Cancer is a disease associated with aging. Its risk increases with age and the number of older adults seeking its treatment has skyrocketed. Apparently, more than a third (around 36%) of cancers are diagnosed in the people aged 75 and over. Although cancer certainly can and does strike young people too, it is, by and large, a disease of aging and it happens to be one of the leading causes of deaths in Americans between 60 and 79 years old. Coping with cancer at any age is difficult enough, but it is really overwhelming and daunting at an advanced age. Along with more years come more health problems. Older people are more sensitive to medication and more susceptible to medication reactions.They often have complicating co-morbidities and more financial hardship with fewer family and friends for support at the same time.
According to the 2010 report, the proportions of all cancers among elderly men and women were 61% and 56% respectively. All cancers have grown almost around seven-fold more frequently among elderly men (2158 per 100,000 person-years) and around four-fold more among elderly women (1192 per 100,000 person-years). As the population ages, many diseases that predominantly affect older individuals will become more prevalent. Moreover many conditions that affect the elderly will occur in combination, thereby complicating care for any specific condition. Advancing age is a high risk factor for cancer, with persons over 65 accounting for 60% of newly diagnosed malignancies and 70% of all cancer deaths. The International Agency for Research on Cancer propounded the following numbers for various cancers in the elderly population.
Risk Factors for Cancer in Elderly – Most cancers are related to environmental, lifestyle or behavioral exposures. Many molecular and cellular changes are involved in the development of cancer, so it is very likely that as a person grows older these changes get accumulated and eventually manifest themselves as cancer. The elderly and the senior population do not realize of them being affected by cancer as there are no specific symptoms of cancer. They frequently have serious health issues viz. high blood pressure, diabetes, depression along with cancer and these conditions can influence their cancer treatment. Although it is impossible to prove what caused a cancer in any particular individual, the following risk factors can still be regarded as the potential causes of cancers.
- Tobacco and smoking – Smoking is a leading cause of cancer and death from cancer. It can cause cancers of the lung, esophagus, larynx, mouth, throat, kidney, bladder, liver, pancreas, stomach, cervix, colon and rectum, as well as acute myeloid leukemia. Over 30% of cancers are potentially avoidable by not using tobacco as it is associated with many forms of cancers, viz. 90% of lung cancers. Similarly alcohol is also a chemical carcinogen that is the leading cause of cancer in as many as 10% males and 3% females.
- Cancers related to occupation and work place – Occupational cancers is caused by exposure to carcinogens in the workplace. There are three different types of carcinogens – biological carcinogens example HIV viruses, Hepatitis B etc; chemical carcinogens example asbestos, vinyl chloride or polycyclic aromatic hydrocarbons etc; and the physical carcinogens such as ultraviolet radiation and alpha, beta and gamma radiations etc that are known to cause skin cancers. These kinds of cancers represent between 2-20% of all cases and affect respiratory organs, or the skin or liver. It has been estimated that at least 200,000 people over the world succumb to cancers that can be attributed to their occupations. Asbestos related diseases alone account100,000 of such deaths worldwide each year.
- Diet and exercise – Diet, physical activity and obesity are related to approximately 30-35% of cancer deaths. In the US, obesity is one of the main factors for ~14-20% of all cancer deaths. According to AACR (American Association for Cancer Research) obesity is tied to many of the most common types of cancers including post-menopausal breast cancer, colorectal cancer, cancers of the endometrium, kidney, thyroid and gallbladder. There have been several reasons behind this – fat tissue produces excess amounts of estrogen, high levels of which have been with the risk of breast and endometrial cancers. Obese people have increased levels of insulin and insulin-like growth factor-1 (IGF-1) in their blood that can promote the development of certain tumors.
- Infections – Worldwide, infections are linked to about 15-20% of cancers. This percentage is relatively higher in developing countries but lower in the US and other developed countries. This proportion is as high as 25% in Africa to less than 10% in the developed world. Infections can raise a person’s risk for cancer in different ways. For example –
(a)Some viruses directly affect the genes inside cells that control their growth. These viruses can insert their genes into the cell, causing the cell to grow out of control.
(b)Some infections can cause long-term inflammation in a part of the body that can lead to changes in the affected cells and in nearby immune systems that helps protect the body from some cancers.
(c)Some infections can suppress a person’s immune system that normally helps protect the body from some cancers.
- Radiations – Up to 10% of invasive cancers are related to radiation exposure, including both ionizing radiation and non-ionizing ultraviolet radiation. The main sources of ionizing radiation are medical imaging and radon gas. This can cause cancer in most parts of the body, in all the animals and at any age, although the solid tumors may take time to clinically manifest. It is estimated that around 0.4% of cancers in 2007 in the US were because of the computerized tomography (CT) scans.
- Heredity – It is uncommon for a cancer to run in a family, but there are, certain types of cancers that do occur more often in some families than in the rest of the population. These kinds of cancers are primarily caused by the genes that we inherit due to the genetic defect. Only less than 0.3% of the population are the carriers of a genetic mutation that has a large effect on cancer risk and these cause less than 3-10% of all cancers. Certain inheritance of mutation in genes BRCA1 and BRCA2 can lead to a 75% risk of the breast and ovarian cancers. Melanoma and cancers of the breast, ovary, prostrate and colon sometimes run in families. Several cases of the same cancer type may be linked to inherited gene changes that may increase the chances of developing cancers. The other such genetic cancer is the Li-Fraumeni syndrome that includes defects in the p53 gene that leads to bone cancers, breast cancers, soft tissue sarcomas, brain cancers etc. Those with Down’s syndrome are known to develop malignancies such as leukemia and testicular cancer.
When an older adult is affected with cancer, the diagnosis also coincides with other physical, psychological and social losses that are taking place that can include diminished eyesight, hearing and mobility. At the same time, the loss of family members and friends begins to occur more frequently and retirement can also change an individual’s financial security. The elderly also tend to face unique challenges. Older adults and their caregivers have special needs and considerations, including increased risk of drug reactions, the presence of additional health conditions, increased financial burdens of care and caregiver stress and strain.
A lot of elderly adults remain active and healthy with advancing years so they can definitely benefit from the available treatments. Because elderly patients commonly have concurrent illnesses or other medical difficulties that are perceived to exacerbate the side effects of chemotherapy, elderly patients are often treated with reduced doses of chemotherapy. Despite the high occurrence of cancers in the elderly, the management of these patients is often less aggressive than that of their younger counterparts in respect to difference in the biology of the tumor, age-related difference in the biology of the tumor, age-related difference in the host physiology, co-morbidity burden and psychological issues, that can impact the efficacy and the side effects of the cancer therapy. Consequently, many patients receive inadequate treatment.