Prognosis of unexpected and expected pathologic N1 non-small cell lung cancer

Clinical N Staging Subclassification for Stage III-N2 NSCLC Patients Undergoing Trimodality Therapy: A Good Beginning Is Half the Battle

BACKGROUND

Lung cancer patients with stage III-N2 disease may benefit from the subclassification of nodal involvement before decision-making. We aimed to evaluate whether the clinical N descriptor subclassification predicts prognosis in patients undergoing trimodality therapy for stage III-N2 non-small cell lung cancer.

METHODS

Using our institutional registry between 2003 and 2019, we analyzed 899 consecutive patients with stage III-N2 non-small cell lung cancer undergoing neoadjuvant concurrent chemoradiotherapy followed by surgery. We subclassified clinical N2 into cN2a and cN2b on the basis of imaging and histopathologic results. Recurrence-free survival and overall survival were compared by N2 subclassification and separately by histologic type, using competing risks models and Cox proportional hazards models.

RESULTS

By the proposed N subclassification, 503 (56.0%) and 396 (44.0%) patients were assigned to cN2a and cN2b, respectively. During a median follow-up of 53.1 months, 492 patients had recurrence and 477 died. The hazard ratios for recurrence comparing cN2b with cN2a after adjustment for age, sex, comorbidities, clinical T category, and histologic type were 1.22 (95% CI, 1.03-1.46). The adjusted hazard ratios for mortality comparing cN2b to cN2a were 1.43 (1.19-1.71). When stratified by histologic type, cN2b had a higher risk of mortality compared with cN2a in both adenocarcinoma and squamous cell carcinoma.

CONCLUSIONS

In our study evaluating the International Association for the Study of Lung Cancer's approach to subclassify the clinical N descriptor for stage III-N2 non-small cell lung cancer patients, cN2b had a higher risk of recurrence and mortality compared with cN2a, suggesting that clinical N subclassification may be a valuable predictor for stage III-N2 patients.

The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for Revision of the Classification of Residual Tumor After Resection for the Forthcoming (Ninth) Edition of the TNM Classification of Lung Cancer

INTRODUCTION

The goal of surgical resection is to completely remove a cancer; it is useful to have a system to describe how well this was accomplished. This is captured by the residual tumor (R) classification, which is separate from the TNM classification that describes the anatomic extent of a cancer independent of treatment. The traditional R-classification designates as R0 a complete resection, as R1 a macroscopically complete resection but with microscopic tumor at the surgical margin, and as R2 a resection that leaves gross tumor behind. For lung cancer, an additional category encompasses situations in which the presence of residual tumor is uncertain.

METHODS

This paper represents a comprehensive review of evidence regarding these R categories and the descriptors thereof, focusing on studies published after the year 2000 and with adjustment for potential confounders.

RESULTS

Consistent discrimination between complete, uncertain, and incomplete resection is revealed with respect to overall survival. Evidence regarding specific descriptors is generally somewhat limited and only partially consistent; nevertheless, the data suggest retaining all descriptors but with clarifications to address ambiguities.

CONCLUSION

On the basis of this review, the R-classification for the ninth edition of stage classification of lung cancer is proposed to retain the same overall framework and descriptors, with more precise definitions of descriptors. These refinements should facilitate application and further research.

Prognostic significance of the N1 classification pattern: a meta-analysis of different subclassification methods

OBJECTIVES

The number of positive lymph node stations has been viewed as a subclassification in the N1 category in the new revision of tumour node metastasis (TNM) staging. However, the survival curve of these patients overlapped with that of some patients in the N2 categories. Our study focused on the prognostic significance of different subclassifications for N1 patients.

METHODS

We systematically searched PubMed, Ovid, Web of Science and the Cochrane Library on the topic of N1 lymph node dissection. Hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were used to assess the prognostic significance of N1 metastases. I2 statistics was used to evaluate heterogeneity among the studies: If significant heterogeneity existed (P ≤ 0.10; I2 >50%), a random effect model was adopted.

RESULTS

After a careful investigation, a total of 17 articles were included in the analysis. The results showed that patients with non-small-cell lung cancer with multistation N1 disease have worse survival compared with those with single-station N1 disease (HR 1.53, 95% CI 1.32-1.77; P < 0.001; I2 = 5.1%). No significant difference was observed between groups when we assessed the number of positive lymph nodes (single or multiple) (HR 1.25, 95% CI 0.96-1.64; P = 0.097; I2 = 72.5%). Patients with positive hilar zone lymph nodes had poorer survival than those limited to the intrapulmonary zone (HR 1.80, 95% CI 1.57-2.07; P < 0.001; I2 = 0%). A subgroup analysis conducted according to the different validated lymph node maps showed a stable result.

CONCLUSIONS

Our result confirmed the prognostic significance of the N1 subclassification based on station number. Meanwhile, location-based classifications, especially zone-based, were also identified as prognostically significant, which may need further confirmation and validation in the staged population.

Salvage proton beam therapy for locoregional recurrence of non-small cell lung cancer

Purpose

This study aimed to evaluate the clinical outcomes and toxicities of salvage proton beam therapy (PBT) in patients with locoregional recurrent non-small cell lung cancer (NSCLC).

Materials and Methods

We retrospectively reviewed 53 patients who received salvage PBT for locoregionally recurrent NSCLC between January 2016 and December 2019. The median clinical target volume (CTV) was 71.2 cm³ (range, 13.3 to 1,200.7 cm³). The median prescribed dose was 64.0 cobalt gray equivalent (CGE) (range, 45.0 to 70.0 CGE). One-third of the patients (32.1%) received concurrent chemoradiotherapy (CCRT).

Results

The patients’ median age was 67 years (range, 44 to 86 years). The initial treatments were surgery in 31 (58.5%), definitive CCRT in 12 (22.6%), and definitive radiotherapy in 10 (18.9%) patients. The median disease-free interval (DFI) was 14 months (range, 3 to 112 months). Thirty-seven patients (69.8%) had a previous radiotherapy history. Among them, 18 patients (48.7%) had in-field recurrence. The median follow-up time after salvage PBT was 15.0 months (range, 3.5 to 49.3 months). During the follow-up period, 26 patients (49.1%) experienced disease progression: local in 13 (24.5%), regional in 14 (26.5%), and distant metastases in 15 (26.5%). The 2-year overall survival (OS) rate, local control rate, and progression-free survival rate were 79.2%, 68.2%, and 37.1%, respectively. Shorter DFI (≤12 months; p = 0.015) and larger CTV (>80 mL; p = 0.014) were associated with poor OS. Grade 3 toxicities occurred in 8 patients (15.1%): esophagitis in 2, dermatitis in 3, and pulmonary toxicities in 4.

Conclusion

Salvage PBT for locoregionally recurrent NSCLC was effective, and treatment-related toxicities were tolerable.

Skip metastasis in mediastinal lymph node is a favorable prognostic factor in N2 lung cancer patients: a meta-analysis

Background

Skip metastasis is a common lymph node metastatic pattern in non-small cell lung cancer (NSCLC). The relationship between skip metastasis and specific clinicopathologic factors and the prognostic value of skip metastasis are controversial.

Methods

A systematic search and analysis of skip metastasis in NSCLC was conducted in the databases of PubMed, EMBASE, and Web of Science up to Dec 2019. Summarized hazard ratio (HR), mean difference (MD), and odds ratio (OR) with associated 95% confidence intervals (CI) were evaluated to investigating the relationship between skip metastasis and overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS) and clinicopathological features in NSCLC.

Results

29 studies with a total of 1,806 skip and 4,670 non-skip N2 patients were included. The upper lobe tumor showed a higher rate of skip metastasis compared with lower lobe one (RR =1.16, 95% CI: 1.00–1.34, P=0.044, I²=39.8%). The presence of skip metastasis correlated with superior overall survival (HR =0.74, 95% CI: 0.66–0.83, P<0.001, I²=48.2%) and DFS or RFS (HR =0.71, 95% CI: 0.61–0.84, P<0.001, I²=18.2%). Further subgroup analyses indicated similar results in articles that reported intrapulmonary lymph node dissection (HR =0.67, 95% CI: 0.57–0.77, P<0.001, I²=0).

Conclusions

The results indicate that the presence of skip metastasis is associated with a marked increase in survival of NSCLC patients compared to patients with non-skip N2 metastasis. These results suggest that skip metastasis might be a distinct subgroup for purposes of N staging of NSCLC patients, and intrapulmonary lymph node assessment is needed.

Surgical Results in Pathological N1 Nonsmall Cell Lung Cancer

BACKGROUND

This retrospective study investigated the prognosis of patients with pathological N1 (pN1) nonsmall cell lung cancer (NSCLC).

METHODS

We included patients with pN1 NSCLC who underwent lobectomy or pneumonectomy with mediastinal lymph node dissection and achieved complete resection (R0) between January 2000 and December 2012. Patients who received neoadjuvant therapy were excluded.

RESULTS

A total of 249 patients were included. The mean age was 63.2 years, and 172 patients were males. Of the 249 patients, 200, 20, and 29 underwent lobectomy, bilobectomy, and pneumonectomy, respectively. The median observation period was 5.5 years. The 5-year overall survival (OS) rate was 64.6% (95% confidence interval: 58.3-70.4). Five-year OS rates were 79.8% for positive lymph nodes at station 13 or 14 (n = 57), 59.6% at station 12 (n = 72), 62.7% at station 11 (n = 69), and 56.9% at station 10 (n = 51) (log-rank test; p = 0.016); furthermore, the 5-year OS rate was 75.2% for patients with positive lymph nodes at a single station (n = 160) and 45.4% for patients with positive lymph nodes at multiple stations (n = 89) (log-rank test; p < 0.001). Five-year cumulative incidences of recurrence were equivalent between patients who received adjuvant chemotherapy and patients who did not (45.9 vs. 55.1%; Gray's test; p = 0.366). Distant recurrence was the most frequent mode of recurrence in both groups (70.8 and 67.3%).

CONCLUSION

The locations and the number of stations of the positive lymph nodes were identified as prognostic factors in patients with pN1 NSCLC. The primary mode of recurrence was distant recurrence irrespective of postoperative adjuvant chemotherapy.

Oncologic Outcomes of Surgery Versus SBRT for Non-Small-Cell Lung Carcinoma: A Systematic Review and Meta-analysis

BACKGROUND

The optimal treatment of stage I non-small-cell lung carcinoma is subject to debate. The aim of this study was to compare overall survival and oncologic outcomes of lobar resection (LR), sublobar resection (SR), and stereotactic body radiotherapy (SBRT).

METHODS

A systematic review and meta-analysis of oncologic outcomes of propensity matched comparative and noncomparative cohort studies was performed. Outcomes of interest were overall survival and disease-free survival. The inverse variance method and the random-effects method for meta-analysis were utilized to assess the pooled estimates.

RESULTS

A total of 100 studies with patients treated for clinical stage I non-small-cell lung carcinoma were included. Long-term overall and disease-free survival after LR was superior over SBRT in all comparisons, and for most comparisons, SR was superior to SBRT. Noncomparative studies showed superior long-term overall and disease-free survival for both LR and SR over SBRT. Although the papers were heterogeneous and of low quality, results remained essentially the same throughout a large number of stratifications and sensitivity analyses.

CONCLUSION

Results of this systematic review and meta-analysis showed that LR has superior outcomes compared to SBRT for cI non-small-cell lung carcinoma. New trials are underway evaluating long-term results of SBRT in potentially operable patients.

Prognostic factor and treatment strategy for clinical N1 non-small cell lung cancer

OBJECTIVES

The aim of this study is to evaluate the surgical results of clinical N1 disease and to clarify the high-risk clinical N1 subgroup.

METHODS

Between 1990 and 2012, 137 patients who were clinically diagnosed as having N1 disease were enrolled. Their medical records were reviewed to assess clinical characteristics, radiologic findings, pathologic results, postoperative outcomes, recurrence patterns, and survival. Logistic regression analysis was used to identify independent predictive factors for pathologic N2 upstaging. To determine which factors were significantly associated with survival, a multivariate analysis using a Cox proportional hazards model was performed.

RESULTS

More cases were pathological N2 in adenocarcinoma than squamous cell carcinoma (p = 0.039). The overall survival rates at 5 years were 54.9%, 36.7% in group upper lobe, middle and lower lobe, respectively (p = 0.013). Logistic regression analyses revealed that #10 positive (p = 0.002, HR 4.625) and adenocarcinoma (p = 0.029, HR 1.544) were significant predictor of pathologic N2 disease. Multivariate analyses revealed that pathologic N2 (p = 0.007, HR 4.186), middle and lower lobe (p = 0.009, HR 2.045) and presence of #10 (p = 0.024, HR 1.871) were independent prognostic factors. Patients with upper lobe and absence of #10 showed a significantly higher 5-year survival rate than patients with middle and lower lobe and presence of #10 (62.1 vs 25.9%: p < 0.0001).

CONCLUSIONS

Among patients with cN1, pathological N2 disease, tumor in middle and lower lobe and clinical #10 lymph node positive were high-risk subgroup. Further analyses using larger numbers of patients with N1 disease from multiple centers are necessary.

Comparison of prognostic values of primary tumor and nodal 18F-fluorodeoxyglucose uptake in non-small cell lung cancer with N1 disease

INTRODUCTION

We hypothesized that, in non-small cell lung cancer (NSCLC) with N1 metastasis, N1 nodal ¹⁸F-fluorodeoxyglucose (FDG) status offers independent and incremental prognostic value.

METHODS

We enrolled 106 NSCLC patients with pathology-confirmed N1 metastasis. N1 node FDG positivity, primary tumor maximum standard uptake value (SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured. Kaplan-Meier method and Cox regression analyses were performed for cancer-specific survival (CSS) and disease-free survival (DFS).

RESULTS

Subjects were 67 males and 39 females (61.9 ± 9.4 years). Eighty-one (76.4%) and 25 (23.6%) had pathologic stage IIB and IIIA NSCLC, respectively. All underwent complete tumor resection. FDG-positive N1 nodes were larger and had higher primary tumor SUV_max. During a follow-up of 42 months, there were 56 recurrences and 31 cancer deaths. Significant univariate predictors were stage, no adjuvant therapy, and FDG-positive nodes for DFS, and stage, no adjuvant therapy, node size, tumor MTV, TLG, and SUV_max, and FDG-positive nodes for CSS. Independent predictors on multivariate analyses were FDG-positive nodes (HR = 3.071, p = 0.003), greater tumor TLG (HR = 3.224, p = 0.002), and no adjuvant therapy (HR = 3.631, p < 0.001) for poor CSS, and FDG-positive nodes (HR = 1.771, p = 0.040) and no adjuvant therapy (HR = 2.666, p = 0.002) for poor DFS. Harrell's concordance and net reclassification improvement tests showed that CSS prediction was significantly improved by the addition of N1 FDG status to a model containing tumor TLG.

CONCLUSION

N1 node FDG status can be useful for predicting the outcome of NSCLC patients with N1 metastasis beyond that provided by other prognostic variables.

KEY POINTS

• In NSCLC with N1 disease, N1 node FDG status is useful as a prognostic predictor. • FDG-positive N1 nodes provide additional prognostic value beyond TLG of primary tumor. • Combining TLG of primary tumor and N1 node uptake can stratify the survival of patients.

Extranodal extension of nodal metastases is a poor prognostic moderator in non-small cell lung cancer: a meta-analysis

Extranodal extension (ENE) of nodal metastasis is defined as the extension of metastatic cells through the nodal capsule into the perinodal tissue. This morphological parameter, recently proposed as an important prognostic factor in different types of malignancy, has not been included in the TNM staging system for non-small cell lung cancer (NSCLC). In this systematic review with meta-analysis, we weighted the prognostic role of ENE in patients with lymph node-positive NSCLC. Two independent authors searched SCOPUS and PubMed through 28 February 2017. Prospective and retrospective studies on NSCLC, comparing patients with presence of ENE (ENE+) ENE+) vs. only intranodal extension (ENE-) and including data regarding prognosis, were considered as eligible. Data were summarized using risk ratios (RR) for the number of deaths/recurrences, and hazard ratios (HR) with 95% confidence intervals (CI) for time-dependent risk related to ENE+, adjusted for potential confounders. We identified 13 studies, including 1709 patients (573 ENE+ and 1136 ENE-) with a median follow-up of 60 months. ENE was associated with a significantly increased risk of mortality of all causes (RR = 1.39, 95% CI: 1.18-1.65, P < 0.0001, I2 = 70%; HR = 1.30, 95% CI: 1.01-1.67, P = 0.04, I2 = 0%) and of disease recurrence (RR = 1.32, 95% CI: 1.04-1.68, P = 0.02, I2 = 42%; HR = 1.93, 95% CI: 1.53-2.44, P < 0.0001, I2 = 0%). We conclude that in NSCLC, requirements for assessment of ENE should be included in gross sampling and ENE status should be included in the pathology report. Inclusion of ENE status in oncology staging systems will allow further assessment of its role as prognostic parameter.

Clinicopathologic Factors Associated With Occult Lymph Node Metastasis in Patients With Clinically Diagnosed N0 Lung Adenocarcinoma

BACKGROUND

In some patients, clinical N0 (cN0) lung adenocarcinoma diagnosed by preoperative computed tomography scanning and positron emission tomography scanning was staged as pathologic N1 (pN1) or N2 (pN2) postoperatively. The aim of this study was to determine the preoperative and postoperative clinicopathologic factors related to nodal upstaging after a surgical operation.

METHODS

We conducted a retrospective chart review of 350 patients treated for cN0 lung adenocarcinoma by curative resection. We analyzed clinicopathologic findings, comparing pN0 patients with the nodal upstaging group.

RESULTS

Of 350 patients treated for cN0 tumors, 305 (87.1%) were confirmed postoperatively as having pN0 tumors, and 45 (12.9%) were confirmed as having pN1 or pN2 tumors. The mean maximum standardized uptake value (SUVmax) was higher in the nodal upstaging group than in the pN0 group (6.9 versus 3.8, p = 0.004); the upstaging group also included more cases in which SUVmax was greater than 5 (70.5% versus 24.8%, p < 0.001). Pleural invasion, lymphatic invasion, and vascular invasion were all more frequently seen in the nodal upstaging group than in the pN0 group (all p < 0.001). The presence of tumors with a micropapillary component was higher in the nodal upstaging group (p < 0.001). Multivariate logistic regression analysis identified SUVmax greater than 5, lymphatic invasion, vascular invasion, and a micropapillary component as significant risk factors for nodal upstaging.

CONCLUSIONS

In lung adenocarcinoma diagnosed as clinical N0 by chest computed tomography and positron emission tomography scanning, the possibility of occult lymph node metastasis increases with SUVmax greater than 5 and when lymphatic invasion, vascular invasion, and a micropapillary component are present.

Clinicopathologic correlates of postoperative N1 or N2 nodal upstaging in non-small cell lung cancer

BACKGROUND

Clinical and pathologic determinations of lymph node staging are critical in the treatment of lung cancer. However, up- or downstaging of nodal status frequently is necessitated by postsurgical findings. This study was conducted to evaluate clinicopathologic features that impact nodal upstaging in patients staged primarily via positron emission tomography/computed tomography (PET/CT) and chest CT prior to surgery.

METHODS

Between years 2011 and 2014, 634 patients underwent surgical treatment for non-small cell lung cancer (NSCLC) at our institution. Excluding 37 patients (given induction chemotherapy), 103 patients pathologically staged as N1 or N2 NSCLC. Nodal upstaging patients were classified into group A and non-upstaging patients into group B. We compared clinical characteristics and pathological results of group A with group B.

RESULTS

Ultimately, 59 patients (57.3%) were assigned to group A and 44 patients (42.7%) to group B. Patients in group A (vs. group B) were significantly younger (61.6 vs. 68.4 years; P<0.001) and more often were female (47.5% vs. 15.9%; P=0.001), with shorter smoking histories (12.2 vs. 28.8 pack years; P<0.001) and lower maximum standardized uptake values (SUVmax) (7.3 vs. 10.4; P=0.001). Most upstaged (group A) tumors (50/59, 84.7%) were adenocarcinomas, displaying micropapillary (MPC; n=36) and lepidic (n=35) component positivity with significantly greater frequency (both, P<0.001); and the frequency of epidermal growth factor receptor (EGFR) mutation (n=36) was significantly greater in this subset (P=0.001). Multivariate analysis (logistic regression) indicated a significant correlation between MPC positivity and nodal upstaging (P=0.013).

CONCLUSIONS

In patients upstaged postoperatively to N1 or N2 stage of NSCLC, occult lymph node metastasis and MPC positivity were significantly related.

Predicted extracapsular invasion of hilar lymph node metastasis by fusion positron emission tomography/computed tomography in patients with lung cancer

Intraoperative detection of hilar lymph node metastasis, particularly with extracapsular invasion, may affect the surgical procedure in patients with lung cancer, as the preoperative estimation of hilar lymph node metastasis is unsatisfactory. The aim of this study was to investigate whether fusion positron emission tomography/computed tomography (PET/CT) is able to predict extracapsular invasion of hilar lymph node metastasis. Between April, 2007 and April, 2013, 509 patients with primary lung cancer underwent surgical resection at our institution, among whom 28 patients exhibiting hilar lymph node metastasis (at stations 10 and 11) were enrolled in this study. A maximum lymph node standardized uptake value of >2.5 in PET scans was interpreted as positive. A total of 17 patients had positive preoperative PET/CT findings in their hilar lymph nodes, while the remaining 11 had negative findings. With regard to extracapsular nodal invasion, the PET/CT findings (P=0.0005) and the histological findings (squamous cell carcinoma, P=0.05) were found to be significant predictors in the univariate analysis. In the multivariate analysis, the PET/CT findings were the only independent predictor (P=0.0004). The requirement for extensive pulmonary resection (sleeve lobectomy, bilobectomy or pneumonectomy) was significantly more frequent in the patient group with positive compared with the group with negative PET/CT findings (76 vs. 9%, respectively, P=0.01). Therefore, the PET/CT findings in the hilar lymph nodes were useful for the prediction of extracapsular invasion and, consequently, for the estimation of possible extensive pulmonary resection.

Prognostic impact of bulky swollen lymph nodes in cN1 non-small cell lung cancer patients

OBJECTIVE

The aim of this study was to analyze clinicopathological backgrounds and prognosis of clinical N1 non-small cell lung cancer and clarify the difference between bulky and non-bulky cN1 diseases.

METHODS

We reviewed 110 patients with completely resected cN1 non-small cell lung cancer and examined the prognostic impact of lymph node size. We classified the swollen lymph nodes into two groups based on their size on chest computed tomography: short-axis diameter ≥20 mm (=bulky group) or <20 mm (=non-bulky group).

RESULTS

The bulky group consisted of 10 patients, and the non-bulky group comprised 100 patients. There was no significant difference in the upstaging rate to pathological N2 between the bulky and non-bulky groups (31% vs. 30%; P = 0.63). The 5-year recurrence-free survival rate and 5-year overall survival rate of both groups did not differ significantly (P = 0.36, P = 0.30, respectively). Our results suggested the possibility that the size of the swollen lymph nodes had no impact on the prognosis in cN1 non-small cell lung cancer patients. In comparison of surgical procedure, pneumonectomy was performed in the bulky group more frequently than the non-bulky group (70% vs. 19%; P < 0.01).

CONCLUSIONS

Bulky cN1 disease was not different from non-bulky disease in the prognosis and the upstaging rate to pN2. Curative resection should be indicated to resectable bulky cN1 disease as with non-bulky disease, with careful pre-operative evaluation and preparation considering the possibility of pneumonectomy.