Medical physicist

A Half-life of Burch

1. Medical Physicist

1920-1949

Youth, war and love

Like teeth and uranium, biographical information has a half-life, decaying with the passage of time. The letters and papers preserved in the Tobacco Documents furnish almost sufficient material for a full-length treatment of Burch’s last 15 years, but the rest must be reconstructed from obituaries and similar sources. This, then, is not even half a life of Philip Burch, for his first 18 years must be passed over in one sentence.

Philip Robert James Burch was born on 15 April 1920 at Alconbury, Huntingdonshire, and was educated at Huntingdon Grammar School.

A British schoolboy who turned 18 in 1938 could not expect the usual comfortable transition from home by way of university to adult life. War with Germany was on the cards, the Munich Agreement had bought nothing but time, and powers of conscription were taken in that year. But the documents do not say what the young Philip Burch did at the Post Office Engineering Department and in the Royal Navy (Air Branch). The Post Office then ran the telephone network (indeed, its Research Department provided the components for the code-breaking machines at Bletchley Park) and a colleague knew that Burch acquired hands-on knowledge of electric circuitry there, but that is all. The Air Branch of the Royal Navy – also called the Fleet Air Arm – guarded Britain’s coasts, operated its aircraft carriers and protected its shipping, but we do not know whether he served by air, sea or land.

VE Day, Hiroshima, Nagasaki, VJ Day. When the war ended, what should have happened did happen. In 1946 Burch went up to read Natural Sciences at Emmanuel College, Cambridge, whose old members include Fred Hoyle (though they did not overlap) and John Harvard. For Part I of his degree he took physics, chemistry, physiology and mathematics as a half subject: for Part II he studied pure physics.

Equally important, it was at Cambridge that Philip met the future Jane Burch, then an undergraduate in Natural Sciences at Newnham College. Jane Ramsey, daughter of the logician Frank Ramsey and niece of Archbishop Michael Ramsey, was Burch’s junior by six years but his contemporary in the postwar university bulge. She was highly intelligent, possessed of a loud, booming voice and taller than she would have wished to be. Many people found her intimidating, but not tall Philip Burch. She invited him to tea, they courted and were married in 1949. Shortly after, they left Cambridge for good.

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1950-1971

The Roentgen years

Both had secured research posts, a stroke of good fortune in those times of austerity, and they were headed for the University of Leeds. They set up home in a small house in Langley Terrace. The Department of Medical Physics, where Philip worked, was concerned with radiotherapy, X-rays and the application of physics to medicine in general. It was a place where he wanted to be. Although radiation was the focus of his work for the next 12 years, he told the head of department on his arrival that he wanted “to understand cancer” and that was his true life’s work.

It was then widely believed that radiation was the main cause of cancer, but Burch knew that other questions needed to be resolved before he could tackle that one. All living things are radioactive to some degree, including the human body, but how much was not then known. From 1949 to 1952, Burch designed and built the first whole-body radiation counter in the country (a major part of the task being to neutralise the effects of cosmic rays) and it won him his Ph.D. in 1953.

Jane Burch, a biochemist, was also awarded her doctorate in that year. Then the Burchs founded a family: their children Stephen, Belinda and Matthew were born in 1953, 1955 and 1958. This meant a ten-year break in Jane’s career as a lecturer – she returned to part-time teaching when Matthew started school – and also a search for a larger house. They found “a wonderful old house with a splendid garden” in Henconner Road, and it was their home for the rest of their lives.

The radiation counter was the first of a series. The original cavity ion chamber device was succeeded by models using the new scintillator materials. Burch worked on the designs meticulously, almost incidentally solving problems of pure physics in the process. He built up an international reputation in radiation physics over this period and was awarded the Roentgen Prize of the British Institute of Radiology in 1958.

Eniwetok, Bikini, Christmas Island. Radiation detectors had other uses during those early years of the nuclear age. The Cold War was on, and fallout from the atmospheric testing of nuclear weapons rained from the sky. Burch built an apparatus to measure it, consisting of “four large disc-shaped high-pressure ionization chambers, one above the other in a light wooden hut with the lowest chamber 10 feet above an undisturbed field”. He also investigated the results of the Windscale fire in 1957, measuring levels of radioactive caesium in milk and iodine in human thyroids.

The academic year 1961-62 saw a change of scene. Burch was invited to spend a year as a visiting scientist at Oak Ridge National Laboratory in Tennessee, once the factory of the Manhattan Project, but at this time (so far as is known) involved with nuclear safety and reactor design. The whole family went, joined by Jane’s mother Lettice. America was then embarked on a decade of change, and years later Jane recalled the racial segregation of the schools, a matter for the state, but not the swimming pool they used, Oak Ridge being a federal institution. They travelled far afield, taking holidays in Florida and Maine, and at the end of it all they returned to Leeds.

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Burnet, Burwell and Burch

In a full biography of Burch a new chapter would open here. Up to now he had held what his curriculum vitae described as “successive appointments” with the Medical Research Council, but in 1963 his department appointed him to a readership in medical physics, recognition that his achievements amply deserved. That year also saw a change of intellectual direction. In the course of 1962 he had come to think that his approach to carcinogenesis had reached “what I felt to be a dead end”. (It may also be significant that atmospheric nuclear testing was banned in 1963.) His new interest was autoimmune disease, which he initially tackled in collaboration with his Leeds colleague R. G. Burwell. Burwell later reminisced:

He was sitting at a table next to me. I knew who he was and something of his work, having read his paper on ‘Radiation Carcinogenesis’, published in Nature in 1960. I forget who spoke first. He started to tell me about a paper he was writing. It concerned the analysis of epidemiological data on inflammatory polyarthritis and rheumatoid arthritis. He explained that by fitting mathematically-derived lines to age-specific prevalence findings, he had concluded that random events were involved in aetiology.

In reply, Burwell described his own work on lymphoid cells and growth control.

Inevitably I asked Burch whether he had considered an even wider theoretical basis for his conclusion, namely that lymphoid tissue was involved in growth-control. ‘No’, he replied, ‘but we must meet again, and you can explain it.’

We met not once but several times to discuss each other’s work. As I explained my views, at first he was incredulous, but at that time Burch was not widely read on facts and theories relating to growth-control in the normal tissues and organs of the body. We soon found common intellectual ground and began to converse easily. We saw that the two theories, his and mine, were not incompatible, but together provided the basis for a unifying theory of growth-control and, at that time, of one disease, namely inflammatory polyarthritis and rheumatoid arthritis.

Burch was investigating hypotheses suggested by the Australian immunologist and Nobel laureate Sir Macfarlane Burnet, converting them into mathematical models and testing them against clinical data, which he collected avidly. Some of them proved untenable while others looked increasingly promising, and a stream of publications ensued. Burwell left Leeds in 1965, but Burch kept abreast of developments in physiology and continued to apply his methods to an increasing number of diseases. The total eventually reached around 200, including many which are not commonly regarded as autoimmune, so that he coined the new term ‘autoaggressive’ to label them. A profile published in the 1970s describes the pattern of work which was established at this time.

Every day from his arrival at Leeds General Infirmary at 8.30 am to his departure at 6 pm, and on into the evening at his home three miles away, is filled with reading and calculation around his theories, on top of his regular lecturing commitments in epidemiology and radiobiology… He admits to ‘lots of assistance’ from his wife, a biochemist who has ‘a very acute mind and is very good at logical thinking’. She ‘vets’ his formulated ideas, as do other groups of colleagues as part of his rigid self-examination process before he constitutes them in written form.

The theory of autoaggressive disease was published in book form as An Inquiry Concerning Growth, Disease and Ageing in 1968.

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“To understand cancer”

The list of autoaggressive diseases in 1968 already included some cancers – leukaemia, Hodgkin’s disease and Burkitt’s lymphoma – but by the end of that year Burch had come to the conclusion that most cancers were caused by the same fundamental mechanism as the autoimmune diseases he had started with. This did not mean there was no place for environmental carcinogens, radiation or infection in explaining how cancer arises. Some of his autoaggressive diseases are undoubtedly infectious, for instance mumps and polio, but Burch held that the somatic mutations hypothesised to cause autoaggressive conditions were a necessary precondition for the infectious agents to do their work as, variously, initiators, promoters and precipitators of disease. The spadework for The Biology of Cancer was done between 1968 and 1970 using the same methods as the earlier book. Burch formulated mathematical models of different forms of cancer and tested them against data, some of which he collected at Leeds General Infirmary. He left lung cancer for last.

There can be no doubt that Burch once shared the almost universal assumption that the main cause of lung cancer was cigarette smoking. As early as 1953 he had persuaded his wife Jane to give up smoking, presumably on the strength of Doll and Hill’s Hospitals Study, and a paper Genetic Carrier Frequency for Lung Cancer published in Nature in 1964 referred to cigarette smoking as “an extrinsic carcinogen”. He delayed consideration of lung cancer for the very reason that he expected the different smoking habits of successive generations to disrupt the patterns he was seeking to the extent of rendering his methodology unworkable. How he came to revise his views is best told in his own words.

I recall attending a lecture delivered by Bradford Hill in 1959 on the subject of smoking and lung cancer. As a physicist, largely innocent of epidemiology, I had no difficulty in accepting the causal theme of the engaging and persuasive Professor. This blissful state of innocence persisted until 1970 when, in the course of writing a book about the biology of cancer I felt, contrary to my original intentions, that I could not, really avoid discussing lung cancer. Indeed, I hoped that my unified theory of growth, cytodifferentiation and age-dependent “natural” disease might shed some light on the biological mechanisms of tobacco carcinogenesis. (That hope remains to be fulfilled.) Accordingly, I began to study for myself the literature and statistics about lung cancer and it was then that doubts about the simple causal theory of its association with smoking first assailed me. They are described in the book that was published in 1976. The shedding of entrenched beliefs is a painful process and it was not until I was directed to Sir Ronald Fisher’s 1959 compilation, Smoking, the Cancer Controversy. Some Attempts to Assess the Evidence, that I gained relief. If the “greatest statistician who ever lived” could indulge such subversive thoughts then who was I to reject constitutional considerations? Brownlee’s thoughtful critique of the first Report of the Surgeon General on smoking and health offered further support.

Burch presented the outline of his autoaggressive theory of carcinogenesis in his paper New Approach to Cancer published in Nature in 1970. The paper is mainly concerned with proposed physiological mechanisms and only discusses two specific cancers (cervix and breast). Neither lung cancer nor smoking is mentioned, but apart from a couple of short letters, he would never publish in Nature again. His career as a heretic was about to begin.

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2. Emergence of a heretic

Continued