Cancer: Past, Present and Future
from 05:30 PM to 06:30 PM
Professor Paul Symonds
Department of Cancer Studies and Molecular Medicine
My first contact with a revolutionary new treatment for cancer was as a Houseman in 1973 when I administered MVPP chemotherapy to patients with lymphomas. One of the components of the combination was mustine, a close relative of the chemical warfare agent mustard gas. This agent in particular made patients vomit profusely and all we had as anti-sickness medicine was large doses of chlorpromazine. However, 70% of patients went into complete remission and a significant proportion were cured.
During the time I have been a Consultant there has been a steady fall in mortality from cancer. In the East Midlands the 10-year survival for operable breast cancer has risen from under 50% in 1975 to 90% currently. There has also been a 15 to 20% increase in five-year survival for colorectal cancer. Since 1988 prostate cancer deaths have fallen by a third. Overall more than 50% of cancer patients are now expected to survive at least five years after treatment. At present 50% of the cures of cancer can be attributed to surgery 39% to radiotherapy and 11% to chemotherapy. Cures due to radiotherapy are partially due to the enormous advance in imaging allowing treatment to be accurately delivered to the tumour. There has been a technological revolution in the way radiotherapy is given allowing less normal tissue to be treated with a lesser risk of late complications. A higher dose can be also administered with a greater prospect of cure.
In 2012 there are now three linear accelerators at the Leicester Royal Infirmary that are capable of delivering any of the newer forms of radiotherapy including intensity modulated radiotherapy, (IMRT) and stereotactic radiotherapy. These linear accelerators are equipped with cone beam CT scanners to check that the tumour is within the treated area during every treatment.
The decline in incidence and the improvement in survival of patients with cervical cancer is instructive. The incidence of this disease has markedly declined in the developing world partially due to cervical screening. It still remains though the most common female cancer in South America, South Asia and sub-Saharan Africa. Cure rates have been improved by combining cisplatin chemotherapy with radiotherapy and the results of clinical trials have been reproduced in a recent audit organised by the Faculty of Oncology of the Royal College of Radiologists. A forthcoming trial will look at the impact of six weeks’ chemotherapy prior to chemoradiotherapy compared to standard chemoradiotherapy alone.
One of the biggest changes in cancer medicine is communications with patients. When I started as a Consultant in 1981 few patients were told the diagnosis of cancer. I led a team in Glasgow in the 1990s that showed over 90% of patients with curable or incurable cancer wanted to know whether they had cancer or not and a large amount of information about the disease and treatment.
A high desire for information has been shown amongst British South Asian patients in Leicester. There is also greater emphasis on treating psychological symptoms due to cancer. Studies in Leicester have shown that British South Asian patients have higher levels of anxiety and depression than White patients. These differences are not due to either cancer beliefs or trust in doctors but are associated with differences in coping styles particularly fatalism, hopelessness/helplessness and denial of the cancer diagnosis.
Future trends in the treatment of cancer include a greater use of radiotherapy. 50% of cancer deaths are due to local recurrence of the cancer and this could be reduced further by new radiotherapy techniques. There will also be a greater use of personalised medicine. Two examples of personalised medicine projects in Leicester are the identification of genes that predispose to late radiation damage and work on an enzyme that may be one of the reasons for chemoradioresistance in rectal cancer. About 5% of patients treated with potentially curative doses of radiotherapy develop serious, chronic, late side-effects. Such patients have abnormally radiosensitive normal tissues and there is increasing evidence that genetic testing can identify these individuals.
A major reason for the improvement in survival in rectal cancer is the use of pre-operative chemoradiotherapy. Some tumours disappear completely with this treatment and others show little or no response. A poor response may be due to high level of a particular enzyme that allows the cells to stop dividing and repair chemotherapy damage.