CANCER is still a dreaded word, a disease most of us fear and one which many among our friends and acquaintances have had to face. Or, if numbers are anything to go by, will face.

George Johnson, a journalist who has been writing on science for a long time, started reading up on cancer when his wife was diagnosed with the disease. He wanted to understand the beast better, to look for treatment options for his wife and to see if there are things that we can do to decrease our chances of getting cancer. His wife survived, though the treatment, as expected, was long and difficult. But some of Johnson’s friends, who also had cancer, did not. And Johnson ended up writing The Cancer Chronicles: Unlocking Medicine’s Deepest Mystery, a small but important book on cancer and its mysteries for the non-specialist.

The ‘disease,’ if it can be called that, has been with us for a long time. Traces of cancers have been found in the bones of animals and humans who died thousands of years ago. And there are reasons for it. Cancers are not just caused by carcinogens in the environment and / or viruses and bacteria. In fact, few cancers are supposedly caused by these. Rather, cancers are due to the mutations that take place at the cell level as a result of normal and regular cell division process.

Research that Johnson reviews in the early chapters shows that the process of cell division can be impacted by many things: exposure to radiation, what we eat and drink, what we breathe, what we are exposed to in the environment, what goes on in our body, what goes on in our cells, what goes on in neighbouring cells, what happens to the bacteria and viruses that reside in our body… the list, so far, seems endless.

Cells replicate themselves in our body all the time. New cells replace the old and old ones die. We have millions of cells in our body. Mistakes, in replicating the DNA strand, happen in the replication process. These mistakes are carried on by new cells within them and in turn passed on. Researchers have shown that there are strong mistake-rectifying processes within cells too. Many mistakes are corrected, many others are harmless and are sometimes carried on by the next generation of cells without impacting us. Some mistakes are even beneficial and can lead to our betterment and evolutionary changes.

However, some mistakes are not so beneficial and create cells that replicate fast, take over areas and become tumours and / or get rooted in organs or body parts, take nutrition from surrounding areas, create artery / vein structures for sustained nourishment and then start causing trouble for the body. These form the bulk of the cancers in us. It might only be a few errors in replication, but the consequences, for the host body, are usually quite considerable.

Mistakes in the replication and division process of cells can happen for a variety of reasons. Scientists do not think they know all the reasons yet, but even the reasons we know are quite plenty. Exposure to radiation (ultra-violet, x-rays, gamma rays, and so on), exposure to carcinogens in the environment or in what we eat and drink, stress on the body (obesity, inflammation) or any of its parts, exposure to certain viruses and bacteria, and even the way neighbouring cells interact with each other can lead to replication mistakes. But, according to Johnson, we do not yet know all the mistakes that lead to cancers and all the ways in which mistakes can be triggered.

Cancer cells, in general, do have some properties. They replicate quickly, and quite often the older cells forget to die. Sometimes, these cells are just replication machines. And once they have enough numbers, they are bound to cause problems for the body. Cancer cells are our own cells but different from the normal cells at the sub-cellular level. And herein lies the rub in finding cures. Cancer cells are hard to find and differentiate from normal cells. We still do not know all the mutations that lead to cancers, the reasons for these mutations and the markers with which to identify cancer cells. And even when we do, it is not easy to find medicines that target cancer cells only. We also do not know how cancer cells can lead to further mutations that allow them to avoid being killed by certain medicines.

We have developed a lot of medicines for fighting cancer, but most medicines only increase life spans, sometimes only by a few months. We have few cures and for a few cancers, and most of these medicines have significant side effects too. For instance, radiation can kill cancers but also cause new ones.

Chemotherapies can do the same. The battle is clearly far from over. And the front is not just coming up with new and better chemicals that can destroy cancer but also understanding what produces cancer, why certain cells become aggressive at certain points, when they become predatory, and how do they create and / or manage their environment (micro-environment). Even on the prevention side, given our lack of understanding of the causes, there is little that can be said with a lot of assurance. We only know a few things with some confidence: obesity and / or inflammations in the body and cancer incidence seem to be related. And as you grow older your chances of getting cancer also increase. But other than these, few relationships are as strong or as probable. Smoking can cause cancer and other diseases, and there are hundreds of carcinogens, natural and human-made, but we do not understand the mechanics as clearly.

Moreover, exposure has to be significant to increase probabilities by even a small number. Though we should bear in mind that a percentage point increase in the likelihood of getting cancer might not be a very significant increase in risk for one individual, if we are talking of increased exposure for a population (say Pakistan with population of 200 million), it is two million more cancer cases.

Given the plethora of carcinogens we face and the exposure to radiation in our everyday life, we can do only a little to protect ourselves from the risks emanating from these directions. But regular exercise and avoidance of obesity might be more doable for most people.

While The Cancer Chronicles is a bit dry and slightly heavy reading at times, it is very well written for non-experts. For those who are interested in understanding “medicine’s deepest mystery,” this and Siddhartha Mukherjee’s The Emperor of All Maladies are a good starting point.

There are plenty of promising ideas in the research surrounding cancer. But though we will continue to make progress on individual medicines and individual cancers, we are far from understanding cancer in general. What is important is that our journey continues. For those who want to have a sense of this journey, Johnson’s book is worth going through.

The Cancer Chronicles: Unlocking Medicine’s Deepest Mystery

(MEDICINE)

By George Johnson

Vintage, US

ISBN 030774230X

284pp.