No nodal cutoff in node-positive breast cancer women treated with mastectomy

Validation of a prognostic scoring system for postmastectomy locoregional recurrence in breast cancer

Background

To date, it remains unclear which patients with breast cancer (BC) benefit from post-mastectomy radiotherapy (PMRT). Cheng et al. developed and validated a scoring system based on 4 prognostic factors for locoregional recurrence (LRR) to identify patients in need for PMRT. These factors include age, estrogen receptor status, lymphovascular status and number of affected axillary lymph nodes.

Purpose

To validate the scoring system for LRR in BC developed by Cheng et al. by using an independent BC database.

Methods and materials

We retrospectively identified 1989 BC cases, treated with mastectomy (ME) with or without PMRT at the University Hospitals Leuven between 2000 and 2007. The primary endpoint was 5-year locoregional control rate with and without PMRT, according to the LRR score.

Results

Median follow-up time was 11.4 years. After excluding patients with missing variables 1103 patients were classified using the LRR scoring system: 688 (62.38%) patients were at low risk of recurrence (LRR score 0–1), 335 (30.37%) patients were at intermediate risk of recurrence (LRR score 2–3) and 80 (7.25%) patients were at high risk of recurrence (LRR score ≥4). 5-year locoregional control rates with and without PMRT were 99.20% versus 99.21% (p = 0.43) in the low-risk group; 98.24% versus 85.74% (p < 0.0001) in the intermediate-risk group and 96.87% versus 85.71% (p = 0.10) in the high-risk group respectively.

Conclusion

Our validation of the LRR scoring system suggests it can be used to point out patients that would benefit from PMRT. We recommend further validation of this scoring system by other independent institutions before application in clinical practice.

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Post-mastectomy radiotherapy.

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Scoring system by Cheng et al.

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Based on 4 factors.

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Age, estrogen receptor, lymphovascular status, affected axillary lymph nodes.

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Intermediate and high-risk patients could benefit from post-mastectomy radiotherapy.

Lymph Node Ratio after Neoadjuvant Chemotherapy for Stage II/III Breast Cancer: Prognostic Value Measured with Gini's Mean Difference of Restricted Mean Survival Times

Restricted mean survival time (RMST), recommended for reporting survival, lacks a tool to evaluate multilevel factors. The potential of the Gini’s mean difference of RMSTs (Δ) is explored in a comparison of a lymph node ratio-based classification (LNRc) versus a number-based classification (ypN) applied to stage II/III breast cancer patients who received neoadjuvant chemotherapy and underwent axillary dissection. Number of positive nodes (npos) classified patients into ypN0, npos = 0, ypN1, npos = [1,3], ypN2, npos = [4,9], and ypN3, npos ⩾ 10. Ratio npos/(number of nodes examined) of 0, (0,0.20], (0.20,0.65], and >0.65, classified patients into Lnr0 to Lnr3, respectively. Unadjusted and Cox-adjusted RMSTs were computed for the ypN and LNRc’s. At a follow-up time horizon of 72 months for 114 node-negative and 254 node-positive patients, unadjusted ypN0-ypN3 RMSTs were 62.4-41.4 months, Δ = 11.9 months (95%CI: 7.4-16.9), and Lnr0-Lnr3 62.4 to 36.3 months, Δ = 14.0 months (95%CI: 10.1-18.1). Cox models’ ypN1-ypN3 hazard ratios were 1.81-3.30, and Lnr1-Lnr3 1.52-4.39. Δ from Cox-fitted survival were ypN 8.1 months (95%CI: 5.9-10.5), LNRc 10.5 months (95%CI: 8.4-12.8). In conclusion, Gini’s mean difference is applicable to well established data in keeping with the literature on LNRc. It provides an alternative view on the improvement gained with a lymph node ratio-classification over using a number-classification.

Axillary Lymph Node Involvement in Breast Cancer: A Random Walk Model of Tumor Burden

We reinvestigate the relationship between axillary lymph node involvement in breast cancer and the overall risk of death. Patients were women from the Surveillance, Epidemiology, and End Results (SEER) program, aged between 50 and 65 years, presenting a first primary T1-T2 (tumor size ≤5 cm), node-positive, non-metastasized unilateral breast carcinoma, diagnosed from 1988 to 1997, treated with mastectomy without radiotherapy. Hazard ratios (HRs) were computed at each percentage of involved nodes using the proportional hazards model, adjusting for the patient's demographic and tumor characteristics. The pattern of the hazard ratios was examined using serial correlations. Significance testing used the "portmanteau" test. Based on 4,387 records available for analysis, the relation between adjusted mortality and axillary lymph node involvement was modeled as Ht - Ht- 1 = μ + at, where t is the percentage of involved nodes, Ht is the mortality hazard ratio at the percentage t, μ is a constant, and at is white noise. The constant μ was estimated at 0.020, corresponding to a 2% increment in the mortality hazard ratio per 1% increase in the percentage of positive nodes. The model was considered acceptable by the "portmanteau" test (P=0.205). We conclude that the effect of the tumor burden might be expressed as a random walk difference model, relating the mortality hazard ratio with the percentage of involved nodes. We will use the model to explore how treatments affect the course of the disease.

Prognostic analysis in a Chinese population with T1-2N1 breast cancer: Did patients with 1 or 2, and 3 positive axillary lymph nodes have similar survival outcomes?

BACKGROUND AND OBJECTIVES

There is a paucity of data examining whether 1-3 positive lymph nodes patients have similar survival outcomes. The present studies separately analyse survival outcomes of T1-2N1 breast cancer patients according to the number of positive lymph nodes.

METHODS

A total of 1,030 patients with T1-2N1 breast cancer were available for analysis. Survival estimates were calculated using the Kaplan-Meier method, univariate, and multivariate logistic regression models

RESULTS

Kaplan-Meier analysis showed progressively worse survival with the increased number of positive lymph nodes. Log-rank test P values were 0.003 (1 vs. 2 positive LNs), <0.0001 (1 vs. 3), and 0.006 (2 vs. 3) for recurrence-free survival (RFS). Log-rank test P values were 0.045 (1 vs. 2), <0.0001 (1 vs. 3), and 0.018 (2 vs. 3) for metastasis-free survival (MFS). Log-rank test P values were 0.101 (1 vs. 2), <0.0001 (1 vs. 3), and 0.005 (2 vs. 3) for overall survival (OS). Multivariate analysis showed that 3 and 2 positive lymph nodes had worse survival compared with 1 positive axillary lymph nodes.

CONCLUSIONS

Our study does suggest that T1-2N1 patients showed progressively worse survival outcomes with the increased number of positive lymph nodes.

Recursive partitioning analysis of lymph node ratio in breast cancer patients

Lymph node ratio (LNR) is a powerful prognostic factor for breast cancer. We conducted a recursive partitioning analysis (RPA) of the LNR to identify the prognostic risk groups in breast cancer patients. Records of newly diagnosed breast cancer patients between 2002 and 2006 were searched in the Taiwan Cancer Database. The end of follow-up was December 31, 2009. We excluded patients with distant metastases, inflammatory breast cancer, survival <1 month, no mastectomy, or missing lymph node status. Primary outcome was 5-year overall survival (OS). For univariate significant predictors, RPA were used to determine the risk groups. Among the 11,349 eligible patients, we identified 4 prognostic factors (including LNR) for survival, resulting in 8 terminal nodes. The LNR cutoffs were 0.038, 0.259, and 0.738, which divided LNR into 4 categories: very low (LNR ≤ 0.038), low (0.038 < LNR ≤ 0.259), moderate (0.259 < LNR ≤ 0.738), and high (0.738 < LNR). Then, 4 risk groups were determined as follows: Class 1 (very low risk, 8,265 patients), Class 2 (low risk, 1,901 patients), Class 3 (moderate risk, 274 patients), and Class 4 (high risk, 900 patients). The 5-year OS for Class 1, 2, 3, and 4 were 93.2%, 83.1%, 72.3%, and 56.9%, respectively (P< 0.001). The hazard ratio of death was 2.70, 4.52, and 8.59 (95% confidence interval 2.32-3.13, 3.49-5.86, and 7.48-9.88, respectively) times for Class 2, 3, and 4 compared with Class 1 (P < 0.001). In conclusion, we identified the optimal cutoff LNR values based on RPA and determined the related risk groups, which successfully predict 5-year OS in breast cancer patients.

Clinical significance of lymph node ratio in locally advanced breast cancer molecular subtypes

BACKGROUND

The ratio of metastatic to dissected lymph nodes (lymph node ratio; LNR) is a sensitive and superior prognostic factor for lymph node evaluation, but its relationship to cancer subtypes is unclear.

PATIENTS AND METHODS

Data from 469 patients with axillary lymph node metastasis out of 640 early breast cancer cases were retrospectively analyzed. They were classified into 4 molecular subtypes; luminal A, luminal B HER2(+), HER2 overexpression, basal-like. LNRs were compared between groups and with other prognostic factors.

RESULTS

The distribution of LNRs was 35.2% in luminal A, 43.2% in luminal B HER2(+), 46.9% in HER2 over-expression, and 39.1% in basal-like. A significant difference was found between luminal A and HER2 over-expression subtypes (p = 0.023). LNR was significantly correlated with tumor size and lymphovascular invasion, but not with other prognostic factors including menopausal status, laterality, grade, and perineural invasion. An LNR of 29.8% was defined as the cut-off value, and significant differences in survival rates were identified accordingly between basal-like and both luminal A (p = 0.003) and luminal B HER2(+) (p = 0.04).

CONCLUSION

The LNR differs between some molecular subtypes of breast cancer, and it correlates with certain prognostic factors and survival. These data support using the LNR to assess breast cancer patients.

Accurate staging of axillary lymph nodes from breast cancer patients using a novel molecular method

Background:

The one-step nucleic acid amplification (OSNA) assay is a molecular-based lymph-node metastasis detection procedure that can assess a whole node and yields semi-quantitative results for the detection of clinically relevant nodal metastases. We aimed to determine the performance of the OSNA assay as an accurate nodal staging tool in comparison with routine histological examination.

Methods:

Subjects comprised 183 consecutive patients with pT1-2 breast cancer who underwent axillary dissection after positive sentinel-node (SN) biopsy with the OSNA assay. Of these, for non-SN evaluation, 119 patients underwent OSNA assay evaluation, whereas 64 had single-section histology. We compared the detection rates of non-SN metastasis and upstaging rates from the SN stage according to the American Joint Committee on Cancer staging between the OSNA and histology cohorts.

Results:

OSNA detected more cases of non-SN metastases than histology (OSNA 66/119, 55.5% vs histology 13/64, 20.3% P<0.001), particularly micrometastases (36/119, 30.3% vs 1/64, 1.6% P<0.001). Total upstaging rates were similar in both cohorts (20/119, 16.8% vs 9/64, 14.1%, P=0.79).

Conclusion:

OSNA detects a far greater proportion of non-SN micrometastases than routine histological examination. However, upstaging rates after axillary dissection were not significantly different between both cohorts. Follow-up of the OSNA cohort is required to determine its clinical relevance.

Age and axillary lymph node ratio in postmenopausal women with T1-T2 node positive breast cancer

PURPOSE

The purpose of this article was to examine the relationship between age and lymph node ratio (LNR, number of positive nodes divided by number of examined nodes), and to determine their effects on breast cancer (BC) and overall mortality.

METHODS

Women aged ≥50 years, diagnosed in 1988-1997 with a unilateral histologically confirmed T1-T2 node positive surgically treated primary nonmetastatic BC, were selected from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER). Generalized Additive Models for Location Scale and Shape (GAMLSS) were used to evaluate the age-LNR relationship. Cumulative incidence functions and multivariate competing risks analysis based on model selection by the Bayesian Information Criterion (BIC) were used to examine the effect of age and LNR on mortality. Low LNR was defined as ≤0.20, mid-LNR 0.21-0.65, and high LNR >0.65.

RESULTS

GAMLSS showed a nonlinear LNR-age relationship, increasing from mean LNR 0.26-0.28 at age 50-70 years to 0.30 at 80 years and 0.40 at 90 years. Compared with a 9.8% [95% confidence interval (CI) 8.8%-10.8%] risk of BC death at 5 years in women aged 50-59 years with low LNR, the risk in women ≥80 years with low LNR was 12.6% [95% CI 10.1%-15.0%], mid-LNR 18.1% [13.9%-22.1%], high LNR 29.8% [22.7%-36.1%]. Five-years overall risk of death increased from 40.8% [37.5%-43.9%] by low LNR to 67.4% [61.4%-72.4%] by high LNR. The overall mortality hazard ratio for age ≥80 years with high LNR was 7.49 [6.54-8.59], as compared with women aged 50-59 years with low LNR.

CONCLUSION

High LNR combined with older age was associated with a threefold increased risk of BC death and a sevenfold increased hazard ratio of overall mortality.

Prognostic significance of number of positive nodes: a long-term study of one to two nodes versus three nodes in breast cancer patients

PURPOSE

Previous reports of breast cancer have generally analyzed patients with one to three positive lymph nodes as a single group, often leading to controversy regarding the practical clinical applicability. The present study separately analyzed the survival outcomes of Stage T1-T2 breast cancer patients according to whether one, two, or three axillary nodes were pathologically positive.

METHODS AND MATERIALS

The records of 5,996 patients were available for analysis from the population-based Saskatchewan provincial registry between 1981 and 1995. Because the reliability of the nodal assessment depends on the number of lymph nodes sampled, only those 755 patients with Stage T1-T2 disease and eight or more nodes examined were analyzed further for overall survival and cause-specific survival (CSS).

RESULTS

Patients with one and two positive nodes had nearly indistinguishable survival plots, but those with three positive nodes had a distinct trend toward worse survival. The overall survival rate of patients with one, two, and three nodes at 5, 10, and 15 years was 82.7%, 77.0%, and 79.0%, 64.8%, 60.9%, and 52.8%, and 48.8%, 48.0%, and 40.9%, respectively (p = .11). The corresponding CSS rates at 5, 10, and 15 years were 89.4%, 82.0%, and 81.3%, 78.87%, 72.9%, and 62.1%, and 72.7%. 69.0%, and 55.6% (p = .0004). The use of regional radiotherapy did not confer any apparent survival benefit in terms of either overall survival or CSS.

CONCLUSION

Patients with one or two positive nodes had a similar CSS. However, those with three positive nodes fared worse, with a significantly reduced CSS compared with those with one or two involved nodes. Thus, the survival data among patients with one to three nodes positive reveals clearly relevant differences when analyzed separately.

The effect of adjuvant radiotherapy on mortality differs according to primary tumor location in women with node-positive breast cancer

PURPOSE

To evaluate the prognostic significance of primary tumor location and to examine whether the effect of adjuvant radiotherapy on survival varies according to tumor location in women with axillary node-positive (ALN+) breast cancer (BC).

PATIENTS AND METHODS

Data were abstracted from the SEER database for 24,410 women aged 25-95 years, diagnosed between 1988-1997 with nonmetastatic T1-T2, ALN+ BC. Subgroup analyses were performed using interactions within proportional hazards models. Event was defined as death from any cause. Prognostic variables were selected using Akaike Information Criteria. Joint significances of subgroups were evaluated with Wald test.

RESULTS

Median follow-up was 10 years. In joint models, statistically significant interactions were found between tumor location, nodal involvement, type of surgery, and radiotherapy. Factorial presentation of interactions showed consistent 13% proportional reduction of mortality in all subgroups, except in women with medial tumors with > or = 4 ALN+ treated with mastectomy. In this subgroup, use of radiotherapy was associated with a 16% proportional increase in mortality.

CONCLUSION

Medial tumor location is a significant adverse prognostic factor that should be considered in treatment decision- making for women with ALN+ BC. Improved survival was observed with radiotherapy use in all subgroups, except in women with medial tumors with > or = 4 ALN+ treated with postmastectomy radiotherapy. These findings raise concern that the favorable effect of radiotherapy may be offset by excess toxicities in the latter subgroup.

The number of positive nodes and the ratio of positive to excised nodes are significant predictors of survival in women with micrometastatic node-positive breast cancer

BACKGROUND

To evaluate the prognostic impact of the number of positive nodes and the lymph node ratio (LNR) of positive to excised nodes on survival in women diagnosed with nodal micrometastatic breast cancer before the era of widespread sentinel lymph node biopsy.

METHODS

Subjects were 62,551 women identified by the Surveillance Epidemiology and End Results database, diagnosed with pT1-2pN0-1 breast cancer between 1988 and 1997. Kaplan-Meier breast cancer-specific survival (BCSS) and overall survival (OS) were compared between three cohorts: node-negative (pN0, n=57,980) nodal micrometastasis all <or=2mm (pNmic, N=1818), and macroscopic nodal metastasis >2mm but <2 cm (pNmac, n=2753). Nodal subgroups were examined by the number of positive nodes (1-3 versus >or= 4) and the LNR (<or=0.25 versus >0.25).

RESULTS

Median follow-up was 7.3 yr. Ten-year BCSS and OS in pNmic breast cancer were significantly lower compared to pN0 disease (BCSS 82.3% versus 91.9%, p<0.001 and OS 68.1% versus 75.7%, p<0.001). BCSS and OS with pNmic disease progressively declined with increasing number of positive nodes and increasing LNR. OS with pNmic was similar to pNmac disease when matched by the number of positive nodes and by the LNR. Both pN-based and LNR-based classifications were significantly prognostic of BCSS and OS on Cox regression multivariate analysis.

CONCLUSION

Nodal micrometastasis is associated with poorer survival compared to pN0 disease. Mortality hazards with nodal micrometastasis increased with increasing number of positive nodes and increasing LNR. The number of positive nodes and the LNR should be considered in risk estimates for patients with nodal micrometastatic breast cancer.

The Ratio of Positive to Excised Nodes Identifies High-risk Subsets and Reduces Inter-Institutional Differences in Locoregional Recurrence Risk Estimates in Breast Cancer Patients With 1–3 Positive Nodes: An Analysis of Prospective Data From British Columbia and the M. D. Anderson Cancer Center

PURPOSE

To examine the power of the nodal ratio (NR) of positive/excised nodes in predicting postmastectomy locoregional recurrence (LRR) in patients with 1-3 positive nodes (N+) and in identifying cohorts at similar risk across independent data sets.

METHODS AND MATERIALS

Data from 82 patients with 1-3 N+ treated without postmastectomy radiotherapy (PMRT) in the British Columbia (BC) randomized trial were compared with data from 462 patients treated without PMRT in prospective chemotherapy trials at the M. D. Anderson Cancer Center (MDACC). Kaplan-Meier LRR curves were compared between centers using the absolute number of N+ and nodal ratios.

RESULTS

The median number of excised nodes was 10 in BC and 16 in MDACC (p < 0.001). Examining LRR by number of N+, the 10-year LRR rate for patients with 1-3 N+ was higher in BC compared with MDACC (21.5% vs. 12.6%; p = 0.02). However, when examining LRR using NR, no differences were found between institutions. In patients with NR < or = 0.20, the 10-year LRR rate was 17.7% BC vs. 10.9% MDACC (p = 0.27). In patients with NR > or = 0.20, the 10-year LRR rate was 28.7% BC vs. 22.7% MDACC (p = 0.32). On Cox regression analysis, NR was a stronger prognostic factor compared with number of N +.

CONCLUSIONS

In patients with 1-3 N+, evaluating nodal positivity using NR reduced inter-institutional differences in LRR estimates that may exist due to variations in numbers of nodes excised. Nodal ratio >0.20 was associated with LRR >20%, warranting PMRT consideration. Nodal ratio may be useful for extrapolating data from prospective trials to clinical practices in which axillary staging extent vary.