The Causes of Cancer

DOLL R andPETO R (1981) The causes of cancer quantitative estimates of avoidable risks of cancer in the United States today , J Nat Cancer Inst, 66, 1191-308. 

We shall begin with a little history, and then move to a discussion of cancer statistics and the causes of cancer, and then provide some background on cancer biology and the mechanisms of tumor development. Some of the general characteristics of chemical carcinogens will also be covered. The methods for identifying chemical carcinogens are the subject of Chapter 6. How their risks are estimated is left to later chapters. 

In 1981, two eminent British cancer experts. Sir Richard Doll and Richard Peto published a paper in the Journal of the National Cancer Institute entitled The causes of cancer Quantitative estimates of avoidable risks of cancer in the United States today. The authors drew upon a vast body of literature of the type mentioned above, and attempted to allocate the deaths caused by cancers among various responsible factors. The authors concluded that a certain percentage of human cancer deaths could be avoided if exposure to the responsible factors could be eliminated or controlled in some way, although the appropriate degree and nature of control for some of the lifestyle factors, especially diet, is still highly uncertain. The Doll and Peto estimates are presented in Table 5.2. The factors are listed in a somewhat different order from how they were listed by the original authors, because of our interest in clearly separating lifestyle factors (the first... 

In the beginning, before there is analysis, there must be accurate description. How much cancer is there, and how do rates of occurrence vary geographically, and between sexes, and with age How do rates of different types of cancer vary over time, and what happens to the rates that occur in specific groups of people when they move from one geographic location to another Information describing these types of differences and trends - which can be compiled with accuracy only when cancer registry information is reliable - are enormously beneficial in providing clues to the causes of cancer. The statistical data presented in Chapter 5 arose from these types of studies. 

In 1867, Heinrich Wilhelm Waldeyer-Hartz proposed, with remarkable foresight, that cancer cells developed from normal cells during cell division and then spread by the blood or lymph to other sites in the body. He was an anatomist who not only realised the cause of cancer but also identified the basic unit of the nervous system, to which he gave the name neuron. 

The use of information on the mode of action in the assessment of potential carcinogens is a main focus of the revised cancer guidelines because of the significant scientific advances that have developed concerning the causes of cancer induction. 

Toxicology informs us about cancer on two accounts. First, toxicology research provided insight into the causes of cancer and likelihood of developing cancer. Second, many of the treatments for cancer have serious toxicological side effects. Cancer treatment must often balance the need to kill the cancerous cells while limiting the damage to the normal cells of the body. 

Doll, R. and Peto, R., eds., The Causes of Cancer Quantitative Estimates of the Avoidable Risks of Cancer in the United States Today. New York Oxford University Press, 1981. 

Early hope that animal, and especially bacterial, tests would produce cheap and definitive information about the causes of cancer in humans has now faded. Disputes over tests are even more controversial than disputes over human evidence, and many scientists consider them unreliable. 

The Causes of Cancer. Oxford, England Oxford University Press. 

R. Doll, R. Peto. In The Causes of Cancer, Oxford Medical Publications, Oxford University Press, Oxford, 1981, p. 1226. 

In Great Britain, radium dial painters with higher total radium-226 intakes and who were younger than 30 years of age at the start of painting showed an excess of breast cancers (Baverstock and Papworth 1989). External gamma ray exposure to the radioactive paint could also have been the cause of cancer in this population. 

In most cases, the cause of cancer is multifactorial. About 75% of cancers are due to environmental factors, some of which are within the control of the individual, e.g. tobacco smoking, exposure to sunlight. Growing understanding of cancer genetics and inherited disease suggests that fewer than 10% of cancers are familial.The different systemic modalities used to treat cancer patients are discussed. Immunosuppressive drugs are described here as they share many characteristics with cytotoxics. 

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