Does ethnicity affect the type of breast cancer you develop and how easily it's detected?

Asian women tend to have denser breasts, which can make cancer harder to detect. Studies also show that certain breast cancer types are more common among some ethnic groups in Singapore. But doctors say ethnicity alone doesn't determine how the disease behaves.

Studies in Singapore have found differences in the subtypes of breast cancer diagnosed among Chinese, Malay and Indian women. (Photo: iStock/PonyWang)

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Much of what we know about breast cancer comes from studies involving Caucasian women in Western countries. But research in Singapore has found differences in certain breast cancer characteristics among Chinese, Malay and Indian women.

Dr Lim Siew Kuan, senior consultant and breast surgeon at Solis Breast Care and Surgery Centre, said that breast cancer is classified in different ways. One classification describes where the cancer originates within the breast, while another describes its biological behaviour and how it is likely to respond to treatment.

For example, invasive ductal carcinoma (IDC) begins in the milk ducts. “It accounts for around 70 to 80 per cent of invasive breast cancers worldwide,” said Dr Lim. “This is true across all ethnic groups, including Asian women.”

HER2-positive breast cancer, on the other hand, refers to a molecular subtype, she added. HER2 stands for human epidermal growth factor receptor 2 – the cancer cells have increased HER2 activity, which can drive their growth.

Adjunct Associate Professor Samuel Ow, senior consultant at the Department of Haematology-Oncology at National University Cancer Institute, Singapore, said Asian women have a slightly higher proportion of HER2-positive breast cancer – around 19 per cent, compared with 14 per cent in Caucasian women.

“HER2 used to have a poor outlook,” he told CNA Women. “The good news is that we now have targeted therapy which specifically blocks HER2, and HER2-positive breast cancer can be treated very effectively.”

BREAST CANCER AND ETHNICITY

Dr Lim said research has shown that breast cancer patterns can vary between populations. Studies from Singapore have identified differences in the distribution of breast cancer subtypes among Chinese, Malay and Indian women.

Breast cancer patterns vary among Chinese, Malay and Indian women in Singapore. (Photo: iStock/JimmyFam)

Chinese women appear to have a higher proportion of hormone receptor-positive breast cancers, whose growth is stimulated by hormones such as oestrogen or progesterone.

Malay and particularly Indian women appear to have a somewhat higher proportion of triple-negative breast cancers, which tend to behave more aggressively, and chemotherapy is commonly an important part of treatment, said Dr Lim.

“However, treatment decisions are based on the characteristics of the individual tumour and not what type of cancer is more common in a patient’s ethnicity,” Dr Lim added.

Dr Lim said certain breast cancer characteristics, such as age at diagnosis, breast density and the distribution of tumour subtypes, may vary between populations. However, the same internationally accepted methods are used to diagnose and treat the disease.

“These local patterns are important for research, screening and healthcare planning, but they do not make breast cancer in Singapore a different disease,” she explained.

ETHNICITY IS JUST ONE FACTOR

Dr Lim said that breast cancer risk and tumour biology are influenced by many factors – not just ethnicity. These include genetics, reproductive history, lifestyle and environmental influences. Even within Asia, there is considerable variation between populations.

“Singapore gives us an interesting opportunity to study this because of our multi-ethnic population,” she said. “We do see differences in breast cancer characteristics and outcomes between ethnic groups, but ethnicity alone cannot predict how a breast cancer will behave.”

Besides ethnicity, genetics, reproductive history, lifestyle and environmental factors can influence breast cancer risk. (Photo: iStock/gahsoon)

She added that the most important information comes from testing the tumour itself, as well as its grade and stage, as these determine prognosis and guide treatment decisions.

Adjunct Assoc Prof Ow said: “Ethnicity can also reflect differences in lifestyle, childbearing and sociocultural factors, which may influence health-seeking behaviour, including whether women come forward for cancer screening, which can affect the stage at which breast cancer is diagnosed.”

Around five to 10 per cent of breast cancers are linked to an inherited genetic predisposition such as BRCA1 or BRCA2, said Adjunct Assoc Prof Ow. He advised women to be familiar with the cancer history on both their mother’s and father’s sides of the family.

ASIAN WOMEN HAVE DENSER BREASTS

One difference between Asian and Western women is breast density, which could impact diagnosis. Adjunct Assoc Prof Ow explained that both dense breast tissue and tumours appear white on a mammogram , making cancer harder to detect.

Both breast tissue and tumours appear white on mammograms, making breast cancer harder to detect in dense breasts. (Photo: iStock/photovideostock)

Having dense breasts is also a risk factor for developing breast cancer. However, Adjunct Assoc Prof Ow said: “This does not mean [Asian women] have a markedly higher overall breast cancer risk than women in the West – breast density is only one of many factors that determine risk.”

Dr Lim said that “breast density is an important factor we consider when deciding how best to assess a woman’s breasts”. This is where 3D instead of 2D mammography could be used.

“Compared with conventional 2D mammography, 3D mammography uses less compression force and provides clearer, more detailed views of breast tissue,” said Dr Lim. “This can improve the detection of breast cancers, particularly in women with dense breast tissue, and may be useful when more detailed imaging is needed to assess a breast concern.”

BREAST CANCER AND YOUNGER WOMEN

Although breast cancer remains primarily a disease of older women, it is increasingly being diagnosed in younger women in Singapore – one in six is under 45 and about one in 10 is below 40.

Adjunct Assoc Prof Ow said breast cancer in a younger demographic reflects the effects of rapid Westernisation and industrialisation among generations born after the 1950s, whose breast cancer risk has increased compared with previous generations.

Contributing factors include having fewer children, giving birth at a later age, starting menstruation earlier and having a higher body mass index (BMI).

Breast cancers in younger women are also more likely to be more aggressive.

“Compared with older patients, younger women have a higher likelihood of developing high-grade tumours and biologically aggressive subtypes, including triple-negative and HER2-positive breast cancers,” said Dr Lim.

Singapore’s revised national guidelines recommend that women aged 40 to 49 have a mammogram every year, and every two years from age 50. Routine screening is generally not recommended below 40 for women at average risk, said Adjunct Assoc Prof Ow.

The eligibility age for mammograms was lowered from 50 to 40 earlier this year, following recommendations by the Screening Test Review Committee, an expert committee appointed by the Ministry of Health.

Women from age 40 are now eligible for mammogram screening, following recommendations by Singapore’s Screening Test Review Committee in February 2026. (Photo: iStock/OntheRunPhoto)

Statistics show that Singapore has the highest rate of breast cancer in Southeast Asia. Adjunct Assoc Prof Ow noted that its rates now resemble those of developed countries.

Contributing factors include later childbearing, having fewer children, longer life expectancy, rising BMI and greater consumption of dietary fat or animal products, which can increase the body’s exposure to oestrogen, a risk factor in breast cancer.

“But there is good news, too – five-year survival in Singapore has improved dramatically, from about 50 per cent in the 1970s to more than 80 per cent today,” Adjunct Assoc Prof Ow said.

“Whatever your age, a persistent breast lump or change should always be checked – you are never too young for a breast symptom to be taken seriously,” he added.

CNA Women is a section on CNA Lifestyle that seeks to inform, empower and inspire the modern woman. If you have women-related news, issues and ideas to share with us, email CNAWomen [at] mediacorp.com.sg .

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亚洲女性的乳腺组织通常较为致密，这可能导致乳腺癌更难被发现。研究还表明，某些类型的乳腺癌在新加坡的某些族裔群体中更为常见。但医生表示，种族本身并不能决定疾病的进展方式。

新加坡的研究发现，华裔、马来裔和印度裔女性所患乳腺癌的亚型存在差异。（图片：iStock/PonyWang）

这段音频由人工智能工具生成。

我们对乳腺癌的了解大多来自西方国家白人女性的研究。但新加坡的研究发现，华裔、马来裔和印度裔女性的乳腺癌某些特征存在差异。

索利斯乳腺护理与外科中心的高级顾问兼乳腺外科医生林秀娟博士表示，乳腺癌的分类方式多种多样。一种分类方式描述了癌症在乳房内的起源位置，而另一种分类方式则描述了癌症的生物学行为以及其对治疗的可能反应。

例如，浸润性导管癌（IDC）起源于乳腺导管。“它约占全球浸润性乳腺癌病例的70%至80%，”林医生说。“这种情况在所有种族群体中都存在，包括亚洲女性。”

她补充说，另一方面，HER2阳性乳腺癌指的是一种分子亚型。HER2代表人表皮生长因子受体2——癌细胞的HER2活性增强，这会促进其生长。

新加坡国立大学癌症中心血液肿瘤科高级顾问、兼职副教授 Samuel Ow 表示，亚洲女性 HER2 阳性乳腺癌的比例略高，约为 19%，而白人女性的比例为 14%。

“HER2阳性乳腺癌以前预后很差，”他告诉CNA Women。“好消息是，我们现在有了靶向疗法，可以专门阻断HER2，因此HER2阳性乳腺癌可以得到非常有效的治疗。”

乳腺癌与种族

林医生表示，研究表明，不同人群的乳腺癌发病模式可能存在差异。新加坡的研究发现，华裔、马来裔和印度裔女性的乳腺癌亚型分布存在差异。

新加坡的华裔、马来裔和印度裔女性的乳腺癌发病模式各不相同。（图片：iStock/JimmyFam）

中国女性似乎患有激素受体阳性乳腺癌的比例较高，这种癌症的生长受到雌激素或孕激素等激素的刺激。

林医生说，马来族女性，尤其是印度裔女性，患三阴性乳腺癌的比例似乎较高，这种癌症往往更具侵袭性，化疗通常是治疗的重要组成部分。

林医生补充说：“然而，治疗方案的选择取决于肿瘤的具体特征，而不是取决于患者所在种族中哪种类型的癌症更为常见。”

林医生表示，某些乳腺癌特征，例如确诊年龄、乳腺密度和肿瘤亚型分布，可能因人群而异。然而，诊断和治疗该疾病所采用的都是国际公认的相同方法。

她解释说：“这些本地模式对于研究、筛查和医疗保健规划很重要，但这并不意味着新加坡的乳腺癌是一种不同的疾病。”

种族只是其中一个因素

林医生指出，乳腺癌风险和肿瘤生物学受多种因素影响，并非只有种族。这些因素包括遗传、生育史、生活方式和环境影响。即使在亚洲内部，不同人群之间也存在相当大的差异。

“新加坡多元种族的人口构成为我们提供了一个绝佳的研究机会，”她说道。“我们确实发现不同种族群体在乳腺癌的特征和预后方面存在差异，但仅凭种族并不能预测乳腺癌的病程发展。”

除了种族之外，遗传因素、生育史、生活方式和环境因素也会影响乳腺癌的风险。（图片：iStock/gahsoon）

她补充说，最重要的信息来自对肿瘤本身及其分级和分期的检测，因为这些因素决定了预后并指导治疗决策。

兼职副教授欧表示：“种族也可以反映生活方式、生育和社会文化因素的差异，这些因素可能会影响人们的就医行为，包括女性是否主动接受癌症筛查，这会影响乳腺癌的诊断阶段。”

欧教授表示，约有5%至10%的乳腺癌与遗传基因易感性有关，例如BRCA1或BRCA2基因。他建议女性了解自己父母双方家族的癌症病史。

亚洲女性的乳房更紧实

亚洲女性和西方女性的一个区别在于乳腺密度，这可能会影响诊断。副教授欧解释说，致密的乳腺组织和肿瘤在乳房X光片上都呈现白色，这使得癌症更难被发现。

在乳房X光片上，乳腺组织和肿瘤都呈现白色，这使得致密型乳腺中的乳腺癌更难被发现。（图片：iStock/photovideostock）

乳腺组织致密也是罹患乳腺癌的风险因素之一。然而，欧副教授表示：“这并不意味着亚洲女性罹患乳腺癌的总体风险明显高于西方女性——乳腺组织密度只是决定风险的众多因素之一。”

林医生表示，“乳腺密度是我们决定如何最佳评估女性乳房时需要考虑的重要因素”。这时就可以使用3D乳腺X光检查而不是2D乳腺X光检查。

林医生表示：“与传统的二维乳腺X光检查相比，三维乳腺X光检查使用的压迫力更小，能够提供更清晰、更详细的乳腺组织图像。这可以提高乳腺癌的检出率，尤其适用于乳腺组织致密的女性，并且在需要更详细的影像检查来评估乳腺问题时非常有用。”

乳腺癌与年轻女性

虽然乳腺癌仍然主要是一种老年女性的疾病，但在新加坡，越来越多的年轻女性被诊断出患有乳腺癌——六分之一的乳腺癌患者年龄在 45 岁以下，十分之一的乳腺癌患者年龄在 40 岁以下。

兼职副教授欧表示，年轻一代乳腺癌病例的增加反映了 20 世纪 50 年代后出生的几代人快速西化和工业化的影响，与前几代人相比，他们的乳腺癌风险有所增加。

导致这种情况的因素包括子女数量较少、生育年龄较晚、初潮年龄较早以及身体质量指数（BMI）较高。

年轻女性的乳腺癌也更容易发展成更具侵袭性的癌症。

林医生说：“与老年患者相比，年轻女性更容易患上高级别肿瘤和生物学侵袭性亚型，包括三阴性乳腺癌和 HER2 阳性乳腺癌。”

新加坡修订后的国家指南建议，40 至 49 岁的女性每年进行一次乳房 X 光检查，50 岁及以上的女性每两年进行一次。副教授欧表示，一般不建议 40 岁以下的普通风险女性进行常规筛查。

今年早些时候，根据卫生部任命的专家委员会——筛查测试审查委员会的建议，乳房X光检查的年龄从50岁降低到40岁。

根据新加坡筛查测试审查委员会2026年2月的建议，40岁以上的女性现在有资格接受乳房X光检查。（图片：iStock/OntheRunPhoto）

统计数据显示，新加坡是东南亚乳腺癌发病率最高的国家。欧副教授指出，新加坡的乳腺癌发病率目前已与发达国家相近。

导致乳腺癌的因素包括晚育、少生孩子、预期寿命延长、体重指数上升以及摄入更多膳食脂肪或动物产品，这些都会增加人体接触雌激素的机会，而雌激素是乳腺癌的一个风险因素。

“但也有好消息——新加坡的五年生存率已经大幅提高，从 20 世纪 70 年代的约 50% 提高到如今的 80% 以上，”副教授欧表示。

“无论年龄多大，持续存在的乳房肿块或变化都应该进行检查——乳房症状无论多小都应该认真对待，”他补充道。

CNA Women是CNA Lifestyle旗下的一个版块，旨在为现代女性提供信息、赋能和启发。如果您有与女性相关的新闻、议题或想法想要与我们分享，请发送电子邮件至CNAWomen[at]mediacorp.com.sg。

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