Is Breast Cancer Increasing in Young Women? Breast Cancer Accounts for One in Every 4 Cancers in Women
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Screening starts at 40, but cancer does not wait: Breast cancer in young women
Breast cancer incidence in women under 50 has been rising for years in Western countries. In Türkiye, almost one-fifth of patients have not yet reached 40 when diagnosed. This article explains what the data show, why tumors behave differently in younger patients, and what women outside the screening program can do.
1. Is the increase real, or are we looking more closely?
When news reports say a disease is becoming "more common", the first question should be: Are there more patients, or are more tests being performed? In young women, this distinction is relatively straightforward. Average-risk women under 40 are not routinely offered mammography screening. A change in screening intensity therefore cannot explain the increase in this age group.
United States: Three independent data sources point in the same direction
According to the American Cancer Society's (ACS) 2024 report, US breast cancer incidence increased by an average of 1% annually during 2012–2021. The increase was steeper in women under 50: 1,4% annually, compared with 0,7% in women aged 50 or older.[1] The same report also shows that breast cancer mortality has fallen by 44% since 1989. The picture therefore has two sides: the disease is becoming more common, but treatment success continues to improve.[1]
Xu and colleagues at Washington University examined 217.815 women aged 20–49 diagnosed with invasive breast cancer during 2000–2019 in SEER. Incidence increased by an average of 0,79% annually. The increase was almost entirely attributable to estrogen receptor-positive (ER+) tumors; ER-negative tumor incidence declined.[2] There is also a noteworthy stage-specific pattern. Stage I tumors increased by 3,45% annually and stage IV by 3,39%, while stage II and III tumors declined.[2] Age-period-cohort analysis found that women born in 1990 had more than 20% higher breast cancer risk than those born in 1955.[2]
France: A 33-year national registry
A study based on France's national cancer registries, encompassing 229.352 cases, showed that the US finding also holds in Europe.[3]
2. Türkiye: Why is breast cancer in young women more visible here?
The national registry program of the Turkish Federation of Breast Diseases Societies (TMHDF) described the situation in Türkiye in three analyses. The initial analysis of 13.240 patients during 2005–2011 found a mean age at diagnosis of 51,6; 17% of patients were under 40.[4] The update covering 20.000 patients during 2005–2017 found a median age of 51 and a proportion under 40 of 17,2%.[5] In MF18-04, published at the end of 2025 and covering 23.594 patients during 1998–2019, the proportion aged 40 or younger reached 19,2%.[6]
Part of this proportion reflects Türkiye's age structure. In a country with a large young population, younger patients naturally account for a larger share of all patients. Thus, comparing "19% in Türkiye versus a lower proportion in the United States" does not by itself mean that a young Turkish woman's risk is higher. Clinically, however, the implication remains: one in five patients attending a breast clinic belongs to an age group outside the national screening program.
Tumors behave differently in younger patients
MF18-04 compared 4.535 patients aged 40 or younger with 19.059 older patients.[6]
Multivariable analysis found high grade, ER and PR negativity, multifocal or multicentric disease, T3–T4 tumors, and axillary involvement independently associated with younger age. Mastectomy (40,9% versus 38,8%) and axillary dissection rates were also higher in younger patients.[6]
3. Why is it increasing? What we know and do not know
The demonstrated cohort effect is an important clue.[2] If women born in later generations have a higher risk at the same age, changes in diagnostic methods alone cannot explain it. This points to lifetime exposures. The concentration of the increase in ER+ tumors also highlights factors that alter lifetime estrogen exposure. The most discussed candidates are older age at first childbirth, fewer births and shorter breastfeeding, early menarche, obesity, and alcohol. However, how much of the increase these factors explain has not yet been measured. The French study's authors explicitly stress the need for new research to explain the trend.[3]
4. Myths and facts
| Common belief | What do the data say? |
|---|---|
| "Breast cancer is a disease of older age." | In Türkiye, approximately 19% of breast cancer patients are aged 40 or younger at diagnosis.[6] US incidence in women under 50 is rising twice as fast as in older women.[1] |
| "If it does not run in my family, it will not happen to me." | In the Turkish registry, 64,4% of patients aged 40 or younger had no family history of any cancer.[6] Family history increases risk, but its absence is no guarantee. |
| "Breast cancer in young women is genetic." | Germline BRCA1/2 variants are more common in younger patients. According to literature cited by the Turkish study, they are found in approximately 12% of patients under 40. Nevertheless, most cases are sporadic.[6] |
| "There is nothing I can do before age 40." | ACR recommends that every woman undergo breast cancer risk assessment by age 25 at the latest. The aim is to identify women who need earlier and additional screening.[7] |
| "If I get breast cancer, I cannot have children." | In POSITIVE, short-term recurrence risk did not increase in women with hormone-positive early-stage disease who interrupted endocrine therapy to become pregnant. Approximately three-quarters of participants became pregnant at least once.[9] |
5. What should be done in practice?
For women
- Know your breasts. In Türkiye, 96,7% of young patients were diagnosed following a symptom, such as a palpable lump or changes in the skin or nipple.[6] There is no screening in this age group, so early awareness relies on your own observations.
- Do not delay assessment of a new, persistent change. Benign lumps are very common in younger breasts, but "you are young, it is nothing" is not an assessment in itself.
- Know your family history. Tell your physician if there is breast cancer at a young age, ovarian cancer, or more than one breast cancer case in your family.
- Start screening at age 40. Women aged 40–69 can receive free mammography every two years through KETEM centers and family health centers.[10]
For physicians
- Risk assessment at age 25: The ACR 2023 update lowered the risk assessment age from 30 to 25.[7]
- High-risk group: Women with genetic susceptibility, a calculated lifetime risk of 20% or more, or chest irradiation at a young age start annual MRI at ages 25–30. For those who received chest irradiation before 30, screening begins at age 25 or 8 years after irradiation, whichever is later.[7]
- Fertility after diagnosis: ESO–ESMO BCY5 emphasizes that fertility, ovarian function suppression, and early menopause are central to treatment planning. Fertility preservation should be discussed before systemic treatment begins.[8]
- Germline testing: The presence of a pathogenic germline variant directly affects risk-reducing approaches, local treatment, and the choice of systemic treatment.[8]
- Desire for pregnancy: Temporary interruption of endocrine therapy is now supported by prospective data in appropriately selected patients with HR+ early-stage disease. The decision should be made through shared decision-making.[9]
POSITIVE: A prospective answer to a major question for young patients
The international, single-arm POSITIVE trial enrolled 516 premenopausal women with stage I–III HR+ breast cancer who had received 18–30 months of endocrine therapy and wished to become pregnant. They temporarily interrupted endocrine therapy to attempt pregnancy.[9] At a median follow-up of 41 months, the 3-year breast cancer event rate was 8,9%. This was comparable with 9,2% in an external SOFT/TEXT control cohort of similar patients. Approximately three-quarters of participants became pregnant at least once, and 86% of those who became pregnant had at least one live birth.[9]
6. Türkiye: The screening program and its limits
Population-based breast cancer screening in Türkiye consists of mammography every two years and clinical breast examination annually for women aged 40–69. Services are delivered through KETEM centers, family health centers, and community health centers.[10] There is no national screening program for average-risk women under 40. This approach is consistent with general practice worldwide, because the benefit of population-based mammography screening in this age group has not been demonstrated.
Registry data point to another gap. The 2019 analysis noted that, despite increased availability of screening centers and free mammography in recent years, a substantial proportion of patients were diagnosed at an advanced stage, primarily because of inadequate awareness.[5] For young women, the solution is not to move screening below age 40. What is needed is wider use of risk-based assessment and rapid referral of symptomatic young women into a diagnostic pathway.
References
- Giaquinto AN, Sung H, Newman LA, et al. Breast cancer statistics 2024. CA Cancer J Clin. 2024;74(6):477–495. doi:10.3322/caac.21863
- Xu S, Murtagh S, Han Y, Wan F, Toriola AT. Breast cancer incidence among US women aged 20 to 49 years by race, stage, and hormone receptor status. JAMA Netw Open. 2024;7(1):e2353331. doi:10.1001/jamanetworkopen.2023.53331
- Pujol P, Remontet L, Lapôtre-Ledoux B, Rogel A, Lafay L, Molinié F. Increasing incidence of breast cancer in young women over time. Breast. 2025;83:104555. doi:10.1016/j.breast.2025.104555
- Özmen V. Breast cancer in Turkey: Clinical and histopathological characteristics (analysis of 13.240 patients). J Breast Health. 2014;10(2):98–105. doi:10.5152/tjbh.2014.1988
- Özmen V, Özmen T, Doğru V. Breast cancer in Turkey; an analysis of 20.000 patients with breast cancer. Eur J Breast Health. 2019;15(3):141–146. doi:10.5152/ejbh.2019.4890
- Cabıoğlu N, Türkyılmaz Z, Özkurt E, et al. Poor prognostic clinicopathological features of young women with breast cancer in the MF18-04 Turkish National Breast Cancer Registry Study. Asian Pac J Cancer Prev. 2025;26(12):4407–4417. doi:10.31557/APJCP.2025.26.12.4407
- Monticciolo DL, Newell MS, Moy L, et al. Breast cancer screening for women at higher-than-average risk: Updated recommendations from the ACR. J Am Coll Radiol. 2023;20(9):902–914. doi:10.1016/j.jacr.2023.04.002
- Paluch-Shimon S, Cardoso F, Partridge AH, et al. ESO–ESMO fifth international consensus guidelines for breast cancer in young women (BCY5). Ann Oncol. 2022;33(11):1097–1118. doi:10.1016/j.annonc.2022.07.007
- Partridge AH, Niman SM, Ruggeri M, et al. Interrupting endocrine therapy to attempt pregnancy after breast cancer. N Engl J Med. 2023;388(18):1645–1656. doi:10.1056/NEJMoa2212856
- Republic of Türkiye Ministry of Health, General Directorate of Public Health. Breast cancer screening program: mammography every two years and annual clinical breast examination for women aged 40–69 (KETEM, ASM, TSM).
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