N. Ireland Cancer Registry

Our body cells are continually growing, dying and being replaced.  Cancer is the result of a breakdown in the normal growth of body cells.  Normal growth is regulated by our genes.  Some genes programme for growth (oncogenes) while others stop growth (tumour suppressor genes).  There are several ways in which a normal cell can become a cancerous cell:

• the 'growth', oncogenes may become overactive, or
• the tumour suppressor gene is underactive or even switched off completely, and
• sometimes the rate of change from normal to faulty genes is increased.  This may be due to a fault in the way the body repairs faulty genes or increased damage to genes, as occurs with carcinogens such as tar products from tobacco.

Whether a damaged cell becomes a cancer is a complex process, involving changes in several types of genes.  Whether a cancer cell spreads depends on the type of cancer, local inflammation, immune response and tumour promoting growth factors.

Once a tumour is established, it may spread locally and to other sites (metastasise).  Treatment depends on the tumour, its size and whether it has spread.  Treatments are surgical, radiation, and drugs (chemotherapy).

In oder to help prevent cancer it is advised to follow the European Code Against Cancer, see below:

Certain cancers may be avoided and general health improved if you adopt a healthier lifestyle;

1. Do not smoke. Smokers, stop as quickly as possible and do not smoke in the presence of others.
2. If you drink alcohol, whether beer, wine or spirits, moderate your consumption.
3. Increase your daily intake of vegetables and fresh fruits. Eat cereals with a high fibre content frequently.
4. Avoid becoming overweight, increase physical activity and limit intake of fatty foods.
5. Avoid excessive exposure to the sun and avoid sunburn especially in children.
6. Apply strict regulations aimed at preventing any exposure to known cancer-causing substances. Follow all health and safety instructions on substances which may cause cancer. 
   
   More cancers may be cured if detected early:
   
7. See a doctor if you notice a lump, a sore which does not heal (including in the mouth), a mole which changes in shape, size or colour or any abnormal bleeding.
8. See a doctor if you have persistent problems, such as a persistent cough, persistent hoarseness, a change in bowel or urinary habits or an unexplained weight loss.
   
   For women:
   
9. Have a cervical smear regularly. Participate in organised screening programmes for cervical cancer.
10. Check your breasts regularly. Participate in organised mammographic screening programmes if you are over 50.

A population based cancer registry aims to collect data on all malignant and certain non-malignant tumours diagnosed in its catchment population. The data includes details on the patient, the tumour and treatment, and deaths. Procedures for cancer registration are widely established throughout the world and generally follow guidelines established by bodies such as the International Union Against Cancer (UICC), the International Agency for Research on Cancer (IARC), the International Association of Cancer Registries (IACR), and the World Health Organisation (WHO).

Population based cancer registries are an important tool for the monitoring of time trends and geographical variations in cancer incidence. In 1989 a working group for the Registrar General's Medical Advisory Committee noted that in addition to these traditional uses of cancer registration the system had become vital in several other areas:  These included:

• the management of the substantial resources required for the preventative, curative and laboratory services for cancer;
• the planning and evaluation of services, particularly the screening programmes for breast and cervical cancer;
• the planning and evaluation of clinical management and treatment based on accurate and unbiased survival data and clinical trials;
• research into causes of cancer, involving case control studies and the flagging of cohorts and information for health education and health promotion for both professionals and the public.

Future uses of cancer registration (especially if linked with other databases) were identified including evaluating programmes of care, quality assurance and relating costs to clinical outcome. Cancer registration is also essential for participation in international research into the aetiology and epidemiology of cancer.

The Cancer Registry collects its information electronically using the hospital Patient Administration System (PAS), the Pathology Laboratory Systems, and to a lesser extent, the Death Certificates and Radiology Systems. Approximately 40,000 notifications are recorded annually for 8,500 new patients (including 2,500 non-melanoma skins cancers). The data are checked electronically, for errors such as wrong site/morphology combinations and wrong sex/site combinations, using programmes from the International Association for Research on Cancer (IARC) and Surveillance, Epidemiology and End Results (SEER) programme in the USA.

Cases are then matched to identify duplicates or new cases. In the majority of cases, each case received from the PAS system will have a pathology or cytology report confirming the diagnosis. However some cancer patients e.g. some lung cancer patients, may not have a microscopically verified tumour as material for a biopsy may be difficult to obtain. Trained Registry staff examines the hospital notes for these 'PAS only' cases so that exact date and method of diagnosis can be assigned to the patient. Additional information is also sought from GP records of cases notified to the Registry solely from death registrations. Once this checking process is complete the records are anonymised for analysis.

Investigation of Alleged Cancer Clusters:

Vigilant individuals will often be concerned that a population has a higher rate of disease than they would expect. Part of this suspicion may reflect the increasing frequency with which cancer is diagnosed in our population.  This increase has several causes:

• Firstly, an ageing population, as we live longer we are more likely to develop diseases of old age, including cancer.
• Secondly, competing causes of deaths such as infection has largely been controlled.
• Thirdly, technological advances have improved the accuracy of diagnosis and so we are better at diagnosing cancer when it occurs.
• Fourthly, lifestyle changes including the use of tobacco, a high fat/low fibre diet combined with increased alcohol consumption and reduced levels of exercise have increased our risk of developing cancer.

The Cancer Registry will follow procedures for cluster investigation as outlined by the Ontario Cancer Treatment and Research Foundation. (Ref: King WD, Darlington G A, Kreiger N. Response of a Cancer Registry to Reports of Disease Clusters, Br J Cancer 1993; Vol. 29: No. 10, 1418 - 25). Such analyses are likely to incur a cost. The steps are as follows.

1. Assessing the Inquiry

• There must be sufficient numbers of cases, (minimum of 5 per unit of analysis and of the same type or body system)
• A plausible biological association must exist with a suspected exposure.
• In many reported clusters it will be impossible to proceed past this stage due to low numbers etc.

2. Verification of Cases

If it is possible to proceed, the Registry will verify the quality of data, prior to analysis. This reduces reporting bias.

3. Analysis

Analysis using special statistical methods designed for the study of spatial, temporal and/or space-time disease clustering will be undertaken in conjunction with the Small Area Health Statistics Unit (SAHSU) in London.

Recommendations based on the steps above may be:

i) no further action
ii) future surveillance or
iii) a detailed study, depending on the satisfaction of criteria on statistical significance, biological

In the strict sense of the word cancer is not a hereditary disease as you will not definitely get cancer if one or more of your parents have had the disease.  You can however inherit a tendency to get a particular cancer, but even if this inheritance occurs it will not definitely result in that cancer actually developing.

Compared to the UK and Ireland as a whole, Northern Ireland has a slightly higher rate of new female cases of cancer diagnosed but has an equivalent male incidence rate.  Mortality rates in Northern Ireland however are lower than UK and Ireland.

There are 4 types of behaviour:

Benign: this is usually a slow-growing tumour that may displace but does not invade or infiltrate surrounding tissues; a tumour considered not to have malignant or invasive potential.
In-situ: an in-situ tumour is one with malignant potential which has remained confined to the tissue in which it originated.
Invasive (also known as Malignant): an invasive tumour is one that is not (or is no longer) confined to the tissue in which it originated.  Most tumours are invasive.
Uncertain: an uncertain tumour is one which, at the time of diagnosis, cannot be classified as either benign or malignant.