Validation of the prognostic value of lymph node ratio in patients with cutaneous melanoma: A population-based study of 8,177 cases

Prognostic Value of Lymph Node Ratio in Cutaneous Melanoma: A Systematic Review

The prognosis of cutaneous melanoma (CM) is based on the histological characteristics of the primary tumor, such as Breslow depth, ulceration, and mitotic rate. The lymph node ratio (LNR) is the ratio of the involved lymph nodes (LNs) divided by the total number of LNs removed during regional LN dissection. LNR is a prognostic factor for many solid tumors; however, controversies exist regarding CM. This study sought to analyze the role of LNR as a prognostic factor in CM.

An extensive literature search was conducted using PubMed, Google Scholar, Medline, and the Cochrane Central Registry of Controlled Trials from January 1966 to July 2015. The keywords included in the search were CM and inclusion of the ratio of positive to the total number of LNs as a prognostic factor. The outcomes analyzed included the number of patients with positive LNs, type of survival analysis, and results from the multivariate analysis.

A total of 11 studies involving 12,011 patients with positive LNs were evaluated. No previous randomized controlled trials, meta-analyses, or systematic reviews were identified in the Cochrane database on the prognostic value of LNR in CM. The primary electronic database search resulted in 333 full-text articles. The LN location examined was the cervical, axillary, and inguinal regions in all studies except for one that examined only the inguinal region. All studies except three studied the prognostic value of the LNR as a categorical variable rather than a continuous variable. LNR was categorized as A (≤0.1), B (0.11-0.25), and C (>0.25). All studies identified LNR as an independent predictor of overall survival (OS), disease-free survival (DFS), or disease-specific survival (DSS). The hazard ratio (HR) and confidence interval (CI) associated with either DFS or OS were available only in a few studies. Moreover, pooled HR for OS was 2.08 (95% CI: 1.48 2.92), for DFS was 1.364 (95% CI: 0.92-2.02), and for DSS was 1.643 (95% CI: 0.89-3.0).

The LNR provides superior prognostic stratification among patients with CM. Additional adequately powered prospective studies are needed to further define the role of LNR and be included in the staging system of CM and direct adjuvant therapy.

Web-based nomograms for predicting the prognosis of adolescent and young adult skin melanoma, a large population-based real-world analysis

Background

Invasive cutaneous melanoma is one of the most common malignant diseases among adolescents and young adults (aged 15–40 years) in the United States. We aimed to develop web-based nomograms to precisely predict overall survival and cancer-specific survival in this group of patients with cutaneous melanoma.

Methods

We analyzed the overall and caner-specific death events in 19,887 patients who underwent surgical resection of cutaneous melanoma from Surveillance, Epidemiology and End Results database and developed web-based clinic-pathologic prediction models for overall survival and cancer specific survival based on Cox regression. C-statistics of Harrell and time-dependent Receiver Operating Characteristic Curve (ROC) were used to evaluate the prognostic accuracy of nomograms.

Results

Multivariate Cox regression model analysis suggested that age, sex, race, tumor location, Clark level, ulceration, thickness, and N stage were independently associated with both overall survival and cancer-specific survival in adolescent and young adult patients with cutaneous melanoma. The nomograms performed excellently in predicting overall survival and cancer-specific survival with C-index being 0.875 (95% CI: 0.847–0.903) and 0.901 (95% CI: 0.876–0.925), respectively. Time-dependent ROC verified that the prognostic accuracy of nomograms was better than that of American Joint Committee on Cancer staging system and other prognostic factors.

Conclusions

These user-friendly nomograms can precisely predict overall survival and cancer-specific survival in cutaneous melanoma patients treated with surgical resection, which may help to make individualized postoperative follow-up and therapeutic schemes.

Lymph node ratio as a prognostic factor in melanoma: results from European Organization for Research and Treatment of Cancer 18871, 18952, and 18991 studies

The aim of this study was to assess the prognostic importance of lymph node ratio (LNR) in stage III melanoma after complete lymph nodal dissections. From European Organization for Research and Treatment of Cancer randomized trials 18871, 18952, and 18991, 2358 patients had full information on positive and examined lymph nodes (LNs) and were included. Cox proportional hazards models stratified by trial were used to assess the prognostic impact of LNR adjusted for confounders on melanoma-specific survival. Optimal cutoff values for LNR were calculated for each LN dissection site (axillary, inguinal, and neck). LNR (≥ vs. <35%: hazard ratio=1.44, 95% confidence interval: 1.23-1.69) and number of positive LNs appeared to be of independent strong prognostic importance. Dissection sites impacted the optimal LNR cutoff: 35% for axillary, 40% for inguinal, and 50% for neck dissections. Combining these into one 'high versus low LNR' resulted in a highly significant multivariately adjusted hazard ratio of 1.48 (95% confidence interval: 1.26-1.74). In subgroup analyses, LNR was only significant in advanced disease (American Joint Committee on Cancer stage N2b, N3; IIIC). LNR was most significant for inguinal dissections, followed by axillary dissections, but seemed less useful in neck dissections. LNR is an independent significant prognostic factor in stage III melanoma patients. Our study showed higher than previously reported cutoffs that differed per dissection site. However, because of conflicting results compared with other studies and apparent limited prognostic impact confined to subgroups, the practical use of LNR seems limited.

Lymph Node Ratio: Is It an Independent Prognostic Factor for Stage III Cutaneous Melanoma?

Objective: Lymph node ratio (LNR) is defined as the ratio of the number of metastatic lymph nodes to the dissected lymph nodes. LNR is a prognostic factor for many tumor types. The present study aimed to evaluate the prognostic value of LNR in melanoma. Methods: This retrospective cohort study was conducted on 123 patients with stage III cutaneous melanoma. Multivariate Cox proportional hazards model was used to evaluate the correlations between LNR and other clinicopathological factors associated with survival. The patients were divided into four groups in terms of the LNR, including groups A (LNR≤0.18), B (0.180.625). Results: Initially, LNR was evaluated as a continuous quantity associated with survival. In the univariate analysis, a significant correlation was observed between LNR, overall survival (OS), and disease free survival (DFS). Meanwhile, the only association observed in the multivariate analysis was between LNR and OS. Increased LNR from group A to group D reduced OS from 46 (±44.09) to 22.5 (±16.33) months (P=0.022). According to the multivariate analysis, prognostic factors in OS were tumor thickness, American joint committee of cancer (AJCC) N stage, interferon administration, and undergoing chemotherapy. Conclusion: According to the results, LNR could be used as an independent prognostic factor for estimating the survival of patients with stage III cutaneous melanoma also designing an effective adjuvant treatment protocol for these patients.

Lymph Node Ratio Is Less Prognostic in Melanoma When Minimum Node Retrieval Thresholds Are Not Met

BACKGROUND

Lymph node ratio (LNR), positive nodes divided by nodes examined, has been proposed for prognostication in melanoma to mitigate problems with low node counts. However, it is unclear if LNR offers superior prognostication over total counts of positive nodes and nodes examined. Additionally, the prognostic value of LNR may change if a threshold number of nodes are examined. We evaluated whether LNR is more prognostic than positive nodes and nodes examined, and whether the prognostic value of LNR changes with minimum thresholds.

METHODS

Using the National Cancer Data Base Participant User File, we identified 74,692 incident cases with nodal dissection during 2000-2006. We compared LNR versus counts of examined and positive nodes based on Harrell's C, a measure of predictive ability. We then stratified by total nodes examined: greater versus fewer than ten for axillary lymph node dissection (ALND) and greater versus fewer than five for inguinal lymph node dissection (ILND).

RESULTS

Overall, LNR had a Harrell's C of 0.628 (95 % confidence interval [CI] 0.625-0.631). Examined and positive nodes were not significantly different from this, with a Harrell's C of 0.625 (95 % CI 0.621-0.630). In ALND, LNR had a Harrell's C of 0.626 (95 % CI 0.610-0.643) with ≥10 nodes versus 0.554 (95 % CI 0.551-0.558) < 10 nodes. In ILND, LNR had a Harrell's C of 0.679 (95 % CI 0.664-0.694) with ≥5 nodes versus C of 0.601 (95 % CI 0.595-0.606) < 5 nodes.

CONCLUSIONS

LNR provides no prognostic superiority versus counts of examined and positive nodes. Moreover, the prognostic value of LNR diminishes when minimum node retrieval thresholds are not met.

Lymph-Node Ratio in Patients with Cutaneous Melanoma: A Multi-Institution Prognostic Study

BACKGROUND

Lymph node ratio (LNR)-the number of metastatic lymph nodes (LNs) over the number of excised LNs after lymphadenectomy-is a prognostic factor for many solid tumors, but controversies still exist for skin melanoma. We investigated the prognostic relevance of LNR in melanoma patients and formulated a proposal for considering the LNR in the current American Joint Committee on Cancer (AJCC) N staging system.

METHODS

Retrospective data of 2,526 melanoma patients with LN metastasis from nine Italian institutions were collected in a multicenter database. The prognostic value of the LNR (categorized as A, ≤0.1; B, 0.11-0.25; and C, >0.25) was assessed by multivariable survival analysis.

RESULTS

LNR was a significant independent prognostic factor for melanoma-specific survival (LNR B vs. A: hazard ratio [HR] 1.47, 95 % CI 1.16-1.87, p = 0.002; LNR C vs. A: HR 1.84, 95 % CI 1.29-2.61, p = 0.001). The LNR had prognostic value in patients with AJCC N1a (one positive LN after sentinel LN biopsy [SLNB], HR 2.33, 95 % CI 1.49-3.63, p < 0.001) and N2a (two to three positive LNs after SLNB, HR 1.62, 95 % CI 1.09-2.40, p = 0.016) substages, but not in those with N1b (one clinically positive LN, p = 0.765), N2b (two to three clinically positive LNs, p = 0.165), and N3 (≥ four positive LNs, p = 0.084) substages.

CONCLUSION

The LNR is a prognostic factor in melanoma patients with one (AJCC N1a) and two to three (AJCC N2a) positive LNs after SLNB. This easy-to-obtain parameter should be considered for the staging of melanoma patients with LN metastasis, along with the number of positive LNs.

The number of excised lymph nodes is associated with survival of melanoma patients with lymph node metastasis

BACKGROUND

Although the number of excised LNs has been associated with patient prognosis in many solid tumors, this association has not been widely investigated in cutaneous melanoma. This study aims to evaluate the association between the number of excised regional lymph nodes (LNs) and melanoma-specific survival.

PATIENT AND METHODS

Clinico-pathological data from 2507 patients with LN metastasis treated at nine Italian centers were retrospectively collected.

RESULTS

The number of excised LNs correlated with younger age (P < 0.001), male sex (P < 0.001), neck LN field (P < 0.001), LN micrometastasis (P < 0.001) and number of positive LNs (P < 0.001). The number of excised LNs was an independent prognostic factor (HR = 0.85; P = 0.002) after adjustment for other staging features. Upon subgroup analysis, the number of excised LNs had a significant prognostic value in patients bearing 1.01-2.00 mm (HR = 0.79; P = 0.032) and 2.01-4.00 mm (HR = 0.71; P < 0.001) thick melanomas, primary tumors showing ulceration (HR = 0.86; P = 0.033) and Clark level V of invasion (HR = 0.86; P = 0.010), LN micrometastasis (HR = 0.83; P = 0.014) and two to three positive LNs (HR = 0.71; P = 0.001). Finally, this study investigated the influence of the number of excised LNs on patient staging: only when ≥11 nodes were excised the AJCC N stage could stratify prognosis (P < 0.001). Considering the number of excised LNs for each lymphatic field, at least 14, 11, 10 and 12 LNs were needed to stage patients according to the AJCC N stage after a lymphadenectomy of the neck, axilla, inguinal and ilioinguinal LN fields, respectively.

CONCLUSIONS

The number of excised LNs can be considered for risk stratification of patients with regional LN metastasis from cutaneous melanoma. We demonstrated that a minimum number of LNs is required for the correct staging of patients. Further research is needed to evaluate the effectiveness of the minimum number of LNs to be dissected.

The Association between Survival and the Pathologic Features of Periampullary Tumors Varies over Time

Introduction. Several histopathologic features of periampullary tumors have been shown to be correlated with prognosis. We evaluated their association with mortality at multiple time points. Methods. A retrospective chart review identified 207 patients with periampullary adenocarcinomas who underwent pancreaticoduodenectomy between January 1, 2001 and December 31, 2009. Clinicopathologic features were assessed, and the data were analyzed using univariate and multivariate methods. Results. In univariate analysis, perineural invasion had a strong association with 1-year mortality (OR 3.03, CI 1.42–6.47), and one lymph node (LN) increase in the LN ratio (LNR) equated with a 5-fold increase in mortality. In contrast, LN status (OR 6.42, CI 3.32–12.41) and perineural invasion (OR 5.44, CI 2.81–10.52) had the strongest associations with mortality at 3 years. Using Cox proportional hazards, perineural invasion (HR 2.61, CI 1.77–3.85) and LN status (HR 2.69, CI 1.84–3.95) had robust associations with overall mortality. Recursive partitioning analysis identified LNR as the most important risk factor for mortality at 1 and 3 years. Conclusions. Overall mortality was closely related to the LNR within the first year, while longer follow-up periods demonstrated a stronger association with perineural invasion and overall LN status. Therefore, the current staging for periampullary tumors may need to be updated to include the LNR.

Measuring Quality in Thyroid Cancer Surgery

Many of the surgical quality measures currently in use are not disease specific. For thyroid cancer, mortality and even recurrence are difficult to measure since mortality is rare and recurrence can take decades to occur. Therefore, there is a critical need for quality indicators in thyroid cancer surgery that are easily measured and disease specific. Here we will review recent research on two potential quality indicators in thyroid cancer surgery. The uptake percentage on postoperative radioactive iodine scans indicates the completeness of resection. Another measure, the lymph node ratio, is the proportion of metastatic nodes to the total number of nodes dissected. This serves as a more global measure of quality since it indicates not only the completeness of lymph node dissection but also the preoperative lymph node evaluation and decision-making. Together, these two quality measures offer a more accurate, disease-specific oncologic indicator of quality that can help guide quality assurance and improvement.

Remnant uptake as a postoperative oncologic quality indicator

BACKGROUND

The purpose of this study was to examine the utility of remnant uptake on postoperative radioiodine scans as an oncologic indicator after thyroidectomy for differentiated thyroid cancer (DTC).

METHODS

We conducted a retrospective review of patients undergoing total thyroidectomy for DTC and subsequent radioactive iodine (RAI) treatment. Of the eight surgeons included, three were considered high volume, performing at least 20 thyroidectomies per year. Patients with distant metastases at diagnosis or poorly differentiated variants were excluded. To control for the effect of varying RAI doses, the remnant uptake was analyzed as a ratio of the percentage uptake to the dose received (uptake to dose ratio [UDR]). Multivariate logistic regression was used to determine the influence of UDR on recurrence.

RESULTS

Of the 223 patients who met inclusion criteria, 21 patients (9.42%) experienced a recurrence. Those with a recurrence had a 10-fold higher UDR compared with those who did not (0.030 vs. 0.003, p=0.001). Similarly, patients with increasing postoperative thyroglobulin measurements (0.339 vs. 0.003, p<0.001) also had significantly greater UDRs compared with those with stable thyroglobulin. The UDRs of high-volume surgeons were significantly smaller than low-volume surgeons (0.003 vs. 0.025, p=0.002). When combined with other known predictors for recurrence, UDR (OR 3.71 [95%CI 1.05-13.10], p=0.041) was significantly associated with recurrence. High-volume surgeons maintained a low level of permanent complications across all UDRs, whereas low-volume surgeons had greater permanent complications associated with higher uptake.

CONCLUSIONS

Remnant uptake is a useful postoperative oncologic quality indicator that can predict a patient's risk of disease recurrence and indicate the completeness of resection.

Limitations of lymph node ratio, evidence-based benchmarks, and the importance of a thorough lymph node dissection in melanoma

BACKGROUND

Stage III melanoma is currently stratified by number of lymph nodes (LNs) involved. However, given the variability of LN retrieval counts we hypothesize that lymph node ratio (LNR) may also provide prognostic information.

METHODS

Retrospective cohort study of 411 patients with stage III melanoma were divided into two groups based on LNR (<0.15, n = 291 and ≥0.15, n = 120).

RESULTS

In multivariate analysis N stage (N3 vs. N1, hazard ratio [HR] = 2.13, p < 0.001), extranodal extension (HR = 1.92, p = 0.002), macrometastasis (HR = 1.70, p = 0.005), non-SLN involvement (HR = 1.65, p = 0.005), risk of N2 disease exceeding 35 % (HR = 1.51, p = 0.03), and LNR ≥0.15 (HR = 1.46, p = 0.03) were associated with overall survival (OS). LNR failed to further stratify stage III melanoma; however, the number of LNs examined was an independent prognostic factor. Patients who had >8 inguinal, >15 axillary, or >20 cervical LNs examined had fewer same nodal basin recurrences (26 [8 %] vs. 20 [20 %], p = 0.0009) and for N1 patients an improved OS (3-year OS 84 % vs. 76 %, 10-year OS 53 % vs. 34 %, p = 0.06) compared with N1 patients who had fewer LNs examined.

CONCLUSIONS

LNR is an important prognostic factor in stage III melanoma; however, it was not independent over the current AJCC TNM staging system. Diligence by the surgeon and pathologist to retrieve and examine >8 inguinal, >15 axillary, or >20 cervical LNs is associated with fewer same nodal basin recurrences and improved survival and is critical to reliable prognostication.

Cultivation-dependent plasticity of melanoma phenotype

Malignant melanoma is a highly aggressive tumor with increasing incidence and high mortality. The importance of immunohistochemistry in diagnosis of the primary tumor and in early identification of metastases in lymphatic nodes is enormous; however melanoma phenotype is frequently variable and thus several markers must be employed simultaneously. The purposes of this study are to describe changes of phenotype of malignant melanoma in vitro and in vivo and to investigate whether changes of environmental factors mimicking natural conditions affect the phenotype of melanoma cells and can revert the typical in vitro loss of diagnostic markers. The influence of microenvironment was studied by means of immunocytochemistry on co-cultures of melanoma cells with melanoma-associated fibroblast and/or in conditioned media. The markers typical for melanoma (HMB45, Melan-A, Tyrosinase) were lost in malignant cells isolated from malignant effusion; however, tumor metastases shared identical phenotype with primary tumor (all markers positive). The melanoma cell lines also exerted reduced phenotype in vitro. The only constantly present diagnostic marker observed in our experiment was S100 protein and, in lesser extent, also Nestin. The phenotype loss was reverted under the influence of melanoma-associated fibroblast and/or both types of conditioned media. Loss of some markers of melanoma cell phenotype is not only of diagnostic significance, but it can presumably also contribute to biological behavior of melanoma. The presented study shows how the conditions of cultivation of melanoma cells can influence their phenotype. This observation can have some impact on considerations about the role of microenvironment in tumor biology.

Melanoma m (zero): diagnosis and therapy

This paper reviews the epidemiology, diagnosis, and treatment of M zero cutaneous melanoma including the most recent developments. This review also examined the main risk factors for melanoma. Tumor thickness measured according to Breslow, mitotic rate, ulceration, and growth phase has the greatest predictive value for survival and metastasis. Wide excision of the primary tumor is the only potentially curative treatment for primary melanoma. The sentinel node biopsy must be performed on all patients who have a primary melanoma with a Breslow thickness > 1 mm, or if the melanoma is from 0,75 mm to 1 mm thick but it is ulcerated and/or the mitotic index is ≥1. Total lymph node dissection consists in removing the residual lymph nodes in patients with positive sentinel node biopsy, or found positive on needle aspiration biopsy, without radiological evidence of spread. Isolated limb perfusion and isolated limb infusion are employed in patients within transit metastases with a rate of complete remission in around 50% and 38% of cases. Electrochemotherapy is mainly indicated for palliation in cases of metastatic disease, though it may sometimes be useful to complete isolated limb perfusion. The only agent found to affect survival as an adjuvant treatment is interferon alpha-2. Adjuvant radiotherapy improves local control of melanoma in patients at a high risk of recurrence after lymph node dissection.

Lymph node ratio predicts recurrence in papillary thyroid cancer

BACKGROUND

Lymph node metastasis occurs in 20%-50% of patients presenting for initial treatment of papillary thyroid cancer (PTC). The significance of lymph node metastases remains controversial, and the aim of this study is to determine how the lymph node ratio (LNR) may predict the likelihood of disease recurrence.

METHODS

We conducted a retrospective review of patients undergoing total thyroidectomy for PTC at our institution from 2005 to 2010. A total LNR (positive nodes to total nodes) and central lymph node ratio (cLNR) was calculated. Regression was used to determine a threshold LNR that best predicted recurrence. Multivariate logistic regression then determined the influence of LNR on recurrence while accounting for other known predictors of recurrence. Kaplan-Meier analysis and the log-rank test were used to compare differences in disease-free survival.

RESULTS

Of the 217 patients undergoing total thyroidectomy for PTC, 69 patients had concomitant neck dissections. Sixteen (23.2%) patients developed disease recurrence. When disease-free survival functions were compared, we found that patients with a total LNR ≥0.7 (p < .01) or a cLNR ≥0.86 (p = .04) had significantly worse disease-free survival rates than patients with ratios below these threshold values. Considering other known predictors of recurrence, we found that LNR was significantly associated with recurrence (odds ratio: 19.5, 95% confidence interval: 4.1-22.9; p < .01).

CONCLUSIONS

Elevated total LNR and cLNR are strongly associated with recurrence of PTC after initial operation. LNR in PTC is a tool that can be used to determine the likelihood of the patient developing recurrent disease and inform postoperative follow-up.

Impact of lymph node ratio on survival in papillary thyroid cancer

BACKGROUND

In papillary thyroid cancer, the role of lymph node dissection remains controversial, and staging systems consider metastatic lymph nodes as a binary entity. The purpose of this study was to determine a threshold lymph node ratio (LNR) that impacted disease-specific mortality (DSM).

METHODS

We utilized the surveillance, epidemiology, and end results (SEER) database to analyze adult patients who underwent thyroidectomy with lymph node dissection. A LNR (metastatic lymph nodes to total lymph nodes) was calculated after eliminating patients with less than three nodes collected. Kaplan-Meier estimates for DSM were plotted for LNRs and compared by the log rank test. The Cox proportional hazards model was used to evaluate LNR with other known clinical and pathologic determinants of prognosis.

RESULTS

A total of 10,955 cases contained data on lymph nodes. Median follow-up time was 25 months (range 0-59 months), and the mean LNR was 0.28 ± 0.37. After comparing Kaplan-Meier survival estimates and overall DSM rates, we found that a LNR ≥0.42 best divided those with lymph node metastasis based on DSM (p < 0.01). Those with a LNR ≥0.42 experienced a DSM rate of 1.72 % while those with a LNR <0.42 had a DSM rate of 0.65 % (p < 0.01). In addition, patients with a LNR ≥0.42 experienced a 77 % higher DSM rate compared to those with metastatic lymph nodes as a whole. When considered with other known determinants of prognosis, we found that LNR was strongly associated with DSM (hazard ratio 4.33, 95 % confidence interval 1.68-11.18, p < 0.01).

CONCLUSIONS

LNR is a strong determinant of DSM, and a threshold LNR of 0.42 can be used to risk-stratify patients with metastatic lymph nodes.

Pathologic staging of pancreatic, ampullary, biliary, and gallbladder cancers: pitfalls and practical limitations of the current AJCC/UICC TNM staging system and opportunities for improvement

Tumors of the ampulla-pancreatobiliary tract are encountered increasingly; however, their staging can be highly challenging due to lack of familiarity. In this review article, the various issues encountered in staging of these tumors at the pathologic level are evaluated and possible solutions for daily practice as well as potential improvements for future staging protocols are discussed. While N-stage parameters have now been well established (the number of lymph nodes required in pancreatoduodenectomies is 12), the T-staging has several issues: for the pancreas, the discovery of small cancers arising in intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs) necessitates the creation of substages of T1 (as T1a, b, and c); lack of proper definition of "peripancreatic soft tissue" and "common bile duct involvement" (as to which part is meant) makes T3 highly subjective. Increasing resectability of main vessels (portal vein) brings the need to redefine a "T" for such cases. For the ampulla, due to factors like anatomic complexity of the region and the under-appreciation of three-dimensional spread of the tumors in this area (in particular, the frequent extension into periduodenal soft tissues and duodenal serosa, which are not addressed in the current system and which require specific grossing approaches to document), the current T-staging lacks reproducibility and clinical relevance, and therefore, major revisions are needed. Recently proposed refined definition and site-specific subclassification of ampullary tumors highlight the areas for improvement. For the extrahepatic bile ducts, the staging schemes that use the depth of invasion may be more practical to circumvent the inconsistencies in the histologic layering of the ducts; better definition of terms like "periductal spread" is needed. For the gallbladder, since many gallbladder cancers are "unapparent" (found in clinically and grossly unsuspected cholecystectomies), establishing proper grossing protocols and adequate sampling are crucial. Since the gallbladder does not have the distinct layering of the other gastrointestinal organs, the definitions of Tis/T1a/T1b lack practicality, and therefore, "early gallbladder carcinoma" category proposed in high-risk regions may have to be recognized instead. Involvement of the Rokitansky-Aschoff sinuses should be a part of the evaluation and management of these early gallbladder cancers; for advanced cancers, documentation of hepatic versus serosal involvement is necessary. In summary, T-staging of ampulla-pancreatobiliary tract tumors has many challenges. Proper grossing and appreciation of histo-anatomic subtleties of this region are crucial in addressing these issues and achieving more applicable and clinically relevant staging systems in the future.

Pathologic lymph node ratio is a predictor of survival in esophageal cancer

BACKGROUND

A ratio between pathologic and examined lymph nodes may have predictive relevance in esophageal cancer. We sought to determine the prognostic value of lymph node ratio (LNR) compared with TNM and N stage using the seventh edition American Joint Commission on Cancer and International Union Against Cancer criteria.

METHODS

We abstracted data from 347 consecutive patients undergoing esophagectomy for esophageal cancer between 1999 and 2010 at our institution. Patients were stratified into surgery alone or induction therapy followed by surgery. Kaplan-Meier and Cox proportional hazard models estimated the survival function using LNR as a continuous variable or categorized into 0, more than 0.0 to less than 0.1, 0.1 to less than 0.2, 0.2 to less than 0.3, and 0.3 or greater. The influence of LNR on survival was assessed by the Wald χ(2) statistic and survival plots.

RESULTS

A total of 173 patients (49.9%) underwent induction therapy. The pathologic complete response rate was 55 of 173 (32%). The median number of examined nodes in surgery alone was 14 (interquartile range, 8 to 21), and induction was 12 (interquartile range, 7 to 17). Patients with nodal disease (n = 137) had a median LNR of 0.2 with equivalent survival regardless of induction therapy. Examination of LNR as a continuous variable demonstrated that LNR is an independent predictor of survival in both groups. After categorization, LNR contributed more toward estimating survival than pN stage in both groups.

CONCLUSIONS

Lymph node ratio is an independent predictor of survival in patients undergoing esophagectomy for esophageal cancer. The LNR makes a greater contribution in estimating overall survival than pN stage, regardless of the utilization of induction therapy.