Prognostic Validation of the American Joint Committee on Cancer 8th Staging System in 24,014 Korean Patients with Breast Cancer

Discriminatory Ability and Clinical Utility of the AJCC7 and AJCC8 Staging Systems for Breast Cancer in a Middle-Income Setting

(1) Background: Differences in access to biomarker testing and cancer treatment in resource-limited settings may affect the clinical utility of the AJCC8 staging system compared to the anatomical AJCC7 system. (2) Methods: A total of 4151 Malaysian women who were newly diagnosed with breast cancer from 2010 to 2020 were followed-up until December 2021. All patients were staged using the AJCC7 and AJCC8 systems. Overall survival (OS) and relative survival (RS) were determined. Concordance-index was used to compare the discriminatory ability between the two systems. (3) Results: Migration from the AJCC7 to AJCC8 staging system resulted in the downstaging of 1494 (36.0%) patients and the upstaging of 289 (7.0%) patients. Approximately 5% of patients could not be staged using the AJCC8 classification. Five-year OS varied between 97% (Stage IA) and 66% (Stage IIIC) for AJCC7, and 96% (Stage IA) and 60% (Stage IIIC) for AJCC8. Concordance-indexes for predicting OS using the AJCC7 and AJCC8 models were 0.720 (0.694-0.747) and 0.745 (0.716-0.774), and for predicting RS they were 0.692 (0.658-0.728) and 0.710 (0.674-0.748), respectively. (4) Conclusions: Given the comparable discriminatory ability between the two staging systems in predicting the stage-specific survival of women with breast cancer in the current study, the continued use of the AJCC7 staging system in resource-limited settings seems pragmatic and justifiable.

Validation of the Prognostic Stage from the American Joint Committee on Cancer 8th Staging Manual in Luminal B-Like Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer

PURPOSE

The 8th edition American Joint Committee on Cancer (AJCC) prognostic staging system (PS) has been validated numerous times; however, the prognostic value of PS for breast cancer based on molecular subtype has rarely been explored. This study aimed to investigate the prognostic value of PS in Chinese patients with luminal B-like human epidermal growth factor receptor 2 (HER2)-negative breast cancer.

METHODS

A total of 407 eligible cases were included in the study. All of the cases were restaged using the 8th edition AJCC Anatomic Staging System (AS) and PS. The Kaplan-Meier method was used to calculate estimated survival and the Log rank test was used to compare the survival differences between groups.

RESULTS

The 5-year disease-specific survival (DSS) and overall survival (OS) rates were 90.3% and 93.5%, respectively, and there were statistically significant differences in the 5-year DSS and 5-year OS rates among the different anatomic and prognostic stage groups. The application of the PS resulted in the assignment of 215 (52.8%) patients to a different group. Different prognostic stage groups restaged from anatomic Stage III had significant differences in both DSS (χ 2 = 4.366, p = 0.037) and OS (χ 2 = 7.549, p = 0.006); additionally, different prognostic stage groups from the anatomic Stage II group had significant differences in DSS (χ 2 = 7.724, p = 0.021) but no significant differences in OS (χ 2 = 5.182, p = 0.075). However, different prognostic stage groups from anatomic Stage I had no significant differences in either DSS (χ 2= 0.159, p = 0.690) or OS (χ 2 = 0.099, p = 0.753).

CONCLUSION

The 8th edition AJCC PS refined the anatomic stage grouping in luminal B-like HER2-negative breast cancer and could lead to a more personalized approach to breast cancer treatment.

Validation of the Eighth American Joint Committee on Cancer Anatomic and Prognostic Staging System for Breast Cancer

BACKGROUND

The eighth edition of new staging systems for breast cancer incorporated four biological factors and the anatomic staging system. Validating analysis on Chinese patients has been limited. Our study performed analysis comparing the prognostic value of the staging system based on Chinese data.

METHODS AND MATERIALS

All patients were classified according to the eighth edition and compared between anatomic and prognostic staging systems. The Kaplan-Meier test was used to calculate the overall survival (OS) and disease-free survival (DFS). We performed Harrell concordance index (C-index) analyses to quantify a models' predictive performance. Akaike information criterion (AIC) via Cox regression analysis was used to conduct bootstrap-based goodness-of-fit comparisons of the competing staging systems.

RESULTS

A total of 1556 patients were enrolled in the cohort. The median follow-up time was 76 mo (range, 4-146 mo), the median age was 48 y old (range, 21-87 y). The ratio of movement between anatomic stage (AS) and prognostic stage (PS) was 50.9%. Of these, 691 (44.5%) AS patients were down staged and 100 (6.4%) patients were upstaged when reclassified based on PS. Significant differences between two stages were achieved for stage IIIC in 5-y OS rates and for IIIB in 5-y DFS rates (63.5% versus 50.0% and 58.0% versus44.0%). The value of the C-index for PS and AS were 0.711 and 0.687 (P = 0.04). The AIC reaches a value of 3452.9 for the PS and a value of 3476.4 for the AS.

CONCLUSIONS

The PS might provide better accuracy than the AS in predicting the prognosis of Chinese female breast cancer patients. It also provides a strong basis for the utility of clinical biomarkers to evaluate the prognosis of patients.

The clinical value of 18F-fluoroestradiol in assisting individualized treatment decision in dual primary malignancies

Background

For patients with previously diagnosed dual primary tumors, it is usually difficult to determine the diagnosis and treatment of stage IV recurrence. The study was to explore the influences of ¹⁸F-fluoroestradiol positron emission tomography/computed tomography (¹⁸F-FES PET/CT) in the diagnosis of estrogen receptor (ER) positive breast cancer combined with other primary tumor with distant metastases.

Methods

Multidisciplinary team were organized to explore the definite clinical value of ¹⁸F-FES PET/CT in stage IV patients suffered from ER-positive breast cancer and another primary tumor synchronously or metachronously. Thirty-two female patients were retrospectively analyzed who underwent ¹⁸F-FES PET/CT scans in our center. Before and after reading ¹⁸F-FES reports, the team members from department of surgery, oncology and radiotherapy should make decisions of management strategy.

Results

Totally, the multidisciplinary team completed the management decision-making of the 32 patients before and after ¹⁸F-FES PET/CT scans. 87.5% (n=28) of the patients were considered to benefit from ¹⁸F-FES reports for diagnosis and treatment decisions. Out of the 28 patients, 7 patients (7/32, 21.9%) were considered to definitely change the management strategies while 12 patients (12/32, 37.5%) was instructive to develop management plans after the scan. The other 9 patients were suggested reassuring decision-making process by ¹⁸F-FES PET/CT.

Conclusions

¹⁸F-FES PET/CT scans have clinical effects on diagnosis and treatment strategies of stage IV patients suffered from ER-positive breast cancer and another primary tumor.

Early SUVmax is the best predictor of axillary lymph node metastasis in stage III breast cancers

Background

Although fluorine-18-labeled 2-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission/computed tomography (PET/CT) imaging has been investigated for its ability to evaluate lymph node metastasis of breast cancer, few comparative analyses have evaluated the preoperative and postoperative regional lymph node metastasis of breast cancer by dual-phase imaging, especially in patients with stage III (N2) disease.

Methods

The clinical, pathological, and imaging data of 40 patients with stage III (N2) breast cancer were retrospectively analyzed. All patients underwent dual-time point ¹⁸F-FDG imaging before surgery and postoperative pathology examinations were obtained. The short-axis lymph node diameter was measured, and the maximum standardized uptake value (SUV_max) and the percentage difference of SUV_max between dual-phase (ΔSUV_max) were calculated to compare metastatic and non-metastatic lymph nodes on dual-time point images.

Results

A total of 398 axillary lymph nodes were inspected, and 209 lymph nodes were matched with those on PET/CT images, including 97 metastatic and 112 non-metastatic lymph nodes. The SUV_max values were significantly different between metastatic and non-metastatic lymph nodes, in both the early and delayed scans (P<0.001). For metastatic lymph nodes, the SUV_max value on the delayed scan (6.17±2.62) was significantly higher compared with the early scan (5.45±1.35; ΔSUV_max =0.08±0.21, P<0.001). Moreover, the SUV_max values were not significantly different between the delayed (2.82±0.91) and early scans (2.79±0.72; ΔSUV_max=-0.00±0.11, P=0.77). The short diameters were not significantly different between metastatic and non-metastatic lymph nodes (P=0.12), and the SUV_max values of metastatic lymph nodes with short diameters of >4.00 and ≤6.00 mm were not significantly different between the early and delayed scans (P=0.06). However, the SUV_max values of metastatic lymph nodes with short diameters of >6.00 and ≤8.00 mm (7.11±0.19 vs. 5.96±0.08) and short diameters of >8.00 and ≤10.00 mm (10.76±0.35 vs. 6.82±0.50) were higher on the delayed scan versus the early scan, respectively (P<0.01 for each comparison). The difference between the ΔSUV_max values among the three subgroups was statistically significant (F=78.98, P<0.001).The receiver operating characteristic (ROC) curve analysis of the lymph nodes showed that the area under the curve (AUC) of the early and delayed PET/CT scans was 0.961 (0.925-0.983, P=0.013) and 0.897 (0.847-0.934, P=0.022), respectively. The ROC curves of the early and delayed scans were also significantly different (z=4.46, P<0.001). AUC of the ΔSUV_max for the early scan was significantly lower compared with delayed scans (z=8.95 vs. 9.13, respectively; P<0.001).

Conclusions

Dual-time point ¹⁸F-FDG PET imaging significantly improved the prediction and detection of axillary lymph node metastasis, compared with prediction based on size of lymph node alone, in patients with stage III breast cancer. We found that lymph nodes with continuously increased SUV_max values tended to show metastasis, and early SUV_max assessment offers the best capacity for prediction of axillary lymph node metastasis.

Evaluation of the AJCC Eighth-Edition Prognostic Staging System for Breast Cancer in a Latin American Cohort

BACKGROUND

The staging of breast cancer has been based on tumor size, lymph node involvement, and presence or absence of distant metastases. The American Joint Committee on Cancer (AJCC) staging system in its eighth edition incorporates hormone receptors, human epidermal growth factor receptor 2 (HER2), and histologic grade due to their prognostic importance. In Latin America, however, the impact of the new edition is unknown. This article evaluates the performance of the AJCC eighth-edition staging system in a cohort of patients with breast cancer at a reference center in Colombia.

METHODS

The study investigated a descriptive cohort of 912 patients who received complete treatment for non-metastatic invasive breast cancer and had information on the anatomic stage and biologic factors,. All the patients were restaged using the AJCC eighth-edition classification. Changes in clinical stages and differences between the two classifications were compared.

RESULTS

The study enrolled 912 patients. Changes in staging occurred for 54.82% (downstaging for 40.3% and upstaging for 14.47%) of these patients. For recurrence-free survival, the C-Index of the eighth-edition AJCC was 0.726, and the AIC was 1323.7, whereas the C-Index of the seventh-edition AJCC was 0.731, and the AIC was 1314.3 (p = 0.99).

CONCLUSIONS

The seventh and eighth editions of the AJCC staging system have similar predictive values in our population for recurrence-free survival. Future studies are necessary to evaluate the performance of the AJCC eighth-edition staging system in predicting overall survival.

Refining breast cancer prognosis by incorporating age at diagnosis into clinical prognostic staging: introduction of a novel online calculator

PURPOSE

American Joint Committee on Cancer (AJCC) clinical staging is used to estimate breast cancer prognosis, but individual patient survival within each stage varies considerably by age at diagnosis. We hypothesized that the addition of age at diagnosis to the staging schema will enable more refined risk stratification.

METHODS

We performed a retrospective population analysis of adult women diagnosed with invasive breast cancer between 2010 and 2015 registered in SEER. Multivariable Cox hazards models were used to evaluate the association of AJCC 8th edition clinical prognostic stage (CPS) and age with risk of overall mortality. Separate hierarchical models were fit to the data: Model 1: CPS alone; Model 2: CPS + age + age²; and Model 3: CPS + age + age² + CPS x age + CPS x age². Models were compared by the Akaike information criterion (AIC), the c-statistic for time-dependent receiver operator characteristic curves, and category-free net reclassification improvement (NRI). Internal validation was performed using bootstrapping samples.

RESULTS

Among 86,637 women, the median follow-up was 36 months and 3-year overall survival was 91.9% ± 0.1%. Age significantly modified the effect of CPS on survival (p < 0.0001). Model 3 was the most precise, with the lowest AIC (126,619.63), the highest c-statistic (0.8212, standard error 0.0187), and superior NRI indices.

CONCLUSION

Age at diagnosis is a highly prognostic variable that warrants consideration for inclusion in future editions of the AJCC Breast Cancer Staging Manual.

Validation of the revised 8th AJCC breast cancer clinical prognostic staging system: analysis of 5321 cases from a single institution

The anatomic stage groups (ASG) have been arguably the most powerful in predicting breast cancer (BC) outcomes. Recognizing the prognostic influence of histologic grade and receptor status, the 8th AJCC mandates their incorporation into the newly established prognostic stage groups (PSG). This staging scheme was subsequently revised to provide pathological and clinical prognostic stage tables (PPSG/CPSG) due to its incapability to categorize a significant subset of BCs, with the former only used for patients having surgical resection as the initial treatment, and the latter for all patients. Given the increasingly used neoadjuvant therapy, PPSG cannot be assigned in a significant proportion of higher staged BCs. In this study, we validated the CPSG in a cohort of 5321 BCs. Compared to ASG, the application of CPSG resulted in assigning 16.1% and 27.2% of cases to a higher or a lower stage group in non-stage IV BCs, respectively. The changes were seen mostly frequently in ASG IB, followed by IIIC, IIB, IIA, IIIA, IIIB, and IA. In 7.9% of cases, the assigned CPSG changed more than one stage group from the ASG. CPSG provided an improved overall discriminating power in predicting BC-specific survival when compared to ASG. Pairwise comparison using the Cox proportional hazard model demonstrated further advantages for CPSG as the latter showed a significant difference in all categories when compared to their proximate groups, except IIA vs. IB and IIIA vs. IIIB. In contrast, a significantly different hazard was only seen when comparing IIB vs. IIA, IIIA vs. IIB, and IV vs. IIIC for ASG. Thus, the revised 8th AJCC CPSG provided a superior overall staging scheme for predicting prognostic outcomes in BC patients receiving standard of care treatment. Further validation using the available data with larger populations and longer follow-up may be needed to refine and improve this table.

Staging for Breast Cancer With Internal Mammary Lymph Nodes Metastasis: Utility of Incorporating Biologic Factors

Purpose

To validate the 8th edition of the American Joint Committee on Cancer (AJCC) pathological prognostic staging system for breast cancer patients with internal mammary lymph nodes (IMN) metastasis (N3b disease, stage IIIC in 7th AJCC anatomical staging).

Methods

Breast cancer patients with IMN metastasis diagnosed between 2010 and 2014 were retrieved from the Surveillance, Epidemiology, and End Results program. Chi-squared test, Log-rank test, Kaplan-Meier method, and Cox proportional hazard analysis were applied to statistical analysis.

Results

We included 678 patients with N3b disease in this study. Overall, 68.4% of patients were downstaged to IIIA and IIIB diseases from the 7th anatomical staging to 8th pathological prognostic staging. The new pathological prognostic staging system had better discriminatory value on prognosis prediction among IMN-metastasized breast cancer patients, with a 5-year breast cancer-specific survival (BCSS) of 92.7, 77.4, and 66.0% in stage IIIA, IIIB, and IIIC diseases, respectively (P<0.0001), and the 5-year overall survival (OS) rates was 85.9, 72.1, and 58.7%, respectively (P<0.0001). The results of the multivariate prognostic analysis showed that the new pathological prognostic staging was the independent prognosis related to BCSS and OS, the 8th AJCC pathological prognostic stages showed worse BCSS and OS with gradually increased hazard ratios.

Conclusion

The 8th AJCC pathological prognostic staging system offers more refined prognostic stratification to IMN-metastasized breast cancer patients and endorses its use in routine clinical practice for this specific subgroup of breast cancer.

Prognostic and Predictive Value of the American Joint Committee on Cancer Pathological Prognostic Staging System in Nodal Micrometastatic Breast Cancer

Introduction

To investigate the prognostic and predictive effect of the American Joint Committee on Cancer (AJCC) 8^th edition pathological prognostic staging system in patients with T1-2N1micM0 breast cancer who underwent mastectomy.

Methods

Data from T1-2N1micM0 breast cancer patients who underwent mastectomy from 2010–2014 were obtained from the Surveillance, Epidemiology, and End Results program. The chi-square test, binomial logistics regression, receiver-operating characteristics curve, competing-risk regression model, Cox proportional hazards regression model, and proportional hazard assumption were used for statistical analyses.

Results

We identified 4,729 patients, including 1,062 patients were received postmastectomy radiotherapy (PMRT). Stage change occurred in 88.2% of the patients, of which 84.4% were downstaged and 3.7% were upstaged. Patients with higher pathological prognostic stages were independently predicted to receive PMRT. The 5-year breast cancer-specific survival (BCSS) was 97.5, 93.7, 90.1, 86.0, and 73.5% in disease stages IA, IB, IIA, IIB, and IIIA, respectively, according to the 8^th edition criteria (P < 0.001). The AJCC 8^th edition demonstrated moderate discriminative ability, and it had a significantly better ability to predict the BCSS than the AJCC 7^th edition criteria (P < 0.001). The multivariate prognostic analysis showed that the new pathological prognostic staging was an independent prognostic factor affecting the BCSS. The BCSS worsened with an increase in the stage. The PMRT did not affect the BCSS regardless of the pathological prognostic stage. Similar trends were found using the competing-risks regression model.

Conclusions

The 8^th AJCC breast cancer pathological prognostic staging system downstaged 84.4% of patients with T1-2N1micM0 disease and the survival outcome prediction with this staging system was more accurate than the AJCC 7^th edition system. Our study does not support using the prognostic stage as a guideline to escalate of PMRT.

Effect of radiotherapy after breast-conserving surgery in elderly patients with early breast cancer according to the AJCC 8th Edition Breast Cancer Staging System in Japan

BACKGROUND

The number of elderly patients in Japan with breast cancer has been gradually increasing. The aim of this study was to determine the efficacy of radiotherapy (RT) after breast-conserving surgery (BCS) for elderly patients with early breast cancer who were restaged according to the 8th Edition Breast Cancer Staging System.

METHODS

We reviewed patients age ≥ 65 years who received BCS and adjuvant RT or BCS alone for breast cancer between 2010 and 2015 in our institution and restaged those patients using the AJCC 8th edition pathological prognostic staging system. We compared relapse-free survival (RFS) and overall survival (OS) rates in the RT group and no RT group.

RESULTS

A total of 170 patients were eligible for analysis: 94 (55.3%) were treated with RT and 76 (44.7%) were treated without RT. Age (p < 0.01) was associated with the use of RT. Adjuvant RT significantly improved RFS (95.75% vs 84.21%, p = 0.02). There was no significant difference between the OS rates in the two groups. Univariate analysis showed that pathologic T stage and N stage were significantly associated with both RFS and OS and that histologic grade, chemotherapy, HER2, and RT were significantly associated with RFS, but not with OS. RT reduced the risk of recurrence (HR = 0.56, 95% CI = 0.19-0.96, p = 0.04).

CONCLUSIONS

RT was associated with significantly improved RFS, but had no significant impact on OS in elderly patients with breast cancer after BCS. Adjuvant RT should be performed even for elderly patients with early breast cancer.

Integration the biologic factors into the staging of breast cancer patients with ipsilateral supraclavicular lymph node metastasis

Purpose: To investigate the accuracy and the discriminatory performance in the prognostic prediction in breast cancer (BC) patients with ipsilateral supraclavicular lymph node (ISLN) metastasis using the between the American Joint Committee on Cancer (AJCC) 7th and 8th edition staging system. Methods: Female patients diagnosed as BC were retrieved from the Surveillance, Epidemiology, and End Results database between 2010 and 2014. Chi-squared test, Kaplan-Meier method, Cox proportional hazard analysis, and the receiver operating characteristics were used to conduct statistical analysis. Results: We included 1097 BC patients with ISLN metastasis (N3c disease), including 29.4% (n=322) and 70.6% (n=775) of patients with non-metastatic and metastatic stage at diagnosis, respectively. In non-metastatic stage patients, 64.9% of the patients categorized as having stage IIIC disease in the 7th edition AJCC staging system were downstaged to stage IIIA or IIIB according to the 8th AJCC staging criteria. The AJCC 8th edition staging system had better discriminatory prognostic value than the 7th AJCC staging (area under the curve: 0.586 vs. 0.577, P=0.0006), with a 5-year breast cancer-specific survival (BCSS) rate of 71.3%, 62.2%, 45.2% and 39.1% in stage IIIA, IIIB, IIIC, and IV cohorts, respectively (P<0.0001). The multivariate prognostic analysis revealed that the AJCC 8th edition staging system was an independent prognostic factor for BCSS, while no statistical difference in BCSS was found between the 8th AJCC stage IIIC and IV patients (P=0.188). Conclusion: The AJCC 8th edition pathological prognostic staging showed a better discriminatory prognostic value in ISLN-metastasized breast cancer patients. An additional clarification strategy in stage IIIC disease based on the 8th AJCC staging should be developed to differentiate patients who are curable with multimodality therapy and patients who have less benefit from curative treatment.

Incorporation of biologic factors for the staging of de novo stage IV breast cancer

This study aimed to investigate the prognostic value of biological factors, including histological grade, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) status in de novo stage IV breast cancer. Based on eligibility, patient data deposited between 2010 and 2014 were collected from the surveillance, epidemiology, and end results database. The receiver operating characteristics curve, Kaplan-Meier analysis, and Cox proportional hazard analysis were used for analysis. We included 8725 patients with a median 3-year breast cancer-specific survival (BCSS) of 52.6%. Higher histologic grade, HER2-negative, ER-negative, and PR-negative disease were significantly associated with lower BCSS in the multivariate prognostic analysis. A risk score staging system separated patients into four risk groups. The risk score was assigned according to a point system: 1 point for grade 3, 1 point if hormone receptor-negative, and 1 point if HER2-negative. The 3-year BCSS was 76.3%, 64.5%, 48.5%, and 23.7% in patients with 0, 1, 2, and 3 points, respectively, with a median BCSS of 72, 52, 35, and 16 months, respectively (P < 0.001). The multivariate prognostic analysis showed that the risk score staging system was an independent prognostic factor associated with BCSS. Patients with a higher risk score had a lower BCSS. Sensitivity analyses replicated similar findings after stratification according to tumor stage, nodal stage, the sites of distant metastasis, and the number of distant metastasis. In conclusion, our risk score staging system shows promise for the prognostic stratification of de novo stage IV breast cancer.

Prognostic value of the AJCC 8th edition staging system for Japanese patients treated with surgery followed by radiotherapy for breast cancer

BACKGROUND

American Joint Committee on Cancer (AJCC) 8th Edition Breast Cancer Staging System, biological information in addition to anatomical information was added as a basis for prognosis evaluation, but its prognostic impact in Japanese patients treated with postoperative radiotherapy has not been discussed. To determine the applicability of the updated prognostic staging system, we evaluated the prognostic value and confirmed the effectiveness of this system in patients in whom postoperative radiotherapy was performed.

MATERIALS AND METHODS

Patients who were treated with postoperative radiotherapy for breast cancer in our institution between January 2011 and December 2015 were restaged by the AJCC 8th pathological prognosis staging system, and then overall survival (OS), disease-free survival (DFS) rates and hazard ratios (HR) were analyzed to compare the predictive fit of the two staging systems.

RESULTS

Five hundred and seven patients who in whom postoperative radiotherapy was performed for breast cancer were enrolled in this study. 36.1% patients were downstaged and 5.3% patients were upstaged from the 7th to 8th editions staging system classification. Kaplan-Meier curves and HRs showed differences in OS and DFS rates between the 7th edition and 8th edition staging systems. The AJCC 8th edition prognostic stage system has a better prognostic prediction of OS and DFS than does the 7th edition anatomic stage system.

CONCLUSIONS

Compared with the 7th edition in breast cancer, AJCC 8th edition prognostic stage system has more precise stratification and superior prognostic value, providing a more accurate reference for the choice of radiotherapy for patients with breast cancer.

Prognostic validation and treatment decision making of the 8th edition of the American Joint Committee on Cancer pathological staging system for elderly women with early-stage breast cancer

Purpose: To determine the prognostication and treatment decision making of the American Joint Committee on Cancer (AJCC) 8^th pathological staging system in elderly women (aged ≥65 years) with T1-2N0M0 breast cancer (BC).

Results: We included 67699 patients, and patients were restaged into stage IA (84.9%), IB (8.9%), and IIA (6.2%) using the 8^th AJCC edition criteria. Overall, 69.4% and 30.6% of them underwent breast-conservation surgery (BCS) and mastectomy (MAST), respectively. In patients who received BCS, 30.3% of them underwent postoperative radiotherapy (RT). Patients with a higher pathological stage were more likely to receive MAST. The 5-year breast cancer-specific mortality rate was 2.2%, 6.5% and 13.7% in stage IA, IB, and IIA, respectively. Patients treated with BCS and RT had significantly lower risk of breast cancer-specific mortality compared to those treated with MAST or with BCS alone regardless of the pathological prognostic stages (P<0.001).

Conclusions: The 8^th AJCC pathological prognostic staging system provides accurate risk stratification and impacts the treatment decision making for elderly women with early-stage BC.

Methods: We identified stage T1-2N0M0 BC patients using the Surveillance, Epidemiology, and End Results database. Statistical analyses were used binomial logistic regression, and multivariable competing risk models in the Cox model framework.

The comparison of the anatomic stage and pathological prognostic stage according to the AJCC 8th edition for the prognosis in Japanese breast cancer patients: data from a single institution

Background

The TNM system, which reflects the anatomical extent of disease, was used for stage definition. In the recently published AJCC 8th edition, the new staging system of the clinical and pathological prognostic stage, which incorporates biological factors, is introduced.

Patients and methods

A total of 2622 patients with primary breast cancer at stage I–III were included in this study. The anatomic stage (aStage) and the pathological prognostic stage (ppStage) for each case were determined according to the definition of the AJCC 8th edition, and the influence of these stages on the prognosis was compared.

Results

The stage distributions of aStage and ppStage were as follows: aStage, stage IA (54.8%), IB (1.1%), IIA (26.1%), IIB (9.2%), IIIA (5.6%), IIIB (0.1%), and IIIC (3.1%); and ppStage, stage IA (66.6%), IB (13.1%), IIA (11.1%), IIB (3.2%), IIIA (3.3%), IIIB (1.4%), and IIIC (1.2%). Compared with the aStage, the ppStage stayed the same in 1710 patients (65.2%), was downstaged in 778 patients (29.7%), and was upstaged in 134 patients. The pathological tumor size (pT2) and lymph node metastasis (pN1) were associated with downstaging, and histological grade 3 was associated with upstaging. ER positivity, PgR positivity, and HER2-positivity were significantly associated with downstaging, and the TN subtype was associated with upstaging. Both the aStage and ppStage were significantly associated with the prognosis; however, the Kaplan–Meier curves for the relapse-free survival (RFS), distant recurrence-free survival (DRFS), and overall survival were better stratified by the ppStage.

Conclusion

The ppStage reflects the prognosis of patients with early breast cancer more accurately than the aStage.

Validation of the 8th edition of the American Joint Committee on Cancer Pathological Prognostic Staging for young breast cancer patients

Purpose: This study aimed to validate the newly proposed American Joint Committee on Cancer (AJCC) pathological prognostic staging system for young breast cancer patients (aged ≤40 years).

Results: We included 12811 women in this study. Overall, 52.8% of patients in the 7^th AJCC stages were restaged to the 8^th AJCC pathological staging system, including 10.7% upstaged and 42.1% downstaged. The receiver operating characteristics analysis showed that the new staging system had a better role in predicting breast cancer-specific survival (BCSS) compared with 7^th edition staging (P<0.001). The results of the multivariate prognostic analysis showed that the hazard ratio of BCSS increased with the 8^th AJCC stages, while the 7^th anatomic stages had no significant difference in BCSS.

Conclusions: The novel pathological staging system could provide more accurate prognostic stratification for young women with breast cancer because of the high proportion of stage migration.

Patients and Methods: Data for young breast cancer patients diagnosed between 2010 and 2014 were included from the Surveillance, Epidemiology, and End Results program. Chi-squared test, Kaplan–Meier method, receiver operating characteristics curve, and Cox proportional hazard analysis were applied to statistical analysis.

Incorporation of clinical and biological factors improves prognostication and reflects contemporary clinical practice

We developed prognostic models for breast cancer-specific survival (BCSS) that consider anatomic stage and other important determinants of prognosis and survival in breast cancer, such as age, grade, and receptor-based subtypes with the intention to demonstrate that these factors, conditional on stage, improve prediction of BCSS. A total of 20,928 patients with stage I–III invasive primary breast cancer treated at The University of Texas MD Anderson Cancer Center between 1990 and 2016, who received surgery as an initial treatment were identified to generate prognostic models by Fine-Gray competing risk regression model. Model predictive accuracy was assessed using Harrell’s C-index. The Aalen–Johansen estimator and a selected Fine–Gray model were used to estimate the 5-year and 10-year BCSS probabilities. The performance of the selected model was evaluated by assessing discrimination and prediction calibration in an external validation dataset of 29,727 patients from the National Comprehensive Cancer Network (NCCN). The inclusion of age, grade, and receptor-based subtype in addition to stage significantly improved the model predictive accuracy (C-index: 0.774 (95% CI 0.755–0.794) vs. 0.692 for stage alone, p < 0.0001). Young age (<40), higher grade, and TNBC subtype were significantly associated with worse BCSS. The selected model showed good discriminative ability but poor calibration when applied to the validation data. After recalibration, the predictions showed good calibration in the training and validation data. More refined BCSS prediction is possible through a model that has been externally validated and includes clinical and biological factors.

Evaluation of the 8th edition of the American joint committee on cancer's pathological staging system in prognosis assessment and treatment decision making for stage T1-2N1 breast cancer after mastectomy

Purpose

The 8th edition of the American Joint Committee on Cancer (AJCC) pathological staging system for breast cancer considers biologic factors in addition to the anatomical features included in the previous systems. The purpose of this study was to determine the validity of the 8th AJCC staging system for T1-2N1 breast cancer and to assess the effect of additional chemotherapy and radiotherapy according to the new pathologic stages.

Methods

The cohort included patients from the Surveillance, Epidemiology, and End Results program (2010–2012) who had stage T1-2N1 invasive breast carcinoma and underwent mastectomy. All patients were restaged using the 8th AJCC staging system. The Kaplan–Meier method, Cox proportional hazards regression, and competing risks models were used for data analysis.

Results

We identified 9908 patients including 3022 (30.5%), 3131 (31.6%), 1940 (19.6%), 1194 (12.1%), and 621 (6.3%) were classified with stage IA, IB, IIA, IIB, and IIIA disease, respectively. The 5-year breast cancer-specific survival (BCSS) was 97.3%, 94.3%, 88.3%, 84.0%, and 71.1% for stage IA, IB, IIA, IIB, and IIIA disease, respectively. Higher pathological stage was associated with a significantly higher risk of breast cancer-related death. Chemotherapy was associated with better BCSS regardless of the pathological stage, but radiotherapy was only associated with better BCSS in stage IIIA disease.

Conclusions

The 8th AJCC pathological staging system provides more refined stratification for T1-2N1 breast cancer patients after mastectomy and may meet the needs of the current trend of individualized decision making for chemotherapy and radiotherapy in this patient subset.

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Higher pathological stage was associated with significantly lower BCSS.

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Chemotherapy was associated with better BCSS regardless of the pathological stage.

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Radiotherapy was associated with better BCSS in only stage IIIA disease.

Comparative Analysis of Proposed Strategies for Incorporating Biologic Factors into Breast Cancer Staging

BACKGROUND

Tumor biology is an important prognostic factor in breast cancer. This study aimed to compare three staging systems incorporating both biologic factors and anatomic staging (AJCC 8th-edition pathologic prognostic staging, Bioscore, and Risk Score) in a large population-based cohort.

METHODS

The Surveillance, Epidemiology and End Results program was used to select patients with primary stages 1-4 breast cancer diagnosed in 2010. Patients with inflammatory carcinoma, those with missing data for biologic factors, and those with stages 1-3 disease not treated with surgery were excluded from the study. Estimates of 5-year disease-specific survival (DSS) were calculated using the Kaplan-Meier method. The Harrel concordance index (C-index) and the Akaike Information Criterion were used to compare each model in terms of predicting DSS.

RESULTS

The study included 21,901 patients with a median age of 60 years. The median follow-up period was 52 months. All the staging models stratified DSS, with a stepwise decrease in DSS for each increase in risk category or score. The C-index of each model incorporating biologic factors was higher than the C-index for anatomic staging alone (C-index: 0.832 vs. 0.856 for AJCC pathologic prognostic staging, 0.856 for Bioscore, and 0.864 for Risk Score, all p < 0.001). The staging systems incorporating biologic factors did not differ significantly in terms of model fit.

CONCLUSION

Staging systems incorporating biologic factors perform better than anatomic staging alone. Implementation of the AJCC 8th-edition pathologic prognostic staging was an important initial step in the inclusion of tumor biology in staging. Given its simplicity and ease of use, the Risk Score should be given consideration as an alternative staging system.

Prognostic validation and therapeutic decision-making of the AJCC eighth pathological prognostic staging for T3N0 breast cancer after mastectomy

BACKGROUND

T3N0 breast cancer might be a distinct clinical and biological entity, with higher heterogeneity and presenting diverse responses to locoregional and systemic therapy. The aim of the current study was to validate the prognostic effect and assess the treatment decision-making of the American Joint Committee on Cancer (AJCC) eighth pathological prognostic staging in T3N0 breast cancer after mastectomy.

METHODS

We retrospectively included 2465 patients with stage T3N0 breast cancer who had undergone mastectomy between 2010 and 2014 using the data from Surveillance, Epidemiology, and End Results program. The primary endpoint of this study was breast cancer-specific survival (BCSS).

RESULTS

Of the entire cohort, 76.0% of patients in the seventh AJCC staging system were restaged to the eighth AJCC pathological prognostic staging system. A total of 1431 (58.1%) and 1175 (47.7%) of them received chemotherapy and postmastectomy radiotherapy (PMRT), respectively. Pathological staging was an independent prognostic factor for BCSS. Using pathological prognostic stage IA as the reference, BCSS gradually became worse with increased hazard ratios. The 5-years BCSS was 96.9%, 95.5%, 91.1%, 85.6%, and 75.5% in pathological prognostic stage IA, IB, IIA, IIB, and IIIA breast cancers, respectively (P < .001). In pathological prognostic stage IA, IB, and IIA breast cancers, the receipt of PMRT or chemotherapy was not correlated with better BCSS. However, PMRT was correlated with better BCSS in pathological prognostic stage IIB disease (P = .006), but not in pathological prognostic IIIA disease. Moreover, chemotherapy was correlated with better BCSS in pathological prognostic stage IIIA disease (P = .006), but not in pathological prognostic stage IIB disease.

CONCLUSIONS

The eighth AJCC pathological prognostic staging system provides more risk stratification of T3N0 breast cancers after mastectomy and might affect individualized decision-making for chemotherapy and PMRT in this patient subset.

Validation of the AJCC prognostic stage for HER2-positive breast cancer in the ShortHER trial

BACKGROUND

The 8th edition of the American Joint Committee on Cancer (AJCC) staging has introduced prognostic stage based on anatomic stage combined with biologic factors. We aimed to validate the prognostic stage in HER2-positive breast cancer patients enrolled in the ShortHER trial.

METHODS

The ShortHER trial randomized 1253 HER2-positive patients to 9 weeks or 1 year of adjuvant trastuzumab combined with chemotherapy. Patients were classified according to the anatomic and the prognostic stage. Distant disease-free survival (DDFS) was calculated from randomization to distant relapse or death.

RESULTS

A total of 1244 patients were included. Compared to anatomic stage, the prognostic stage downstaged 41.6% (n = 517) of patients to a more favorable stage category. Five-year DDFS based on anatomic stage was as follows: IA 96.6%, IB 94.1%, IIA 92.4%, IIB 87.3%, IIIA 81.3%, IIIC 70.5% (P < 0.001). Five-year DDFS according to prognostic stage was as follows: IA 95.7%, IB 91.4%, IIA 86.9%, IIB 85.0%, IIIA 77.6%, IIIC 67.7% (P < 0.001). The C index was similar (0.69209 and 0.69249, P = 0.975). Within anatomic stage I, the outcome was similar for patients treated with 9 weeks or 1 year trastuzumab (5-year DDFS 96.2% and 96.6%, P = 0.856). Within prognostic stage I, the outcome was numerically worse for patients treated with 9 weeks trastuzumab (5-year DDFS 93.7% and 96.3%, P = 0.080).

CONCLUSIONS

The prognostic stage downstaged 41.6% of patients, while maintaining a similar prognostic performance as the anatomic stage. The prognostic stage is valuable in counseling patients and may serve as reference for a clinical trial design. Our data do not support prognostic stage as guidance to de-escalate treatment.

TRIAL REGISTRATION

EUDRACT number: 2007-004326-25; NCI ClinicalTrials.gov number: NCT00629278.

18F-FES PET/CT Influences the Staging and Management of Patients with Newly Diagnosed Estrogen Receptor-Positive Breast Cancer: A Retrospective Comparative Study with 18F-FDG PET/CT

PURPOSE

We compared the clinical value of 16a-18F-fluoro-17b-estradiol (¹⁸F-FES) positron emission tomography (PET)/computed tomography (CT) and ¹⁸F-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) PET/CT and investigated whether and how ¹⁸F-FES PET/CT affects the implemented management of newly diagnosed estrogen receptor positive breast cancer patients.

MATERIALS AND METHODS

We retrospectively analyzed 19 female patients newly diagnosed with immunohistochemistry-confirmed estrogen receptor (ER)-positive breast cancer who underwent ¹⁸F-FES and ¹⁸F-FDG PET/CT within 1 week in our center. The sensitivity of ¹⁸F-FES and ¹⁸F-FDG in diagnosed lesions were compared. To investigate the definite clinical impact of ¹⁸F-FES on managing patients with newly diagnosed ER positive breast cancer, we designed two kinds of questionnaires. Referring physicians completed the first questionnaire based on the ¹⁸F-FDG report to propose the treatment regime, and the second was completed immediately after reviewing the imaging report of ¹⁸F-FES to indicate intended management changes.

RESULTS

In total, 238 lesions were analyzed in 19 patients with newly diagnosed ER-positive breast cancer. Lesion detection was achieved in 216 sites with ¹⁸F-FES PET and in 197 sites with ¹⁸F-FDG PET/CT. These results corresponded to sensitivities of 90.8% for ¹⁸F-FES versus 82.8% for ¹⁸F-FDG PET/CT in diagnosed lesions. Thirty-five physicians were given the questionnaires referring to the treatment strategy, with 27 of them completing both questionnaires. The application of ¹⁸F-FES in addition to ¹⁸F-FDG PET/CT changed the management in 26.3% of the 19 patients with newly diagnosed ER-positive breast cancer.

CONCLUSION

Performing ¹⁸F-FES PET/CT in newly diagnosed ER-positive breast cancer patients increases the value of diagnosis equivocal lesions and treatment management compared with ¹⁸F-FDG PET/CT.

IMPLICATIONS FOR PRACTICE

This study investigated whether 16a-18F-fluoro-17b-estradiol (¹⁸F-FES) positron emission tomography (PET)/computed tomography (CT) affects the clinical management of patients with newly diagnosed estrogen receptor (ER)-positive breast cancer. Physicians completing two questionnaires comparing the clinical impact of 18F-FES and 18F-FDG on individual management plans in patients with newly diagnosed ER-positive breast cancer confirmed that 18F-FES scans led to change in management in 26.3% of the 19 patients with newly diagnosed ER positive breast cancer. This retrospective study indicates the potential impact of 18F-FES PET/CT on intended management of patients with newly diagnosed estrogen receptor positive breast cancer in comparison to 18F-fluoro-2-deoxy-D-glucose PET/CT.

Validation of a Risk Score Incorporating Tumor Characteristics into the American Joint Committee on Cancer Anatomic Stage for Breast Cancer

Purpose

The American Joint Committee on Cancer 8th edition (AJCC8) prognostic stage (PS) was implemented January 1, 2018, but it is complex due to multiple permutations. A North American group proposed a simpler system using the anatomic stage with a risk score system (RSS) of 1 point each for grade 3 tumor and human epithelial growth factor receptor 2 (HER2) and estrogen receptor (ER) negativity. Here we aimed to evaluate this risk score system with our database of Asian breast cancer patients and compare it against the AJCC8 PS.

Methods

Patients diagnosed with breast cancer stage I–IV in 2006–2012 were identified in the SingHealth Joint Breast Cancer Registry. Five-year breast cancer-specific survival (CSS) and overall survival (OS) were calculated for each anatomic stage according to the risk score and compared with the AJCC8 PS.

Results

A total of 6,656 patients were analyzed. The median follow-up was 61 (interquartile range, 37–90) months. There was a high receipt of endocrine therapy (84.6% of ER+ patients), chemotherapy (84.3% of node-positive patients), and trastuzumab (86.0% of HER2+ patients). Within each anatomic stage, there were significant differences in survival in all sub-stages except IIIB. On multivariate analysis, the hazard ratio for negative ER was 1.74 (1.48–2.06), for negative HER2 was 1.49 (1.26–1.74), and for grade 3 was 1.84 (1.55–2.19). On multivariate analysis controlled for age, ethnicity, and receipt of chemotherapy, the RSS (Akaike information criterion [AIC] = 10,649.45; Harrell's Concordance Index [C] = 0.85) was not inferior to the AJCC8 PS (AIC = 10,726.65; C = 0.84) for CSS, nor was the RSS (AIC = 14,714.4; C = 0.82) inferior to the AJCC8 PS (AIC = 14,784.69; C = 0.81) for OS.

Conclusion

The RSS is comparable to the AJCC8 PS for a patient population receiving chemotherapy as well as endocrine- and HER2-targeted therapy and further stratifies stage IV patients.

New and important changes in breast cancer TNM: incorporation of biologic factors into staging

INTRODUCTION

Cancer staging has historically been based solely on the anatomic extent of the tumor (T), spread to lymph nodes (N), and the presence of distant metastases (M). More recently biologic factors have been added to modify TNM stage groups to provide more accurate prognosis for patients. Areas covered: The American Joint Committee on Cancer (AJCC) updated breast cancer staging in 2016 to include T, N, M, tumor grade and expression of estrogen and progesterone receptors and HER2. Addition of these factors changed the stage group for a large fraction of cases compared to prior TNM stage groupings. This updated 'prognostic stage' provides more robust and precise prognosis information. Expert opinion: Inclusion of biological information in staging changes the meaning and the use of stage in clinical practice. This paper reviews the evidence supporting these changes, limitations affecting staging, and discusses the implications for clinical practice and the future of breast cancer staging.