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Screen Time: Is breast-cancer screening the right move?

An estimated 700 women will die of breast cancer in Hong Kong this year.
The government is under mounting pressure to introduce a population-wide screening programme to improve early detection. But are there any downsides?

Vanessa Lai was in her early 40s when she discovered an abnormality in her left breast in September 2015. After undergoing a biopsy, doctors delivered the terrible news: she had stage 1B breast cancer. In the two months that followed, the beauty consultant underwent a lumpectomy to remove the cancerous tissue, followed by four gruelling sessions of chemotherapy.

Following her recovery, Lai applied for breast screenings at her local government hospital in Hong Kong. However, it wasn’t as easy to schedule a screening as she had expected. As a cancer survivor, Lai carries a higher than normal risk of developing further cancer due to the likelihood of a recurrence – something which can happen in 3-23 per cent of cases depending on the severity of cancer and treatment received. She believed that having regular mammograms would enable doctors to catch potential cancer early, when it was more treatable.

A few weeks after registering for the service, Lai received a shocking note: “Even as a breast cancer survivor, I was told I would have to wait at least two years to get a mammogram at a government hospital,” Lai says. “The letter even suggested that if I wasn’t happy to wait, I should pay to go to private clinic.”

Which is exactly what she did. To date, Lai has spent around HK$3,000 on breast cancer screenings, on top of HK$400,000 for her previous surgery and treatment. Her experience is a familiar one for many Hong Kong women. To some experts, it reflects the government’s failure to protect women from the increasing threat of breast cancer.

Cancer on the rise

Statistics from the Hong Kong Cancer Registry show that 4,108 women were diagnosed with breast cancer and 702 died in 2016. That means 11 women are diagnosed with cancer in Hong Kong every single day.

Disturbingly, the figures reveal an upward trend, with the number of cases tripling over the last 20 years. One in every 16 women will find themselves battling breast cancer during their lifetime, making it the most common cancer and the third most deadly cancer among Hong Kong women.

Although it is not known exactly why some people develop cancer and others do not, studies have identified certain factors such as lifestyle, genetics and hormones which increase a person’s risk of developing cancer in their lifetime.

According to the Hong Kong Breast Cancer Foundation (HKBCF) around 5 per cent of breast cancer cases in the city are thought to be caused by genetics, more specifically, the BRCA1 and 2 gene mutations. The former is carried by actress Angelina Jolie and results in an 80 per cent chance of the carrier developing breast cancer in their lifetime.

For women who do not carry these genes, diets rich in animal fat and dairy products are believed to increase risk, along with smoking, drinking alcohol and lack of exercise. With breast cancer, female hormones are also believed to play a role, which is why women who have greater exposure to hormones during their reproductive lifetime – such as those who do not have children, have fewer children, and those who start menstruation early or go through the menopause late – may be more at risk to breast cancer.

A survey conducted by the Hong Kong Breast Cancer Registry last year has also found that high stress levels increase the risk of breast cancer by 240 per cent. According to Dr Polly Cheung Suk-yee, founder of HKBCF, the alarming increase in breast cancer cases in Hong Kong might be the result of industrialisation.  

“The economy improved and people became wealthier, diets changed to include more meat and dairy products, people drank more alcohol and exercised less,” says Dr Cheung. “Women are having fewer children, breastfeeding less and working more. These are all things that heighten the risk of breast cancer.”

It’s a global concern, too. According to the American Institute for Cancer Research, there were over 2 million new breast cancer cases worldwide in 2018 compared with 1.7 million in 2012. As the incidence rate rises, some women are even having preemptive mastectomies, following genetic testing.

One such famous case was that of actress Angelina Jolie who, in May 2013 at the age of 37, announced she had undergone a double mastectomy and reconstructive surgery after discovering she carried the BRCA1 gene and had an 87 per cent lifetime risk of developing breast cancer. At the time, the actress, whose own mother had died of cancer aged 56, explained her decision in the New York Times saying: “I decided to be proactive and to minimise the risk as much as I could.”  

Cases like Jolie’s are rare – and genetic testing are only usually advised when a woman has a family history of breast cancer. For the general population, the World Health Organisation recommends that governments in well-resourced countries adopt population-wide screenings in the form of regular mammograms for women aged 50-69. Such programmes have already been implemented in at least 34 countries and regions, including Taiwan, South Korea, Japan, the UK and Australia, often with a good success rate in reducing cancer deaths.

Hong Kong doesn’t feature on that list. The SAR does not have a screening programme and, currently, the government only recommends annual screening for women who are considered high risk, such as those with a family history of breast cancer or those carrying the BRCA1 and 2 gene mutations.

However, according to the HKBCF, this high-risk definition applies to only 5 per cent of breast cancer patients which means that the current government guidelines deprive the remaining 95 per cent of women of the means of detecting cancer early.

As a result, many women in Hong Kong either seek free and subsidised screening from NGOs and charities or pay between HK$800 and HK$3,600 for screenings at private clinics and hospitals. Even those with private health insurance may end up funding screening themselves, as although most policies cover treatment for cancer, not all cover preventive measures.

More alarmingly, “some choose to go without,” says HKBCF’s Dr Cheung. The HKBCF is a non-profit organisation dedicated to promoting breast health awareness and providing free and subsidised screening and support for cancer patients. As such, it comes into contact with around 40 per cent of all breast cancer cases in Hong Kong.

“Our experience is that 85 per cent [of those cases] involve women incidentally discovering a lump that turns out to be cancer,” she says. “This is the way of diagnosis in Hong Kong, and it is far backwards compared to other developed cities. Only 6-8 per cent of cases are detected through mammograms. That is peanuts.”

It’s a statistic Dr Cheung finds unacceptable, especially as the screening rate is even lower among low-income women, who often lack awareness of breast cancer, as well as the time and money to undergo mammograms.

A 2011 study by the HKBCF revealed that more than 80 per cent of breast cancer patients living in low-income households had never had a mammogram before diagnosis. It also found that poorer women were more likely to be diagnosed with advanced-stage breast cancer.

Dr Cheung says the numbers speak for themselves. Around 24 per cent of breast cancer cases are diagnosed at an advanced stage, compared with 15 per cent in countries that have implemented population-wide screening, according to the HKBCF.

“It is crucial to discover breast cancer early, and screening can detect hidden cancers [those at stages 0 and 1],” she says. “At an early stage, the survival rate is 90 per cent. More than 60 per cent of patients do not need chemotherapy and only need a lumpectomy [removal of cancer tumour and surrounding tissue] rather than a mastectomy.”

In contrast, when discovered at stage 4, the average five-year survival rate is only 20 per cent, and just 10 per cent for 10 years, she adds. “We conduct about 4,000-5,000 mammograms a year. But this is a very small number when you consider there are 1.4 million women in Hong Kong over the age of 40 who should be receiving screenings every two years.”

Professor Ava Kwong Hoi-wa performing a mastectomy at Hong Kong University
Professor Ava Kwong Hoi-wa performing a mastectomy at Hong Kong University.

Testing for survival

It’s a dire picture, particularly when juxtaposed with countries where government-backed screening programmes appear to be effective. In Taiwan, a study found that biennial mammography screenings cut the incidence of breast cancer mortality by 40 per cent and reduced the cases of stage 2 and later cancer by nearly 30 per cent over a period of 10 years.

Why, then, has Hong Kong not implemented the initiative? Some reports have raised fears over the amount of radiation exposure contained in mammograms and questioned whether it was safe for women to undergo exposure at this level on a regular basis.

However, Dr Cheung points out that the dose of radiation received from a mammogram is very low at 0.36 millisieverts (mSv) per mammogram. “It is very safe. In Hong Kong, we are exposed to background radiation of 2-3 mSv a year – that’s like having eight mammograms a year,” she says. “We have not seen any reports of screening mammogram-induced cancer.”

Another argument used consistently by the Hong Kong government against a population-wide screening programme is the lack of local data to support it, adding that differences in breast cancer incidences between Western countries and Asia has furthered the argument that more local studies were needed. 

“It was thought that women here would not have the same breast cancer rate as the Western population, but the Taiwan study offers solid data involving Chinese women and it is definitely something Hong Kong should be looking at,” says Dr Cheung.

It is these statistics that the HKBCF used last year in a public policy submission urging the government to strengthen awareness and work with the private sector and NGOs to introduce screening in three phases: the first covering high-risk women; the second for low-income women; and a final phase of population-wide screening.

Dr Cheung says the Hong Kong government’s Department of Health (DoH) – the body that oversees public healthcare policies in the city – acknowledged receipt of the submission but had not responded to their requests.

It also declined a face-to-face or phone interview for this article. In a written response to our questions, however, a press spokesperson said that “the government attaches great importance to cancer prevention and current policy is grounded on fact, scientific evidence, and public interest.”

The response also added that the Taiwanese data used to criticise Hong Kong has been misinterpreted by screening advocates, and the evidence reported is “far less robust” and possibly “misleading.”

“From a scientific perspective, that particular Taiwan study does not add weight to the scientific debate of universal mammography screening programme,” said the statement.

According to the DoH, population-wide mammography screening continues to be a subject of controversy, and there is insufficient evidence to support its introduction in Hong Kong. “Increasing studies from the West reveal potential harm, such as false-positives, false negatives, over-diagnosis and potential complications arising from subsequent invasive investigations or treatment that may outweigh benefits.”

Due to the absence of local data on breast screening, the DoH has commissioned a study by the University of Hong Kong that will investigate risk factors. This is due to be completed later this year and will be used to formulate a future plan for screening.

In the meantime, the DoH advises any woman considering a mammogram for their own “personal protection” to seek advice from their doctor about the benefits and harms before going ahead.

Professor Ava Kwong Hoi-wa – an expert in breast cancer genetics, chief of breast surgery at the Department of Surgery of the University of Hong Kong, and the founder of the Hong Kong Hereditary Breast Cancer Family Registry charity – is involved in the study. She believes it is right to adopt a cautious approach to screening, especially in the light of recent research.

One such piece of research, a 2013 review by global independent medical research network Cochrane, analysed data from several studies and concluded that for every 2,000 women screened over a 10-year period, one was prevented from dying. Meanwhile 10 healthy subjects were treated unnecessarily and 200 suffered psychological stress as a result of false positive results.

A false positive occurs when the mammogram picks up an abnormality which after further investigation turns out to be something other than a cancer, such as scar tissue or a calcium deposit.

“After that Cochrane review came out, the whole world started to rethink screening, asking ‘Should we be screening everyone or just those at major risk?’” she says. “In a way, the government is being diligent in wanting to look more into screening.”

“Japan and Korea would want their own data before making a decision. I think it would be wrong if the government was only looking at its own data and not looking at other countries data. But that is not the case. They are looking at all data. They want to make sure whatever they decide it is the right thing for Hong Kong.”

Doctors performing a mastectomy
Professor Ava Kwong Hoi-wa performing a mastectomy at Hong Kong University.

A balanced approach

There are logical reasons why the DoH wants local data: one being that breast cancer is known to vary by race and ethnicity. Professor Kwong points out that the medical community has already recognised there are differences between breast cancer incidences and women in the West and those in Asia, the latter being more likely to be diagnosed at an earlier age, with the median of diagnosis being 56 years compared to 62 in the United States and 60 in Australia.

She says women in Asia also have denser breast tissue, which can affect the sensitivity of mammograms; dense tissue can look like an abnormality during screening and lead to false positives or false negatives.

One study by the Institute of Radiology at the University of Prishtina, Kosovo, in 2009 found that the sensitivity of mammograms was reduced as the level of breast density increased, ranging from 82.2 per cent sensitivity for fatty breasts compared to 23.7 per cent for dense breasts.

“As a breast cancer surgeon, of course, I want women to be diagnosed early but I can see both the positive and negative sides of population-wide screening,” says Professor Kwong.

She says it is logical to wait for the study’s results, adding that even if the government decides population-wide screening is the way forward, it does not currently have the trained staff or resources to implement such a programme overnight – a successful screening programme will require diligent planning.

In recent years, the government has increased its efforts to raise public awareness of breast cancer. But for those who have experienced cancer, like Vanessa Lai, these efforts are still lacking. Waiting lists for mammograms are too long and too many women still do not understand their risks or where to go for help, she says.

While Lai knew how to perform self-examinations and caught her cancer early, others don’t have the same recovery story to tell. “I hope that will change. I hope the government will pay more attention to the issue of breast cancer and will consider population-wide screening. If it is caught early, the survival and recovery rate is much higher, and more women, like me, will have the chance of complete recovery.”