Sometimes a patient suffering from cancer begins, for no obvious reason, to improve. If the manifestations of his disease become less serious for a time he is said to have experienced a spontaneous remission, and if these manifestations disappear he is said to have experienced a spontaneous regression or even spontaneous cure of the disease. It is likely, of course, that these remissions or regressions are not truly spontaneous, but instead have a cause, which might be the stimulation of the patient's immune system when he contracts an infection, such as erysipelas (Chapter 9), or changes his diet. The number of true spontaneous regressions that have been reported is usually given as 200 or 300 (Everson and Cole, 1966), but the number must in fact be much larger, because such a regression that occurred while the patient was undergoing treatment would be attributed to the treatment. Spontaneous regressions have been observed not only for patients with early malignant lesions but also for those with the most advanced disease.
Evidence
about the occurrence of spontaneous regressions combines with other
evidence to strengthen the belief that the natural protective mechanisms
of the human body operate to overcome many malignant tumors. For
example, cervical cytology (the Pap test) indicates that about 15
percent of women have "positive smears" at some time in their lives -
that is, cells that show signs of malignancy - but only about 0.37
percent die of cancer of the cervix. This means that cancer of the
cervix is a far commoner disease than we usually think it to be, but in
39 cases out of 40 the disease is controlled. Also, in many European
hospitals meticulous autopsies are performed without regard to the cause
of death, and these autopsies reveal a remarkably high incidence of
cancers that were never suspected in life. For some cancers the number
of these unrevealed cases is far greater than the number of revealed
cases. For example, cancer of the thyroid and cancer of the pancreas are
found to be 30 or 40 times as common in autopsy findings as are
presented in the doctor's office. Autopsy cancer of the prostate
increases steadily with increasing age until after age 75 it is found in
every second male, yet only about 2 percent of males die of prostate
cancer.
What are these
mysterious cancers that turn up in such profusion in the dead but seem
to have refrained from causing trouble during life? The tumors are
usually small, but when they are looked at through the microscope they
are seen to have essentially all the characteristics of a growing
invasive cancer. Cancer is therefore far more common than we usually
realize, and not such a vicious disease as is commonly thought, except
when it gets out of control. The great majority of cancers are held in
check by the body; they grow for a while, then regress and disappear,
and it is only an occasional one that escapes from control and forms a
progressive cancer.
It
seems likely that, even in well-established cancers, "spontaneous
regression" could be playing a more important part in treatment than we
have realized in the past. If a cancer patient is treated and then lives
for five years in good health, it is natural to assume that the
treatment is responsible for this happy outcome. But this is not
necessarily so. Almost every surgeon can remember carrying out
resections that, for technical reasons, were less than adequate, and yet
being gratified to find that the inadequately treated patient is still
alive and in apparent good health many years later.
There is increasing
awareness that the doctor is not the only factor involved in the
treatment situation, and that we have to rely a good deal upon nature to
back up our efforts. Thus it is often good surgery to remove the main
tumor even when it is known or strongly suspected that spread beyond the
field of possible removal has already taken place. We then rely upon
the immune system or natural resistance to destroy the remaining
malignant cells. This sort of action can be seen quite strikingly in
some patients with kidney cancer that has already spread to the lungs.
The diseased kidney is removed, and sometimes the lung metastases then
wither away and disappear completely. This, it must be stressed, is a
very rare occurrence, but the fact that it can occur at all is truly
remarkable.
When one
talks of spontaneous regressions one usually thinks of the patient with
hopelessly advanced disease, who, without any treatment, suddenly starts
to get better, and may continue to get better until he is completely
well. These near-miracles are extremely rare, but some hundreds of such
instances have now been thoroughly documented. Spontaneous regression
teaches us that doctors and their treatments are not all-powerful, and
that there exists in every one of us a mechanism with the potential to
cure cancer, working alongside whatever treatment is adopted. It is
regrettable that it is not completely effective in every patient. A goal
for cancer research is to find the ways to make this mechanism more
effective.
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