Diagnosing cancer, especially when the tumour is small enough to be curable, can be difficult. After all, as we have seen, there are some 200 different cancers, each of which can produce a distinctive pattern of symptoms. The average GP in England sees seven new cases of cancer a year.3 Most of these will be the common malignancies – skin, breast, prostate and so on – so most GPs lack experience recognizing the less common cancers.
Nevertheless, despite advances in screening, about 17 in every 20 cancers are diagnosed after a person presents with symptoms.1 To complicate diagnosis further, however, many ‘minor’ illnesses cause the same symptoms as a cancer.1 Indigestion (heartburn), headaches and backache might be the first sign of gastric (oesophageal or stomach), brain or pancreatic cancer respectively, but they are much more likely to be caused by a poor diet, dehydration and a pulled muscle respectively.
All the same, you should see your GP if the symptom persists. Public Health England, for instance, suggests that people who have indigestion on most days for three weeks or more should see their GP. Always see your GP if you have an alarm symptom or red flag (see Table 3.1). These can also be signs of a recurrence, second primary or progressive cancer.
Table 3.1 Examples of alarm symptoms or red flags for cancer3, 50
Red flags for lung cancer |
Persistent coughing of blood (haemoptysis) in a smoker or an ex-smoker, especially if more than 40 years of age |
Breathlessness |
Pain in the chest or shoulder or both |
One or more of the following symptoms that are unexplained or last for more than three weeks: cough, wheeze or weight loss |
Red flags for upper gastrointestinal tract cancer (such as stomach and oesophagus) |
Dysphagia – difficulty or discomfort swallowing |
Persistent vomiting and weight loss |
Unexplained iron-deficiency anaemia |
Unexplained weight loss |
Unexplained abdominal pain and weight loss |
A ‘mass’ (abnormal growth) in the upper abdomen |
Jaundice – a yellowing of the skin and ‘whites’ of the eyes |
General red flags |
Blood in your stools or urine |
Cough that lasts longer than three weeks |
Coughing up blood or blood-stained mucus |
Diarrhoea that lasts longer than three weeks |
Indigestion lasting longer than three weeks or not relieved by medicines, such as antacids |
Lump, such as in the breast or testicle, or changes in the way they feel |
Rectal bleeding |
Swallowing problems (dysphagia) |
Unintentional weight loss |
Unusual symptoms
Sometimes people develop symptoms that are not commonly caused by a malignancy but do turn out to be due to cancer, so it is sensible to get anything unusual checked.
For example, feeling a lump in the breast is often the first indication of breast cancer. In some women, however, the first sign of breast cancer is instead a scab on the breast or nipple that covers a small, weeping sore which does not heal.10 Indeed, about 1 in 6 women (17 per cent) with breast cancer go to their doctors with a symptom other than a lump, according to research presented at the 2016 National Cancer Research Institute conference, such as the following:
•about 1 in 17 women with breast cancer consulted their doctor because of abnormal nipples (7 per cent) or breast pain (6 per cent);
•less commonly, women went to their doctor with back pain (1 per cent) or unexplained weight loss (0.3 per cent);
•other changes that might indicate breast cancer include skin abnormalities, ulcers, changes in shape and an infected or inflamed breast.
Taking a look inside the body
Doctors can look inside your body to see if a tumour might account for your symptoms. For example, they might use ultrasound, X-rays or a flexible camera called an endoscope, which is a thin tube with a camera and light at the end. A surgeon can put the endoscope into your abdomen through a small cut to look at your internal organs on a video screen.
To look in more detail, your team may use computed tomography (CT) or computerized axial tomography (CAT ) and magnetic resonance imaging (MRI) scans. CT and MRI scans can visualize the inside of your body in often awe-inspiring detail. Imaging helps diagnose cancer and allows the team to ‘stage’ the cancer. For example, the cancer team might see if the tumour is restricted to the site of origin, has moved to the lymph nodes or has metastasized.3
Plain X-rays and fluoroscopy
‘Plain’ (standard) X-rays may, for example, detect tumours in the lung or bone, but X-rays often do not adequately differentiate normal and healthy tissue outside the skeleton. So sometimes the radiologist will inject a ‘contrast agent’, which increases the visibility of some organs and reveals fine detail when using X-rays, CT and fluoroscopy.
The radiologist might also use radioisotopes. These radioactive chemicals accumulate in certain parts of the body where there is increased activity. Some radioisotopes, for example, accumulate where bone is breaking down or being repaired. This helps detect cancers and metastases in the skeleton. Other radioisotopes are absorbed the same way as glucose. Because cancer cells are typically more active than healthy cells, they need more glucose and, in turn, take up more of the radioisotopes.3
Fluoroscopy uses continuous X-rays to produce moving images in real time, a bit like taking a video rather than a still image. Fluoroscopy can help surgeons to find obstructions that are blocking the bowel, bile duct or blood vessel, or to image the skeletal, digestive, urinary, respiratory and reproductive systems. The cancer team might also use fluoroscopy to place lines or ports for chemotherapy and to deliver treatment directly to a malignancy, such as microscopic, radioactive spheres to tumours in the liver.3
Sounding out cancer
When you are next in a cave or an empty room, shout your name. (Go on – it’s fun.) You will hear an echo. The sound wave produced by your voice hits the wall and bounces back. In some caves you will hear more than one echo. The first echoes occur when the sound waves bounce back from nearby surfaces. The more the echo is delayed, the further away is the surface that bounced the sound wave back.
Ultrasound uses a much more sophisticated version of the same general idea. The machine generates high-frequency sound waves that ‘bounce back’, and create images of the inside of the body. The basic approach used to image cancer is the same as that used to take a scan of an unborn baby. As this suggests, ultrasound is safer than X-rays.
Ultrasound is especially good at assessing malignancies in some organs, such as staging liver cancer. For example, ultrasound can detect liver tumours that are only a few millimetres across. Endoscopic ultrasound inserts the probe into the body on the end of a tube. This is especially valuable for examining the chest – the tube can move along the airways in the lung or down the oesophagus – or abdomen.3
Computed tomography
CT uses a beam of X-rays to produce numerous – often more than a hundred – ‘slices’ through your body, and can image the whole body in a few seconds. The beam varies in width, depending on the level of detail needed. A computer rebuilds the slices into a single three-dimensional, high-definition image. CT is used to stage most cancers, helps plan treatment and evaluate the response, and can detect suspected relapses.3
CT delivers a relatively large dose of X-rays, however. According to <www.radiologyinfo.org>, a normal X-ray of your arm – if you have a suspected broken wrist, for instance – delivers about the same amount of radiation you would receive from the normal background sources (see page 14) in three hours. A dental X-ray delivers about the same amount of radiation you would normally receive in a day. A CT scan of the spine or chest, however, delivers the same amount of radiation you would normally receive in two years. A CT scan of the abdomen and pelvis repeated with and without a contrast agent delivers as much radiation as you would normally receive in seven years.
As a result, CT might account for about 1 in 50 (1.5–2 per cent) cancers in the USA.3 If you are worried about the risks, speak to the cancer team. Cancers typically take many years to develop. Most people with cancer tend to be older or, unfortunately, might have a more limited life expectancy. So even if a scan triggers a cancer, the malignancy might not have time to develop. In other words, the benefits offered by X-rays generally far outweigh the risks.
Magnetic resonance imaging
MRI uses powerful magnetic fields to provide an even more detailed view than CT or ultrasound, so is especially useful when distinguishing healthy and malignant tissue can be difficult (such as in rectal, uterine and cervical cancers). MRI is also often the best way to image the brain and spinal cord to detect cancers and show if a cancer is causing spinal cord compression (see page 11).3 You must always remind your doctor if you have a pacemaker – MRI might interfere with some pacemakers.3
Sampling cancer
Doctors will probably run blood tests and look at a small sample of the tumour or tissue (called a biopsy) under a microscope. During a biopsy the doctor uses a needle to take a small sample of tissue that might be malignant. Usually you will be under a local anaesthetic. In some cases doctors perform the biopsy during an ultrasound or CT scan, which guides the needle to the abnormal area. From the sample, the cancer team can determine whether or not you have a malignancy and ascertain the stage – such as whether the tumour is well- or poorly differentiated (see page 3).
During an operation, the surgeon might take a biopsy of the tissue surrounding the tumour (the margin) or nearby lymph nodes to see if the cancer has spread or to ensure it has all been removed. After surgery the pathologist will examine the tissue removed. This might help characterize the risk of recurrence and assist oncologists in planning adjuvant treatment (see page 39).3
During Mohs surgery, commonly used to treat some skin cancers, the pathologist checks the tissue during the operation to ensure all the tumour has been removed. So rather than cut out a lump of tissue, the surgeon takes thin ‘peelings’. The pathologist examines the sample during the procedure and tells the surgeon whether or not to take another peeling.2 Mohs surgery cures almost all primary basal cell carcinomas (99 per cent) and primary squamous cell carcinomas (97 per cent).2
Increasingly, medical laboratories test a biopsy to, for example, identify the genetic fingerprint. As we will see later, this can have a big impact on the choice of treatment for some cancers. Indeed, the characteristics and, therefore, the best drug can change over time (see page 68). The cancer team may also examine a sample of your blood for genetic mutations. This allows the team to gain a ‘real-time’ portrait of the cancer and its response to treatment (liquid biopsy).
Complications of biopsies
Occasionally, biopsies can produce complications, although these are often minor and short-lived. Prostate biopsies, for example, can result in blood in the urine and sperm, difficulty passing urine and erectile dysfunction. For instance:
•between 1 in 17 (6 per cent) and a quarter (25 per cent) of men experience a short-lived exacerbation of urinary symptoms caused by the enlarged prostate;
•just over a third (34 per cent) have difficulty obtaining and maintaining an erection a week after the biopsy (none of the men had erectile dysfunction before the biopsy.)
In general, the complications improve after one to three months.51 Nevertheless, in one study, 1 in 37 (2.7 per cent) prostate biopsies caused a serious complication, 1 in 86 (1.2 per cent) in hospitalization and 1 in 57 (1.7 per cent) in an infection.52
Some parts of the body, such as the liver, have a very rich blood supply. This means that in these parts of the body, a biopsy can cause bleeding. If you have liver cancer, Cancer Research UK warns, there is a small risk that the malignancy could spread along the ‘tunnel’ left by the needle. The same might apply to some other cancers. Again, have a full discussion with your cancer team – but the benefits usually outweigh any risks.