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Construct Overview of Prostate Cancer

Please note that this section is an archive and is no longer being updated.

Background

Prostate cancer is cells in the prostate that grow in an abnormal manner. Prostate cancer is one of the most common of all cancers, which is the second most common cause of death in men in the United States.^1-2 The American Cancer Society estimates that 234,460 new cases of prostate cancer will be diagnosed in 2006.³ There has been an increased incident rate of prostate cancer in recent years. From 1974 to 1994, the rate of American men diagnosed with prostate cancer increased by 130% for Caucasian men and 140% for African American men.⁴ These high percentages may have been due to PSA testing to detect sub-clinical prostate cancer. Prostate cancer can be detected early and life expectancy may be increased with proper screening procedures. The American Cancer Society recommends that individuals start getting screened for prostate cancer beginning at the age of 50 and at age 45 for high risk individuals. The American Cancer Society encourages individuals to get screened using digital rectal examination (DRE) and serum prostate specific antigen (PSA).⁵ Research has found that the benefits of early detection may not help those who are older, beyond 70 years of age, because they may be more likely to die from other comorbid conditions.⁶

VA Relevance

Prostate cancer may be diagnosed in one in six men over the age of 60 years.⁷ Research suggests that factors that may increase the chance of veterans having prostate cancer are: being African American, family history of prostate cancer, previous vasectomy, tobacco use, and Agent Orange exposure.⁸ The Veterans Administration has made efforts to ensure that veterans get the best quality of care, including attempts to reduce financial barriers to health related services for veterans to equalize access.⁹ The VA has promoted prostate cancer screening within the veteran population by educating patients on the benefits of screening. Many Veteran Affairs primary care providers have found the need to screen African Americans and men with a family history of prostate cancer more than any other groups within the VA.⁸ The prevalence of prostate cancer appears to be about the same in the veteran population as found in the general population.

Epidemiologic researchers have suggested that there may be an association between Agent Orange and prostate cancer.¹⁰ Agent Orange is an herbicide defoliant that was sprayed in Vietnam between August 1965 and February 1971.¹⁰ Dioxin, which is found in Agent Orange is what has been linked to several types of cancer. In a pilot study the risk of being diagnosed with prostate cancer after the exposure to Agent Orange was examined in the Vietnam veteran population. The study found that veterans with prostate cancer were approximately two times more likely to have had previous exposure to Agent Orange.¹⁰ However, in a different study no significant relationship between prostate cancer and Agent Orange exposure was found.¹¹ Additional studies are needed in order to fully understand the relationship between Agent Orange and prostate cancer.

Measurement

Various aspects related to prostate cancer have been measured using different instruments. The quality of life of individuals who have been diagnosed with prostate cancer has been widely investigated within the veteran population as well as in the general population. There have been many instruments that were created to measure quality of life in individuals with prostate cancer. Quality of life most often refers to one's overall well-being and happiness. Measuring the quality of life can be difficult to do because it tends to be a subjective construct. Thus, different quality of life measures have been developed to measure the quality of life in specific population groups, such as cancer. Other factors that have been measured regarding prostate cancer are health status, and coping strategies. The instruments that have been used to measure these factors include structured interviews and self-administered questionnaires.

Structured interviews enable clinicians to accurately obtain information about a patient. Self-administration of instruments can allow patients to report their own symptoms in a clear manner. Some of the instruments that have been used in patients with prostate cancer have been found to be valid and reliable.12 Therefore, the quality of life in patients with prostate cancer may be measured more precisely.

Through literature review, METRIC identified three commonly used interviewer-administered and self-report instruments used with prostate cancer patients and ranked them according to number of citations, as determined by the ISI Web of Knowledge.12 What follows is a brief summary of each instrument and three applicable references.

Most Frequently Cited Instruments

1. European Organization for Research and Treatment of Cancer-Quality of Life Questionnaire (EORTC-QLQ)
   [86 Citations]
2. Prostate Cancer Index (PCI)
   [75 Citations]
3. Functional Assessment of Cancer Therapy-Prostate (FACT-P)
   [14 Citations]

Expert-recommended Instruments

1. Medical Outcomes Study Short Form-36 Health Survey (SF-36)

1. Monga U, Kerrigan AJ, Thornby J, Monga TN, Zimmerman KP. Longitudinal Study of Quality of Life in Patients with Localized Prostate Cancer Undergoing Radiotherapy. Journal of Rehabilitation Research & Development. 2005; May/June: 42(3): 391-400. [Abstract]
2. Knight SJ, Chmiel JS, Kuzel T, Sharp L, Albers M, Fine R, Morgan EM, Nadler RB, Sharifi R, Bennett CL. Quality of Life in Metastatic Prostate Cancer among Men of Lower Socioeconomic Status: Feasibility and Criterion Related Validity of 3 Measures. The Journal of Urology. 1998; November: 160(5): 1765-1769. [Abstract]
3. Cancer Facts & Figures 2006. Accessed April 2006. Available: http://www.cancer.org/docroot/STT/stt_0.cfm
4. Fouad MN, Mayo CP, Funkhouser EM, Irene Hall H, Urban DA, Kiefe CI. Comorbidity Independently Predicted Death in Older Prostate Cancer Patients, More of Whom Died with than from their Disease. Journal of Clinical Epidemiology. 2004; 57:721-729. [Abstract]
5. Grubb RL, Roehl KA, Antenor JA, Catalona WJ. Results of Compliance with Prostate Cancer Screening Guidelines. The Journal of Urology. 2005; August: 174: 668-672. [Abstract]
6. Howard DH. Life Expectancy and the Value of Early Detection. Journal of Health Economics. 2005; 24: 891-906. [Abstract]
7. Shannon J, Tewoderos S, Garzotto M, Beer TM, Derenick R, Palma A, Farris PE. Statins and Prostate Cancer Risk: A Case-Control Study. American Journal of Epidemiology. 2005; 162(4): 318-325. [Abstract]
8. Terris MK, Ruff PA, Marotte JB. Primary Care Providers' Attitudes toward Prostate Cancer Risk Factors at a Veterans Affairs Health Care Facility. Military Medicine. 2005; 170(2): 154-157. [Abstract]
9. Freeman VL. Durazo-Arvizu R, Arozullah AM, Keys LC. Determinants of Mortality Following a Diagnosis of Prostate Cancer in Veterans Affairs and Private Sector Health Care Systems. Research and Practice. 2003; October: 93(10): 1706-1712. [Abstract]
10. Giri VN, Cassidy AE, Beebe-Dimmer J, Smith DC, Bock CH, Cooney KA. Association between Agent Orange and Prostate Cancer: A Pilot Case-Control Study. Urology. 2004; 63(4): 757-760. [Abstract]
11. Zafar MB, Terris MK. Prostate Cancer Detection in Veterans with a History of Agent Orange Exposure. The Journal of Urology. 2001; July: 166: 100-103. [Abstract]
12. Esper P, Mo F, Chodak G, Sinner M, Cella D, Pienta KJ. Measuring Quality of Life in Men with Prostate Cancer Using the Functional Assessment of Cancer Therapy-Prostate Instrument. Urology. 1997; 50(6): 920-928. [Abstract]
13. ISI Web of Knowledge. Accessed October 2005. Available: http://isi01.isiknowledge.com/portal.cgi/wos/.