Effects of postmastectomy radiotherapy on survival in different age groups for patients with T3N0M0 breast cancer.

BACKGROUND: Postmastectomy radiotherapy (PMRT), as an important regional treatment, improves the survival rate of patients with T3N0M0 breast cancers. However, the therapeutic effect of PMRT on T3N0M0 patients in different age groups is unclear. METHODS: Using Surveillance, Epidemiology, and End Results database, we identified 4840 T3N0M0 patients between 2000 and 2015. The primary and secondary outcomes were overall survival (OS) and breast cancer-specific survival (BCSS). Survival outcomes were compared using Kaplan-Meier survival test, COX regression analysis, propensity score matching and forest plot, which present the relationship between age and PMRT. RESULTS: Survival analysis demonstrated that for young patients (aged 18-45 and 46-55), there was no significant difference in OS between with and without PMRT. However, for patients older than 65 years, PMRT could significantly improve survival time (P < 0.001). Multivariate Cox analysis of OS showed older patients with PMRT had a lower hazard ratio (HR) than those without PMRT (aged 56-65: HR = 0.67, P = 0.014; aged >65: HR = 0.60, P < 0.001), and little benefit for young patients. The consistent results were also observed in 1:1 matched cohort. Subgroup analysis revealed the survival HRs of with versus without PMRT for patients older than 65 years were significant in most subgroups. CONCLUSION: The effect of PMRT in T3N0M0 patients is related to the age. PMRT is associated with improved survival in older patients with T3N0M0 breast cancer, especially those older than 65 years. While the benefit of PMRT is limited in T3N0M0 patients of young age. The observation suggests the importance of age for T3N0M0 patients when individualized treatment is made.

SYTL4 downregulates microtubule stability and confers paclitaxel resistance in triple-negative breast cancer.

Background: Taxanes are frontline chemotherapeutic drugs for patients with triple-negative breast cancer (TNBC); however, chemoresistance reduces their effectiveness. We hypothesized that the molecular profiling of tumor samples before and after neoadjuvant chemotherapy (NAC) would help identify genes associated with drug resistance. Methods: We sequenced 10 samples by RNA-seq from 8 NAC patients with TNBC: 3 patients with a pathologic complete response (pCR) and the other 5 with non-pCR. Differentially expressed genes that predicted chemotherapy response were selected for in vitro functional screening via a small-scale siRNAs pool. The clinical and functional significance of the gene of interest in TNBC was further investigated in vitro and in vivo, and biochemical assays and imaging analysis were applied to study the mechanisms. Results: Synaptotagmin-like 4 (SYTL4), a Rab effector in vesicle transport, was identified as a leading functional candidate. High SYTL4 expression indicated a poor prognosis in multiple TNBC cohorts, specifically in taxane-treated TNBCs. SYTL4 was identified as a novel chemoresistant gene as validated in TNBC cells, a mouse model and patient-derived organoids. Mechanistically, downregulating SYTL4 stabilized the microtubule network and slowed down microtubule growth rate. Furthermore, SYTL4 colocalized with microtubules and interacted with microtubules through its middle region containing the linker and C2A domain. Finally, we found that SYTL4 was able to bind microtubules and inhibit the in vitro microtubule polymerization. Conclusion: SYTL4 is a novel chemoresistant gene in TNBC and its upregulation indicates poor prognosis in taxane-treated TNBC. Further, SYTL4 directly binds microtubules and decreases microtubule stability.

Clinicopathological characteristics and treatment outcomes of occult breast cancer: a SEER population-based study.

BACKGROUND: Occult breast cancer (OBC) is a rare type of breast cancer that has not been well studied. The clinicopathological characteristics and treatment recommendations for OBC are based on a limited number of retrospective studies and thus remain controversial. PATIENTS AND METHODS: We identified 479 OBC patients and 115,739 non-OBC patients from 2004 to 2014 in and the Surveillance, Epidemiology, and End Results (SEER) database. The clinicopathological characteristics and survival outcomes were compared between OBC and non-OBC patients. We used the propensity score 1:1 matching analysis to evaluate OBC vs non-OBC comparison using balanced groups with respect to the observed covariates. We further divided the OBC population into four groups based on different treatment strategies. Univariable and multivariable analyses were used to calculate and compare the four treatment outcomes within the OBC population. RESULTS: OBC patients were older, exhibited a more advanced stage, a higher rate of negative estrogen receptor and progesterone receptor status, a higher rate of HER2-positive status, and a higher rate of ≥10 positive lymph nodes, and were less likely to undergo surgical treatment than non-OBC patients. After adjustments for clinicopathological factors, the OBC patients exhibited a significantly better survival than the non-OBC patients (P<0.001). This result was confirmed in a 1:1 matched case-control analysis. Within the four OBC treatment groups, we observed no difference in survival among the mastectomy group, the breast-conserving surgery (BCS) group, and the axillary lymph node dissection (ALND)-only group. The multivariable analysis revealed that the sentinel lymph node dissection-only group had the worst prognosis (P<0.001). Conclusion: OBC has unique clinicopathological characteristics and a favorable prognosis compared with non-OBC. BCS plus ALND and radiotherapy showed a survival benefit that was similar to that of mastectomy for OBC patients.

Decreased survival in patients with carcinoma of axillary tail versus upper outer quadrant breast cancers: a SEER population-based study.

BACKGROUND: Carcinoma of the axillary tail of Spence (CATS) is a poorly studied type of breast cancer. The clinicopathological characteristics and prognostic features of CATS are unclear. METHODS: Using the Surveillance, Epidemiology, and End Results database, we identified 149,026 patients diagnosed with upper outer quadrant breast cancer (UOBC) (n=146,343) or CATS (n=2,683). The median follow-up was 88 months. The primary and secondary outcomes were breast cancer-specific survival (BCSS) and overall survival. The survival outcomes of UOBC and CATS were compared using competing risks analysis, log-rank test, Cox proportional hazards regression model, and propensity score matching method. Multivariate logistic regression was utilized to present the relationship between CATS and lymph node (LN) metastasis. RESULTS: CATS presented a higher grade, higher negative hormone receptor rate, and more positive nodal metastasis. The 10-year BCSS rate was worse for CATS than for UOBC (85.1% vs 87.3%, P=0.001). The multivariate Cox analysis showed a higher hazard ratio (HR) for CATS over UOBC (BCSS: HR =1.20, P=0.001; overall survival: HR =1.11, P=0.019). The difference in the BCSS was also observed in a 1:1 matched cohort (BCSS P=0.019). A subgroup analysis revealed the inferior outcomes of CATS in the metastatic LN subgroup and the hormone receptor-negative subgroup. The multivariate logistic regression indicated that CATS is an independent contributing factor to LN metastasis. CONCLUSION: CATS had distinct clinicopathological characteristics and was more likely associated with LN metastasis. Compared to UOBC, CATS had adverse impacts on BCSS.