Preventing late recurrence in hormone receptor-positive early breast cancer: a review

Retrospective analysis to validate the CTS5 in patients from El Álamo IV registry and GEICAM adjuvant studies

BACKGROUND

Identifying high-risk of late recurrence (beyond 10 years) in patients with hormone receptor-positive HER2-negative early breast cancer (EBC) is crucial. The Clinical Treatment Score post-5 years (CTS5) score assesses recurrence risk after 5 years of endocrine therapy (ET). This study validated CTS5 as a prognostic tool for late recurrence by examining its association with Distant Recurrence-Free Survival using GEICAM study data and evaluating model calibration.

PATIENTS AND METHODS

We retrospectively analyzed 5739 hormone receptor-positive HER2-negative EBC patients from the El Álamo IV registry (N = 3509, diagnosed between 2002 and 2005) and 4 adjuvant GEICAM studies (N = 2680, conducted between 1996 and 2006). All patients were distant recurrence-free and alive 5 years after starting adjuvant ET.

RESULTS

The CTS5 classified 43.9% of patients as low-risk, 32.2% as intermediate-risk, and 23.9% as high-risk. Significant differences in DR were observed: hazard ratio (HR) for intermediate- vs. low-risk was 2.55 (95% CI, 1.85-3.51, P < .0001), and HR for high- vs. low-risk was 5.77 (95% CI, 4.28-7.78, P < .0001). Similar results were found across subgroups by menopausal status, duration of adjuvant ET, and prior adjuvant chemotherapy (CT). Calibration showed CTS5 overestimated DR rates in low-risk (P = .0314) and high-risk (P < .0001) patients compared to observed rates.

CONCLUSIONS

The CTS5 categorized patients based on late DR risk regardless of menopausal status, ET duration, or CT treatment. However, the model tended to overestimate events, particularly in high-risk groups, especially among those treated with ET for less than 60 months or not receiving CT.

Metastatic recurrence in women diagnosed with non-metastatic breast cancer: a systematic review and meta-analysis

BACKGROUND

To assess proportions of metastatic recurrence in women initially diagnosed with non-metastatic breast cancer by stage at diagnosis, breast cancer subtype, calendar period and age.

METHODS

A systematic search of MEDLINE and Web of Science databases (January 2010-12 May 2022) was conducted. Studies reporting the proportion of distant metastatic recurrence in women with non-metastatic breast cancer were identified and outcomes and characteristics were extracted. Risk of bias was assessed independently by two reviewers. Random-effects meta-analyses of proportions were used to calculate pooled estimates and 95% confidence intervals (CIs).

RESULTS

193 studies covering over 280,000 patients were included in the main analysis. Pooled proportions of metastatic recurrence increased with longer median follow-up time from 12.2% (95% CI 10.5-14.0%) at 1-4 years post diagnosis, 14.3% (95% CI 12.9-15.7%) at 5-9 years to 23.3% (95% CI 20.1-26.8) at 10 years or more. Regional variation was observed with pooled estimates ranging from 11.0% (95% CI 8.5-13.7%) in Europe to 26.4% (95% CI 16.7-37.4%) in Africa (1-4 years follow-up). Proportions of recurrence were higher in studies with diagnosis before 2000 (22.2%, 95% CI 15.1-30.3) compared to studies with diagnosis from 2000 onwards (12.8%, 95% CI 11.7-14.0). At 1-4 years median follow-up, pooled proportions of metastatic recurrence were higher in women with hormone receptor negative (15.2%, 95% CI 12.0-18.7%) compared with receptor positive disease (9.6%, 95% CI 6.2-13.6%) and in women with locally advanced (33.2%, 95% CI 24.7-42.3%) relative to early disease at initial diagnosis (4.8%, 95% CI 2.5-7.8%). Proportions were higher in those under 50 years compared with 70+ years, 18.6% (95% CI 15.9-21.4%) versus 13.3% (95% CI 9.2, 18.0%), respectively. Heterogeneity was high in all meta-analyses and results should be interpreted with caution.

CONCLUSIONS

Higher proportions of metastatic recurrence in patients initially diagnosed at an advanced stage and in earlier calendar period emphasises the importance of early detection and treatment advancements. As the global number of breast cancer survivors increases, research and health policy efforts should be directed towards timely diagnosis and access to effective treatments and care.

STUDY REGISTRATION

PROSPERO CRD42022314500.

MICAL-L2, as an estrogen-responsive gene, is involved in ER-positive breast cancer cell progression and tamoxifen sensitivity via the AKT/mTOR pathway

Endocrine treatment, particularly tamoxifen, has shown significant improvement in the prognosis of patients with estrogen receptor-positive (ER-positive) breast cancer. However, the clinical utility of this treatment is often hindered by the development of endocrine resistance. Therefore, a comprehensive understanding of the underlying mechanisms driving ER-positive breast cancer carcinogenesis and endocrine resistance is crucial to overcome this clinical challenge. In this study, we investigated the expression of MICAL-L2 in ER-positive breast cancer and its impact on patient prognosis. We observed a significant upregulation of MICAL-L2 expression in ER-positive breast cancer, which correlated with a poorer prognosis in these patients. Furthermore, we found that estrogen-ERβ signaling promoted the expression of MICAL-L2. Functionally, our study demonstrated that MICAL-L2 not only played an oncogenic role in ER-positive breast cancer tumorigenesis but also influenced the sensitivity of ER-positive breast cancer cells to tamoxifen. Mechanistically, as an estrogen-responsive gene, MICAL-L2 facilitated the activation of the AKT/mTOR signaling pathway in ER-positive breast cancer cells. Collectively, our findings suggest that MICAL-L2 could serve as a potential prognostic marker for ER-positive breast cancer and represent a promising molecular target for improving endocrine treatment and developing therapeutic approaches for this subtype of breast cancer.

USP46 enhances tamoxifen resistance in breast cancer cells by stabilizing PTBP1 to facilitate glycolysis

Tamoxifen (TAM) is the primary drug for treating estrogen receptor alpha-positive (ER+) breast cancer (BC). However, resistance to TAM can develop in some patients, limiting its therapeutic efficacy. The ubiquitin-specific protease (USP) family has been associated with the development, progression, and drug resistance of various cancers. To explore the role of USPs in TAM resistance in BC, we used qRT-PCR to compare USP expression between TAM-sensitive (MCF-7 and T47D) and TAM-resistant cells (MCF-7R and T47DR). We then modulated USP46 expression and examined its impact on cell proliferation, drug resistance (via CCK-8 and EdU experiments), glycolysis levels (using a glycolysis detection assay), protein interactions (confirmed by co-IP), and protein changes (analyzed through Western blotting). Our findings revealed that USP46 was significantly overexpressed in TAM-resistant BC cells, leading to the inhibition of the ubiquitin degradation of polypyrimidine tract-binding protein 1 (PTBP1). Overexpression of PTBP1 increased the PKM2/PKM1 ratio, promoted glycolysis, and intensified TAM resistance in BC cells. Knockdown of USP46 induced downregulation of PTBP1 protein by promoting its K48-linked ubiquitination, resulting in a decreased PKM2/PKM1 ratio, reduced glycolysis, and heightened TAM sensitivity in BC cells. In conclusion, this study highlights the critical role of the USP46/PTBP1/PKM2 axis in TAM resistance in BC. Targeted therapy against USP46 may represent a promising strategy to improve the prognosis of TAM-resistant patients.