Over the next 20 years, the number of new cancer cases diagnosed annually in the United States will increase by 45 percent, from 1.6 million in 2010 to 2.3 million in 2030, with a dramatic spike in incidence predicted in the elderly and minority populations, according to a study published April 29 in Journal of Clinical Oncology.

The study, conducted by researchers at University of Texas M. D. Anderson Cancer Center in Houston, is the first to determine such specific long-term cancer incidence projections. The authors predicted a 67 percent increase in the number of adults age-65-or-older diagnosed with cancer, from 1 million in 2010 to 1.6 million in 2030. In non-white individuals within the same 20-year span, the incidence is expected to increase by 100 percent, from 330,000 to 660,000.

Ben Smith, MD, adjunct assistant professor in M. D. Anderson's department of radiation oncology, said that the study underscores cancer's growing stress on the U.S. healthcare system.

"In 2030, 70 percent of all cancers will be diagnosed in the elderly and 28 percent in minorities, and the number of older adults diagnosed with cancer will be the same as the total number of Americans diagnosed with cancer in 2010," said Smith, the study's senior author. "Also alarming is that a number of the types of cancers that are expected to increase, such as liver, stomach and pancreas, still have tremendously high mortality rates."

Unless specific prevention and/or treatment strategies are discovered, cancer death rates also will increase dramatically, said Smith, who is currently on active military duty at Lackland Air Force Base in San Antonio.

Smith and his colleagues accessed the U.S. Census Bureau statistics, updated in 2008 to project population growth through 2050, and the National Cancer Institute's (NCI) Surveillance, Epidemiology and End Results registry, a population-based cancer registry representing 26 percent of the country's population. They calculated cancer incidence rates by multiplying the age, sex, race and origin-specific population projections by the age, sex, race and origin-specific cancer incidence rates.

The researchers found that from 2010 to 2030, the population is expected to grow by 19 percent (from 305 to 365 million). The total number of cancer cases will increase by 45 percent (from 1.6 to 2.3 million), with a 67 percent increase in cancer incidence in older Americans (1 to 1.6 million), compared to an 11 percent increase in those under the age of 65 (.63 to .67 million).

With respect to race, a 100 percent increase in cancer is expected for minorities (.33 to .66 million); in contrast, in white Americans, a 31 percent increase is anticipated (1.3 to 1.7 million), according to the authors. The rates of cancer in blacks, American Indian-Alaska Native, multi-racial, Asian-Pacific Islanders and Hispanics will increase by 64 percent, 76 percent, 101 percent, 132 percent and 142 percent, respectively.

Regarding disease-specific findings, Smith and his team found that the leading cancer sites are expected to remain constant - breast, prostate, colon and lung. However, cancer sites with the greatest increase in incidence expected are: stomach (67 percent); liver (59 percent); myeloma (57 percent); pancreas (55 percent); and bladder (54 percent).

Given the statistics, the role of screening and prevention strategies becomes all the more vital and should be strongly encouraged, Smith said. In the study, the authors said: vaccinations for hepatitis B and HPV; the chemoprevention agents tamoxifen and raloxifene; interventions for tobacco and alcohol; and removal of pre-malignant lesions, such as colon polyps.

The findings also highlighted two issues that must be addressed simultaneously: clinical trial participation and the increasing cost of cancer care. Historically, both older adults and minorities have been under-represented in such studies, and, therefore, vulnerable to sub-optimal cancer treatment.

Simultaneously, the authors wrote that over the past decade in particular, the cost of cancer care is growing at a rate that is not sustainable.

"The fact that these two groups have been under-represented in clinical research participation, yet their incidence of cancer is growing so rapidly, reflects the need for therapeutic trials to be more inclusive and address issues that are particularly relevant to both populations," Smith said. "In addition, as we design clinical trials, we need to seek not only the treatment that will prolong survival, but prolong survival at a reasonable cost to patients. These are two issues that oncologists need to be much more concerned about and attuned to."

Another issue that needs to be addressed is the shortage of healthcare professionals predicted. For example, according to a workforce assessment by American Society for Clinical Oncology (ASCO), the shortage of medical oncologists will impact the healthcare system by 2020. Smith said that ASCO and other medical organizations beyond oncology are aware of the problem, and are engaged in efforts to grow the number of physicians, as well as encourage the careers of nurse practitioners and physician assistants who are part of the continuum of care.

"There's no doubt the increasing incidence of cancer is a very important societal issue. There will not be one solution to this problem, but many different issues that need to be addressed to prepare for these changes," Smith said. "I'm afraid if we don't come to grips with this as a society, health care may be the next bubble to burst."