Biological subtype predicts locoregional recurrence after postmastectomy radiotherapy in Chinese breast cancer patients

Molecular subtypes of breast cancer predicting clinical benefits of radiotherapy after breast-conserving surgery: a propensity-score-matched cohort study

BACKGROUND

Based on the molecular expression of cancer cells, molecular subtypes of breast cancer have been applied to classify patients for predicting clinical outcomes and prognosis. However, further evidence is needed regarding the influence of molecular subtypes on the efficacy of radiotherapy (RT) after breast-conserving surgery (BCS), particularly in a population-based context. Hence, the present study employed a propensity-score-matched cohort design to investigate the potential role of molecular subtypes in stratifying patient outcomes for post-BCS RT and to identify the specific clinical benefits that may emerge.

METHODS

From 2006 to 2019, the present study included 59,502 breast cancer patients who underwent BCS from the Taiwan National Health Insurance Research Database. Propensity scores were utilized to match confounding variables between patients with and without RT within each subtype of breast cancer, namely luminal A, luminal B/HER2-negative, luminal B/HER2-positive, basal-like, and HER2-enriched ones. Several clinical outcomes were assessed, in terms of local recurrence (LR), regional recurrence (RR), distant metastasis (DM), disease-free survival (DFS), and overall survival (OS).

RESULTS

After post-BCS RT, patients with luminal A and luminal B/HER2-positive breast cancers exhibited a decrease in LR (adjusted hazard ratio [aHR] = 0.18, p < 0.0001; and, 0.24, p = 0.0049, respectively). Furthermore, reduced RR and improved DFS were observed in patients with luminal A (aHR = 0.15, p = 0.0004; and 0.29, p < 0.0001), luminal B/HER2-negative (aHR = 0.06, p = 0.0093; and, 0.46, p = 0.028), and luminal B/HER2-positive (aHR = 0.14, p = 0.01; and, 0.38, p < 0.0001) breast cancers. Notably, OS benefits were found in patients with luminal A (aHR = 0.62, p = 0.002), luminal B/HER2-negative (aHR = 0.30, p < 0.0001), basal-like (aHR = 0.40, p < 0.0001), and HER2-enriched (aHR = 0.50, p = 0.03), but not luminal B/HER2-positive diseases. Remarkably, when considering DM, luminal A patients who received RT demonstrated a lower cumulative incidence of DM than those without RT (p = 0.02).

CONCLUSION

In patients with luminal A breast cancer who undergo BCS, RT could decrease the likelihood of tumor metastasis. After RT, the tumor's hormone receptor status may predict tumor control regarding LR, RR, and DFS. Besides, the HER2 status of luminal breast cancer patients may serve as an additional predictor of OS after post-BCS RT. However, further prospective studies are required to validate these findings.

Long-term outcomes of non-metastatic breast cancer patients by molecular subtypes

Background

Today, with the progress of medical sciences, increasing the cure probability and survival time is an important goal of cancer treatment. This study compared long-term disease-free survival (DFS) of non-metastatic breast cancer patients based on different molecular subtypes.

Methods

This retrospective cohort study consisted of 1287 patients diagnosed with breast cancer and treated at Motamed Cancer Institute from 2000 to 2016 and followed up until 2018. Kaplan–Meier curve was fitted to data based on molecular subtypes. Then the semi-parametric mixture cure model was applied to determine the survival and cure probability of molecular subtypes by adjusting clinical and demographic factors.

Results

Among 1287 breast cancer patients, 200 (15.5%) cases died. The mean age of patients was 47.00 ± 10.72 years. Women with the HR+/HER2-subtype had the best 5-year survival rate (84.2%), whereas other subtypes had a lower rate as follows: HR+/HER2+ (77.3%), triple-negative (76.5%), and HR−/HER2+ (62.3%). Kaplan–Meier curve calculated a cure rate of about 60% and patients who survived more than 150 months were intuitively considered cured. After adjustment for clinical and demographic variables, the cure probability of HR−/Her2+ patients was substantially lower than HR+/HER2– patients (OR = 0.22), though there were no significant variations in short-term DFS based on molecular subtypes (HR = 0.91).

Conclusions

Our results confirm that the most prevalent breast cancer was HR+/HER2− tumor type which had the best prognosis. It is also concluded that HR−/HER2+ patients had the worst outcomes, with the highest rates of recurrence and metastasis and the lowest overall and disease-free survival rates.

Real-World Practice of Hypofractionated Radiotherapy in Patients With Invasive Breast Cancer

Purpose

Application of hypofractionated radiotherapy (HFRT) is growing in patients with breast cancer (BC). This study aimed to explore a real-world practice of HFRT in early and locally advanced BC.

Methods

Patients with invasive BC between 2015 and 2019 were retrospectively reviewed. Radiotherapy (RT) was delivered by HFRT and conventionally fractionated radiotherapy (CFRT). Locoregional recurrence-free survival (LRRFS) and disease-free survival (DFS) were calculated by Kaplan–Meier curve and compared by Log-rank test. The effect of treatment modality on DFS was estimated by univariate and multivariable analyses.

Results

A total of 1,010 patients were included in this study, and 903 (89.4%) were treated with HFRT. At a median follow-up of 49.5 months, there was no significant difference in a 4-year cumulative incidence of LRRFS in HFRT group (1.5%) and in CFRT group (3.8%) (p = 0.23), neither in different nodal stages nor in N2–3 patients with different molecular subtypes. The 4-year DFS was 93.5% in HFRT group compared with 89.9% in CFRT group with no significant difference either (p = 0.17). Univariate and multivariable analyses also showed no significant difference in DFS between HFRT and CFRT group. However, DFS of HFRT group tended to be lower in N2–3 patients with triple negative BC compared with that of CFRT group (76.2% versus 100%).

Conclusion

HFRT can achieve similar cumulative incidence of LRRFS and DFS in patients with BC after lumpectomy or mastectomy, and also in different nodal stage, and in locally advanced stage with different molecular subtypes.

Trastuzumab Provides a Comparable Prognosis in Patients With HER2-Positive Breast Cancer to Those With HER2-Negative Breast Cancer: Post Hoc Analyses of a Randomized Controlled Trial of Post-Mastectomy Hypofractionated Radiotherapy

Background and Purpose

We investigated the locoregional effect of trastuzumab, and determined whether patients with human epidermal growth factor receptor (HER)2-positive breast cancer (BC) treated with trastuzumab could achieve comparable efficacy to that of patients with HER2-negative BC.

Materials and Methods

This was post hoc analyses of data of 793 BC patients from a randomized controlled trial comparing post-mastectomy hypofractionated radiotherapy with conventional fractionated radiotherapy. Survival rates were analyzed by the Kaplan–Meier method and compared by the log-rank test.

Results

Patients were classified into three groups: HER2-negative (HER2⁻; n = 547), HER2-positve with trastuzumab (HER2⁺ + T; n = 136), and HER2-positive without trastuzumab (HER2⁺ − T; n = 110). The HER2⁺ + T group had significantly lower locoregional recurrence (LRR, 6.0% vs. 13.9%), distant metastasis (DM, 17.4% vs. 33.8%) and higher disease-free survival (DFS, 81.2% vs. 61.9%) at 5 years than that of the HER2⁺ − T group (P <.05). The HER2⁻ group had significantly lower LRR (6.8% vs. 13.9%), DM (22.4% vs. 33.8%) and higher DFS (76.1% vs. 61.9%) at 5 years than that of the HER2⁺ − T group (P <.05). The difference in LRR, DM and DFS at 5 years was not significant between the HER2⁺ + T group and HER2⁻ group (P >.05). Different annual LRR patterns was found among groups according to HR status.

Conclusion

Trastuzumab reduces LRR in patients with locally advanced HER2-positive BC who have received post-mastectomy radiotherapy. It provides comparable DFS to that with patients with HER2-negative BC.

Intraoperative radiotherapy versus whole-breast external beam radiotherapy, and other factors associated with the prognosis of early breast cancer treated with breast-conserving surgery and radiotherapy: a retrospective study from SEER database

BACKGROUND

This study was aimed to investigate the prognostic factors of early breast cancer treated with breast-conserving surgery (BCS) and radiotherapy. Besides, we focused our attention exclusively on the comparison of the impact on prognosis between intraoperative radiotherapy (IORT) and whole-breast external beam radiotherapy (EBRT).

METHODS

An observational cohort study was performed on patients with Tis-2 N0-1 M0 breast cancer from the Surveillance, Epidemiology, and End Results (SEER) database who treated with BCS and radiotherapy. Cox regression analysis, Kaplan-Meier analysis, and propensity score matching (PSM) were used to estimate risk factors for overall survival (OS) and breast cancer-specific survival (BCSS).

RESULTS

Of the 98,614 early breast cancer patients treated with BCS and radiotherapy, 97,164 (98.5%) patients underwent EBRT and 1,450 (1.5%) underwent IORT. Multivariable Cox regression analysis showed that early breast cancer patients with age ≥65, poor marital status, lack of medical insurance, histological grade III/IV (SEER 4 grades), high T stage, high N stage, and TNBC were associated with a decreased OS/BCSS, whereas ER-positive and PR-positive were associated with an improved OS/BCSS. No significant difference was observed in survival between IORT and EBRT groups (P=0.213 for OS, P=0.180 for BCSS), or between intraoperative beam radiation and intraoperative radioactive implants groups (P=0.319 for OS, P=0.972 for BCSS).

CONCLUSIONS

Our study can help clinicians identify patients with poor prognosis after breast-conserving therapy. IORT may be an alternative to EBRT for early breast cancer patients who are unable to complete the long-term postoperative radiation treatment. Beam radiation and radioactive implants are both ideal alternatives for patients who choose IORT.

PD-1/PD-L1 counterattack alliance: multiple strategies for treating triple-negative breast cancer

Despite extensive research into adjuvant and neoadjuvant chemotherapy, triple-negative breast cancer (TNBC) remains a common breast cancer (BC) subtype with poor prognosis. Given that it has higher immune cell infiltration, theoretically, it should be a protagonist of potential BC immunotherapies. However, only mild responses have been observed in monotherapy with anti-programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) antibodies. In this review, we reappraise PD-1/PD-L1 inhibitor combination immunotherapy and effective experimental compounds, focusing the level of PD-L1 expression, neoantigens, abnormal signaling pathways, and tumor microenvironment signatures, to provide guidance for future clinical trials based on the molecular mechanisms involved.

Biological subtype predicts locoregional recurrence after postmastectomy radiotherapy in Chinese breast cancer patients

Aim

To investigate the impact of biological subtypes in locoregional recurrence in Chinese breast cancer patients receiving postmastectomy radiotherapy (PMRT).

Methods and Materials

About 583 patients who received postmastectomy radiation between 2010 and 2012 were retrospectively analyzed. According to immunohistochemical staining profile, patients were classified into: Luminal A‐like, Luminal B‐like, HER2‐positive, and triple‐negative breast cancer (TNBC). Local and regional recurrence (LRR) cumulative incidences were calculated by competing risks methodology and the power of prognostic factors was examined by Gray's test and the test of Fine and Gray.

Results

The median follow‐up was 70.9 months. About 34 LRR events occurred. For Luminal A, Luminal B, HER2‐positive, and TNBC patients, the 5‐year LRR cumulative incidence rates were 1.57%, 4.09%, 10.74%, and 10.28%. Compared with Luminal A, HER2‐positive subtype and TNBC had a significant increased risk of LRR (HR was 5.034 and 5.188, respectively). In univariate analysis, predictive factors for higher LRR were HER2‐positive subtype (HR = 4.43, P < .05), TNBC (HR = 4.70, P < .05), and pN3 (HR = 5.83, P < .05). In the multivariate model, HER2‐positive subtype (HR = 5.034, P < .05), TNBC (HR = 5.188, P < .05), and pN3 (HR = 9.607, P < .01) were independent predictors of LRR. LRR without trastuzumab was similar to that of TNBC (without vs TNBC, 17.88% vs 10.28%, P > .05) in HER2‐positive subtype patients, while LRR with trastuzumab was approximate to Luminal A (with vs Luminal A, P > .05). Additionally, endocrine therapy also significantly reduced LRR incidence in the luminal subtype cohort (without vs with therapy, 6.25% vs 2.89%, HR = 0.365, P < .1).

Conclusions

Biological subtype was a prognostic factor of LRR in the PMRT setting among Chinese breast cancer patients.