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Women who smoke have a 10 to 20 times higher risk of developing lung cancer compared to non-smokers, said consultant medical oncologist Wong Seng Weng, medical director of The Cancer Centre at Mount Elizabeth Novena Specialist Centre. — Picture courtesy of Istock via TODAYWomen who smoke have a 10 to 20 times higher risk of developing lung cancer compared to non-smokers, said consultant medical oncologist Wong Seng Weng, medical director of The Cancer Centre at Mount Elizabeth Novena Specialist Centre. — Picture courtesy of Istock via TODAYSINGAPORE, Oct 29 — When 58-year-old Sim Siew Hong tells someone she has Stage 4 lung cancer, she is invariably asked if she smokes a lot.

Unlike her husband, a heavy smoker who easily goes through a packet of cigarettes a day, Mdm Sim said she used to light up only once every few weeks. She did so in her thirties on her mother’s encouragement, believing that it could relieve her nasal congestion.

Symptoms of cancer surfaced in May in the form of a cough that would not let up, even after visits to multiple general practitioners and traditional Chinese medicine physicians.

By July, she was so out of breath and lethargic that she could barely walk, stand or sleep through the night. A chest X-ray revealed large amounts of fluid in her chest cavity. When the fluid was drained, a 5-cm tumour was found in her left lung.

Sharing her story ahead of lung cancer awareness month next month to warn other women of the disease, Mdm Sim said in Mandarin: “Although I smoked infrequently, I’ve always been known to be quite health-conscious. Many of my friends and relatives found it strange I ended up with this cancer that is more common in heavy smokers. Plus, no one else in my family has this cancer.”

Although lung cancer is the second-most common cancer that claims the lives of women here, awareness of the disease remains low. Many think the disease affects only men or heavy smokers.

It is the third most common cancer among women in Singapore, accounting for one in 13 cases of cancers detected in women, according to latest 2015 report by the Singapore Cancer Registry.

Women who smoke have a 10 to 20 times higher risk of developing lung cancer compared to non-smokers, said consultant medical oncologist Wong Seng Weng, medical director of The Cancer Centre at Mount Elizabeth Novena Specialist Centre.

But the majority of women diagnosed here have never touched a cigarette or have quit the habit. A local study found that about eight in 10 women with lung cancer here are non- or former smokers, said oncologist Daniel Chan of Icon SOC, who is currently treating Mdm Sim. They are likely to be above the age of 50, he said.

Genes are to be blamed in some cases, but the news is not entirely bleak.

“In non-smokers, particularly women, lung cancer tends to carry a particular genetic mutation, which makes these cancers very susceptible to a new form of targeted therapy. It blocks the growth switch on these cancers known as the epidermal growth factor reception,” said Dr Wong.

Second-hand smoke, as well as exposure to chemicals such as solvents, thinners and paint may also raise lung cancer risk, said Dr Chan. Women exposed to passive smoking have a 25 per cent increased risk of the disease than those not similarly exposed, said Dr Wong.

Wok-frying may potentially raise lung cancer risk

Research from Singapore and China has suggested that wok stir-frying, a common method of cooking, may be a risk factor, added Dr Wong.

The hypothesis is that fumes generated from heated oil used in wok cooking, including the stir-frying and deep-frying of meat, contain potentially cancer-causing compounds.

In the study published in the journal PLOS One in 2015 on more than 300 Singapore Chinese women who were non-smokers, researchers found elevated levels of potentially toxic and cancer-causing substances in the urine samples of those who regularly cooked at home. This indicated that the women were possibly exposed to toxic substances found in fumes produced during cooking.

Although more research is needed to prove a causal relationship between cancer and stir-frying, the study authors recommended taking preventive measures such as improving ventilation in kitchens to efficiently remove cooking-oil fumes.

Common red flags suggestive of lung cancer include a persistent or worsening cough, chest pain, shortness of breath, lethargy and coughing up blood or rust-coloured phlegm. Such symptoms may not always be apparent in the early stages.

The lack of early signs, together with poor awareness of the disease, means the majority of cases are detected only in the late stages, as in Mdm Sim’s case.

Eight in 10 diagnosed when disease has advanced

According to Dr Wong, seven to eight in 10 women with lung cancer are diagnosed when it has advanced to Stage 4, which is when the disease has spread to other organs or areas of the body.

Unlike some women cancers such as breast and cervical cancer, there is currently no effective screening programme for lung cancer here.

“Studies using normal chest X-rays to screen for the disease have failed to improve survival as the poor resolution of the X-rays could not pick up many cancers in the very early stages,” said Dr Wong.

A lung cancer screening programme using the Computed Tomography (CT) scan is available in the United States, but it is available only for selected high-risk individuals who are above the age of 55 and have a smoking history of 30 or more years, said Dr Wong.

While CT scans may be able to pick up early disease, the imaging procedure is not routinely used for screening measure as it is costly and exposes the patient to substantial radiation.

Women generally survive the cancer better than men but regardless of gender, non-smokers have better survival rates, said Dr Chan.

The overall five-year survival rate for women with lung cancer is about 17 per cent, compared to 10 per cent for men, said Dr Wong.

Survival rates are better when the disease is detected earlier. For instance, women with Stage 1 lung cancer have a five-year survival rate of almost 70 per cent while for Stage 4 disease, it is under 5 per cent, according to 2010 to 2014 figures of the Singapore Cancer Registry.

New treatments have also allowed more patients with advanced cancers to live longer.

In May, the Health Sciences Authority approved the use of a form of immunotherapy as the first treatment of choice for patients with non-small cell lung cancer that has spread – which accounts for about 85 per cent of all lung cancer cases.

The treatment harnesses the body’s own immune system to attack the lung cancer, particularly in patients whose tumours express large amounts of a type of protein, known as PD-L1, on their cell surface, said Dr Chan.

Clinical trials showed that patients who received the immunotherapy first, instead of chemotherapy, had a 50 per cent lower risk of dying or worsening of the cancer, said Dr Wong. Those who received immunotherapy also lived longer, with a median survival of 30 months instead of 14.2 months for those on chemotherapy, added Dr Chan.

The downside: The treatment comes at a high price, typically costing more than S$10,000 (RM31,000) per month, said Dr Wong. There are currently no government subsidies for the treatment.

Although uncommon, severe side effects may also occur in some patients, said Dr Wong. Cases of the life-threatening skin reactions, Stevens-Johnson syndrome and toxic epidermal necrolysis, have been reported.

On the new immunotherapy since August, Mdm Sim’s tumour has shrunk by half. Despite battling a Stage 4 cancer, she is well enough to care for her two grandchildren.

“If I don’t reveal my condition, no one can tell that I have cancer. I don’t feel like I am sick or am suffering,” she said.

The former food stall assistant may have to stop immunotherapy soon as she has depleted her savings, but she remains hopeful.

“My daughter cried when she learnt about my cancer but not once did I feel sad or afraid. I ended up consoling her instead. Medicine is so advanced now, I told her I won’t die so soon,” said Mdm Sim. — TODAY

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