Radiation therapy for primary tumor of de novo stage IV breast cancer

Effect of locoregional surgery in primary tumors on overall survival in patients with de novo stage IV breast cancer: a systematic review and meta-analysis

Background

Due to the controversy in the therapeutic effect of locoregional surgery in primary tumors for patients with de novo stage IV breast cancer, the aim of this study was to evaluate the effect of locoregional surgery on overall survival in patients with de novo stage IV breast cancer.

Methods

A computer-based search of PUBMED, Embase, and American Society of Oncology (ASCO) annual meetings abstracts was conducted to identify the prospective trials of the combination of locoregional surgery in primary tumors and systemic therapy in comparison with standard systemic therapy alone for patients with de novo stage IV breast cancer. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated by universal inverse variance and combined across articles. Random-effects model and subgroup analyses were performed to ascertain the origin of this heterogeneity.

Results

A total of 2029 patients from 8 studies were included, with 1014 patients (49.98%) underwent locoregional surgery in primary tumors (surgery group) and 1015 ones (50.02%) with standard systemic therapy alone (no surgery group). Compared to patients in the no surgery group, participants with ER/PR positive breast cancer in the surgery group had improved overall survival (OS) (HR=0.77, 95%CI 0.55-0.93, P=0.01), and improved locoregional progression-free survival (HR=0.36, 95%CI 0.14-0.95, P=0.04) for all participants in the surgery group. And patients with bone-only metastases in the surgery group had insignificantly favorable OS than those in no surgery group (HR=0.70, 95%CI, 0.47-1.04, P=0.08).

Conclusion

Our study demonstrated that locoregional surgery in primary tumors was associated with improved OS for participants with ER/PR positive de novo stage IV breast cancer, and locoregional surgery in primary tumors could be worthy of clinical recommendation for patients with ER/PR positive de novo stage IV breast cancer.

Locoregional Radiotherapy in Patients with Advanced Breast Cancer Treated with Cyclin-Dependent Kinase 4/6 Inhibitors Based on Real-World Data

BACKGROUND

The use of locoregional radiotherapy (RT) in patients with advanced ER-positive, HER2-negative breast cancer remains a topic of ongoing debate. In this study, we aimed to evaluate the efficacy of locoregional RT in advanced breast cancer patients treated with cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) in a first-line setting.

METHODS

We conducted a retrospective analysis of patients diagnosed with advanced breast cancer between 2018 and 2023 who received treatment with CDK4/6i and underwent locoregional radiotherapy.

RESULTS

Among the 371 patients treated with CDK4/6i as part of their first-line therapy, 23 received locoregional RT either concurrently or sequentially with CDK4/6 inhibitors. Disease progression within the breast occurred in 19 patients (5.1%). Among these cases, five patients had previously undergone breast RT (5/23, 21.7%), while 14 did not (14/348, 4.0%, p = 0.004). All cases of local progression after RT followed palliative doses and were accompanied by early systemic progression. The 2-year PFS in the entire cohort of patients treated with locoregional RT was 65.7% (95% CI: 40.5-82.3%). Notably, patients who received higher RT doses had longer 2-year PFS (83.3%, 95% CI: 27.3-97.5%) than those with palliative RT doses (59.3%, 95% CI: 30.7-79.3%); however, the results were not statistically significant (p = 0.58). Furthermore, the 2-year local control in the entire cohort with locoregional RT was 73.0% (95% CI: 46.5-87.9%). Importantly, no local progression was observed after RT when using high doses.

CONCLUSIONS

The addition of locoregional radiotherapy to first-line CDK4/6 inhibitors warrants further investigation across various clinical scenarios in advanced breast cancer. Palliative radiation regimens delivered early in breast oligoprogression may not always suffice, emphasizing the need for comprehensive studies in this context.

HR+/HER2- de novo metastatic breast cancer: a true peculiar entity?

De novo metastatic breast cancer (dnMBC) accounts for ~6-10% of all breast cancers and for ~30% of MBC with increasing incidence over time. Hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR⁺/HER2^-) tumours are the most frequent subtype with a similar incidence to that observed amongst recurrent MBC (rMBC). Higher frequency of PI3KCA and ARID2 mutations and a lower frequency of ESR1 mutations and of genes involved in DNA damage, as compared with rMBC, have been reported in HR⁺/HER2^- dnMBC; however, these are not correlating with prognosis, whilst tumour mutational burden is inversely correlated with outcome. Bone represents the most frequent metastatic site, being the single site in up to 60% of patients with dnMBC. HR⁺/HER2^- dnMBC has been generally reported to have better outcomes than rMBC, with a median overall survival ranging from 26 months to nearly 5 years in patients with favourable features such as age <40 years and bone-only disease, but not when compared with patients with late recurring disease (≥2-5 years). Analyses of the de novo cohorts within randomized clinical trials and large real-world series report a better outcome after treatment with CDK4/6 inhibitors and endocrine agents as compared to rMBC. Despite the limitations of retrospective studies and controversial results of the randomized trials, locoregional treatment of the primary tumour after response to systemic therapy appears to confer a survival benefit, particularly in patients with favourable prognostic factors. Altogether genomic, biological and clinical findings highlight HR⁺/HER2^- dnMBC as a peculiar entity as compared with rMBC and deserve a dedicated treatment algorithm. This article is part of the Tackling clinical complexity in breast cancer Special Issue: https://www.drugsincontext.com/special_issues/tackling-clinical-complexity-in-breast-cancer/.

An Insight into Molecular Targets of Breast Cancer Brain Metastasis

Brain metastasis is one of the major reasons of death in breast cancer (BC) patients, significantly affecting the quality of life, physical activity, and interdependence on several individuals. There is no clear evidence in scientific literature that depicts an exact mechanism relating to brain metastasis in BC patients. The tendency to develop breast cancer brain metastases (BCBMs) differs by the BC subtype, varying from almost half with triple-negative breast cancer (TNBC) (HER2^- ER^- PR^-), one-third with HER2⁺ (human epidermal growth factor receptor 2-positive, and around one-tenth with luminal subclass (ER⁺ (estrogen positive) or PR⁺ (progesterone positive)) breast cancer. This review focuses on the molecular pathways as possible therapeutic targets of BCBMs and their potent drugs under different stages of clinical trial. In view of increased numbers of clinical trials and systemic studies, the scientific community is hopeful of unraveling the underlying mechanisms of BCBMs that will help in designing an effective treatment regimen with multiple molecular targets.

Biocompatible polymer-modified gold nanocomposites of different shapes as radiation sensitizers

Radiation therapy is a powerful approach for cancer treatment due to its low invasiveness. The development of radiation sensitizers is of great importance as they assist in providing radiation therapy at a low dose. In this study, poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC)-modified gold nanocomposites of different shapes were created using the grafting-to approach to serve as a novel radiation sensitizer with high cellular uptake. The effect of the shape of the nanocomposite on cellular uptake by the breast cancer cell line MCF-7 was also investigated. The PMPC-modified gold nanostars showed the highest cellular uptake compared to the other gold nanocomposites (spheres and rods), whereas cell cytotoxicity was negligible among all candidates. Furthermore, the therapeutic effect of radiation of PMPC-modified nanostars was the highest among all the gold nanocomposites. These results clearly indicate that the shape of the gold nanocomposite is an important parameter for cellular uptake and radiation sensitizing effects in breast cancer cells.