Unexplained weight loss, persistent fatigue – doctors reveal cancer warning signs you shouldn't ignore

CNA

6 hours ago

When it comes to the Big C, we know that early detection often leads to a better prognosis. 'Cancer remains a leading health concern in Singapore, but early detection can save lives,' said Dr Terrance Tan, a specialist in medical oncology and a senior consultant at Raffles Cancer Centre.
But what are the symptoms to look out for when there are so many different types of cancer?
And more perplexing, cancer may not present with symptoms in their early stages, according to Dr Zee Ying Kiat, a senior medical oncologist from Parkway Cancer Centre at Mount Elizabeth Hospital. 'As cancer grows and possibly spreads to other parts of the body, it might, in turn, cause general symptoms and/or symptoms affecting specific areas,' he said.
When and what should you be vigilant about? Here's what the experts say:
ARE THERE COMMON CANCER SYMPTOMS IN THE FIRST PLACE?
Not really, said the oncologists that CNA Lifestyle spoke to. 'We don't have specific patterns of the most common signs seen in patients,' said Dr Samuel Ow, a senior consultant with National University Cancer Institute, Singapore's Department of Haematology-Oncology.
'But typically, the presenting signs and symptoms are representative of the most common cancers in Singapore,' said Dr Ow, who is also an assistant professor at National University of Singapore's Department of Medicine, Yong Loo Lin School of Medicine.
Take colorectal cancer, the second-most common cancer in Singaporeans, for example. 'The symptoms arising from the colon might include changes in bowel habit and passing blood,' said Dr Zee. Indications that it has spread might include persistent abdominal pain, he added.
In breast cancer, continued Dr Zee, the symptoms might include a breast lump and bleeding/abnormal discharge from the nipple. Symptoms that point to the cancer's spread to the bone or liver might include bone pain or abdominal pain respectively.
IF YOU'RE BETWEEN AGES 20 AND 50, WHAT ARE THE CANCERS YOU SHOULD WATCH FOR?
Since cancer symptoms are specific to the type of cancer, it makes sense to pay attention to the common cancers in men and women in Singapore. Citing the Singapore Cancer Registry (2017-2021), Dr Tan lists the top five cancers for men and women aged 20 to 59 – and their potential red flags:
WOMEN
Breast cancer: Check for a breast lump, nipple discharge, breast pain or skin changes such as dimpling.
Colorectal cancer: Symptoms include blood in the stool, abdominal discomfort, bowel changes or weight loss.
Cervical cancer: Look out for abnormal vaginal bleeding, pelvic pain, pain during intercourse or unusual discharge.
Lung cancer: Be vigilant about a persistent cough, shortness of breath, chest pain or blood in the sputum.
Thyroid cancer: Be aware of a lump in the neck, difficulty swallowing, hoarseness or swollen lymph nodes.
MEN
Colorectal cancer: Look for blood in the stool, abdominal pain, altered bowel habits or unexplained weight loss.
Lymphoma: Watch for swollen lymph nodes, persistent fatigue, night sweats or weight loss.
Testicular cancer: Note lumps or swellings in the testicles, scrotal discomfort or lower abdominal pain.
Lung cancer: Be alert for a chronic cough, shortness of breath, chest pain or coughing up blood.
Liver cancer: Symptoms include abdominal pain, jaundice, weight loss or loss of appetite.
​​​​​​​SYMPTOMS VS SIGNS – IS THERE A DIFFERENCE?
Oncologists do differentiate between 'symptoms' and 'signs'. Symptoms are experienced and reported by patients, whereas signs are findings observed by a healthcare professional, clarified Dr Zee Ying Kiat, a senior medical oncologist from Parkway Cancer Centre at Mount Elizabeth Hospital.
CAN THERE BE OTHER SYMPTOMS?
Yes, there can be. It pays to take note of non-specific symptoms, said Dr Ow, which can include persistent tiredness, headaches, giddiness, weight loss, shortness of breath, unusual bleeding or unexplained pain.
'Even if they are not due to an underlying cancer, they can still be due to other conditions that need to be dealt with such as anaemia from heavy menstrual bleeding or dietary insufficiency,' he said.
MANY OF THE NON-SPECIFIC SYMPTOMS SEEM HARMLESS. HOW DO YOU KNOW WHEN TO ACT?
Losing a few kilograms might seem like good news, especially if you've been working on your weight. However, losing 5 per cent or more of your body weight in six months, especially if unintended, is not normal and should be evaluated, cautioned Dr Ow.
'The weight loss is a general warning that may indicate a wide range of malignancies,' explained Dr Evelyn Wong, a consultant with National Cancer Centre Singapore's Division of Medical Oncology. 'It suggests that the cancer is using up the body's energy or causing poor nutritional absorption.'
Extreme tiredness or fatigue that doesn't improve with rest or recovery is another non-specific sign to look out for. 'It is often due to anaemia, bone marrow suppression or the body's inflammatory response to cancer,' said Dr Wong.
Another red flag is the shortness of breath, even when you're not running or climbing the stairs. It could indicate the spreading of cancer to the lungs or the cancer causing the lungs to produce water, said Dr Ow.
Be wary, too, if you experience difficulty in swallowing or persistently feel full, cautioned Dr Ow. 'This can be due to cancer in the swallowing tract. If the cancer has spread to the abdomen, it can cause water retention or liver enlargement that presses on the stomach. Advanced cancer can also result in significant reduction in appetite.'
HOW LONG SHOULD YOU OBSERVE THE SYMPTOMS FOR?
'A good rule of thumb is to see a doctor if a symptom persists for more than three to four weeks or if it gets worse over time,' said Dr Wong.
Similarly, go to a family doctor if you feel uncomfortable, advised Dr Ow, who can then take a detailed history and physical examination, and decide if further investigations are required. 'Understanding your family history of cancer or other medical issues can also help decide if the suspicion of cancer is high,' he said.
For that matter, seeing a doctor is more urgent if you have a family history of cancer or a known genetic risk, such as Lynch syndrome or BRCA mutations, said Dr Wong. 'Being proactive such as knowing your family history and not delaying care can make a difference.
IF THE SYMPTOMS ARE INTERMITTENT, ARE THEY LESS LIKELY TO POINT TO CANCER?
Persistent symptoms are generally more concerning but intermittent ones shouldn't be ignored, especially with risk factors such as a family history of cancer or smoking, said Dr Tan. Intermittent symptoms should still be evaluated, especially if they 'recur regularly or worsen over time', he said.
For instance, cancers of the colon and ovaries may cause intermittent symptoms in the early stages due to the intermittent tumour growth affecting nearby tissues, said Dr Tan. 'For example, intermittent abdominal bloating may precede persistent symptoms in ovarian cancer.'
He added that intermittent symptoms are often benign but recurring patterns (such as bloating every few days for months) warrant investigation to rule out cancer. 'Regular recurrence over weeks to months should prompt a doctor's visit.'
ARE THE SYMPTOMS LESS WORRYING IF YOU'RE YOUNGER?
Age does indeed play a role in increasing the risk of cancer development, said Dr Wong. 'This is due to various factors, such as cellular damage accumulation due to ageing and longer exposure to risk factors like smoking, drinking alcohol or unhealthy habits,' she said. 'Hormonal changes also play a role; women after menopause may have a higher risk of certain women's cancers.'
The statistics prove that, too. According to the Singapore Cancer Registry 2022 Annual Report, older individuals make up the majority of cancer cases – and this proportion is growing. 'Between 1968 and 1972, and 2018 and 2022, the percentages of cancer diagnoses among those aged 70 and above rose from 15.7 per cent to 45.3 per cent in males, and from 17 per cent to 35.3 per cent in females,' cited Dr Wong.
However, it doesn't mean that if you're below 50, you're off the hook. 'There are two important considerations as far as age is concerned,' said Dr Zee. 'One, while it is true that the risk of developing cancer increases with age, it is also a fact that younger people are affected by cancer as well.' For example, about one in 10 patients diagnosed with colorectal cancer in Singapore is younger than age 50, he said.
Two, 'the types of cancers that younger people develop might sometimes be different from those that affect older people,' added Dr Zee. 'For example, testicular cancer occurs more commonly in younger males who might present with a lump in the scrotum.'
Dr Ow also reiterated that you should not disregard the symptoms just because you're not of 'cancer age'. 'Sometimes, younger people may disregard symptoms such as a breast lump because it can't be cancer since they are young,' he said. 'But if the symptom is persistent, one should definitely get it evaluated.'
​​​​​​​WHAT ARE THE CANCER-SCREENING TESTS YOU SHOULD BE GOING FOR?
If you aren't already familiar, these are the basic screening tests you should be going for, according to age:
Mammogram, every two years: Women aged 50 to 69
Pap smear, every three years: Women aged 25 to 29
Human Papillomavirus (HPV) Test, every five years: Women aged 30 and above
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HOW DO YOU AVOID BECOMING A HYPOCHONDRIAC AND WORRY ABOUT EVERY SINGLE THING?
'Monitor mild, non-specific symptoms (such as bloating or fatigue) for two to three weeks,' advised Dr Tan. 'If they resolve or are linked to clear causes, including diet or stress, cancer is unlikely.'
Also, avoid over-testing, added Dr Tan, including unnecessary tumour marker tests as false positives can fuel anxiety. 'Consult a doctor for personalised screening plans,' he said.
While no test can provide 100-per-cent guarantee that cancer is not present, there are assuring signs that you are likely to be cancer-free, said Dr Wong, referring to the following:
You've kept up with the recommended screenings such as mammogram, Pap smear, and Faecal Immunochemical (FIT) Test or colonoscopy – and the results are normal.
Your symptoms resolved on their own or improved with standard treatment.
Your doctor has performed a full evaluation and found no cause for concern.
'Ultimately, cancer prevention isn't about fearing every symptom,' said Dr Wong. 'It's about making informed, healthy choices and knowing when to seek medical help. With the right habits, regular check-ups and consistent care, you can protect and take control of your health with greater confidence and peace of mind.'