This section is designed to provide perspectives on the incidence and prevalence of cancer and related pain syndromes. Cancer is a significant public health problem in the United States, as well as in other developed countries. The incidence of cancer has increased worldwide by 19% in the past decade, most of which has been attributed to cases in developing countries.¹ By 2020, it has been estimated, up to 70% of the 20 million new cases of cancer predicted to occur yearly will be in the developing world.² Survival rates in developing countries are often less than one third of those for site-specific cancers in the developing world.³ Cancers observed in developed countries tend to reflect hormonal and dietary profiles of their populations, with a high incidence of breast, colorectal, and prostate cancers. By contrast, populations in developing countries are susceptible to cancers stemming from infectious disease or nonmalignant disease associated with chronic infections; there is a greater incidence of cervical, liver, stomach, oropharyngeal, and esophageal cancers.

Men have a higher (45%) lifetime probability of developing cancer than women (38%); however, because of the relatively early age of breast cancer onset, women have a slightly higher probability of developing cancer before 60 years of age. Cancer is a major cause of death (22.8% of total deaths) in the United States and is second only to heart diseases (26.6% of total deaths). A total of 1,437, 180 new cancer cases and 565,650 deaths from cancers were expected to occur in the United States in 2008.⁴ One in four deaths that year in the United States was expected to be due to cancer. In 2008, approximately 560,000 Americans died from cancer: more than 1,500 deaths per day. Significant trends in the incidence and mortality rates of cancer include stabilization of the age-standardized, delay-adjusted incidence rates for all cancers combined, in men, from 1990 through 2004; a continuing increase in the incidence rate for women by 0.3% per year; and a 13.6% total decrease in age-standardized cancer death rates among men and women, combined, between 1991 and 2004. Overall cancer death rates in 2004 decreased by 18.4% and 10.5%, respectively, for men since 1990 and for women since 1991. The 5-year relative survival rate from cancer is 68% for whites and 57% for African Americans. For many sites, survival rates in African Americans are 10% to more than 20% lower than in whites. This is due, in part, to African Americans being less likely to receive a cancer diagnosis at an early, localized stage, when treatment can improve chances of survival. Additional factors that contribute to the survival differential include unequal access to medical care and tumor characteristics (Table 1.1). Survival rates for all cancers combined and for certain site-specific cancers have improved significantly since the 1970s, due, in part, to both earlier detection and advances in treatment. Survival rates markedly increased for cancers of the prostate, breast, colon, and rectum and for leukemia (Table 1.2).

Cancers of the prostate, lung and bronchus, and colon and rectum account for about 50% of all newly diagnosed cancers in men. Prostate cancer accounts for about 25% of incident cases in men. Approximately 91% of the new cases of prostate cancer will be diagnosed at local or regional stages, for which 5-year relative survival approaches 100%. For women in 2008, the three most commonly diagnosed types of cancer are cancers of the breast, lung and bronchus, and colon and rectum; these accounted for half of estimated cancer cases. Among all new cancer diagnoses in women, breast cancer alone accounts for 26% or 182,460 cases. Cancers of the lung and bronchus, prostate, and colon and rectum in men, and cancers of the breast, lung and bronchus, and colon and rectum in women continue to be the most common fatal cancers. These four cancers account for half of the total cancer deaths among men and women. Lung cancer surpassed breast cancer as the leading cause of cancer death in women in 1987 and accounted for 26% of all female cancer deaths in 2008. Death rates in the U.S. for all cancer sites combined
decreased by 2.6% per year from 2002 to 2004 in men and by 1.8% per year in women during the same period. Mortality rates have continued to decrease across all four major cancer sites in men and in women, except for lung cancer in women, where rates continued to increase by 0.2% per year from 1995 to 2004.⁴