Aging, cancer, and cancer vaccines

Abstract

World population has experienced continuous growth since 1400 A.D. Current projections show a continued increase - but a steady decline in the population growth rate - with the number expected to reach between 8 and 10.5 billion people within 40 years. The elderly population is rapidly rising: in 1950 there were 205 million people aged 60 or older, while in 2000 there were 606 million. By 2050, the global population aged 60 or over is projected to expand by more than three times, reaching nearly 2 billion people 1. Most cancers are age-related diseases: in the US, 50% of all malignancies occur in people aged 65-95. 60% of all cancers are expected to be diagnosed in elderly patients by 2020 2. Further, cancer-related mortality increases with age: 70% of all malignancy-related deaths are registered in people aged 65 years or older 3. Here we introduce the microscopic aspects of aging, the pro-inflammatory phenotype of the elderly, and the changes related to immunosenescence. Then we deal with cancer disease and its development, the difficulty of treatment administration in the geriatric population, and the importance of a comprehensive geriatric assessment. Finally, we aim to analyze the complex interactions of aging with cancer and cancer vaccinology, and the importance of this last approach as a complementary therapy to different levels of prevention and treatment. Cancer vaccines, in fact, should at present be recommended in association to a stronger cancer prevention and conventional therapies (surgery, chemotherapy, radiation therapy), both for curative and palliative intent, in order to reduce morbidity and mortality associated to cancer progression.

Figure 1

Pro-inflammatory mechanisms probably involved in cancer development and progression at old age.

Figure 2

The importance of estimating life expectancy and comorbidities, in association with the Comprehensive Geriatric Assessment, in order to guide cancer therapy in the elderly. Independently from the intent, the maintenance of Quality of Life and the control of cancer-related symptoms should be the first aim of the treatment.

Figure 3

Potential risks and benefits of cancer therapy in the elderly.

Figure 4

Possible decisional algorithm for cancer therapy in the elderly, from screening to treatment, Step 1-2.

Figure 5

Possible decisional algorithm for cancer therapy in the elderly, Step 3. The entire flow-chart enlightens the possibilities of administration and association of cancer vaccines at different steps of the evaluation of malignancies, from prevention to curative and palliative treatments.