Every year in Ireland, 20,000 people are diagnosed with cancer. In the last part of our series, Dr Muiris Houston, Medical Correspondent, examines the most common types of cancer and describes the types of treatment available
There are almost 20,000 new cases of cancer in the Republic every year, according to the first five-year report from the National Cancer Registry, which covered 1994 to 1998. Apart from skin cancer, the three most common cancers here are those of the lung, large bowel and breast, each of which is examined in detail below.
Some 20 per cent of cancer deaths were due to lung cancer, which has a particularly poor prognosis. Only 8 per cent of men who develop lung cancer are alive five years after diagnosis. The overall risk of developing cancer increases with age, with the risk doubling in every successive decade of life. There is a one in three chance of having cancer by age 74.
The incidence of cancer in the Republic is quite similar to that in neighbouring countries. For the most common cancers, rates here are lower than in Scotland, Wales and Northern Ireland and higher than in England.
When All-Ireland Cancer Statistics from the period 1994 to 1996 were analysed and compared with EU average rates, women here has a slightly higher risk of breast and colon cancer and a significant increased risk of developing lung cancer. Of the commonest cancers, men had a elevated risk of large bowel cancer and a reduced risk of lung cancer compared to the EU average (see chart below). Generally, those living in urban areas and occupying lower socio-economic groups experience higher rates of cancer.
The majority of patients in the Republic have their cancer treated surgically while a steady increase in the number of people receiving chemotherapy and radiotherapy is also evident (see panel). There is no major difference in the cancer treatment received by men and women but older patients here are much less likely to have cancer-specific treatment.
The five-year report also notes regional differences in treatment depending on where the patient lives. The most striking example of this is the lower percentage of lung and breast cancer patients receiving radiotherapy in the Western and Mid-Western Health boards.
Comparing cancer treatment patterns here with other states is "technically very demanding", according to Dr Harry Comber, director of the National Cancer Registry (NCR). "It is possible to compare surgical intervention rates, and the registry will publish work in this area next year," he says.
Lung cancer
Lung cancer is almost exclusively a disease of smokers with 95 per cent of cases related to smoking. There were 1,780 cases of the disease in the Republic last year. The largest number of cases and deaths occur in patients aged 70 to 75 years.
In the period 1994 to 1997 the number of cases of lung cancer in males dropped by 5 per cent; however there was a marginal increase in the number of lung cancers in women, trends which reflect a change in male/female smoking habits. We are likely to see an epidemic of lung cancer in women within five to 10 years. According to Dr Finbar O Connell, consultant in respiratory medicine at St James's Hospital, Dublin, "75 per cent of lung cancer cases are already advanced by the time a diagnosis is made. This is reflected in a three-year survival rate of less than 3 per cent for patients with late stage lung cancer in the Republic."
There are basically two types of lung cancer based on a tissue diagnosis made following biopsy; small cell lung cancer (SVLC) and non-small cell lung cancer (NSCLC). The distinction is important for treatment reasons. NSCLC, which accounts for 80 per cent of lung cancer cases, is operable in its early stages, while SCLC is treated exclusively by chemotherapy and radiotherapy.
As the accompanying patient story illustrates, even a relatively early diagnosis of SCLC does not guarantee a successful outcome. This is not the case with NSCLC and if improvements are made in the early detection and treatment of lung cancer, it will improve the outcome for this group of patients.
"Lung cancer is perceived by many people as a hopeless diagnosis, whereas if the service for lung cancer patients were better organised, it would not be quite as hopeless," O'Connell says, pointing out that even if you improved the five-year survival rate to 15 per cent you will have helped a lot of people. Studies in Britain have shown that better organised services can improve the number of patients who are having curative surgery.
Lung cancer services certainly appear to be the poor relation compared with those available for colorectal and breast cancer. But apart from prioritising treatment services, what else can be done to improve the awful outcome for lung cancer patients? Doctors at the radiology department of Beaumont Hospital are studying the use of low dose CT scanning as a method of detecting early lung cancer in people at high risk. In September the National Cancer Institute in the US launched a study of 50,000 people aimed at assessing the best method screening for lung cancer.
The ultimate answer to the depressing scenario of lung cancer statistics is to prevent it in the first place, To put it bluntly, if there was no smoking, there would be virtually no lung cancer.
"Tobacco is the biggest healthcare issue in the world today", O'Connell says, "but the tobacco industry is so powerful that they are winning the smoking battle and look like they will continue to win for the foreseeable future."
With more deaths from lung cancer in the Republic than from breast and colon cancer combined, it is surely time that the "Cinderella" of the cancer services received the attention and priority it deserves.
Colorectal cancer
Cancer of the large bowel is the second most common cause of death from cancer in the Republic: 2,500 new cases are diagnosed every year and there are 1,000 deaths annually from the disease. However, if caught early, 80 per cent of patients with colorectal cancer will be alive five years after diagnosis.
The large bowel is made up of the colon and the rectum. Because of the tissue similarity between the two, malignancies in these two bowel segments are usually classified together. Anatomically, the colon refers to the upper five or six feet of the large intestine and the rectum to the last five or six inches.
Most colorectal cancers originate as benign growths of the intestinal lining, called polyps. These are tiny mushroom-shaped or flat growths that develop when cells lining the bowel wall multiply. Sometimes the polyps grow and turn malignant.
Between a half and one per cent of bowel cancer patients have hundreds of polyps, giving them an extremely high risk of getting (developing) bowel cancer.
Apart from a genetic predisposition to the disease, there is strong evidence that high levels of dietary fat promote colon cancer. High fat intake seems to promote the development of polyps with a consequent risk of these turning cancerous. Following years of promoting a high-fibre diet as a means of preventing colon cancer, recent research has questioned the role of dietary fibre. However, it may be that it is the type of fibre which is important and it is certainly too early to discuss the benefits of a high-fibre diet in preventing cancer.
The worrying signs to look out for which may indicate bowel cancer and which should be brought to the attention of your doctor include:
a change in your bowel habit - either more frequent visits to the toilet or a change in the consistency
blood in the stool
a feeling that your bowel is not emptying properly
unexplained weight loss
The treatment of bowel cancer is primarily surgical. Radiotherapy is important when the tumour is in the rectum. And chemotherapy drugs now help in cases where the tumour has spread outside the bowel.
Should we have a screening programme for bowel cancer? Dr Padraig McMathúna, consultant gastroenterologist at the Mater Hospital has a special interest in the treatment of colorectal cancer. "Screening is controversial," he says. "Do you go for 'average risk' screening or do we aim a screening programme at 'at risk' individuals with a family history of colorectal cancer?" A European Advisory Group looked into the issue in 2000 and concluded that there was, as yet, no evidence base to support whole population screening of those at average risk of bowel cancer.
Because the polyps which precede bowel cancer are benign, screening for the disease has the strong advantage that you can, in theory, pick up cases before the actual cancer begins to grow. However no ideal method for whole population screening exists.
In North America, they are committed to carrying out a full endoscopic examination of the colon (colonoscopy) of everyone between the ages of 50 and 60. This requires huge resources of both manpower and infrastructure which we simply do not have in the Republic.
However, if screening is aimed at high risk individuals with a family history - for example, if you have a firstdegree relative diagnosed with colon cancer under the age of 50 - targeted screening using virtual colonoscopy offers the possibility of picking up 95 per cent of tumours.
Virtual colonoscopy involves the use of a special CT scanner which takes pictures of the entire colon and reproduces a three-dimensional image of the bowel similar to that seen by a gastroenterologist using a real colonoscope. Because it is non invasive, it is much more acceptable to patients as a screening tool. For the minority of patients who are found to have a polyp, a full colonoscopy can then be carried out and a biopsy taken.
Dr McMathúna feels that screening of "at risk" individuals using virtual colonoscopy is a viable option for the future. "From a positive point of view the Department of Health has been very proactive in the last number of years in prioritising the whole area of cancer care. They have appointed cancer-coordinators and oncologists and started screening for breast cancer. I think we can now make a good case for other cancers, like colorectal cancer, to be screened for ."
Breast cancer
The breast clinic at St James's Hospital is one of the best organised in the Republic. Ninety per cent of urgent GP referrals are seen within three weeks. For a woman with a worrying breast lump her GP will fax a referral note to the breast cancer office at St James's Hospital. This information is evaluated by a breast care nurse in conjunction with a specialist breast surgeon and the patient is offered an appointment within two weeks.
When she arrives for her appointment, the specialist nurse talks the patient through what lies ahead. The assessment of a suspicious lump involves three separate approaches: an examination by a consultant surgeon; a mammogram (specalised X-ray of the breast) which is reported on by a radiologist on the spot; and, if appropriate, the aspiration of fluid from the lump by a specialist pathologist, who then examines the cells under a microscope to see if they show any changes suggestive of cancer.
Eighty per cent of patients receive a same-day diagnosis. This is particularly reassuring for the majority of women who will be told the problem is benign. But even for the unlucky 12 to 15 per cent who have cancer, they are immediately counselled by the nurse and the surgeon.
All cases seen in the Triple Assessment Breast Clinic are discussed at a weekly multidisciplinary conference. Patients with a malignancy are discussed a second time after their surgery, when all the pathological information is available. This means that each case is reviewed from both a diagnostic and a treatment point of view.
The patient will be seen at the oncology clinic one week after discharge from hospital. As well as discussing chemotherapy with the consultant oncologist, she will have the opportunity to meet a consultant radiotherapist, who holds his clinic at the same time. Usually chemotherapy lasts for three to six months, followed by radiotherapy in St Luke's Hospital in certain cases.
However, not all women in the State can access such a centre of excellence. Dr John Kennedy, consultant oncologist at the Breast Unit in St James's Hospital and member of the Irish Cancer Society medical committee says: "Even though the National Cancer Forum recommended the establishment of 13 specialist breast units in 2000, it is clear that two years on, women in many parts of the country are still waiting for the setting up of a proper centre of excellence in their area".
"Cancer does not take politics into account. Women with breast cancer have a right to be treated in a specialist breast unit. A doctor needs to see 100 to 150 breast cancers a year to maintain expertise in its treatment and this requires a local population of 250,000 to 300,000 people," Kennedy says.
The latest data indicates that the five-year survival rate for breast cancer is about 70 per cent in the Republic, while in the US it is over 80 per cent. Prof Niall O'Higgins, professor of surgery at St Vincent's Hospital, author of the report Development of Services for Symptomatic Breast Disease has pointed out that by establishing the 13 specialist units, it will be possible to reduce the number of deaths from breast cancer by 20 per cent. Dr Kennedy reiterates this, saying: "If we do not act now, we'll pay a lot more in the long run both in human and financial terms."
He also called on the Minister for Health to set out a timetable for the expansion of Breast Check, the national breast screening service which is still confined to three health boards in the State. "Screening can detect breast cancer up to 18 months before it appears in a lump and so we cannot afford to delay the complete roll-out of this vital national breast screening programme."
The Irish Cancer Society can be contacted at 01 6681855