THE FUTURE
The future for cancer patients should be viewed with a mixture of hope and caution. Certainly there is much that can be done to treat cancers through the skilled application of present knowledge. There is also great reason to expect improvements in prevention, diagnosis and care in the future.
However, just as there will be great advances in the prevention and management of cancer in the future, so too will there be new challenges. The condition AIDS is one such example: it is a new health problem unknown 35 years ago. Affected people have increased susceptibility to infections and to malignant tumour development, especially lymphoma or Kaposi’s sarcoma. The discovery of new antiviral drugs has led to control of the disease manifestations in patients with AIDS but not a cure. These patients now live a relatively normal life without the severe infections or malignancy.
People who have had organ transplants and are dependent on immunosuppressive drugs to prevent rejection of the organ also have an increased risk of developing cancer. This also is a relatively new problem, unknown 40 years ago.
The sexual revolution has exposed young women to an increased risk of cancer of the cervix. However, there is an expectation that the new vaccine available will, in the future, eliminate cervical cancer just as polio was eliminated.
It is not known what potential other modern drugs, especially illegal drugs, might have to increase the risk of cancer. It was many years before the dangers of tobacco smoking became obvious. Studies suggest that for long-term smokers of marijuana, the risk of cancer is similar to that for tobacco smokers.
PREVENTION
The most obvious way to reduce the risk of cancer is to avoid smoking. This has been known for some years but, human nature being what it is, this precaution has been widely disregarded. As long as there are large profits to be made from the sale of tobacco products, there will be resistance to the introduction of statutory measures aimed at reducing smoking.
Another useful measure is to encourage fair-skinned people to take greater protection against exposure to the sun.
More attention can also be paid to removal of pre-malignant conditions such as hyperkeratoses, leukoplakia, stomach and bowel polyps and papillomas, and to the prevention of such infections as hepatitis and HIV.
Diet and changes in lifestyle
Changes in lifestyle should include a reduction of animal fats, artificial additives and other contaminants in the diet, and a greater intake of fibre, fresh fish, fresh fruits and vegetables, nuts and protective legumes. This sensible diet will also reduce the risks of obesity, diabetes and cardiovascular disease. Moderation in the use of alcohol should be encouraged.
There will continue to be advances in understanding of the role of diet based on epidemiological information and a better understanding of the protective qualities of high-fibre diets, and of the apparent protective qualities of other agents, such as the naturally occurring hormones (phytoestrogens) present in soy and other plant foods and the antioxidants such as lycopene, the red colouring matter in tomatoes and some other red fruits.
Open-mindedness towards ‘alternative’ and naturopathic practices
More might be learned from alternative medicine and naturopathic practices as well as traditional practices from ancient and undeveloped communities. Several effective anti-cancer drugs are extracted from plants used in other cultures, and it is likely that other such anti-cancer agents will be discovered among plants being used in other cultures or by alternative practices. However, care must be taken to properly analyse such practices and not allow wishful thinking, emotion or fashion to cloud scientific and clinical judgement.
Improved environmental and industrial laws and practices
The reduction of atmospheric pollutants, vigilant observation of protective industrial laws and protection against radioactive sources are other important factors in the prevention of cancer.
Improved cancer screening
Another measure of increasing importance is regular screening of people at special risk for certain types of cancer so that any early lesions can be detected and treated before an advanced cancer develops. At present this seems to be the most appropriate way to detect early breast cancer, skin cancers including melanoma, cancer of the cervix, cancer of the stomach (in some countries) and large-bowel cancer.
It is anticipated that simpler and more accurate screening measures will be available in the future. These may involve simple blood-screening tests for cancer antibodies or other tumour markers to indicate the presence of cancer before symptoms have developed and at a more curable stage. The recognition that heredity plays a role in certain families, together with predictive DNA testing, will also play a larger role in the future.
EARLY DETECTION AND TREATMENT: IMPROVED DIAGNOSTIC TECHNIQUES
Improved diagnostic measures will also allow more accurate diagnosis at an earlier stage. Already, improvements in CT scanning and other organ-imaging techniques have made considerable advances, and further advances are assured. Magnetic resonance imaging (MRI) has added to these improved diagnostic and imaging methods. It is anticipated that the newer method of organ imaging, PET (positron emission tomography), may make an even greater impact within a few years because of the additional information it gives about the activity, composition and survival of tumour cells and its capacity to detect secondary cells at an earlier stage than has been possible in the past.
Fine-needle aspiration cytology, frozen-section techniques and other improved pathology techniques have allowed major progress in detecting and establishing the nature of tumours. Improvements in the ability to examine body cavities with the use of flexible fibrescopes have allowed considerable progress in detecting and assessing early cancers in recent years, too. These instruments and their applications will undoubtedly continue to be improved.
IMPROVED AGENTS AND MORE EFFECTIVE USE OF CHEMOTHERAPY
Improvements in treatment, with more effective and more specific anti-cancer drugs, is ongoing. So too is knowledge of how best to use such drugs in combinations and appropriate treatment schedules for achieving greater anti-tumour effects with a reduced risk of toxicity and unwanted side effects. New and more effective anti-cancer agents such as monoclonal antibodies or small designer drugs directed at specific cancer-cell targets are now producing, in combination with chemotherapy, improved outcomes for a wide range of cancers. Many drugs are being made safer and more effective with the increasing availability of agents that protect bone marrow and other body tissues.
Advances in molecular biology coupled with the sequencing of the human genome have led to analysis of the arrangement of DNA in genes in a genome (called microarray) of common human cancers. This is leading to a more accurate prediction of long-term outcomes and better selection of treatment modalities for individual patients in various clinical trials.
IMPROVEMENTS IN RADIOTHERAPY
Treatment by radiotherapy is also being constantly improved, with sophisticated computer-planning technology coupled with CT, MRI and PET scans that accurately image tumour targets. The ability to combine radiotherapy with chemotherapy has improved treatment results too. More effective use of chemotherapy and radiotherapy integrated with surgery can be anticipated as cancer specialists become better organised in multidisciplinary teams focusing on specific cancer types. The best example of this has been in the treatment of breast cancer. The combined effects of earlier diagnosis with less mutilating surgery and either adjuvant chemotherapy or hormonal therapy has seen the death rate from this disease fall by over 20% in the last 15 years.
Newer forms of radiation therapy are available and being tested in trials in a small number of world specialist centres. One such form is a Cyberknife, which is basically an advanced linear-accelerator technique that rotates around the cancer region, focusing the irradiation onto a limited central region. This equipment and technique is being especially studied in Washington DC. Another newly developed treatment is proton-beam therapy, which directs irradiation to deep, specially targeted cancers. This equipment and technique is being chiefly studied in Boston and in Loma Linda in California. Another recent development in radiotherapy is the use of a neutron beam. Early studies show it to be effective in treating an otherwise resistant type of salivary-gland tumour called an adenocystic carcinoma.
HEAT THERAPY AND CRYOSURGERY
Another treatment possibility, as yet not well exploited, involves the known increased susceptibility of cancer cells to heat. Studies of the application of heat to selectively eradicate cancer cells, possibly in combination with anti-cancer drugs, may produce improved treatment techniques for certain types of cancer in the future. At the same time the application of extreme cold to cancer cells (cryosurgery) is being further developed, especially as a technique to cure secondary cancers in the liver.
IMMUNOTHERAPY
An enormous amount of research in universities, hospitals and cancer-research institutions is attempting to better understand the role of immunological defence mechanisms against cancer. There is hope that specific immunological tumour markers will lead to earlier diagnosis of certain cancers. This would improve outcomes, for instance, in ovarian cancer. Monoclonal tumour antibodies are now widely used in the treatment of certain forms of breast cancer and lymphoma, and their use may extend to many other tumour types. There is hope that a more reliable means of stimulating the immune defence system through various vaccine-like treatments may also emerge, despite many negative past results. Studies with products of the immune defence system such as interferon and the interleukins (see Section 2) have not as yet had the impact originally expected.
GENETIC ENGINEERING
New techniques of molecular DNA biology offer a different approach to combating cancer. It may soon be possible to change the structure of DNA in cells and thus change the nature of actually or potentially malignant cells into cells without the properties of malignant growth. The new science of genetic engineering also has potential for changing the basic nature of cells to prevent cancer developing or to change the nature of malignant cells.
TARGETED SMALL-MOLECULE SIGNAL INHIBITORS
There is now a very detailed understanding of the growth and cell division of biochemical pathways in normal and cancer cells. Specific mutations or changes in these pathways are responsible for the abnormal growth of cancer cells. Many new drugs have been and continue to be developed that specifically inhibit these steps. (The best known is a drug called Glivec, which is very effective in treating chronic myeloid leukaemia.) These are being introduced into clinical trials in conjunction with the older chemotherapy drugs, with improved outcomes in several cancer types.
IMPROVED PALLIATIVE CARE
For those people with advanced cancer and in great discomfort or pain, methods of relieving the suffering are now better understood. Such measures are now more readily available and there is little need for patients to suffer greatly from pain or other distressing symptoms of cancer. These facilities will be further improved and made more readily available to those who need them.
HOPE FOR THE FUTURE
For those with serious but not terminal disease, there are now good prospects for recovery: there is a probability of cure for increasing numbers of patients with cancer. Today, even excluding the relatively simple skin cancers, overall cure rates are well over 50%. Even for those with what is still considered to be terminal disease, worthwhile palliation is available to improve quality of life, and there remains the hope that for some, further improvement in treatment methods may soon bring a better prospect of cure.