherin expression was significantly reduced in the area of TCD compared with the SAM located over the TCD area (P < 0.001). CONCLUSIONS: The TCD score is an important predictive marker for lymph node metastasis in SESCC. Clinical evaluation of TCD scores in endoscopic mucosal resection (EMR) specimens would enable accurate prediction of lymph node metastasis and extend the indication of EMR treatment for SESCC.     

Endoscopic resection for T1a-MM and T1b-SM1 squamous cell carcinoma of the esophagus

In Japan, the first paper on endoscopic resection (ER) for squamous cell carcinoma (SCC) of the esophagus confined to the mucosa was reported as endoscopic mucosal resection (EMR) in 1988. Since publication of that article, ER has been recommended as the standard treatment for squamous and mucosal cancer of the esophagus. T1a-EP and T1a-LPM esophageal cancer seldom involves lymph node metastasis. However, in cases of T1a-MM and T1b-SM1 esophageal cancer with lymph node metastasis (10% to 30%), the indication of ER is limited. The risk factors for lymph node metastasis in T1a-MM and T1b-SM1 esophageal cancer were cleared by clinical and pathological studies. Endoscopic findings such as type 0–I or type 0–III, size of 50 mm or more, and pathological findings such as lymphatic permeation, venous permeation, poorly differentiated SCC and INFb or INFc were suggestive of high risk for lymph node metastasis. In addition, histopathological findings of small cancer nests, defined as “budding” or “droplet infiltration,” suggest frequent lymph node metastasis. In cases of T1a-MM and T1b-SM1 esophageal cancer with high risk of lymph node metastasis, adjuvant therapy including chemoradiotherapy and radical esophagectomy are recommended after ER. A recent advance in ER for esophageal cancer is the establishment of endoscopic submucosal dissection (ESD). It has allowed us to perform an en-block resection of a large mucosal lesion of the esophagus and detailed histopathological examination. However, ESD requires more difficult manipulation than EMR. The indication of EMR or ESD is sought.     

Risk factors of lymph node metastasis in T1 esophageal squamous cell carcinoma

Background and Aim: To perform endoscopic mucosal resection (EMR) for T1 esophageal cancer, it is essential to estimate the lymph node status exactly. In order to evaluate the feasibility of EMR for esophageal cancers, we evaluated the clinicopathological features of T1 esophageal squamous carcinomas with an emphasis on the risk factors and distribution patterns of lymph node metastasis. Methods: From 1994 to 2006, a total of 200 patients with T1 esophageal carcinoma were treated surgically in our institution. Among them, clinicopathological features were evaluated for 197 consecutive patients with T1 squamous cell carcinoma. Results: The frequency of lymph node involvement was 6.25% (4/64) in mucosal cancers and 29.3% (39/133) in submucosal cancers (P < 0.001). In patients with M1 (n = 32) and M2 (n = 14) cancers, no lymph node metastasis was found. In multivariate analysis, size larger than 20 mm, endoscopically non‐flat type, and endo‐lymphatic invasion were significant independent risk factors for lymph node metastasis. The differentiation of tumor cell was not a risk factor for lymph node metastasis. Conclusions: We suggest that EMR may be attempted for flat superficial squamous esophageal cancers smaller than 20 mm. After EMR, careful histological examination is mandatory.     

The use of minimally invasive surgery for lymph node recurrence after endoscopic mucosal resection of superficial esophageal cancer

A 73-year-old man was diagnosed with superficial esophageal cancer, and endoscopic mucosal resection was performed. Histologically, the lesion was found to be a squamous cell carcinoma invading the muscularis mucosae without vascular invasion. The patient was followed without being given adjuvant therapy, and lymph node recurrence along the lesser curvature of the stomach was found after 2.5 years. He underwent laparoscopic removal of the metastatic lymph node and cholecystectomy for cholecystolithiasis. He had two courses of adjuvant chemotherapy and showed no recurrence during 3 years of observation. Although the effectiveness of surgical resection for nodal recurrence of esophageal cancer remains controversial, this case highlights the possibility of salvage resection using minimally invasive surgery.     

Krukenberg tumor from gastric mucosal carcinoma without lymphatic or venous invasion: report of a case

A 49-year-old woman was admitted because of early gastric carcinoma. Subtotal gastrectomy was performed. In the resected specimen, gastric mucosal carcinoma without lymph node metastases was located in the prepyloric region. Histologic type was moderately differentiated adenocarcinoma and signetring cell carcinoma, and there was no lymphatic or venous invasion. One year after operation, a left ovarian tumor was detected. At the second operation, bilateral oophorectomy and hysterectomy were performed. Pathological findings revealed Krukenberg tumors originating from the gastric carcinoma in the bilateral ovaries. One year after the second operation, a hard mass due to cancer recurrence developed in the pelvis with symptoms including tenesmus and abdominal pain. Chemotherapy and palliative colostomy were performed. She died of peritonitis carcinomatosa six years and two months after the first operation. We experienced a rare case of Krukenberg tumor with two interesting points; its origin was gastric mucosal carcinoma without lymphatic or venous invasion, and the patient survived for more than four years after the diagnosis.     

Squamous cell carcinoma of unknown origin in middle mediastinum.

We report a rare case of squamous cell carcinoma located in the middle mediastinum as a solitary mass. Histologically, lymphatic tissues remained together with nests of squamous cell carcinoma which were occupying the greater part of the mass. Examinations of the whole body failed to detect a primary site of the squamous cell carcinoma. It is considered that the carcinoma cells reflect metastasis from a primary-unknown carcinoma (most likely TO lung squamous cell carcinoma) or that they originated from benign epithelial inclusions in a mediastinal lymph node.     

Early esophageal cancer with epidermization diagnosed and treated with endoscopic resection

The patient was a 57-year-old man who had undergone endoscopic submucosal dissection for early esophageal cancer (distance from incisor tooth, 30 cm) when he was 50 years of age. Pathological findings showed squamous cell carcinoma invading the lamina muscularis mucosae and mild lymphatic invasion. Considering the possibility of lymph node metastasis and distant metastasis, we administered radiation chemotherapy (CDDP+ 5-FU, total radiation 41.4 Gy) in the same year. Two years later, follow-up endoscopy revealed a white, flat, elevated lesion in the thoracic esophagus (distance from incisor tooth, 36 cm) that was not stained by Lugol’s iodine. A biopsy of this lesion was performed. Although esophageal epidermization was seen, there were no findings suggestive of malignancy. The lesion grew slightly during four and a half years of follow-up after identification. We performed a repeat biopsy of the lesion, and the tissue was diagnosed as atypical epithelium, so we performed endoscopic mucosal resection for diagnostic and therapeutic purposes. The postoperative pathological diagnosis was squamous cell carcinoma of T1a-LPM with epidermization due to its histological features. To the best of our knowledge, this is the first report of esophageal cancer accompanied by epidermization.     

Basaloid squamous carcinoma of the esophagus developed from achalasia: report of a case

A 57-year-old man, who had been diagnosed as having flask type, grade II achalasia of the esophagus at the age of 26, underwent Heller’s esophagomyectomy in a nearby hospital in 1971. A type 0-Is lesion measuring 2 cm in size was found on the middle thoracic esophagus in September 2002. A protruding tumor with a central depression, not stained with iodine, was detected by endoscopic examination. Standard subtotal esophagectomy with three-field lymph node dissection was performed. By histopathological examination, the esophageal lesion was classified as basaloid squamous carcinoma, extending to the middle part of the submucosa (T1b; sm2), without lymph node metastasis. The majority of the invasive carcinoma was composed of basaloid carcinoma, while a part showed as squamous cell carcinoma at the mucosal site. Achalasia of the esophagus is considered as a risk factor for squamous cell carcinoma by persistent mucosal inflammation caused by chronic stasis and food retention. Most of the reported carcinomas developing from esophageal achalasia are squamous cell carcinoma histologically. An extremely rare case of superficial basaloid squamous carcinoma with achalasia is presented.     

Recurrence after endoscopic mucosal resection of esophageal squamous cell carcinoma invading the muscularis mucosae or upper submucosa

Background: Endoscopic mucosal resection (EMR) is recommended for cases of squamous cell carcinoma of the esophagus in which the tumor is confined to the lamina propria mucosa. However, EMR is often performed in patients whose tumors invade the muscularis mucosae (m3) or upper submucosa (sm1) to minimize surgical invasion, despite the increased risk of lymph node metastasis. We evaluated patients who were found to have distant or lymph node metastasis after EMR for such lesions. Methods: Thirty‐four consecutive patients with esophageal carcinoma invading m3 or sm1 who underwent EMR during the period from June 1992 through March 2001 (extended EMR group) were studied. Results: Five of these patients were found to have distant or lymph node metastasis on follow up. Patient 1 died of lung metastasis 34 months after EMR. Patient 2 underwent chemotherapy because of an abnormally high value of squamous cell carcinoma (SCC) antigen. Patient 3 died of upper mediastinal lymph node metastasis 62 months after EMR. Patient 4 underwent total gastrectomy because of gastric wall metastasis 41 months after EMR and underwent chemoradiotherapy because of upper mediastinal lymph node metastasis 87 months after EMR. Patient 5 was found to have cardiac lymph node metastasis by follow‐up endoscopic ultrasonography examination 42 months after EMR and underwent curative lymph node dissection. Conclusion: It is unlikely that patient 1 and patient 2, both with probable distant metastasis, received inadequate treatment. Surgery with lymph node dissection usually cannot prevent distant metastasis. The patients with lymph node recurrence (patient 3 and patient 4) should have been followed up more carefully. We believe that patients with early lymph node metastasis, such as patient 5 in this study, should undergo curative surgical resection. Patients undergoing extended EMR should be carefully followed up for a long period to enable early detection and treatment of lymph node metastasis.     

Feasible endoscopic therapy for early gastric cancer

AIM: To analyze the relationship between lymph node metastasis and clinical pathology of early gastric cancer(EGC) in order to provide criteria for a feasible endoscopic therapy.METHODS: Clinical data of the 525 EGC patients who underwent surgical operations between January 2009 and March 2014 in the West China Hospital of Sichuan University were analyzed retrospectively. Clinical pathological features were compared between different EGC patients with or without lymph node metastasis, and investigated by univariate and multivariate analyses for possible relationships with lymph node metastasis.RESULTS: Of the 2913 patients who underwent gastrectomy with lymph node dissection, 529 cases were pathologically proven to be EGC and 525 cases were enrolled in this study, excluding 4 cases of gastric stump carcinoma. Among 233 patients with mucosal carcinoma, 43(18.5%) had lymph node metastasis. Among 292 patients with submucosal carcinoma, 118(40.4%) had lymph nodemetastasis. Univariate analysis showed that gender, tumor size, invasion depth, differentiation type and lymphatic involvement correlated with a high risk of lymph node metastasis. Multivariate analysis revealed that gender(OR = 1.649, 95%CI: 1.091-2.492, P = 0.018), tumor size(OR = 1.803, 95%CI: 1.201-2.706, P = 0.004), invasion depth(OR = 2.566, 95%CI: 1.671-3.941, P = 0.000), histological differentiation(OR = 2.621, 95%CI: 1.624-4.230, P = 0.000) and lymphatic involvement(OR = 3.505, 95%CI: 1.590-7.725, P = 0.002) wereindependent risk factors for lymph node metastasis. Comprehensive analysis showed that lymph node metastasis was absent in patients with tumor that was limited to the mucosa, size ≤ 2 cm, differentiated and without lymphatic involvement.CONCLUSION: We propose an endoscopic therapy for EGC that is limited to the mucosa, size ≤ 2 cm, differentiated and without lymphatic involvement.     

Constrictive pericarditis caused by a pericardial-occupying tumor due to esophageal cancer

A 61-year-old female was admitted to our hospital for esophageal cancer treatment. Esophagectomy with 2-field lymphadenectomy was performed. Postoperative findings revealed the lesion was a poorly differentiated squamous cell carcinoma invading into the diaphragm and there were no carcinoma cells on the surgical margins. Eight months after surgery, a recurrence was suspected by the presence of tumors at the pericardia, right axillary lymph node and around the descending aorta. The patient was re-admitted for chemotherapy and administrated fluorouracil and cisplatin 4 days after admission. After 7 days, she complained of dysphagia. Esophagogastroduodenoscopy showed no abnormal lesion that could cause the symptom. Computed tomography revealed massive progression of the pericardial tumor, bilateral pleural effusion and congested liver. Echocardiography showed the diffuse pericardial tumor caused restriction of ventricular dilation and hemodynamics of constrictive pericarditis. The patient died 29 days after re-admission. Autopsy revealed squamous cell carcinoma involving the mediatinum and pericardium. The pericardium was completely full of cancer tissue but no fluid. We concluded that the direct cause of death was neoplastic constrictive pericarditis.     

Case of metastatic breast cancer from esophageal cancer.

Metastasis to the breast from extramammary malignancies is rare. This is the third case report of metastatic breast cancer from esophageal cancer. We report the clinical, radiographic, and pathologic findings of a 57-year-old woman who underwent esophagectomy for esophageal cancer and developed metastatic cancer 2 years later. Pathologic examination of a resected specimen of the breast revealed squamous cell carcinoma invading the mammary glands. Estrogen receptor and axillary lymph node metastasis were negative with immunostaining. She is alive 6 months after the modified radical mastectomy.     

Direct Intraesophageal Growth from Metastatic Mediastinal Lymphadenopathy in Thymic Carcinoma

We herein report a case of thymic carcinoma that initially exhibited dysphagia and an intraesophageal mass lesion. A 68-year-old man was admitted to our hospital because of dysphagia. An endoscopic examination revealed a mass on the middle esophagus. Chest computed tomography (CT) showed a huge anterior mediastinal mass and subcarinal lymph node swelling, directly invading into the esophageal lumen. An immunohistological examination of the esophageal and anterior mediastinal masses revealed squamous cell carcinoma originating from the thymus. This is the first report of a thymic carcinoma spreading into the esophageal lumen and forming a mass lesion.     

T1肺癌淋巴结转移特点及临床意义

目的探讨T1肺癌淋巴结转移频度、分布范围及特点,为淋巴结清除术提供依据.方法按Naruke肺癌淋巴结分布图对215例T1肺癌施行了手术及广泛肺内、叶间、纵隔淋巴结清除术并对其进行统计分析.结果清除淋巴结1 674组.N1转移率11%,N2转移率6%.肿瘤最大直径≤1.5 cm㎝和1.6～3.0 cm者的淋巴结转移率分别为5%和8%.肿瘤最大直径≤1.5 cm的鳞癌N1、N2均无转移.N2转移在鳞癌、腺癌、小细胞癌分别为5%、23%和3/9,差异有极显著性(P＜0.01).N2转移鳞癌为某一组淋巴结转移的为3/4,腺癌≥3组转移占40%,跳跃式转移占N2转移的41%.N2阳性上叶肺癌下纵隔转移占14%,N2阳性下叶肺癌上纵隔转移占60%.结论瘤体增大,淋巴结转移频度增加,腺癌比鳞癌转移活跃,小细胞癌最活跃,肺癌可跨区域纵隔转移.除肿瘤最大直径≤1.5 cm的鳞癌不进行淋巴结清除亦有可能达到根治外,其余类型T1肺癌均应广泛清除肺内及纵隔淋巴结.     

Double primary cancer of the esophagus consisting of ectopic gastric mucosa-derived adenocarcinoma and squamous cell carcinoma: a first case report

Most esophageal cancers are either squamous cell carcinomas or Barrett??s mucosa-derived adenocarcinomas. A 64-year-old man with a long history of alcohol drinking and smoking was found to have a tumor in the cervical esophagus on screening esophagography. Subsequent work-up revealed double primary cancer of the esophagus consisting of adenocarcinoma arising from ectopic gastric mucosa in the cervical esophagus and squamous cell carcinoma in the abdominal esophagus. He underwent subtotal esophagectomy. On microscopic examination of the resected specimen, the Ip tumor in the cervical esophagus was confirmed to be an adenocarcinoma derived from ectopic gastric mucosa that had invaded the muscularis mucosa, and the 0-IIb tumor located near the esophagogastric junction was confirmed to be a squamous cell carcinoma that had invaded the proper mucosal layer. No lymph node metastases were noted. Adenocarcinoma from ectopic gastric mucosa is rare, and its coexistence with squamous cell carcinoma is extremely rare.     

Lymph node dissection with cervical approach as a salvage surgery for locoregional failure after definitive chemoradiotherapy in a patient with recurrent esophageal carcinoma: report of a case

Salvage surgery is one important therapeutic option after locoregional failure of definitive chemoradiotherapy (dCRT) in patients with advanced or recurrent esophageal carcinoma. We have performed cervical lymph node dissection as a salvage surgery after chemoradiotherapy in a patient with recurrent esophageal carcinoma. A 54-year-old Japanese man was admitted to our hospital because of multiple lymph node metastases after endoscopic submucosal dissection (ESD) for early-stage esophageal carcinoma. The patient underwent a circumferential ESD of early-stage esophageal carcinoma in another hospital. The esophageal carcinoma, measuring 75 × 60 mm in size, was a superficial spreading type located in the middle portion of the thoracic esophagus. Histology of the resected specimen revealed a moderately to poorly differentiated squamous cell carcinoma, and the depth of invasion was limited within the mucosal layer associated with a small area being attached to the muscularis mucosae. Five months after ESD, lymph node metastases in the regions of right recurrent nerve and the left tracheobronchus were found, for which dCRT was performed. These metastatic lymph nodes disappeared in the chest CT scan images. Lymph node metastasis in the region of the right recurrent nerve then reappeared 8 months after the completion of CRT. Considering the solitary lymph node metastasis and surgical invasiveness, lymph node dissection using a cervical approach was selected as a salvage surgery. Cervical approach for the lymph node dissection in the region of right recurrent nerve may be one feasible option as a minimally invasive salvage surgery for patients with recurrent esophageal carcinoma after dCRT.