Management of sentinel lymph nodes in malignant skin tumors using dynamic lymphoscintigraphy and the single-photon-emission computed tomography/computed tomography combined system

Background The differentiation of true sentinel lymph nodes from nonsentinel lymph nodes is difficult in cases of multiple radiolabeled or dyed lymph nodes. Methods We examined the locations of sentinel lymph nodes in melanoma and other malignant skin tumors by using dynamic lymphoscintigraphy and the single-photon-emission computed tomography/computed tomography (SPECT/CT) combined system. Results Sentinel lymph nodes were detected in 45 of the 53 patients examined using only the ordinary blue dye method (85%), and were detected in all 35 patients examined using the SPECT/CT method (100%). Twenty of the 35 patients mentioned above had one sentinel lymph node. Multiple sentinel lymph nodes were demonstrated in the head and neck areas using the SPECT/CT method. Significant differences (P = 0.0015) in the numbers of sentinel lymph nodes were found between the blue dye method only and the SPECT/CT method in the neck area. Popliteal sentinel lymph nodes were recognized in three patients, and cubital sentinel lymph nodes were recognized in two patients. Two patients had plural regional lymph nodes: one had popliteal and groin sentinel lymph nodes, while the other had cubital and axillary sentinel lymph nodes. The probe counts of the popliteus and cubitus were significantly lower (P = 0.0241) than the counts in the groin, axilla, and neck areas. Micrometastatic sentinel lymph nodes were recognized in four patients, and two patients had metastases in both sentinel and nonsentinel lymph nodes. Conclusions Dynamic lymphoscintigraphy was useful when we were concerned about cubital and popliteal lymph nodes. The SPECT/CT combined system was useful in recognizing the anatomical location of sentinel lymph nodes before biopsy. The detection rate of sentinel lymph nodes using the SPECT/CT method was always better than that with the blue dye method (P = 0.0197).     

Clinical impact of false-negative sentinel lymph nodes in breast cancer

Aims

To evaluate the incidence of false-negative (FN) sentinel lymph node (SLN) cases, their correlation with a series of clinico-pathologic parameters and their impact on adjuvant treatment indications and on clinical axillary relapse in the setting of a multicentric clinical trial comparing SLN biopsy with axillary lymph node dissection (ALND).

Methods

A series of 697 patients with primary breast cancer ≤ 3 cm were randomized to SLN biopsy associated with ALND (ALND arm) or to SLN biopsy followed by ALND only if the SLN was metastatic (SLN arm). The FN SLN rate was assessed in the ALND arm. A series of 11 clinico-pathological parameters were tested for a possible association with FN results. The indications for adjuvant treatments were evaluated by considering both the FN nodal stages, as indicated by the SLN, and the true positive axillary status, as indicated by completion ALND. The occurrence of clinically evident axillary recurrences was evaluated in the two arms.

Results

The FN rate was 16.7%. Of the clinico-pathologic parameters tested, only a tumour size ≤ 2 cm and the presence of a single metastatic axillary node was significantly associated with a risk of FN (p = 0.033 and p = 0.018, respectively). The FN SLN would have led to different adjuvant therapy indications in 12/18 cases. At 56 months, no clinically evident axillary nodal recurrences were present in the ALND arm patients, whereas one case of axillary recurrence was detected in the SLN arm patients.

Conclusions

FN SLN biopsy is not uncommon, especially in the presence of a small primary tumour with a single nodal metastasis. An FN finding can lead to less than optimal adjuvant treatment. However, the clinical impact of FN in terms of axillary recurrence at 56 months was minimal.     

前哨淋巴结活检指导保留乳房手术患者行选择性腋窝淋巴结清除术的研究

目的研究通过前哨淋巴通道（SLC）行前哨淋巴结活检（SLNB）以指导保留乳房手术（breast—conservingtherapy,BCT）患者行选择性腋窝淋巴结清除术（ALND）的可行性。方法采用非随机对照研究,在BCT患者中采用联合示踪法通过SLC行SLNB。对术中检出的前哨淋巴结（SLN）行细胞印片和冰冻切片检查,根据SLN的术中病理结果行选择性ALND,其中SI。N阳性、行ALND者为A组,SI。N阴性仅行SLNB者为B组。定性资料的比较选用Y。检验,两组均数的比较采用t检验。结果2009年1月至2009年12月采用联合示踪法行SLNB的BCT患者共43例,检出42例,A组28例,B组14例。两组患者的SLC均被显影。每例患者被检出SLN1～3枚,平均1．4枚,共被检出59枚。SLNB检出率为97．7％（42／43）。术后病理检查共检出阳性SI,N29例,其中术中细胞印片、冰冻切片及二者联合病理检测分别检出阳性淋巴结27、27、28例。A组ALND相关并发症发生率明显高于B组（P=0．003）。结论通过SLC行SLNB有助于准确定位SLN,能够指导BCT患者行选择性ALND,降低术后并发症。     

Impact of completion axillary lymph node dissection in patients with breast cancer and isolated tumour cells or micrometastases in sentinel nodes

BackgroundOmission of completion axillary lymph node dissection (ALND) is a standard practice in patients with breast cancer (BC) and negative sentinel nodes (SNs) but has shown insufficient evidence to be recommended in those with SN invasion.MethodsA retrospective analysis of a cohort of patients with BC and micrometastases (Mic) or isolated tumour cells (ITCs) in SN. Factors associated with ALND were identified, and patients with ALND were matched to patients without ALND. Overall survival (OS) and recurrence-free survival (RFS) were estimated in the overall population, in Mic and in ITC cohorts.FindingsAmong 2009 patients analysed, 1390 and 619 had Mic and ITC in SN, respectively. Factors significantly associated with ALND were SN status, histological type, age, number of SN harvested and absence of adjuvant chemotherapy. After a median follow-up of 60.4 months, ALND omission was independently associated with reduced OS (hazard ratio [HR] 2.41, 90 confidence interval [CI] 1.36–4.27, p = 0.0102), but not with increased RFS (HR 1.21, 90 CI 0.74–2.0, p = 0.52) in the overall population. In matched patients, the increased risk of death in case of ALND omission was found only in the Mic cohort (HR 2.88, 90 CI 1.46–5.69), not in the ITC cohort. The risk of recurrence was also significantly increased in the subgroup of matched Mic patients (HR 1.56, 90 CI 0.90–2.73).InterpretationA separate analysis of Mic and ITC groups, matched for the determinants of ALND, suggested that patients with Mic had increased recurrence rates and shorter OS when ALND was not performed. Our results are consistent with those of previous studies for patients with ITC but not for those with Mic. Randomised controlled clinical trials are still warranted to show with a high level of evidence if ALND can be safely omitted in patients with micrometastatic disease in SN.     

Clinical utilities and biological characteristics of melanoma sentinel lymph nodes

An estimated 73870 people will be diagnosed with melanoma in the United States in 2015, resulting in 9940 deaths. The majority of patients with cutaneous melanomas are cured with wide local excision. However, current evidence supports the use of sentinel lymph node biopsy (SLNB) given the 15%-20% of patients who harbor regional node metastasis. More importantly, the presence or absence of nodal micrometastases has been found to be the most important prognostic factor in early-stage melanoma, particularly in intermediate thickness melanoma. This review examines the development of SLNB for melanoma as a means to determine a patient’s nodal status, the efficacy of SLNB in patients with melanoma, and the biology of melanoma metastatic to sentinel lymph nodes. Prospective randomized trials have guided the development of practice guidelines for use of SLNB for melanoma and have shown the prognostic value of SLNB. Given the rapidly advancing molecular and surgical technologies, the technical aspects of diagnosis, identification, and management of regional lymph nodes in melanoma continues to evolve and to improve. Additionally, there is ongoing research examining both the role of SLNB for specific clinical scenarios and the ways to identify patients who may benefit from completion lymphadenectomy for a positive SLN. Until further data provides sufficient evidence to alter national consensus-based guidelines, SLNB with completion lymphadenectomy remains the standard of care for clinically node-negative patients found to have a positive SLN.     

Accuracy of sentinel lymph node biopsy after neo-adjuvant chemotherapy in patients with locally advanced breast cancer and clinically positive axillary nodes

Background

Feasibility and accuracy of sentinel node biopsy (SLNB) after the delivery of neo-adjuvant chemotherapy (NAC) is controversial. We here report our experience in NAC-treated patients with locally advanced breast cancer and clinically positive axillary nodes, and compare it with the results from our previous randomized trial assessing SLNB in early-stage breast cancer patients.

Patients and methods

Sixty-four consecutive patients with large infiltrating tumor and clinically positive axillary nodes received NAC and subsequent lymphatic mapping, SLNB and complete axillary lymph node dissection (ALND). The status of the sentinel lymph node (SLN) was compared to that of the axilla.

Results

At least one SLN was identified in 60 of the 64 patients (93.8%). Among those 60 patients, 37 (61.7%) had one or more positive SLN(s) and 23 (38.3%) did not. Two of the patients with negative SLN(s) presented metastases in other non-sentinel nodes. SLNB thus had a false-negative rate, a negative predictive value and an overall accuracy of 5.1%, 91.3% and 96.7%, respectively. All these values were similar to those we reported for SLNB in the settings of early-stage breast cancer.

Conclusion

SLNB after NAC is safe and feasible in patients with locally advanced breast cancer and clinically positive nodes, and accurately predicts the status of the axilla.     

Recurrence after sentinel lymph node biopsy with or without axillary lymph node dissection in patients with breast cancer

BACKGROUND: A regional nodal recurrence is a major concern after a sentinel lymph node biopsy (SLNB) alone in patients with breast cancer. In this study we investigated patterns and risk factors of regional nodal recurrence after SLNB alone. PATIENTS AND METHODS: Between January 1999 and March 2005, a series of 1,704 consecutive breast cancer cases in 1,670 patients (34 bilateral breast cancer cases) with clinically negative nodes or suspicious nodes for metastasis who underwent SLNB at a single institute (Saitama Cancer Center) were studied. All 1,704 cases were classified based upon presence or absence of a metastatic lymph node, treated with or without axillary lymph node dissection (ALND). The site of first recurrence was classified as local, regional node, or distant. The regional node recurrences were subclassified as axillary, interpectoral, infraclavicular, supraclavicular, or parasternal. RESULTS: After a median follow-up period of 34 months (range, 2-83 months), first recurrence occurred in local sites in 32 (1.9%) cases, regional nodes in 26 (1.5%) cases, and distant sites in 61 (3.6%) cases. In 1,062 cases with negative nodes treated without ALND and 459 cases with positive nodes treated with ALND, 11 (1.0%) and 15 (3.3%) recurred in regional nodes, respectively, and 4 (0.4%) and 2 (0.6%) recurred in axillary nodes, respectively. Of 822 cases of invasive breast cancer with negative nodes treated with SLNB alone, 10 (1.4%) recurred in regional nodes, and 4 (0.5%) recurred in axillary nodes. In the 10 patients with regional nodal failure, all of the tumors were negative for estrogen receptor (ER) and/or progesterone receptor (PR) and were nuclear grade (NG) 3. CONCLUSIONS: The axillary recurrence rate was low in patients treated with SLNB alone. Omitting ALND is concluded to be safe after adequate SLNB. Risk factors for regional nodal failure after SLNB alone are negative hormone receptor status and high NG.     

Avoidance of axillary lymph node dissection in selected patients with node-positive breast cancer

Aims

Currently, it is standard practice to avoid ALND in patients with negative SLN, whereas this procedure is mandated for those with positive SLN. However, there has been some debate regarding the necessity of complete ALND in all patients with positive SLN. This review article discusses the issues related to eliminating the need for ALND in selected patients with positive nodes.

Methods

A review of the English language medical literature was performed using the MEDLINE database and cross-referencing major articles on the subject, focusing on the last 10 years.

Results

Currently, complete ALND is mandated in patients with SLN macrometastases as well as those with clinically positive nodes. It is not clear whether SLN biopsy is appropriate for axillary staging in patients with initially clinically positive nodes (N1) that become clinically node-negative (N0) after neoadjuvant chemotherapy. Although there is debate regarding whether ALND should be performed in patients with micrometastases in the SLN, it seems premature to abandon ALND in clinical practice. Moreover, it remains unclear whether it is appropriate to avoid complete ALND in patients with ITC-positive SLN alone.

Conclusions

In the absence of data from randomised trials, the long-term impact of SLN biopsy alone on axillary recurrence and survival rate in patients with SLN micrometastases as well as those with ITC-positive SLN remains uncertain. These important issues must be determined by careful analysis of the results of ongoing clinical trials.     

早期乳腺癌前哨淋巴结阳性患者腋窝管理方式的研究进展

乳腺癌的发病率居女性肿瘤之首,近年来随着诊断技术的发展及相关知识的普及,早期乳腺癌的检出率大大增加。淋巴结转移为乳腺癌最常见的转移方式,前哨淋巴结活检广泛用于术中评估肿瘤是否侵犯腋窝淋巴结。近年来有多项探讨关于前哨淋巴结局限阳性患者最佳腋窝管理方式的研究,引起较大争议,国内外临床处理的方式也不尽相同。本文将对前哨淋巴结阳性患者腋窝管理方式的最新研究进展作一综述。     

The role of preoperative axillary ultrasound and fine-needle aspiration cytology in identifying patients with extensive axillary lymph node involvement

Introduction

In the recent past, both clinically node-positive and node-negative but sentinel node-positive patients underwent axillary lymph node dissection (ALND), although the two groups seem to have substantially different degree of nodal involvement.

Added value of the presence of blue nodes or hot nodes in sentinel lymph node biopsy of breast cancer

BACKGROUND: Combined use of blue dye and radiocolloid is considered to be useful for sentinel lymph node (SLN) biopsy of breast cancer. Whether both techniques together is superior to either alone was analyzed. PATIENTS AND METHODS: A consecutive series of 308 cases of breast cancer who underwent SLN biopsy using the combination technique was used. The frequency of a blue node or hot node was analyzed in all cases and only node-positive cases. Furthermore, the frequency of a blue node and hot node together, or either alone, and the highest radiocount of the SLNs in each case were examined for correlation with 8 clinicopathologic features. Three types of SLN containing both blue dye and radioactivity (blue-hot node), blue dye alone (blue-only node) and radioactivity alone (hot-only node), and the SLN radiocounts were analyzed for correlation with metastatic tumor. RESULTS: Of 308 cases, a blue node was present in 298 (97%), a hot node in 295 (96%), and either a blue or hot node in 306 (99%). The presence of a blue node or hot node was similarly affected by previous surgical biopsy and body mass index (BMI), and the presence of a hot node was also affected by age and tumor location. However, the presence of either a blue node or hot node was not affected by any of these characteristics. Of 77 node-positive cases, 8 (10%), 15 (19%) and 6 (8%) were considered to be node-negative based on blue node, hot node and either blue node or hot node positivity, respectively. The frequency of positivity for SLN metastasis decreased in order from blue-hot, blue-only to hot-only nodes. Of 62 cases with metastatic hot nodes, six (10%) were negative when the hottest node was examined, but the second-hottest node was positive. CONCLUSIONS: The added value of the presence of blue node or hot node was confirmed in the SLN biopsy using the combination technique, which suggests that all blue nodes and hot nodes need to be harvested.     

低负荷前哨淋巴结阳性早期乳腺癌患者腋窝处理策略

前哨淋巴结阳性患者的常规处理是进一步行腋窝淋巴结清扫,但腋窝淋巴结清扫会带来血清肿、上肢功能障碍、水肿等并发症。Z0011、IBCSG 23-01和AMAROS的Ⅲ期随机对照临床研究探索均为在临床N0期患者中安全减免前哨淋巴结活检阳性后的腋窝淋巴结清扫,为这部分患者的腋窝处理提供了新选择,但也给辅助放疗决策带来了新问题。本文将主要基于上述三项临床研究和腋窝淋巴结转移复发风险相关最新文献,针对包括手术和辅助放疗在内的低负荷前哨淋巴结阳性患者腋窝处理策略进行综述。     

Clinical and pathologic factors predicting axillary lymph node involvement in breast cancer

The diagnosis of axillary disease remains a challenge in the management of breast cancer and is a subject of controversy. In 1998, the Japanese Breast Cancer Society conducted a study assessing axillary lymph node involvement in breast cancer. The study included (a) clinical assessment by pre-operative imaging modalities, (b) histologic assessment for peritumoral lymphatic invasion, (c) biologic assessment by gelatinolytic activity using film in situ zymography, and (d) sentinel lymph node (SLN) biopsy. Clinical assessments by CT, PET, and US as well as biologic assessment were limited in their ability to detect axillary lymph node disease, although these imaging techniques may be useful to exclude node-positive patients from the need for SLN biopsy. Histologic assessment for peritumoral lymphatic invasion was useful, particularly for detecting false-negative cases by SLN biopsy. Nevertheless, the utility of SLN biopsy in assessing axillary nodal status was confirmed. Axillary lymph node dissection (ALND) can be avoided in patients with a small tumor and a negative SLN. However, further studies will be required to investigate the value of SLN biopsy for predicting regional control and survival before it can replace routine ALND as the optimal staging procedure for operable breast cancer.     

Histopathologic examination of axillary sentinel lymph nodes in breast carcinoma patients

The axillary sentinel lymph node biopsy (SLNB) has gained increasing popularity as a novel surgical approach for staging patients with breast carcinoma and for guiding the choice of adjuvant therapy with minimal morbidity. Patients with negative SLNB represent a subset of breast carcinoma patients with definitely better prognosis, because their pN0 status is based on a very thorough examination of the sentinel lymph nodes (SLNs), with a very low risk of missing even small micrometastatic deposits, as compared with routine examination of the 20 or 30 lymph nodes obtained by the traditional axillary clearing. The histopathologic examination of the SLNs may be performed after fixation and embedding in paraffin, or intraoperatively on frozen sections. Whatever is the preferred tracing technique and surgical procedure, the histopathologic examination of each SLN must be particularly accurate, to avoid a false-negative diagnosis. Unfortunately, because of the lack of standardised guidelines or protocols for SLN examination, different institutions still adopt their own working protocols, which differ substantially in the number of sections cut and examined, in the cutting intervals (ranging from 50 to more than 250 microm), and in the more or less extensive use of immunohistochemical assays for the detection of micrometastatic disease. Herein, a very stringent protocol for the examination of the axillary SLN is reported, which is applied either to frozen SLN for the intraoperative diagnosis, and to fixed and embedded SLN as well.     

Tuberculosis of axillary lymph nodes with primary breast cancer

A rare case of tuberculosis of axillary lymph nodes occurring with primary breast cancer is presented. A 78-year-old woman with no history of pulmonary tuberculosis was admitted to our hospital to undergo examination for a lump in her right breast. The tumor was in the upper outer quadrant of the right breast. On palpation, the tumor was 1.2 cm in diameter and axillary lymph node swelling was noted. Mammography disclosed a spiculated mass and swelling and calcification of the axillary lymph nodes. Sonography showed an irregular hypoechoic mass in the right breast and lymph node swelling in the right axilla, indicating breast cancer with axillary lymph nodes metastases. Chest X-ray showed clustered calcifications in the right axilla and a granular shadow in the right upper lobe. Breast conserving therapy was carried out. Invasive papillotubular carcinoma of the right breast and granulomas with calcification of lymph nodes, compatible with tuberculosis, was diagnosed. Tubercle bacillis were detected by culture of lymph nodes. This case suggests that X-ray is useful for diagnosing lymph node tuberculosis. Lymph node tuberculosis should be suspected when lymph node swelling is noted and X-ray shows clustered calcifications in axillary lymph nodes.     

Management of the axilla in patients with breast cancer and positive sentinel lymph node biopsy: An evidence-based update in a European breast center

The surgical approach to the axilla in breast cancer has been a controversial issue for more than three decades. Data from recently published trials have provided practice-changing recommendations in this scenario. However, further controversies have been triggered in the surgical community, resulting in heterogeneous diffusion of these recommendations.The development of clinical guidelines for the management of the axilla in patients with breast cancer is a work in progress. A multidisciplinary team discussion was held at the research hospital Policlinico San Matteo from the Università degli Studi di Pavia with the aim to update recommendations for the management of the axilla in patients with breast cancer. An evidence-based approach is presented.Our multidisciplinary panel determined that axillary dissection after a positive sentinel lymph node biopsy may be avoided in cN0 patients with micro/macrometastasis to ≤2 sentinel nodes, with age ≥40y, lesions ≤3 cm, who have not received neoadjuvant chemotherapy and have planned breast conservation (BCS) with whole breast radiotherapy (WBRT). Cases with gross (>2 mm) ECE in SLNs are evaluated on individual basis for completion ALND, axillary radiotherapy or omission of both. Patients fulfilling the criteria listed above who undergo mastectomy, may also avoid axillary dissection after multidisciplinary discussion of individual cases for consideration of axillary irradiation. Women 70 years or older with hormone receptors positive invasive lesions ≤3 cm, clinically negative nodes, and serious or multiple comorbidities who undergo BCS with WBRT, may forgo axillary staging/surgery (if mastectomy or larger tumor, comorbidities and life expectancy are taken into account).     

The real-time intra-operative evaluation of sentinel lymph nodes in breast cancer patients using One Step Nucleic Acid Amplification (OSNA) and implications for clinical decision-making

Introduction

One Step Nucleic Acid Amplification (OSNA) method for the intraoperative analysis of sentinel lymph nodes (SLNs) in breast cancer, obviates a second operation to the axilla and thereby expedites progression to adjuvant therapy. Recent NICE guidelines have approved OSNA as a method of sentinel node diagnosis to support the above case.¹

Method

This is a single centre prospective cohort analysis of all patients undergoing breast cancer surgery including sentinel node biopsy from February 2010 to June 2012. Patients with negative SLN(s) on OSNA had no further axillary surgery. A validation phase was performed prior to using OSNA routinely. Those with micrometastases underwent a level 1 clearance, and >one SLN with macrometastases, underwent treatment by level 2 axillary dissection. The length of time from sentinel node retrieval to OSNA result was recorded.

Results

Four hundred and forty nodes were analysed in 212 patients with a mean age of 55 years (range 24–98). The sensitivity and specificity of OSNA was 93% and 94% respectively in cases of macrometastases. The process required additional median anaesthesia time of 20 min (range −48 to +65 min). Non-sentinel node positivity was 5% and 48% for micrometastasis and macrometastasis respectively.

Conclusion

OSNA identified 62 of 212 patients with at least one positive sentinel node, thereby sparing 29% from a second procedure to clear the axilla subsequently. The median waiting time of 20 min for node results from completion of breast procedure is acceptable and allows for an efficient operating list. OSNA can be incorporated into routine practice and with improved methods of imaging preoperatively, can be an excellent adjunct to the breast cancer patient pathway of care.     

前哨淋巴结时代乳腺癌的精准区域处理：演进与展望

区域淋巴结状况是乳腺癌重要的预后指标之一,可以指导分期和辅助治疗策略的制定。近30年来乳腺癌前哨淋巴结活检术（sentinel lymph node biopsy,SLNB）研究发展迅速,循证医学Ⅰ类证据支持其为临床腋窝淋巴结阴性早期乳腺癌患者安全、有效的腋窝分期技术,前哨淋巴结阴性及低肿瘤负荷患者SLNB替代腋窝淋巴结清扫术后腋窝复发风险和并发症极低。乳腺癌局部区域控制新理念——应该综合考虑远处转移风险、全身治疗效果与不良反应以及局部区域治疗（手术/放疗）效果与不良反应——推动了SLNB适应人群不断扩展,新辅助治疗与SLNB、内乳SLNB将进一步促进区域淋巴结处理降阶梯,豁免腋窝手术临床研究值得期待。SLNB标志着乳腺癌区域淋巴结迈入微创化精准诊疗时代。本文就前哨淋巴结时代乳腺癌的精准区域处理的演进过程和最新进展进行总结,以期为广大临床工作者提供参考。     

Accuracy of the non-sentinel node risk score (N-SNORE) in patients with cutaneous melanoma and positive sentinel lymph nodes: A retrospective study

Background

Sentinel node (SLN) biopsy in patients with melanoma permits identification of those at risk for further metastases in non-sentinel lymph nodes (NSLN). However, a mere 20% of SLN-positive patients have metastases in NSLN. Therefore we need criteria to predict NSLN-positivity. A new score system known as the non-sentinel risk score, (N-SNORE) based on five clinical and pathological characteristics (gender, regression in primary melanoma, proportion of SNs containing melanoma, perinodal lymphatic invasion, and SN tumor burden), was first published in 2010. In this study, the accuracy of N-SNORE was validated in melanoma patients with positive SLN.

Methods

A total of 106 melanoma patients with positive SLN, who had undergone complete lymph node dissection (CLND) subsequently, were included in the study. The N-SNORE was calculated in all patients, and the risk was compared to the frequency of NSLN metastases. Statistical analysis of the data was performed.

Results

Thirteen patients were at very low risk for NSN metastasis (score 0), 63 patients at low risk (score 1–3), 19 at intermediate risk (score 4–5), 6 at high risk (score 6–7), and 5 at very high risk (score >8). NSLN positivity rates for these 5 risk groups were 7.7%, 18.2%, 21.1%, 33.3%, and 80%, respectively. According to Fisher's exact test, the contingency coefficient was .322; the p-value was .025.

Conclusion

An increasing N-SNORE was clearly correlated with a higher risk of NSLN positivity. Based on the p-value and the contingency coefficient, the overall accuracy of the N-SNORE was proven on statistical calculation.