The purpose of this study was to describe the clinicopathological characteristics and prognosis of primary small cell carcinoma of the breast (PSCCB) and compare PSCCB with breast invasive ductal carcinoma (IDC).

A retrospective cohort study.

Data of patients with PSCCB and breast IDC were identified from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2016.

Eighty-three patients with PSCCB and 410 699 patients with breast IDC were enrolled in the present cohort study.

Patients with PSCCB and breast IDC were identified from the SEER database between 2004 and 2016. The clinicopathological characteristics and survival of patients with PSCCB and IDC were compared. Propensity score matching (PSM) analysis was performed to adjust for differences in baseline characteristics when comparing overall survival (OS) and cancer-specific survival (CSS). Moreover, OS-/CSS-specific nomograms were established to predict the prognosis of PSCCB.

Compared with IDC, PSCCB was significantly correlated with older age, male, higher pathological grade, higher TNM (tumour, node, metastases) stage, a higher proportion of triple-negative breast cancer, a lower proportion of ER/PR positivity and significantly worse clinical outcome. The median OS and CSS of patients with PSCCB were 23.0 m (95%CI 13.0 to 56.0) and 28.0 m (95%CI 18.0 to 66.0), respectively. The 5-year OS and CSS rates in the PSCCB group were 36.1% and 42.4%, respectively. In the matched cohort after PSM analysis, patients with PSCCB had significantly worse OS and CSS than IDC patients. Multivariate Cox regression analysis demonstrated that T stage and administration of chemotherapy were independent prognostic factors for both OS and CSS in patients with PSCCB. The C-index for OS-/CSS-specific nomogram was 0.75 (95%CI 0.66 to 0.85)/0.79 (95%CI 0.69 to 0.89), respectively. The calibration curve in the ROC analysis indicated that the predicted value was consistent with the actual observation value. Decision curve analysis suggested that the nomogram model has a significant positive net benefit from the risk of death and are better than the traditional TNM staging system.

PSCCB has distinct clinicopathological characteristics, and patients with PSCCB have significantly worse clinical outcomes than those with IDC.

The individual, societal and economic benefits of stroke prevention are high. Even though most risk factors can be reduced by changes to lifestyle habits, maintaining new and healthy activity patterns has been shown to be challenging.

The aim of the study is to evaluate the impact of an interdisciplinary team-based, mHealth-supported prevention intervention on persons at risk for stroke. The intervention is mediated by engaging everyday activities that promote health. An additional aim is to describe a process evaluation that serves to increase knowledge about how the programme leads to potential change by studying the implementation process and mechanisms of impact.

The study will be a randomised controlled trial including 104 persons at risk for stroke. Persons at risk of stroke (n=52) will be randomised to an mHealth-supported stroke prevention programme. Controls will have ordinary primary healthcare (PHC) services. The 10-week programme will be conducted at PHC clinics, combining group meetings and online resources to support self-management of lifestyle change using engaging everyday activities as a mediator. Primary outcomes are stroke risk, lifestyle habits and participation in health-promoting activities. Assessments will be performed at baseline and at follow-up (11 weeks and 12 months). The effects of the programme will be analysed using inferential statistics. Implementation will be analysed using qualitative and quantitative methods.

The study has been approved by the Swedish Ethical Review Authority. Study results will be disseminated in peer-reviewed journals and at regional and international conferences targeting mixed audiences.

NCT05279508.