View report page

60
In this particular field, some recent studies have shown the
possibility of immunising animals against injection of known
carcinogenic cells by first introducing hybrid cells formed by fusing
these malignant cells with normal cells of another animal. Extension
of these researches into the human problem is awaited with
more than academic interest.
Although, in the absence of full knowledge, pragmatic action
can usually be justified, finding the cause of cancer is a prerequisite
to an effective preventive service.
The World Health Organisation's Expert Committee on Prevention
of Cancer has estimated the "potential preventability" of
most cancers by early diagnosis and prompt appropriate treatment
to be as high as 50% but, because of the varied and illusive nature
of cancer causation, control rather than prevention becomes the
immediate task of public health authorities.
In addition to exfoliative cytology, early detection techniques
include thermography, use of ultra sonics, immunological tests for
liver cancer. X-ray mammography and xeroradiography for detection
of breast cancer, not forgetting self-examination. Opportunities
for far less drastic treatment are presaged by improved
sigmoidoscopy which enables pre-malignant lesions of rectum and
colon to be more easily detected.
Some cancers appear to be virus induced—some protein grown
moulds such as aspergillus flavus are capable of producing carcinogenic
toxins—certain chemicals, useful to man in many ways, are
suspect—cigarette-smoking and atmospheric pollution as well as
radiation have already been indicated as cancer stimulating. Indeed,
it is possible that many environmental carcinogens of low
concentrations, of little moment singly, could together produce
malignancy. Although it would seem that little of the environmental
scene is exempt from blame, we must at all costs avoid
the onset of "cancerphobia".
Nevertheless, more intensive epidemiological studies are called
for and to this end the W.H.O. is encouraging the establishment of
standard criteria of diagnosis and has set up International Reference
Centres for individual classes of tumours, London being the
centre for thyroid and intestinal tumours.
With expanding knowledge of the molecular biology of the
cancer cell and health education coupled with ever increasing
methods of detection and treatment, it is certain that evolution of
preventive measures for many, if not all malignances will not long
be delayed.