it will take two and a half years for the mass of cells to reach the size of a small grape, about one billion cells. In other words, even if we could detect every tumour when it was grape-sized, the tumour would still have had two and a half years of reproduction before we found it. So most cancers do not, in fact, grow very fast.
This reality is very different from what most people think—and is another unfortunate result of lumping all two hundred or so cancers together under a single label. From reports in the media most people get the impression that every case of cancer is an emergency. This impression is also (in part) the result of the way we give priority to patients receiving treatment for cancer. Many types of treatment need a very exact time schedule. Chemotherapy and radiation, for example, must both be given on an exact schedule. Missing some days or doses is hazardous both in terms of loss of efficacy and in terms of possible side effects. Now while this, quite appropriately, means that cancer patients receiving treatment must get priority, it does not mean that the cancer itself is an emergency, although most people assume it is.
The result is that it becomes almost conventional wisdom to imagine that all cases of cancer will cause serious medical problems in a very short time, and that once a cancer begins, it will cause noticeable or detectable problems in a few days or weeks.
In the vast majority of cases—and it is worth stressing this point again—the situation is nothing like this. There are actually very few situations in which a cancer causes problems in so short a time. But the sense of dread and fear is amplified by the sense of urgency that often accompanies it. So in many cases the answer to the question, ‘Why could it not have been detected earlier?’ is related to the time-scale of the cancers themselves, not the failure to do tests often enough.
Third, how often does the same symptom occur when there is nothing serious going on? As the saying goes, ‘Headaches are common, brain tumours are rare.’ Some cancers—in fact, quite a few—may initially cause symptoms that are very common indeed.
This means that it can be very difficult to identify the few cases in which something potentially serious is going on from the very large number of benign cases, where nothing much is happening. That is why symptoms that might be associated with a cancer should be checked out by a doctor. This is particularly true for headaches, for example. Your doctor, taking some details of the headaches, may well decide which situations need further tests and which do not. Another example is bleeding during or after a bowel movement. Once again, haemorrhoids are common and colo-rectal cancer is by comparison fairly rare, but if you have bleeding and your doctor does not see any haemorrhoids, then further testing might well be important.
These two examples illustrate how difficult it can be to identify the rare case of a cancer. I am not saying this as an apologist for the medical profession. I simply want to point out that we generally do our best, and that all biological problems—including symptoms and cancers—are quite variable.
Looking back on a problem, you can almost always identify a moment when a symptom began, and it is very tempting to blame yourself for not having gone to the doctor sooner, or to blame the doctor for not having made the correct diagnosis instantly.
As a cancer doctor I often see this reaction. It is sometimes called retrospective guilt, or even retrospective blame. People often feel that any period of time that elapses during the process of diagnosis has somehow jeopardised them. In fact, that is very rare. Those feelings are part of the baggage that is brought in with all the reactions to the word cancer.
STEP TWO
‘Do I actually need all these tests?’
Staging
Staging tests are, according to some, ‘the insult that is added to the injury’. Often, they seem to do no more than delay getting the treatment started. But they do matter, and this section explains why.
In particular, the way the treatment for a cancer is planned often depends largely on the stage it has reached. Early stages are frequently treated differently from later stages.
This section will help you to understand why staging tests, although they seem to be a nuisance and an irritation, really do matter.
The principles of staging tests
One patient compared staging tests to ‘a patrol of the premises by security guards—they usually don’t find anything, but they know how to sound the alert if there’s trouble.’
The point is that some cancers can invade to a greater extent locally than is apparent when the doctor examines you, and some can spread to distant areas of the body without causing any symptoms or noticeable trouble. If either of these things has happened, the treatment plan will have to be modified accordingly. So the screening tests are done in order to find out if there is anything unexpected going on. And that means that a very large number of people will be having tests which turn out not to show anything unexpected. It’s a nuisance, but it’s important.
The staging tests are selected on two basic and simple principles which we can best express as the answers to these two important questions:
If this particular cancer were to spread, where in the body it is most likely to spread to?
Which tests both have a high likelihood of detecting something wrong at an early stage and do not usually produce a false-alarm or false-positive? That means they don’t give the appearance of a serious abnormality when there is actually nothing wrong.
I can best illustrate these two principles with two tests in breast cancer—a bone scan, and a blood test called the carcino embryonic antigen (CEA).
The bone scan is actually quite a useful—and subtle—test. A small dose of a harmless radioactive isotope called technetium is given to you by intravenous injection. When the technetium circulates in the body, it is taken up almost exclusively by the cells in the bone that actually make the bone tissue. These cells are called osteoblasts, and where they take up the isotope the bone scan will show a fine pattern of tiny black dots.
In many cancers, the cancer cells settle in the bone and start destroying the bits of bone around them. This provokes a reaction by the defence team, the osteoblasts.
This reaction is almost always provoked if a group of breast cancer cells lodges in the bone. With other cancers, that reaction doesn’t always happen. But with breast cancer if there is even a relatively small group of cancer cells spreading to and settling in a bone—such as the spine, or the long bones of the arms or legs—the bone scan is highly likely to show them as a larger than average black splodge, or hot spot as it is called.
Now it also happens that other problems—particularly in the joints, such as arthritis—can also produce hot spots on the bone scan, but arthritis and most noncancerous problems usually look different (and appear in different patterns and places) from cancer metastases. So in the great majority of cases, an experienced radiologist can look at the bone scan and state with considerable certainty whether there are any areas that might be secondaries or not. In some cases, the bone scan itself cannot distinguish between a probably benign appearance such as arthritis and a probably metastatic appearance. Then, x-rays of the area or CT scans of the area will be required.
So even if the patient has no symptoms related to that area—no pain or discomfort—the bone scan will probably pick up an early secondary or metastasis. That’s what makes it so useful as a staging test, and that’s why it’s worth having one, when recommended, even though you may have no symptoms or problems in your bones.
Because breast cancer has a high predilection for spreading to the bones, in any situation where the breast cancer has demonstrated a higher than average risk of spreading—if the lymph nodes are postive, for example—a bone scan is worth doing.
It’s a different story for the carcino embryonic antigen (CEA). CEA is a substance secreted by several different cancer cells, including colo-rectal, breast, and some lung cancers. In breast cancer, however, the levels of CEA are usually normal