Validation of the AJCC 8th prognostic system for breast cancer in an Asian healthcare setting

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.

Expanding the Staging Criteria for T1-2N0 Hormone-Receptor Positive Breast Cancer Patients Enrolled in TAILORx

BACKGROUND

The American Joint Committee on Cancer (AJCC) 8th edition pathologic prognostic staging (PPS) incorporates anatomic and biologic factors. The OncotypeDX Breast Recurrence Score (RS) was included based on the initial report of the TAILORx trial, with T1-2N0 hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer patients who had a RS < 11 staged as PPS 1A. This study examined whether the RS criteria for PPS 1A can be further expanded using patients enrolled in the TAILORx trial.

METHODS

The TAILORx trial enrolled 10,273 HR+HER2- T1-2N0 patients. Those with incomplete HR-status/grade and T3 disease were excluded for analysis. The recurrence-free interval (RFI) was compared between the patients who did and those who did not fall into the current PPS 1A category using the Kaplan-Meier method.

RESULTS

The study enrolled 9535 patients for analysis. The RS was < 11 in 16.1%, 11-17 in 35.9%, 18-25 in 32.4%, and > 25 in 15.6% of the patients. The majority (91.2%) of the patients (including all the T1N0 patients regardless of RS) were PPS 1A, and 8.8% were not-PPS 1A. The median follow-up time was 95 months. The PPS 1A patients had an 8-year RFI of 94.2%, which was similar to that of the patients with a RS of 11-17 who were not-PPS 1A (91.7%; p = 0.07) and better than that of the patients with a RS ≥ 18 who were not-PPS 1A (85.4% for a RS of 18-25, 76.0% for a RS > 25; both p < 0.01). Similar RFI trends were seen in patients who received endocrine therapy or chemotherapy followed by endocrine therapy.

CONCLUSIONS

Patients with T1-2N0 HR+HER2- breast cancer and a RS < 18 have an RFI similar to that of patients staged as PPS 1A by the current AJCC staging system, regardless of treatment, suggesting that the criteria for PPS 1A can be expanded to include a RS < 18.

Correlation between contrast-enhanced cone-beam breast computed tomography features and prognostic staging in breast cancer

OBJECTIVE

To evaluate whether contrast-enhanced cone-beam breast CT (CE-CBBCT) features can risk-stratify prognostic stage in breast cancer.

METHODS

Overall, 168 biopsy-proven breast cancer patients were analysed: 115 patients in the training set underwent scanning using v. 1.5 CE-CBBCT between August 2019 and December 2019, whereas 53 patients in the test set underwent scanning using v. 1.0 CE-CBBCT between May 2012 and August 2014. All patients were restaged according to the American Joint Committee on Cancer eighth edition prognostic staging system. Following the combination of CE-CBBCT imaging parameters and clinicopathological factors, predictors that were correlated with stratification of prognostic stage via logistic regression were analysed. Predictive performance was assessed according to the area under the receiver operating characteristic curve (AUC). Goodness-of-fit of the models was assessed using the Hosmer-Lemeshow test.

RESULTS

As regards differentiation between prognostic stage (PS) I and II/III, increased tumour-to-breast volume ratio (TBR), rim enhancement pattern, and the presence of penetrating vessels were significant predictors for PS II/III disease (p < 0.05). The AUCs in the training and test sets were 0.967 [95% confidence interval (CI) 0.938-0.996; p < 0.001] and 0.896 (95% CI, 0.809-0.983; p = 0.001), respectively. Two features were selected in the training set of PS II vs III, including tumour volume [odds ratio (OR)=1.817, p = 0.019] and calcification (OR = 4.600, p = 0.040), achieving an AUC of 0.790 (95% CI, 0.636-0.944, p = 0.001). However, there was no significant difference in the test set of PS II vs III (P＞0.05).

CONCLUSION

CE-CBBCT imaging biomarkers may provide a large amount of anatomical and radiobiological information for the pre-operative distinction of prognostic stage.

ADVANCES IN KNOWLEDGE

CE-CBBCT features have distinctive promise for stratification of prognostic stage in breast cancer.

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.

Prognostic elements extraction from documents to detect prognostic stage

For cancer prediction, the prognostic stage is the main factor that helps medical experts to decide the optimal treatment for a patient. The main objective of this study is to predict prognostic stage from the medical records of various health institutions. Total 465 pathological and clinical reports of people living with breast cancer has been collected from India's reputed treatment institutions. Different anatomic and biologic factors are extracted from unstructured medical records using a novel combination of natural language processing (NLP) and fuzzy decision tree (FDT) for prognostic stage detection. This study has extracted the anatomic and biologic factors from medical reports with high accuracy. The average accuracy of the prognostic stage prediction found 93% and 83% in rural and urban regions, respectively. A generalized method for cancer staging with great accuracy in a different medical institution from dissimilar regional areas suggest that the proposed research improves the prognosis of breast cancer.

Information extraction for prognostic stage prediction from breast cancer medical records using NLP and ML

For cancer prediction, the prognostic stage is the main factor that helps medical experts to decide the optimal treatment for a patient. Specialists study prognostic stage information from medical reports, often in an unstructured form, and take a larger review time. The main objective of this study is to suggest a generic clinical decision-unifying staging method to extract the most reliable prognostic stage information of breast cancer from medical records of various health institutions. Additional prognostic elements should be extracted from medical reports to identify the cancer stage for getting an exact measure of cancer and improving care quality. This study has collected 465 pathological and clinical reports of breast cancer sufferers from India's reputed medical institutions. The unstructured records were found distinct from each institute. Anatomic and biologic factors are extracted from medical records using the natural language processing, machine learning and rule-based method for prognostic stage detection. This study has extracted anatomic stage, grade, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) from medical reports with high accuracy and predicted prognostic stage for both regions. The prognostic stage prediction's average accuracy is found 92% and 82% in rural and urban areas, respectively. It was essential to combine biological and anatomical elements under a single prognostic staging method. A generic clinical decision-unifying staging method for prognostic stage detection with great accuracy in various institutions of different regional areas suggests that the proposed research improves the prognosis of breast cancer.

The Will Rogers phenomenon, breast cancer and race

BACKGROUND

The Will Rogers phenomenon [WRP] describes an apparent improvement in outcome for patients' group due to tumor grade reclassification. Staging of cancers is important to select appropriate treatment and to estimate prognosis. The WRP has been described as one of the most important biases limiting the use of historical cohorts when comparing survival or treatment. The main purpose of this study is to assess whether the WRP exists with the move from the AJCC 7th to AJCC 8th edition in breast cancer [BC] staging, and if racial differences are manifested in the expression of the WRP.

METHODS

This is a retrospective analysis of 300 BC women (2007-2017) at an academic medical center. Overall survival [OS] and disease-free survival [DFS] was estimated by Kaplan-Meier analysis. Bi and multi-variate Cox regression analyses was used to identify racial factors associated with outcomes.

RESULTS

Our patient cohort included 30.3% Caucasians [Whites] and 69.7% African-Americans [Blacks]. Stages I, II, III, and IV were 46.2, 26.3, 23.1, and 4.4% of Whites; 28.7, 43.1, 24.4, and 3.8% of Blacks respectively, in anatomic staging (p = 0.043). In prognostic staging, 52.8, 18.7, 23, and 5.5% were Whites while 35, 17.2, 43.5, and 4.3% were Blacks, respectively (p = 0.011). A total of Whites (45.05% vs. 47.85%) Blacks, upstaged. Whites (16.49% vs. 14.35%) Blacks, downstaged. The remaining, 38.46 and 37.79% patients had their stages unchanged. With a median follow-up of 54 months, the Black patients showed better stage-by-stage 5-year OS rates using 8th edition compared to the 7th edition (p = 0.000). Among the Whites, those who were stage IIIA in the 7th but became stage IB in the 8th had a better prognosis than stages IIA and IIB in the 8th (p = 0.000). The 8th showed complex results (p = 0.176) compared to DFS estimated using the 7th edition (p = 0.004).

CONCLUSION

The WRP exists with significant variability in the move from the AJCC 7th to the 8th edition in BC staging (both White and Black patients). We suggest that caution needs to be exercised when results are compared across staging systems to account for the WRP in the interpretation of the data.

A critical analysis of the 8th edition TNM staging for head and neck cutaneous squamous cell carcinoma with lymph node metastases and comparison to N1S3 stage and ITEM risk score: A multicenter study

BACKGROUND AND OBJECTIVES

We performed a critical analysis of the 8th edition American Joint Committee on Cancer (AJCC) staging for head and neck cutaneous squamous cell carcinoma (HNcSCC) with nodal metastases and compared the performance to the N1S3 and ITEM systems.

METHODS

Multicenter study of 990 patients with metastatic HNcSCC treated with curative intent. The end points of interest were disease-specific (DSS) and overall survival (OS). Model fit was evaluated using Harrell's Concordance Index (C-index), proportion of variation explained (PVE), Akaike information criterion, and Bayesian information criterion.

RESULTS

N1S3 and ITEM demonstrated good distribution into risk categories in contrast to the AJCC system, which classified the majority (90.6%) of patients as N2-3 and Stage IV due to the high rate of extranodal extension. The N2c and N3a categories appeared redundant. There was considerable discordance between systems in risk allocation on an individual patient basis. N1S3 was the best performed (DSS: C-index 0.62, PVE 10.9%; OS: C-index 0.59, PVE 4.5%), albeit with relatively poor predictive value.

CONCLUSIONS

The AJCC N category and tumor node metastasis stage have poor patient distribution and predictive performance in HNcSCC. The AJCC stage, N1S3, and ITEM score all provide limited prognostic information based on objective measures highlighting the need to develop a staging system specific to HNcSCC.

Validation of the Prognostic Stage of American Joint Committee on Cancer Eighth Edition Staging Manual in Invasive Lobular Carcinoma Compared to Invasive Ductal Carcinoma and Proposal of a Novel Score System

Purpose: The objective of this study was to evaluate the American Joint Committee on Cancer (AJCC) pathological prognostic stage among patients with invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) and to propose a modified score system if necessary.

Methods: Women diagnosed with IDC and ILC during 2010–2015 in the Surveillance, Epidemiology, and End Results (SEER) database were retrospectively identified. Disease-specific survival (DSS) and overall survival (OS) were estimated by Kaplan–Meier method. Predictive performances of different staging systems were evaluated based on Harrell concordance index (C-index) and Akaike Information Criterion (AIC). Multivariate Cox models were conducted to build preferable score systems.

Results: A total of 184,541 female patients were included in the final analyses, with a median follow-up of 30.0 months. In IDC cohort, the pathological prognostic stage (C-index, 0.8281; AIC, 110274.5) was superior to the anatomic stage (C-index, 0.8125; AIC, 112537.0; P < 0.001 for C-index) in risk stratification with respect to DSS. In ILC cohort, the prognostic stage (C-index, 0.8281; AIC, 7124.423) didn't outperform the anatomic stage (C-index, 0.8324; AIC, 7144.818; P = 0.748 for C-index) with respect to DSS. Similar results were observed with respect to OS. The score system defined by anatomic stage plus grade plus estrogen receptor and progesterone receptor (AS+GEP) allows for better staging (C-index, 0.8085; AIC, 7178.448) for ILC patients.

Conclusion: Compared with anatomic stage, the pathological prognostic stage provided more accurate stratification for patients with IDC, but not for patients with ILC. The AS+GEP score system may fit ILC tumors better.

Improved Prognostication for the Updated AJCC Breast Cancer Pathological Prognostic Staging Varied in Higher-Stage Groups

BACKGROUND

In addition to TNM-based anatomical staging (AS), a novel pathological prognostic staging (PPS) has been proposed by the American Joint Committee on Cancer (AJCC). PPS demonstrated better prognostication, but its superiority in breast cancer subtypes and related to staging discrepancies between AS and PPS are not clear.

METHODS

A cohort of 1729 patients with breast cancer was staged into AS and PPS according to the latest AJCC staging. Patient characteristic and restaging outcomes were compared.

RESULTS

Compared with AS, 799 and 135 cases were upstaged and downstaged respectively in PPS, mostly involved stage I cases. For the overall cohort, PPS demonstrated superior prognostic power over AS in both disease-free survival (DFS) and breast cancer-specific survival. However, such superiority was found mainly in estrogen receptor (ER)/progesterone receptor (PR)+ but not ER-PR- cancers. Comparing the restaged cases within the same PPS, PPS 1A cases showed similar survival irrespective of the original AS. Interestingly, in other PPS groups (PPS 1B and higher), there was a difference in outcome among patients with same PPS but different AS. Within PPS 1B patients, downstaged cases from higher AS showed worse DFS (3A>1B vs. 2A>1B: χ² = 4.732, P = .030).

CONCLUSIONS

PPS may provide a more accurate prognostication, mostly among ER/PR+ cancers and with PPS 1A patients. Patients restaged to higher PPS stages showed significant differential survival even within the same PPS. Also, only limited improvement was observed for ER-PR- cancers. Caution needs to be exercised in using PPS for patient prognostication, as in some cases the outcome can be variable with the same PPS.

Assessment of the Prognostic Staging System of American Joint Committee on Cancer 8th Edition for Breast Cancer: Comparisons with the Conventional Anatomic Staging System

Purpose

The 8th edition of the American Joint Committee on Cancer (AJCC) staging manual introduced a new prognostic staging system for breast cancer. This study aimed to evaluate the changes in staging distribution and predictive power of the new staging system.

Methods

Of the 12,275 patients with breast cancer identified from the Severance Breast Cancer Registry who underwent surgery between 1978 and 2016, 12,125 patients met the inclusion criteria.

Results

In both the 7th and 8th staging systems, stage I patients constituted the largest proportion (38.2% and 48.4%). Migration from the 7th to 8th edition of the AJCC manual resulted in a decrease in stage II population and an increase in stage I and III populations. A total of 1,293 (15.4%) patients were upstaged, and 1,201 (14.3%) were downstaged. Downstaged patients had better recurrence-free and overall survival (p < 0.001). Pathologic complete response after neoadjuvant therapy showed good prognosis as p stage 0, and yp stages I and III showed poorer outcomes than the same p stage (p < 0.001).

Conclusions

Staging migrations are common in early breast cancer under the prognostic staging system. The prognostic staging system of the 8th edition of the AJCC manual discriminates survival outcomes better than the anatomical staging system of the 7th edition of the AJCC manual.

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.

Insights Into Breast Cancer in the East vs the West: A Review

Importance

During the past few decades, the incidence of breast cancer (BC) has been increasing rapidly in East Asia, and BC is currently the most common cancer in several countries. The rising incidence is likely related to changing lifestyle and environmental factors in addition to the increase in early diagnosis with BC awareness and screening. The understanding and management of BC are generally based on research and data from the West. However, emerging differences in BC epidemiology and tumor and host biology in Asian populations may be clinically relevant.

Observations

A higher proportion of premenopausal BCs occur in Asia, although this factor is possibly an age-cohort effect. Although the relative frequencies of different immunohistochemical subtypes of BC may be similar between the East and West, the higher prevalence of luminal B subtypes with more frequent mutations in TP53 may be confounded by disparities in early detection. In addition, Asian BCs appear to harbor a more immune-active microenvironment than BCs in the West. The spectra of germline mutations in BC predisposition genes and single-nucleotide polymorphisms contributing to BC risk vary with ethnicity as well. Differences in tolerability of certain cytotoxic and targeted agents used in BC treatment may be associated with pharmacogenomic factors, whereas the lower body mass of the average woman in East Asia may contribute to higher toxicities from drugs administered at fixed doses. Phenotypic characteristics, such as lower breast volume, may influence the type of surgery performed in East Asian women. On the other hand, increased breast density may affect the sensitivity of mammography in detecting BCs, limiting the benefits of screening mammography.

Conclusions and Relevance

Breast cancer has become a major health problem in Asia. The inclusion of more women from Asia in clinical trials and epidemiologic and translational studies may help unravel the interethnic heterogeneity of BCs and elucidate the complex interplay between environmental and intrinsic factors in its pathogenesis. These insights may help to refine prevention, diagnosis, and management strategies for BC in the setting of ethnic diversity.

Impact of biomarkers and genetic profiling on breast cancer prognostication: A comparative analysis of the 8th edition of breast cancer staging system

The 8th edition of the American Joint Committee on Cancer (AJCC) staging guidelines combine traditional TNM system with biomarkers to reflect our current understanding of tumor biology and targeted therapy. In this study, we investigated the impact of the TNM + Biomarkers staging system and the additive value of Oncotype Dx™ genomic profile recurrence score (RS) (TNM + Biomarkers+RS <11) for the staging of breast cancer (BC) using data from two tertiary referral cancer centers. Compared to TNM alone, the TNM + Biomarkers system changed the stage group in 32.7% of BCs (27% downstage, 5.7% upstage). Most (98.3%) of the downstaged BCs were estrogen receptor (ER)+/progesterone receptor (PR)+, whereas 78% of the upstaged BCs were ER-/PR-/human epidermal growth factor receptor 2 (HER2)-. Compared to TNM + Biomarkers staging, the addition of genetic profile data (TNM + Biomarker+RS <11) downstaged only <1% BCs. Our analysis suggests that for T1-T2N0 ER+/HER2- BCs, Oncotype Dx™ RS <11 provides added value as a staging parameter only in a very small group of cases compared to TNM + Biomarkers alone.

Evaluation of the Incorporation of Recurrence Score into the American Joint Committee on Cancer Eighth Edition Staging System in Patients with T1-2N0M0, Estrogen Receptor-Positive, Human Epidermal Growth Receptor 2-Negative Invasive Breast Cancer: A Population-Based Analysis

BACKGROUND

The current study aimed to evaluate the predictive performance of the American Joint Committee on Cancer eighth edition staging system in patients with invasive breast cancer based on the Surveillance, Epidemiology, and End Results database.

SUBJECTS, MATERIALS, AND METHODS

Patients diagnosed with T1-2N0M0, estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer from 2010 to 2014 were retrospectively recruited in this analysis. Patients were reassigned to different stages according to the anatomic staging system (AS), prognostic staging system (PS), and prognostic and genomic staging criteria downstaging patients with recurrence score (RS) lower than 11 (PGS_RS11). Cox models were conducted for multivariate analyses, and likelihood ratio (LR) χ², Akaike information criterion (AIC), and Harrell's concordance index (C-index) were calculated for the comparison of different staging systems. Additionally, adjustments were made to generate prognostic and genomic staging criteria downstaging patients with RS lower than 18 (PGS_RS18) and RS lower than 25 (PGS_RS25).

RESULTS

PGS_RS11 was an independent predictor for breast cancer-specific survival, as were PS and AS. Adjusted for age and ethnicity, PGS_RS11 (AIC = 2,322.763, C-index = 0.7482, LR χ² = 113.17) showed superiority in predicting survival outcomes and discriminating patients compared with AS (AIC = 2,369.132, C-index = 0.6986, LR χ² = 60.80) but didn't outperform PS (AIC = 2,320.992, C-index = 0.7487, LR χ² = 114.94). The predictive and discriminative ability of PGS_RS18 was the best (AIC = 2297.434, C-index = 0.7828, LR χ² = 138.50) when compared with PS and PGS_RS11.

CONCLUSION

PGS_RS11 was superior to AS but comparable with PS in predicting prognosis. Further validations and refinements are needed for the better incorporation of RS into staging systems.

IMPLICATIONS FOR PRACTICE

Staging systems are of critical importance in informing prognosis and guiding treatment. This study's objective was to evaluate the newly proposed staging system in the American Joint Committee on Cancer eighth edition staging manual, which combined biological and genomic information with the traditional TNM classification for the first time to determine tumor stages of breast cancer. The superiority of the prognostic and genomic staging system was validated in our cohort and possibly could encourage the utility of genomic assays in clinical practice for staging assessment and prognosis prediction.

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.