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

The Added Prognostic Value of Oncotype Recurrence Score to AJCC Prognostic Staging System in Stage III ER+/HER2- Breast Cancer

INTRODUCTION

Prognostic prediction based on prognostic stage (PS) with the Oncotype DX recurrence score (RS) has not been validated in stage III ER+/HER2- breast cancer. This study aimed to evaluate the added prognostic significance of RS incorporated with the PS system and to compare the prognostic prediction improvement with anatomic TNM stage (AS) using nomogram construction.

METHODS

The SEER database was indexed to identify ER+/HER2- invasive ductal or lobular breast cancer in AS IIIA-IIIC with RS results diagnosed from 2004 to 2013. Patients with RS < 18, 18-30 and > 30 were categorized into low-, intermediate- and high-risk RS groups. Comparisons of the distribution of clinical-pathologic characteristics among RS risk groups were performed using Pearson's chi-square test. Breast cancer-specific survival (BCSS) was estimated using the Kaplan-Meier method and compared across RS or PS by log-rank test. Cox regression was used to evaluate the factors independently related to BCSS. A nomogram comprised of PS and RS was constructed with discrimination, calibration and clinical benefit evaluated.

RESULTS

Altogether 629 patients who received RS were enrolled. There were 326 cases (51.8%) with low-risk RS, 237 (37.7%) with intermediate-risk RS and 66 (10.5%) with high-risk RS; 344 patients (54.7%) had PS IB, 84 (13.4%) had IIB, 150 (23.8%) had IIIA, 46 (7.3%) had IIIB, and only 5 had (0.8%) IIIC. Both PS and RS were independent prognostic factors for BCSS. There were significant or trends of differences in survival among RS within subtypes stratified by PS. There were significant differences in survival among PS only within intermediate-risk RS. A nomogram prediction 5-year BCSS was constructed with a c-index of 0.811. Lower histologic grade, positive PR and fewer positive lymph nodes were independently correlated with low-risk RS.

CONCLUSION

PS incorporated with RS had improved prognostic significance for stage III ER+/HER 2- breast cancer.

The Predictive Effect of the 8th AJCC Pathological Prognostic Staging on the Benefit of Postmastectomy Radiotherapy in N2/N3 Breast Cancer

Background

The role of the 8th American Joint Committee on Cancer (AJCC) pathological prognostic staging (PPS) on treatment-decision making of breast cancer (BC) remains unclear. This study aimed to investigate the predictive effect of the 8th AJCC PPS on the benefit of postmastectomy radiotherapy (PMRT) in N2/N3 BC.

Methods

We included women with stage N2/3 BC diagnosed between 2010 and 2018 from the Surveillance, Epidemiology, and End Results database. The effect of PMRT on breast cancer-specific survival (BCSS) was evaluated using the multivariate Cox proportional-hazards models.

Results

A total of 13,445 patients were identified, including 10,547 (78.4%) patients treated with PMRT. All patients had reassigned stages based on the 8th AJCC PPS. There were 7102 patients (52.8%) that had stage changed, including 1160 patients (8.6%) were upstaged and 5942 patients (44.2%) were downstaged from the 7th AJCC anatomical staging (AS) to the 8th AJCC PPS. Regarding the 7th AJCC AS, 7603 (56.5%), 948 (7.1%), and 4895 (36.4%) were stage IIIA, IIIB, and IIIC diseases, respectively. Using the 8th AJCC PPS, 3525 (26.2%), 460 (3.4%), 1335 (9.9%), 3457 (25.7%), 2169 (19.1%), and 2100 (15.6%) patients were restaged as IB, IIA, IIB, IIIA, IIIB, and IIIC diseases, respectively. The PPS displayed increased prognostic accuracy and improved model fit with respect to BCSS compared to the 7th AS (C-index, 0.731 vs 0.605, P < 0.001; Akaike Information Criterion, 42141 vs 43118). Regarding the AS, the receipt of PMRT was associated with a better BCSS in those with stage IIIA (P = 0.004), IIIB (P = 0.003), and IIIC (P < 0.001) diseases. Using the PPS, the receipt of PMRT was not associated with a better BCSS among patients with stage IB (P = 0.446), IIA (P = 0.140), and IIB (P = 0.248) disease, while the receipt of PMRT was associated with a better BCSS for those with stage IIIA (P = 0.009), IIIB (P < 0.001), and IIIC (P < 0.001) disease.

Conclusion

The 8th AJCC staging provides superior risk stratification and a better tool to predict the benefit of PMRT in N2/3 BC.

OUP accepted manuscript

Background

Methods

Results

Conclusion

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.

The significance of highlighting the oestrogen receptor low category in breast cancer

The latest ASCO/CAP guideline has recommended to report oestrogen receptor (ER) low cases (ER^lo; 1-10%) as "ER low positive category", prompting us to compare the clinicopathologic features, biomarkers, survival and treatment of the ER^lo cases with other subgroups (ER negative (ER^neg) and ER high (ER^hi)). ER^lo cases revealed more similar clinicopathologic and biomarker profiles (including younger age, larger tumour, high proliferation, HER2 and basal markers expression) to ER^neg than ER^hi cancers. The ER^lo cases receiving hormonal therapy showed a similarly poor outcome as ER^neg cancers. However, majority of ER^lo cases were downstaged to stage I in the 8th AJCC pathological prognostic staging, highlighting a risk of potential under treatment. Overall, our data highlighted the differences of ER^lo from other ER^pos cases and their management should be considered separately.