Survival following radiotherapy in young women with localized early-stage breast cancer according to molecular subtypes

Association of molecular subtypes and treatment with survival in invasive micropapillary breast cancer: an analysis of the Surveillance, Epidemiology, and End Results database

BACKGROUND

This study aims to examine the features, treatments, and survival of invasive micropapillary carcinoma (IMPC) according to different molecular subtypes.

METHODS

In this cohort study, data between 2010 and 2018 were retrospectively reviewed from the Surveillance, Epidemiology, and End Results database. Molecular subtypes were categorized into four varieties: hormone receptor (HR)+/HER2- (Luminal A), HR+/HER2+ (Luminal B), HR-/HER2- [triple-negative (TN)], and HR-/HER2+ (HER2 enriched).

RESULTS

In this study, 1,180 IMPC patients were included, with 99 patients (8.39%) of the 1,180 patients having an overall mortality, and 53 patients (53.54%) of the 99 patients having a breast cancer-specific mortality. The follow-up duration was 40.00 (18.50, 61.00) months. TN molecular subtype was associated with worse OS and BCSS in IMPC patients. Treatment of chemotherapy, radiation, and combination therapy were associated with better survival in HR+/HER2+ molecular subtype and HR+/HER2- molecular subtype. However, in HR-/HER2- molecular subtype, treatment of chemotherapy was associated with a poor BCSS, and treatment of radiation was not associated with OS and BCSS. Surgery treatment was not associated with survival in HR+/HER2+ molecular subtype and HR+/HER2- molecular subtype. However, surgery treatment of mastectomy was associated with better OS in HR-/HER2- molecular subtype (P < 0.05).

CONCLUSION

The prognosis of IMPC was significantly influenced by different molecular subtypes. Chemotherapy and radiotherapy are beneficial in HR+/HER2+ and HR+/HER2- patients. However, they should be used with caution in HR-/HER2- (TN) patients.

Survival comparison between postoperative and preoperative radiotherapy for stage I-III non-inflammatory breast cancer

To compare the survival benefit between preoperative and postoperative radiotherapy for stage I-III non-inflammatory breast cancer patients, we conducted a retrospective cohort study using surveillance, epidemiology and end results databases. Our study recruited patients who had been diagnosed with stage I-III breast cancer and underwent surgery and radiotherapy. The overall survival was calculated by Kaplan-Meier method. Cox risk model was used to determine the impact of radiotherapy according to stage, molecular subtype and other risk factors. Propensity score matching was used to balance measurable confounding factors. Of all the 411,279 enrolled patients varying from 1975 to 2016, 1712 patients received preoperative radiotherapy, and 409,567 patients received postoperative radiotherapy. Compared with the postoperative radiotherapy group, the preoperative radiotherapy group showed significantly higher risks of overall mortality and breast cancer-specific mortality. Survival differences in treatment sequences were correlated with stage, molecular subtypes and other risk factors. According to the results of this study, preoperative radiotherapy did not show a survival advantage, and postoperative radiotherapy is still the primary treatment. However, preoperative radiotherapy also has some theoretical advantages, such as phase reduction and recurrence reduction. Therefore, it is still worthy of further exploration.

GSTP1 c.313A > G mutation is an independent risk factor for neutropenia hematotoxicity induced by anthracycline-/paclitaxel-based chemotherapy in breast cancer patients

Background

The link between glutathione S-transferase P1 (GSTP1) c.313A > G polymorphism and chemotherapy-related adverse events remains controversial. The goal of this study was to assess how this variant affected the toxicity of anthracycline-/paclitaxel-based chemotherapy in patients with breast cancer.

Methods

This study retrospectively investigated pharmacogenetic associations of GSTP1 c.313A > G with chemotherapy-related adverse events in 142 breast cancer patients who received anthracycline and/or paclitaxel chemotherapy.

Results

There were 61 (43.0%), 81 (57.0%), 43 (30.3%), and 99 (69.7%) patients in the T0-T2, T3-T4, N0-N1, and N2-N3 stages, respectively. There were 108 (76.1%) patients in clinical stages I–III and 34 (23.9%) patients in clinical stage IV. The numbers of patients with luminal A, luminal B, HER2 + , and triple-negative breast cancer (TNBC) were 10 (7.0%), 77 (54.2%), 33 (23.2%), and 22 (15.5%), respectively. The numbers of patients who carried GSTP1 c.313A > G A/A, A/G, and G/G genotypes were 94 (66.2%), 45 (31.7%), and 3 (2.1%), respectively. There were no statistically significant differences in the proportion of certain toxicities in patients with A/G, G/G, and A/G + G/G genotypes, except for neutropenia, in which the proportion of patients with A/G + G/G (χ² = 6.586, P = 0.035) genotypes was significantly higher than that with the AA genotype. The logistic regression analysis indicated that GSTP1 c.313A > G mutation (A/G + G/G vs. A/A genotype) (adjusted OR 4.273, 95% CI 1.141–16.000, P = 0.031) was an independent variable associated with neutropenia.

Conclusions

The findings of this study indicate that the GSTP1 c.313A > G mutation is an independent risk factor for neutropenia hematotoxicity in breast cancer patients induced by anthracycline-/paclitaxel-based chemotherapy.

The survival benefit of postmastectomy radiotherapy for breast cancer patients with T1-2N1 disease according to molecular subtype

OBJECTIVE

To evaluate the significance of postmastectomy radiotherapy (PMRT) in female breast cancer patients with T1-2N1M0 disease according to molecular subtypes and other risk factors.

METHOD

We conducted a retrospective cohort-based study utilizing the Surveillance, Epidemiology, and End Results database. Patients who were diagnosed with T1-2N1M0 invasive breast cancer and received mastectomy between 2010 and 2014 were enrolled in our study. Overall survival (OS) was calculated with Kaplan-Meier method, and multivariant Cox hazard model was conducted to identify the impact of PMRT according to molecular subtypes and other risk factors. Propensity score matching (PSM) was applied to balance measurable confounders.

RESULTS

Of all the 16,521 enrolled patients, 5775 (35.0%) cases received PMRT. The distribution of molecular subtype is 71.4% for Luminal A, 13.2% for Luminal B, 5.1% for HER2 enriched, and 10.3% for TNBC. The OS was significantly better for patients in PMRT group than the Non-PMRT group (P < 0.0001). Stratified by molecular subtype, PMRT significantly prolonged survival in Luminal A patients (HR: 0.759, 95% CI: 0.651-0.884, P < 0.001), Yet it brought no significant survival advantage in Luminal B, TNBC or HER2 enriched subtype (P = 0.914, P = 0.124, P = 0.103, respectively). Also, PMRT bore prognostic significance among those patients who were older than 56 years old, single, white, exempt from reconstruction and chemotherapy, and were with ductal, GradeⅡtumor (all P < 0.05). After PSM, the survival benefit of PRMT sustained in Luminal A patients with T1 tumor concomitant with one positive lymph node.

CONCLUSION

Our study demonstrates a beneficial impact for PMRT on overall survival among Luminal A subtype breast cancer patients with T1-2N1 disease. The selection of PMRT should be stratified by molecular subtype and other risk factors.

Survival following radiotherapy in young women with localized early-stage breast cancer according to molecular subtypes

Background

To evaluate the significance and benefit of radiotherapy (RT) in young early‐stage breast cancer patients according to different molecular subtypes.

Methods

We conducted a retrospective cohort study utilizing the Surveillance, Epidemiology, and End Results database with known hormone receptor (HoR) and human epidermal growth factor receptor 2 (HER2) status. Female patients aged 18‐45, received RT treatment, and diagnosed with stage T1‐3, N0‐3, M0 primary breast cancer between 2010 and 2013 were identified.

Results

Of all the 23 148 included patients, 14 708 (63.54%), 3385 (14.62%), 1225 (5.29%), and 3830 (16.55%) were diagnosed with luminal‐A (HoR + HER2‐), luminal‐B (HoR + HER2+), HER2‐enriched (HoR‐HER2+), and triple‐negative (HoR‐HER2‐) breast cancer, respectively. RT was significantly correlated with improved overall survival (OS, HR: 0.295; 95% CI:0.138‐0.63, P = 0.002) and breast cancer‐specific survival (BCSS, HR: 0.328; 95% CI: 0.153‐0.702, P = 0.004) in HER2‐enriched patients. In addition, a significantly prolonged OS was also observed when RT was given to luminal‐A (HR: 0.696; 95% CI: 0.538‐0.902, P = 0.006) and luminal‐B (HR: 0.385; 95% CI:0.199‐0.744, P = 0.005) breast cancer patients compared to those without RT. Multivariable‐adjusted analyses showed that HER2 was a significant favorable factor for RT benefit in breast cancer patients.

Conclusions

RT could offer significant survival benefit in luminal‐A, luminal‐B, and especially HER2‐enriched young early‐stage breast cancer female patients. The results enabled clinicians to predict the benefits of RT and improve evidence‐based treatment for breast cancer patients.