Cancer Screening: Seeing the Future?
Cancer is the second-leading cause of death in the United States.
Cancer is the second-leading cause of death in the United States.1,2 In 2015, cancer shortened the lives of 595,930 people, comprising 22% of all deaths in the United States, according to the CDC.3 This number continues to rise, and it is estimated that by the end of 2017, cancer will have taken more than 600,000 lives this year.4 According to the Agency for Healthcare Research and Quality, in 2014 an estimated $87.8 billion was spent in the United States to provide health care services related to cancer.1 Screenings are available to assist patients in the war against cancer, but that is where the conundrum begins. Early detection on occasion leads to early and unnecessary treatments. The medical profession needs to be astute as these test results are interpreted. Early cancer testing is available for multiple types of malignancies. Screenings for early detection have favorably altered the survival rates from different types of cancer by up to 35%, according to the National Institutes of Health.5 Cancer screenings not only increase survival rates but also potentially reduce costs for both the health care system and patients.
What Is Cancer Screening?
A cancer screening test is used to detect a specific type of tissue malignancy. Each screening is catered toward detecting a different type of cancer, eg, breast, cervical, colorectal, lung, ovarian, prostate, or skin. Common methods of screening for cancer include blood work, diagnostic imaging, genetic testing, and physical examination.5 The rationale behind a cancer screening is that by discovering malignant tissue or changes in tissue early in the disease state, the patient’s rate of survival may be increased by treating cancer in the earlier stages, when it is most responsive to therapy. However, the tests may generate false negatives or false positives, which can result in missed opportunities or trigger unnecessary treatments that may not be in the patient’s best interest.
The primary goal is identification of high-risk populations and early cancer screening of candidates to reduce mortality. Appropriate early screening may not only alter mortality but also offer a chance for a lengthened and improved quality of life for the patient. Breast cancer, for example, is one of the leading causes of death among women with a malignancy. Statistics produced by the National Cancer Institute have shown that those women who underwent a regular mammogram reduced the risk of death by 15% to 20%.6 Generally, overall screening compliance is low, meaning that the number of individuals who should be tested for certain cancers is not optimal. For example, in 2014 the CDC indicated that just 65.7% of patients over 50 were up-to-date with their colon cancer screenings, while an astonishing 27.3% had never been screened.7 Investigators at the University of Michigan in Ann Arbor found that every patient within the appropriate criteria standards who underwent regular colon cancer screenings could prevent 90% of colon cancer diagnoses.8 According to the CDC, 9 of 10 patients who found colon cancer through regular screening procedures were still alive 5 years post diagnosis.7 Additionally, individuals participating in cancer prevention programs, such as lifestyle alterations and smoking cessation, can contribute to lower out-of-pocket costs and a reduction in overall health care expenses. In some cancers, early intervention prior to metastasis can improve treatment options and outcomes.
New Screening Tests on the Horizon
Investigators at Johns Hopkins University in Baltimore, Maryland, conducted a new method of cancer detection known as targeted error correction sequencing. It is used to detect even the lowest levels of circulating tumor DNA, which is commonly found in those with early-stage cancers. In the study, 200 samples were taken from individuals with breast, colorectal, lung, and ovarian cancer, which identified 62% of stage I and II cancers. In addition, no false positives were found in 44 healthy individuals who were tested.9 This has been a drawback of other methods of cancer screenings. Various biomarkers have been identified for a host of cancers, including breast, colorectal, lung, ovarian, and prostate. In 2016, 15,000 patients with 50 different types of cancer underwent liquid biopsy testing, yielding detectable changes in 6 different types of biomarkers, such as the epidermal growth factor receptor expressed in late-stage lung cancers, and proto-oncogene B-Raf, which has been linked to an increased incidence of melanoma, with 94% to 100% specificity of similar tissue biopsies.10 This could allow for potential targeted therapies geared toward gene-specific cancers to be personalized and treatment opportunities for those not previously eligible. Liquid biopsies (Table) could help reduce the risk of cancer recurrence by detecting circulating DNA after colon cancer surgery. In 2016, a study found that measuring tumor DNA from the blood of patients with stage II colon cancer could predict patients with a high risk of recurrence by detecting any remnants of residual circulating DNA from the tumor. Those who had circulating tumor DNA after surgery were more likely to suffer recurrence, while those who were screened postoperatively with liquid biopsies were 90% less likely to develop recurrence.10 The liquid biopsy may help identify those who could benefit from postoperative chemotherapy.
What Is the Role of the Health Care Provider?
Health care providers can play a vital role in the prevention of cancer. Screening tests are sometimes invasive and often will have a cost associated with the diagnostic testing. The health care provider can identify a high-risk population and offer assistance to modify risk factors. According to the American Cancer Society, 45% of cancer deaths could have been prevented. The top contributors were cigarette smoking, obesity, alcohol, ultraviolet radiation, and lack of physical activity.12 As health care providers, we must continue to improve cancer detection protocols and testing. Effectively identifying and educating patients will improve their outcomes. Health care providers must discern what screening needs to be completed and what results need to be treated.
Jerry Barbee Jr, PharmD, BCPS, CPh, and Glenn Schulman, PharmD, MS, BCPS, BCACP, BCGP, are clinical pharmacists at HCA West Florida Hospital in Pensacola, Florida. Matthew Bailey and Amanda Boyer are PharmD candidates at Auburn University in Alabama.
- American Cancer Society. Cancer facts & figures 2017. https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/annual-cancer-facts-and-figures/2017/cancer-facts-and-figures-2017.pdf. Published 2017. Accessed on November 28, 2017.
- Statistics for different types of cancer. CDC website. cdc.gov/cancer/dcpc/data/types.htm. Updated June 26, 2017. Accessed November 29, 2017.
- National Center for Health Statistics. Health, United States, 2016: with chartbook on long-term trends in health. https://www. cdc.gov/nchs/data/hus/hus16.pdf. Published 2017. Accessed on November 28, 2017.
- Siegel RL, Miller KD, Jemal A. Cancer statistics, 2017. CA Cancer J Clin. 2017;67(1):7-30. doi: 10.3322/caac.21387.
- National Cancer Institute. Cancer screening overview (PDQ)—health professional version. cancer.gov/about-cancer/screening/hp-screening-overview-pdq. Accessed Updated April 21, 2017. November 24, 2017.
- National Cancer Institute. Breast cancer screening (PDQ)—health professional version. cancer.gov/types/breast/hp/breast-screening-pdq. Updated October 3, 2017. Accessed November 24, 2017.
- Basic information about colorectal cancer. CDC website. cdc.gov/cancer/colorectal/basic_info/index.htm. Updated March 23, 2017. Accessed November 24, 2017.
- Fawcett N. Colon cancer screening key to prevention, increased survival. Michigan Medicine, University of Michigan, website. uofmhealth.org/news/111colon-cancer-screening-key-to-prevention. Published March 25, 2008. Accessed November 25, 2017.
- Pietrangelo A. Noninvasive cancer blood test could detect disease at earliest stages. Healthline website. healthline.com/health-news/cancer-blood-test-detects-at-earliest-stages#1. Published on August 28, 2017. Accessed on November 28, 2017.
- American Society of Clinical Oncology. Looking to the future. asco.org/research-progress/reports-studies/clinical-cancer-advances/looking-future. Accessed November 28, 2017.
- Blood test for genetic changes in tumors shows promise as alternative to tumor biopsy. National Cancer Institute website. cancer.gov/news-events/cancer-currents-blog/2016/asco-liquid-biopsy. Published June 14, 2016. Accessed November 28, 2017.
- Mendes E. More than 4 in 10 cancers and cancer deaths linked to modifiable risk factors. American Cancer Society website. cancer.org/latest-news/more-than-4-in-10-cancers-and-cancer-deaths-linked-to-modifiable-risk-factors.html. Published on November 21, 2017. Accessed on November 28, 2017.