Evidence map›Paper›PMID 41528580›Full record

ArticleBreast cancer research and treatment2026

Trends in postmastectomy radiotherapy for early and locally advanced breast cancer in Switzerland: a population-based cross-sectional and longitudinal analysis.

Marcel Blum, Sonja Marion Koch, Mohsen Mousavi, Denise Vorburger, Andreas Müller, Michel Eric Nicolas Zimmermann, Christoph Oehler, Daniel Rudolf Zwahlen

Abstract read
PubMed Publisher
In one paragraph

Article in Breast cancer research and treatment, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Marcel BlumCancer Registry Eastern Switzerland, St. Gallen, Switzerland.
Sonja Marion KochDepartment of Radiation Oncology, Kantonsspital Winterthur, Winterthur, Switzerland.
Mohsen MousaviCancer Registry Eastern Switzerland, St. Gallen, Switzerland.
Denise VorburgerDepartment of Gynecology, Kantonsspital Winterthur, Winterthur, Switzerland.
Andreas MüllerDepartment of Medical Oncology, Kantonsspital Winterthur, Winterthur, Switzerland.
Michel Eric Nicolas Zimmermann *Department of Radiation Oncology, Kantonsspital Winterthur, Winterthur, Switzerland.
Christoph Oehler *Department of Radiation Oncology, Kantonsspital Winterthur, Winterthur, Switzerland. Christoph.oehler@ksw.ch.ORCID http://orcid.org/0000-0003-1649-9187
Daniel Rudolf Zwahlen *Department of Radiation Oncology, Kantonsspital Winterthur, Winterthur, Switzerland.

Funding

Krebsliga Schweiz HSR-4663-11-2018
6 · The paper itself

Abstract

purposePostmastectomy radiotherapy (PMRT) reduces locoregional recurrence and improves survival in high-risk breast cancer (BC), yet its real-world use remains variable. Population-based data on PMRT utilization and guideline adherence in Switzerland are lacking. We evaluated PMRT patterns, determinants, and adherence to ASCO-ASTRO-SSO recommendations among women with stage I-III BC over two time periods and interpreted findings in the context of the 2025 guideline.

methodsThis retrospective, population-based study analyzed data from seven Swiss cancer registries, including Eastern Switzerland (2003-2005; n = 4,246), and from Eastern Switzerland alone (2015-2017; n = 976). Eligible patients were women aged ≥ 18 years with stage I-III invasive BC treated by simple mastectomy. PMRT use was examined across original ASCO-ASTRO-SSO-defined risk groups: low-risk (T1-2N0), intermediate-risk (T1-2N1, T3N0), and high-risk (T4 or N2-3). Multivariable regression identified clinicopathologic determinants of PMRT use. Trends in PMRT guideline adherence and regional nodal irradiation (RNI) were evaluated within the framework of evolving clinicobiologic risk paradigms. Overall survival (OS) was analyzed using Kaplan-Meier and Cox regression methods.

resultsOverall PMRT utilization remained low (25-30%) across both periods. PMRT was independently associated with younger age, higher T-/N-stage, lymphovascular invasion (p < 0.01), positive margins, G3 histology, and ER negativity (p < 0.05). Adherence to guidelines improved in low-risk patients (93% to 96%) but declined in high-risk patients (64% to 54%), with decreasing PMRT use in T4 (53% to 27%), N2 (73% to 57%), and N3 disease (83% to 73%). In contrast, PMRT use increased among intermediate-risk patients (23% to 39%), particularly in T1-2N1 disease (19% to 38%) and in the presence of adverse features: LVI + (21%), HER2 + (23%), TNBC (30%), G3 (38%), and age < 45 years (57%). Supraclavicular/axillary RNI declined overall but increased in node-negative patients, paralleling reduced axillary dissection and increased sentinel biopsy (26% to 70%). PMRT was not associated with a statistically significant OS benefit; supraclavicular RNI showed a non-significant trend toward improved OS in N2-3 disease.

conclusionsThis first national analysis provides real-world evidence that PMRT utilization in Switzerland remains low, with underuse in high-risk patients and selective, biologically informed escalation in intermediate-risk disease. While patterns reflect evolving multidisciplinary care, persistent gaps in ASCO-ASTRO-SSO guideline implementation underscore the need for continued surveillance and individualized, risk-adapted PMRT decision-making.

Indexed as

Breast NeoplasmsMastectomyNeoplasm Recurrence, LocalAdultAgedAged, 80 and overCross-Sectional StudiesFemaleGuideline AdherenceHumansLongitudinal StudiesMiddle AgedNeoplasm StagingRadiotherapy, AdjuvantRegistriesRetrospective StudiesBreast cancerGuideline adherenceMastectomyPMRTRegional nodal irradiation (RNI)Risk-adapted therapy

Identifiers

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.