Evidence map›Paper›PMID 41721033›Full record

ArticleBJC reports2026

An international cohort study of breast cancer survival in young women.

Victoria Sopik, Jan Lubiński, Jacek Gronwald, Tomasz Huzarski, Cezary Cybulski, Laufey Tryggvadóttir, Kazem Zendehdel, Azin Nahvijou, Shama Virani, Imjai Chitapanarux and 8 more

Abstract read
In one paragraph

Article in BJC reports, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

What it found

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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

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3 · Its place in the literature

Who cites it

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No citing paper in PubMed yet.

4 · The record

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5 · Who and what money

Authors and funding

18 authors.

Victoria SopikWomen's College Research Institute, Women's College Hospital, Toronto, ON, Canada.
Jan LubińskiInternational Hereditary Cancer Center, Department of Genetics and Pathology, Pomeranian Medical University, Szczecin, Poland.
Jacek GronwaldInternational Hereditary Cancer Center, Department of Genetics and Pathology, Pomeranian Medical University, Szczecin, Poland.
Tomasz HuzarskiInternational Hereditary Cancer Center, Department of Genetics and Pathology, Pomeranian Medical University, Szczecin, Poland.
Cezary CybulskiInternational Hereditary Cancer Center, Department of Genetics and Pathology, Pomeranian Medical University, Szczecin, Poland.
Laufey TryggvadóttirThe Icelandic Cancer Registry, Reykjavik, Iceland.
Kazem ZendehdelCancer Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.
Azin NahvijouCancer Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.
Shama ViraniInternational Agency for Research on Cancer (IARC/WHO), Genomic Epidemiology Branch, Lyon, France.
Imjai ChitapanaruxDepartment of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
Patumrat SripanResearch Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand.
Patravoot VatanasaptKhon Kaen Cancer Registry, Cancer unit, Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Donsuk PongnikornLampang Cancer Registry, Lampang, Thailand.
Hutcha SriplungEpidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
Ophira GinsburgCenter for Global Health, National Cancer Institute Rockville Maryland, Rockville, MA, USA.
Ping SunWomen's College Research Institute, Women's College Hospital, Toronto, ON, Canada.
Mohammad AkbariWomen's College Research Institute, Women's College Hospital, Toronto, ON, Canada.
Steven NarodWomen's College Research Institute, Women's College Hospital, Toronto, ON, Canada. steven.narod@wchospital.ca.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundThere is large variation in case-fatality rates of breast cancer in young women across the world. The objective of this study was to estimate the ten-year overall survival of women diagnosed with breast cancer before age 40 in six countries, by clinical presentation and by treatments received.

methodsData were supplied by seven centers in six countries, including the USA, Canada, Poland, Iceland, Iran and Thailand, totaling 36,861 women diagnosed with breast cancer before age 40, from 1977 to 2020. American patients from the SEER registry were sub-divided into (Non-Hispanic) White and Black. The following factors were compared across countries: year of diagnosis, tumor size, lymph node status, estrogen receptor (ER) status, use of chemotherapy, use of tamoxifen and use of radiotherapy. The Kaplan-Meier method was used to estimate ten-year overall survival for patients in each center. Cross-center comparisons are provided. The Cox Proportional Hazards model was used to estimate the impacts of the various factors on death for each center separately and for all centers combined, for all patients and for patients with stage I breast cancer. For these comparisons, SEER white women were considered the reference group.

resultsThe mean age of diagnosis was 35.4 years. The percentage of patients with node-positive breast cancer ranged from 48.5% in Poland to 53.4% in Iceland. Mean tumor size ranged from 2.1 cm in Poland to 3.5 cm in Iran. The percent of patients with ER-negative breast cancer ranged from 34.0% in USA White women to 47.4% in Canada. The use of chemotherapy ranged from 65.4% in Thailand to 78.8% in Poland. Ten-year survival rates ranged from 52.5% (95%CI: 50.4%-54.7%) in Thailand to 77.9% (95%CI: 75.5%-80.3%) in Poland. A two-fold variation in case-fatality across centers persisted after adjusting for year of diagnosis, stage, tumor features and treatment. The difference in case-fatality across countries was greatest for patients with stage I breast cancer (four-fold variation).

conclusionsThere is a wide disparity around the world in the long-term survival of women diagnosed with breast cancer before age 40, which cannot be accounted for by differences in screening, tumor stage at presentation or other tumor features. It is possible that differences in survival are due to inherent ethnic differences and/or differences in cancer management, but more research is required.

Identifiers

PMID41721033
PMCPMC12923670

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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.