"Two spaces" lateral lymph node dissection based on fascia anatomy for low rectal cancer / 中华胃肠外科杂志

As a treatment of rectal cancer, lateral lymph node dissection (LLND) is still a controversial issue. The argument against LLND is that the procedure is complicated, and consequently results in a high incidence of postoperative urogenital dysfunction. The surgical modality from fascia to space is adopted by lateral lymph node dissection in "two spaces". This operation has significant advantages of clear location of nerves and blood vessels and simplified surgical procedures, so the surgical procedure can be repeated and modulated. The fascia propria of the rectum, urogenital fascia, vesicohypogastric fascia and parietal fascia constitute the dissection plane for lateral lymph node dissection.Two spaces refer to Latzko's pararectal space and paravesical space. During the establishment of fascia plane, the dissection of external iliac lymph node (No.293), commoniliac lymph node (No.273) and abdominal aortic bifurcation lymph node (No.280) can be performed. While in the "space" dissection, internal iliac lymph node (No.263), obturator lymph node (No.283), lateral sacral lymph node (No.260) and median sacral lymph node (No.270) can be removed. LD2 or LD3 lateral lymph node dissection prescribed by the Japanese Society of Colorectal Cancer can be completed according to the needs of the disease. This article describes the anatomical basis and standardized surgical procedures.

Clinical value of fascia orientated laparoscopic lateral lymph node dissection in radical excision for advanced low rectal cancer / 中华消化外科杂志

Objective:To investigate the clinical value of fascia orientated laparoscopic lateral lymph node dissection (LLND) in radical excision for advanced low rectal cancer.Methods:The retrospective and descriptive study was conducted. The clinicopathological data of 100 patients with advanced low rectal cancer who were admitted to Peking University First Hospital from January 2013 to August 2021 were collected. There were 69 males and 31 females, aged 58(range, 32?85)years. Patients underwent laparoscopic total mesorectal excision and fascia oriented LLND. Observation indicators: (1) surgical situations; (2) postoperative situations; (3) results of histopathological exa-mination; (4) follow-up. Follow-up was conducted by telephone interview, outpatient examination and medical records review to detect survival, disease progression, tumor recurrence and metastasis of patients up to August 2021. Survival time was from the surgery date to death or the last follow-up time of patients. Measurement data were represented as M(range). Count data were represented as absolute numbers. Kaplan-Meier method was used to draw survival curves and calculate survival rates. Results:(1) Surgical situations. Of the 100 patients, 44 cases underwent neoadjuvant therapy and 56 cases didn′t receive preoperative therapy. Of the 100 patients with laparoscopic radical excision for advanced low rectal cancer, 60 cases underwent low anterior resection of rectal cancer including 49 cases with unilateral LLND and 11 cases with bilateral LLND,20 cases underwent abdomin-operineal resection for rectal cancer including 16 cases with unilateral LLND and 4 cases with bilateral LLND, 12 cases underwent total pelvic exenteration including 6 cases with unilateral LLND and 6 cases with bilateral LLND, 5 cases underwent Hartmann surgery including 3 cases with unilateral LLND and 2 cases with bilateral LLND, 3 cases underwent posterior pelvic exenteration including 2 cases with unilateral LLND and 1 case with bilateral LLND. The operation time and volume of intraoperative blood loss were 258(range,200?325)minutes and 100(range, 50?200)mL. There were 19 patients with low anterior resection of rectal cancer and protective ileostomy simultaneously. Three patients encountered intraoperative lymph node invasion of the obturator nerve, causing injury of the nerve at dissection. Of the 100 patients, 12 cases with total pelvic exenteration were dissected the ureterohypogastric nerve fascia and 88 cases were preserved the complete ureterohypogastric nerve fascia. (2) Postoperative situations. There was no perioperative death in the 100 patients. The time to postoperative catheter removal and duration of hospital stay of the 100 patients were 4(range, 3?7)days and 11(range, 9?15)days, respectively. There were 26 cases with postoperative complications. (3) Results of histopathological examination. The maximum tumor diameter was 4.5(range, 3.8?5.9)cm. There were 21 patients with mass type of tumor pross and 79 cases with ulcerative type. There were 82 cases with high and moderate differentiation of tumor differentiation degree, 18 cases with low differentiation and undifferentiated adenocarcinoma (signet ring cell carcinoma). There were 14 cases in TNM stage Ⅰ, 38 cases in TNM stage Ⅱ, 48 cases in TNM stage Ⅲ. There were 16 cases in stage T0?2 and 84 cases in stage T3?4. There were 52 cases in stage N0 and 48 cases in stage N1?2. The total number of lymph node dissected was 23(range, 18?27)per person and the total number of unilateral LLND was 5(range, 3?9)per person. There were 36 of 100 patients with positive lateral lymph nodes, including 14 cases with neoadjuvant therapy. (4) Follow-up. Of the 100 patients, 97 cases were followed up for 21(range, 1?69)months. The 2-year overall survival rate was 81.6% and 2-year disease progression free survival rate was 70.6%. During the follow-up, 4 of 97 patients had presacral tumor recurrence and 1 case had tumor recurrence in the LLND region. There were 11 cases with liver metastasis, 5 cases with bone metastasis, 2 cases with the contralateral lymph node metastasis of unilateral LLND, 2 cases with paraaortic lymph node metastasis, 2 cases with transcoelomic spread. Of the 97 patients who were followed up, 76 cases survived with free disease, 4 cases survived with tumor, 15 cases died of tumor and 2 cases died of other diseases.Conclusion:The fascia orientated laparoscopic LLND is safe and feasible in radical excision for advanced low rectal cancer.

Lateral lymph node dissection and key technical points in 4K laparoscopic surgery for rectal cancer / 中华消化外科杂志

Lateral lymph node metastasis (LLNM) is the main metastatic mode and the major cause of locoregional recurrence of mid-low rectal cancer. Single chemoradiotherapy cannot achieve good local control for LLNM, while the argument against performing lateral lymph node dissection (LLND) is the increased rate of urinary and sexual dysfunction after surgery. Ultra-high definition surgical field and delicate resolution by 4K laparoscopic surgical system will be helpful to achieve good tumor clearance and function preservation by identification and exposure of the important anatomic structures such as pelvic autonomic nerve and internal iliac vessels. Therefore, selective LLND can reduce local recurrence rates, particularly in the pelvic sidewall. LLND with autonomic nerve preservation by 4K laparoscopic system is expected to further decrease the risk of perioperative complications and urinary and sexual dysfunction in appropriate patients with neoadjuvant chemoradiotherapy.

Thirty years' changes of the strategy of lateral lymph node dissection in low rectal cancer: treatment experience and prognostic analysis of 289 cases in one single center / 中华胃肠外科杂志

Objective: The surgical indications, resection extent and management principle of lateral lymph node dissection (LLND) in lower rectal cancer have been controversial between Eastern and Western countries. This study aims to provide a theoretical basis for the rational implementation of LLND by reviewing the changes of LLND strategy over the past 30 years in a single-center, and analyzing prognostic factors for the survival outcomes of patients with lateral lymph node metastasis (LLNM). Methods: A retrospective observational study was performed. Clinical data of 289 patients with rectal cancer who received LLND at the Department of General Surgery of Peking University First Hospital from 1990 to 2019 were collected. Patients were divided into three groups based on decades. There were 89 cases in 1990-1999 group, 92 cases in the 2000-2009 group, and 108 cases in the 2010-2019 group. Data analyzed: (1) patient baseline data; (2) surgery and postoperative recovery; (3) lateral lymph node dissection; (4) postoperative survival and prognosis of patients with positive lateral lymph nodes. The surgical methods and pathological results of LLND were compared between groups, and the prognostic risk factors of patients with LLNM were analyzed. Results: A total of 289 patients underwent radical resection with LLND' accounting for 6.3% of the 4542 patients with rectal cancer during the same period in our hospital. Except decade-by-decade increase in tumors with distance from anal verge ≤ 7 cm, the proportion of ulcerated tumors, and the proportion of neoadjuvant radiochemotherapy, the differences in other baseline data were not statistically significant among 3 decade groups (all P>0.05). The proportion of LLND in the 3 groups decreased decade by decade [9.9% (89/898) vs. 8.0% (92/1154) vs. 4.3% (108/2490), χ(2)=40.159, P<0.001]. The proportion of laparoscopic surgery and unilateral LLND increased, while the mean operative time, intraoperative blood loss, surgical complications above grade III and postoperative hospital stay decreased decade by decade. These 289 patients completed a total of 483 lateral dissections, including 95 cases of the unilateral dissection and 194 cases of the bilateral dissection. The proportion of LLND in the 3 groups decreased decade by decade [9.9% (89/898) vs. 8.0% (92/1154) vs. 4.3% (108/2510), P<0.001]. The median number of dissected lymph nodes in the internal iliac artery and obturator regions increased (2 vs. 3 vs. 3, P<0.001), but those in the common iliac and external iliac regions decreased significantly (4 vs. 3 vs. 2, P=0.014). A total of 71 patients with LLNM were identified. The rate of LLNM in the 2010-2019 group was significantly higher than that in the previous two groups [37.0% (40/108) vs. 16.9% (15/89) vs. 17.4% (16/92), P=0.001]. The patients with LLNM showed a poorer overall survival (OS) and disease-free survival (DFS) compared with negative lateral lymph nodes (P<0.001). There were statistically significant differences in 5-year OS rate (30.9% vs. 27.2% vs. 0, P=0.028) and 5-year DFS rate (28.3% vs. 16.0% vs. 0, P=0.038) among patients with only internal iliac lymph node metastasis, patients with only obturator lymph node metastasis, and patients with external iliac or common iliac lymph node metastasis. Multivariate analysis of prognostic factors showed that external iliac or common iliac lymph node metastasis was an independent risk factor for OS (HR=1.649, 95%CI: 1.087-2.501) and DFS (HR=1.714, 95%CI: 1.173-2.504) in patients with LLNM (all P<0.05) . The OS and DFS were not significant different in patients with LLNM among 3 decade groups. Conclusions: In the past decade, the proportion of LLND in rectal cancer has decreased significantly. However, LLNM rate has been significantly increased due to preoperative imaging assessments focusing on suspicious LLNM without compromising the survival. Internal iliac artery and obturator lymph nodes can be regarded as regional lymph nodes with a satisfactory prognosis after LLND. For suspected external iliac or common iliac lymph node metastasis, the significance of LLND remains to be further evaluated.

Chinese expert consensus on the diagnosis and treatment for lateral lymph node metastasis of rectal cancer (2019 edition) / 中华胃肠外科杂志

Lateral lymph node metastasis represents a major cause of local pelvic recurrence after curative resection for mid-low rectal cancer. Considerable controversies over issues remain among eastern and western countries, with respect to the diagnosis of lateral lymph node metastasis, the multidisciplinary management regime, indication for lateral pelvic lymph node dissection, and the prognosis of surgical dissection. The purpose of this expert consensus is to improve the understanding of this condition among Chinese specialists, and to help standardizing the diagnosis and therapeutic strategies for lateral lymph node metastasis. Each statement and recommendation in this consensus were generated based on suggestions from at least three experts, agreed by a majority of experts from the Chinese expert panel. The evaluation criteria by U.S. Preventive Services Task Force was adopted for the grading of recommendations. In respect to the aforementioned controversies, the present consensus produced 21 statements on diagnosis and treatment for lateral lymph node metastasis. The pending issues in this consensus need further high-quality clinical practice and research.

Transanal lateral lymph node dissection surgery for 5 cases of mid-low rectal cancer / 中华胃肠外科杂志

Objective@#To evaluate the feasibility and safety of transanal lateral lymph node dissection for mid-low rectal cancer.@*Methods@#A descriptive case series research method was used. Clinical and pathological data of 5 mid-low rectal cancer patients who underwent transanal lateral lymph node dissection at Department of Colorectal Surgery, the Sixth Affiliated Hospital of Sun Yat-sen University from November 2018 to May 2019 were retrospectively collected and analyzed. Of 5 cases, 4 were male and 1 was female with mean age of (43.2±13.2) years and mean body mass index of (21.2±2.6) kg/m2; the mean diameter of tumor was (3.2±2.4) cm; the mean distance between tumor and anus was (6.3±2.5) cm; 3 received preoperative neoadjuvant chemotherapy. In preoperative TNM staging, 2 cases were T3N1M0, 1 was T3cN2aM0, 1 was T3cN2bM0, and 1 was T2N1M0. All the patients had no intestinal obstruction before operation. Surgical methods: (1) total mesorectal excision: using general transanal and transabdominal methods to mobilize and resect total mesorectum, and dissect No.252, No.253 lymph nodes; (2) transanal lateral lymph node dissection: dissect the adipose lymphoid tissue on the surface of the iliococcygeal muscle, the coccygeal muscle, and the obturator muscle (the No.283 lymph nodes) upward, and dissect No.263d and No.263p lymph nodes with fat tissue sequentially till the bifurcation of the internal and external iliac artery; (3) take out the specimen from anus, and make anastomosis between proximal colon and anal canal. Intraoperative and postoperative variables was observed.@*Results@#All the 5 patients completed surgery successfully, and no patient needed to convert to open approach. The mean operative time was (295.6±97.7) minutes, and the median intraoperative blood loss was 70 (50-500) ml. The mean length of specimen was (12.9±3.0) cm, and the mean number of harvested lymph node was 30.4±9.9. The positive lateral lymph nodes were founder in 4 patients. The median distance between tumor and distal resection margin was 1.5 (1.2-8.0) cm. The resection margin in all the patients was negative. The mean time to postoperative flatus was (4.2±1.6) days, the mean postoperative spontaneous urination was (3.0±1.9) days, time to drainage tube removal was (5.6±1.9) days, and the mean postoperative hospital stay was (9.4±2.1) days. The postoperative TNM staging by pathology was 1 case with T1N0M0, 1 with T2N1M0, 1 with T3N2bM0, and 2 with T3N2M0. Five patients were moderately differentiated adenocarcinoma. Only 1 patient developed postoperative abdominal bleeding, who was healed after conservative treatment. The other 4 patients did not develop any perioperative complications, such as incision infection, presacral abscess, pelvic abscess, anastomotic leakage, or anastomotic stricture. Four patients underwent postoperative chemotherapy. All the patients were followed up for 2 to 28 weeks after surgery and they all felt well. The patients with stoma had fluent bowel.@*Conclusions@#Transanal lateral lymph node dissection is feasible and safe in the treatment of mid-low rectal cancer, which can achieve the purpose of extended radical resection of mid-low movement rectal cancer. Moreover, this procedure is a new method to treat rectal cancer patients with lateral lymph node metastasis.

Chinese expert consensus on the diagnosis and treatment for lateral lymph node metastasis of rectal cancer (2019 edition) / 中华胃肠外科杂志

Lateral lymph node metastasis represents a major cause of local pelvic recurrence after curative resection for mid-low rectal cancer. Considerable controversies over issues remain among eastern and western countries, with respect to the diagnosis of lateral lymph node metastasis, the multidisciplinary management regime, indication for lateral pelvic lymph node dissection, and the prognosis of surgical dissection. The purpose of this expert consensus is to improve the understanding of this condition among Chinese specialists, and to help standardizing the diagnosis and therapeutic strategies for lateral lymph node metastasis. Each statement and recommendation in this consensus were generated based on suggestions from at least three experts, agreed by a majority of experts from the Chinese expert panel. The evaluation criteria by U.S. Preventive Services Task Force was adopted for the grading of recommendations. In respect to the aforementioned controversies, the present consensus produced 21 statements on diagnosis and treatment for lateral lymph node metastasis. The pending issues in this consensus need further high-quality clinical practice and research.

Controversy and consensus on lateral lymph node dissection for rectal cancer / 中国实用外科杂志

Lateral lymph node metastasis is a common problem in the diagnosis and treatment of patients with low rectal cancer. Eastern and western scholars are still controversial about the combination of lateral lymph node dissection in TME surgery for middle and low rectal cancer.The study of correlation between laparoscopic or robotassisted lateral lymph node dissection and open surgery is still in retrospective analysis, and prospective cohort studies are needed to further confirm their superiority. Whether neoadjuvant radiochemotherapy can replace lateral lymph node dissection is still inconclusive, and it is related to the cognition that the lateral lymph node metastasis belongs to the regional or the systemic metastasis of the oriental and occidental scholars.

Lower rectal lymphatic drainage and necessity of lateral lymph node dissection for low rectal cancer / 中国实用外科杂志

There are three lymphatic drainage pathways in lower rectal cancer,including upper,lower and lateral lymphatic drainage pathway. Lateral metastasis of rectal cancer caused by lateral lymphatic drainage pathway is an important cause of pelvic recurrence. Evidence-based medical evidence shows that preoperative concurrent chemoradiotherapy and radiotherapy can not completely kill the lymph node metastasis to the lateral side,and the positive residual rate is more than 60%. For cases with lateral lymph node metastasis after preoperative concurrent chemoradiotherapy,surgical removal of metastatic lymph nodes is the most important treatment,even the only way for patients to achieve long-term survival. Strictly grasping the indications of lateral clearance surgery to improve the positive coincidence rate of pathology,and implementing standard clearance to reduce the incidence of surgical complications through precise operation are expected to bring double benefits of local control and prolonged survival to patients with lateral metastasis of rectal cancer.

Several issues worthy of attention in clinical research of low rectal cancer / 中国实用外科杂志

Total mesorectal excision(TME) regulates the extent of resection of low rectal cancer surgery and is the gold standard for low rectal cancer. Colorectal surgeons need to comprehensively consider the comprehensive treatment strategy for rectal cancer to reduce the risk of local recurrence,how to protect patients' anal,sexual and urinary function,and improve their quality of life,and consider how to reduce surgical trauma. At present,the research hotspots in the fieldof rectal cancer diagnosis and treatment turn to how to betterprotect the function and further reduce the risk of localrecurrence. Among them,the "watch and wait" strategy of "clinical complete response" after neoadjuvant chemoradiotherapy,the lateral lymph node dissection and the procedure of transanal total mesorectal excision,is a hot issue in clinical research.

The effect of lateral lymph node dissection on the treatment of stageⅡ/Ⅲlow rectal cancer with mesorectal excision / 中国医师进修杂志

Objective To confirm the noninferiority of mesorectal excision (ME) alone to ME combined with lateral lymph node dissection (LLND) in terms of efficacy. Methods Eligibility criteria included histologically proven rectal cancer at clinical stageⅡ/Ⅲ; main lesion located in the rectum. Patients were intra-operatively allocated to undergo ME combined with LLND or ME alone in a randomized manner. The primary endpoint was relapse-free survival, with a noninferiority margin for the hazard ratio of 1.34. Secondary end points included overall survival and local-recurrence-free survival. Results In total, 502 patients from November 11, 2010 to October 1, 2017 were randomized to the ME combined with LLND (252 patients) and ME alone (250 patients) groups. The 5-year relapse-free survival in the ME combined with LLND and ME alone groups were 73.4% and 73.3%, respectively (hazard ratio:1.07, 90.9% CI 0.84— 1.36), with one sided P value for noninferiority of 0.0547. The 5-year overall survival, and 5-year local-recurrence-free survival in the ME combined with LLND and ME alone groups were 92.6% and 90.2% , and 87.7% and 82.4% , respectively. The numbers of patients with local recurrence were 21 cases (8.3%) and 43 cases (17.2%) in the ME combined with LLND group and ME alone group (P=0.024). Conclusions The noninferiority of ME alone to ME combined with LLND is not confirmed in the intent-to-treat analysis. ME combined with LLND has a lower local recurrence, especially in the lateral pelvis, compared to ME alone.

Meta-analysis of lateral lymph node dissection for low rectal cancer / 中国现代普通外科进展

Objective:To explore the significance of lateral lymph node dissection for low rectal cancer.Methods:Retrieval the Cochrane Library,PubMed,EMBASE,CBM,VIP,CNKI,WANFANG DATA,the time is from January 2000 to October 2015.Bring into the comparative studies about lateral lymph node dissection for low rectal cancer.Processing data using the revman 5.2 to reaserch the significance of lateral lymph node dissection for low rectal cancer.Results:9 clinical comparative studies were included in this study.The observation group was the lateral lymph node dissection group and the control group was the traditional operation group.Results showed that the length of incision of the observation group was longer [MD=-42.48,95％CI (32.92,-52.04),P＜0.00001],The amount of bleeding in observation group was more[MD=-18.72,95％Cl(5.60,31.83),P＜0.005],The local recurrence rate in the observation group was Iower[OR=-0.52,95％CI (0.38,0.71),P＜0.0001],The 3 year survival rate and the 5 year survival rate in the observation group were higher than those in the control group,the difference was statistically significant,Their combined OR and 95％CI were [OR=2.65,95％ CI (1.76,3.99),P＜0.00001] and [OR=3.57,95％ CI (2.05,6.22),P＜0.00001].Conclusion:Lateral lymph node dissection increasing operation time、hemorrhage volume and postoperative complication risk,but could increase the survival rate of the patients.

Clinical value of improved lateral lymph node dissection for stageⅢ lower rectal cancer / 中国癌症杂志

Background and purpose:The extent of lymph node dissection for the stageⅢ lower rectal cancer is still a subject of debate. Some Japanese researchers recommend improved lateral lymph node dissection for stageⅢ lower rectal cancers while American scholars claim that total mesorectal excision is sufficient. This study aimed to explore the clinical significance of improved lateral lymph node dissection for stageⅢ lower rectal cancer in patients treated with radical resection.Methods:Sixty-six patients with stageⅢ lower rectal cancer were enrolled. Among these patients, 31 had been treated with radical resection combined with improved lateral lymph node dissection, whereas the others received radical resection without improved lateral lymph node dissection.Results:In the group of improved lateral lymph node dissection, five patients had positive lateral node including four poorly differentiated adenocarcinoma and one mucinous cell carcinoma. Compared with the group without improved lateral lymph node dissection, the group of improved lateral lymph node dissection showed significant difference in sexual disturbance, dysuresia and operation duration (P0.05). Furthermore, patients had lower rate of pelvis recurrence and better 5-year rate of survival for the group of improved lateral lymph node dissection (P<0.05).Conclusion:Radical resection with improved lateral lymph node dissection may decrease the pelvis recurrence rate and increase survival rate in patients with stageⅢ lower rectal carcinoma.

Lateral Neck Lymph Node Metastasis in Papillary Thyroid Cancer / 대한내분비외과학회지

PURPOSE: Papillary thyroid carcinoma (PTC) is the most common thyroid cancer and lymph node (LN) metastasis is common in PTC. Lateral LN metastasis is associated with local recurrence of PTC. The aim of this study is to evaluate the patterns of lateral LN metastasis of PTC. METHODS: One-hundred seventy four patients who undergone total thyroidectomy, central LN and ipsilatereal or bilateral LN dissection due to PTC 'from 2007 to 2008 in Seoul National University Hospital were retrospectively reviewed. The average age of the patients was 50.4 years and the male to female ratio was 1:4.12. Sixty-seven patients (38.5%) had central LN metastasis and 47 patients (27.0%) had lateral node metastasis. RESULTS: The factors related with lateral LN metastasis of PTC are male gender, the tumor size, extrathyroidal extension, multifocality and central LN metastasis. The level III LN group was the most frequent site of lateral LN metastasis followed by the jugular, level IV, level II, and level V groups. The jugular LN metastasis is mainly related with the metastasis of the upper lateral neck area, including level II LNs, and the lymphatic pathway to the lower lateral neck area, including level IV, seems to be independent from the jugular LNs. Ten cases had lateral LN metastasis without central LN metastasis (skip metastasis). CONCLUSION: Lateral LN metastasis of PTC has a certain pattern. The operator must consider this pattern when managing patients with lateral LN metastasis of PTC.

Is the Supraspinal Accessory Lymph Node Dissection Always Necessary in Thyroid Carcinoma Patients with Lateral Neck Node Metastasis? / 대한내분비외과학회지

PURPOSE: Controversy still exists concerning the extent of neck nodedissection in thyroid carcinoma patients. A modified neck dissection is usually performed for the treatment of thyroid carcinoma patients with positive lateral neck nodes. When performing a neck dissection, removal of the nodes superior to the spinal accessory nerve (level IIB) is difficult and time consuming. This study was performed to determine whether level IIB node dissection is always necessary in therapeutic neck dissection for metastatic papillary thyroid carcinoma. METHODS: A total of 200 neck dissections were performed in 175 papillary thyroid carcinoma patients with positive lateral neck nodes between September 2005 and June 2007. The patterns of lateral neck metastasis were analyzed with respect to neck level, but the level IIB nodes were studied as separate specimens. Potential factors predicting level IIB node metastasis were also evaluated. RESULTS: The most common site of metastasis was level III, showing 95.0% (190/200), followed by level IV 66.0% (132/200), level IIA 54.0% (108/200), and level V 15.5% (31/200). Level IIB metastases were seen in 12 necks (6.0%) and seen only in the necks with positive level IIA nodes. In 11 of the 12 necks, the primary tumors were located in the upper pole of the thyroid. CONCLUSION: Level IIB node dissection is not necessary when there is no level IIA metastasis. Even when there is level IIA metastasis, level IIB node dissection is not always necessary, unlessthe primary tumors are located in the upper pole of the thyroid.