Age is not an independent factor in cancer survival rates, but clinical trials exclude older patients

Nov 7 2008

Age is not an independent factor in cancer survival rates and should not influence decisions about how to treat older patients, according to a study in the November issue of IJCP, the Independent Journal of Clinical Practice.

A team of hospital and University-based researchers from Barcelona, Spain, carried out a detailed study of more than 200 patients diagnosed with cancer.

"We found that there were a number of factors that influence survival rates – including physical quality of life and how far the cancer had spread – but age was not one of them" says lead researcher Dr Eva Domingo from Hospital Vall d'Hebron.

"Despite this fact, and the challenges that clinicians face from an ageing population, there has been little research into how to treat older cancer patients, who often have complex medical needs because of other health issues.

"They have been systematically excluded from clinical trials for cancer treatments. Although 60 per cent of cancers occur in patients over 65, their participation in clinical trials does not exceed 25 per cent.

"This has made it difficult to predict how older patients will tolerate and respond to the latest cancer treatments and has provided an obstacle to making evidence-based clinical decisions."

Dr Domingo and her colleagues teamed up with researchers from the University of Barcelona to look at 224 patients diagnosed with cancerous tumours.

The patients ranged from 32 to 92 years of age and three-quarters of them were male. Thirty-nine per cent of the patients were under 65 and 61 per cent were 65 or over.

The most common tumours were respiratory (43 per cent) and gastrointestinal (29 per cent). 42 per cent of the patients had a localised tumour.

Just under two-thirds of the patients (62 per cent) died during the one-year follow-up period.

The data from each patient, which included body mass index and quality of life scores as well as various clinical tests, was subjected to a detailed analysis.

This showed that there were four independent factors that played a significant role in predicting whether a patient survived. These were:

• Metastatic dissemination, which measures how widely the cancer has spread.
• The level of functional impairment the patient experienced, as measured by the Karnofsky Perfomance Status Scale.
• The patient's physical quality of life, as measured by the eight criteria on the Short Form 36 questionnaire.
• Serum albumin levels, a major protein that is produced in the liver and is essential for maintaining pressure in the vascular system.

Patients had better survival rates if they had a good physical quality of life and fewer problems with functional impairment. High serum albumin levels were also important, as were a lack of metastatic dissemination.

"The patient's age was not an independent factor that predicted how likely they were to survive cancer" stresses Dr Domingo. "Because of this, age, in itself, should not be used to limit diagnostic or therapeutic decisions."

The number of older cancer patients is rising as the worldwide population ages. But not enough it being done to meet their needs, argue the authors.

"Consciously or unconsciously, age often becomes a decisive element when diagnostic or therapeutic strategies are designed" says Dr Domingo.

"Older people tend to have more complex health needs, such as other illnesses, and that is one of the reasons that has frequently been put forward for not treating their cancers aggressively. However our study found that comorbidity, like age, was much less significant than factors like physical quality of life.

"Other reasons given include the limited long-term benefits, compared with younger patients, and the lack of financial, logistical and social support."

The authors hope that their research will reduce the focus that other clinicians put on age when they treat older patients with cancer.

"We would like to see less decisions taken on the basis of age and more research that explores the complex needs of older people, so that they can be treated more effectively and enjoy a better quality of life" concludes Dr Domingo.

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