CHAPTER ONE 1.0            INTRODUCTION

1.1       Background to the Study

Cancer is a term for diseases in which abnormal cells divide without control and can

invade nearby tissues(National Cancer Institute, 2015). One defining feature of cancer is

the rapid creation of abnormal cells that grow beyond their usual boundaries, and which

can then invade adjoining parts of the body and spread to other organs, the latter process

is referred to as metastasis(National Cancer Institute, 2015). Metastases are a major cause

of death from cancer (World Health Organisation, 2017). Cancer is the second leading

cause of death globally, and was responsible for 8.8 million deaths in 2015. Globally,

nearly 1 in 6 deaths is due to cancer (World Health Organisation, 2017). Ageing is a

fundamental factor for the development of cancer because the incidence of cancer rises

dramatically with age, most likely due to a build-up of risks for specific cancers that

increase with age (World Health Organisation, 2017).The incidence of malignancies after

the age of 65 years has increased 11-fold compared to younger adults (Marosi & Köller,

2016). Nearly 80% of all cancers are diagnosed in persons beyond the age of 55 years

(Palli, Fortpied, & Wedding, 2010). The median age of diagnosis in many tumours lies

beyond the age of 60 years, for example, hormone-sensitive breast cancer, multiple

myeloma, renal, prostate and colon cancer(Arnold, Karim-Kos, & Coebergh, 2015).

The prevalence of cancer pain is estimated in 25 to 50% for recently diagnosed patients,

in 33 to 80% for patients under treatment, and in approximately 75 to 100% for those in

advanced and terminal states (Oliveira, Sobrinho, & Cunha, 2016). Research suggests

that 70-90% of people with advanced cancer experience persistent pain (Kapoor, Kalwar,

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Singhal, Nirban, & Kumar, 2015). Further statistics indicate that the over-60s are likely

to stay more than twice as long in hospital for conditions associated with persistent pain

than those aged 59 and below. While pain management has advanced significantly in

recent decades, older people remain less likely than younger people to receive good pain

management, with older women and being more at risk of under-treatment than older

men(McLachlan, Bath, Naganathan, & Hilmer, 2011).As the number of individuals older

than 65 years continues to rise, frailty and chronic diseases associated with pain will

likely increase (Cavalieri, 2005). Reports from the developed world have shown that in

general, the prevalence of pain at the time of cancer diagnosis and early in the course of

disease is estimated to be approximately 50%, increasing to 75% at advanced stages

(International Association for the Study of Pain, 2009).

Persistent pain experienc