Prostate cancer is the most common cancer and the second leading cause of cancer deaths in men in the United States http://www.cancer.org
. It is estimated that in 2004, 230,110 men in the U.S. will be diagnosed with prostate cancer (PCa) and 29,900 will die of the disease. The 5-year overall relative survival rate for prostate cancer increased from 79.6% between 1983–90 to 98% in 2004. More than 75% of men diagnosed with prostate cancer are over age 65. In view of decreasing death rates, medical treatments for cancer patients are increasingly being evaluated by quality of life (QOL) issues as well as life extension [1
]. Psychometric assessment and decision theory are the two main approaches used to study QOL [2
]. The psychometric approach theorizes separate dimensions and measures for QOL, and the SF-36 is a tool frequently used in this approach. In the decision theory approach, various dimensions of health are weighted in order to provide a single holistic index of QOL. Health-related QOL is a multidimensional construct that reflects the impact of illness and treatment on physical, psychological, social and functional dimensions of well being [3
Men undergoing treatment for prostate cancer report negative physiological and psychological health effects. The varied symptoms reported may be a function of the cancer itself, or the type of therapy received; or the symptoms may have been present prior to the development of prostate cancer and receipt of treatment. A recent study examined quality of life related to bowel, bladder and sexual symptoms in men receiving treatment for PCa. Participants were not examined by treatment type and psychological variables were not included in the study. Researchers found that the strongest predictors of poor QOL were bowel, sexual and urinary symptoms respectively [4
Eton and Lepore [5
] reviewed several studies of symptoms associated with treatment for localized PCa. Urinary and bowel dysfunction were found to be the result of treatment. Urinary function was most affected in men who were treated with radical prostatectomy compared to those receiving external beam radiation with or without brachytherapy, hormone therapy or those treated with observation alone. Bowel function was most affected by external beam radiotherapy and brachytherapy. In the same review, researchers reported that sexual problems were related to the disease and were exacerbated by treatment, particularly standard radical prostatectomy.
Although psychological variables have been shown to be more important than treatment morbidity to the QOL of patients with prostate cancer, most studies of patients with prostate cancer continue to focus on symptoms such as urinary, bowel and sexual dysfunction [6
]. The ability of prostate cancer patients to maintain psychosocial functioning and healthy psychological states (e.g., freedom from mood distress or excessive anxiety) has been less frequently considered [6
]. The experience of living with cancer, from the time of diagnosis and treatment decisions, through treatment itself and survival is fraught with psychological distress. Increased attention to mood is reflected in chronic illness literature describing effects of mood on health related quality of life [7
Perceived stress is based on the relationship between the person and environment. It is the degree to which the individual appraises events as unpredictable, uncontrollable, and overloading. Perceived stress drives the coping response [8
]. Coping is defined as one's response to perceived external stressors. Two types of coping have been conceptualized: Problem-Focused Coping and Emotion-Focused Coping. Problem-Focused Coping refers to those actions taken to resolve the environmental stressor. Emotion-Focused Coping refers to efforts taken by the individual to mediate the emotional responses to the stressor [8
Anxiety and the ability to cope with cancer are influenced by perceptions. These include the meaning men give to prostate cancer and its treatment and the way these factors impact their lives. Roth and associates [9
] reported on a sample of men receiving treatment for PCa and screened for anxiety and depression using the Hospital Anxiety and Depression Scale. Thirty-two percent of patients with PCa scored at or above the anxiety cutoff score.
] asserted that psychosocial variables, such as self-efficacy, strongly influence the perceived quality of one's life. Self-efficacy is described as the coordinator of psychological change, operating by changing expectancies of personal mastery. Robust efficacy beliefs may help to marshal coping responses that reduce stress and anxiety. Peoples' self-efficacy may regulate their emotional states in several ways. People who believe they can manage threats are less distressed by them; those who lack self-efficacy are more likely to magnify risks. People with high self-efficacy lower their stress and anxiety by acting in ways that make the environment less threatening. People with high coping capacities have better control over disturbing thought.
] noted a need for the study of QOL and indicators of adjustment in men treated for prostate cancer. He suggested using three types of measures: a generic measure of health, a measure of symptoms specific to prostate cancer, and psychosocial measures. Litwin [11
] also noted a need for the study of QOL in men receiving different treatments for PCa in order to improve the specificity of research findings.
Intensity Modulated Radiation Therapy (IMRT) is a new technology in radiation oncology that delivers radiation more precisely to the tumor and is more sparing of surrounding normal tissues. IMRT has wide application in most aspects of radiation oncology because of its ability to create multiple targets and multiple avoidance structures, to treat different targets simultaneously at different doses, as well as to weight targets and avoidance structures according to their importance. By delivering radiation with greater precision, IMRT has been shown to minimize acute treatment-related morbidity, making dose escalation feasible, which may ultimately improve local tumor control [12
]. Furthermore, IMRT can be combined with brachytherapy and High Dose Rate (HDR).
Brachytherapy is a prostate cancer (PCa) treatment in which radioactive sources are implanted into the prostate gland. The most commonly performed brachytherapy treatment is permanent radioactive seed implantation. This out-patient, minimally invasive procedure is performed by inserting small needles through the perineum into the prostate gland under ultrasound visualization. Radioactive Palladium or Iodine seeds are then injected through the needles. These low energy radioactive sources have limited tissue penetration allowing for a sharp drop-off at the edge of the gland, thus limiting radiation delivery to normal tissues. The precision and conformation of the brachytherapy dose allows a much higher dose to be delivered to the prostate gland than can be delivered with external beam radiation (IMRT + seed implantation).
Another form of brachytherapy that has been used to treat PCa is high dose rate brachytherapy (HDR). Plastic catheters are temporarily inserted into the gland and are used as a delivery system for an Iridium source of high activity. Patients receiving this therapy for PCa are treated 4 times over a 36-hour hospital stay [13
Analysis of Medicare data shows that brachytherapy is replacing radical prostatectomy (RP) as the treatment of choice for early stage PCa [13
]. An important component in the consideration of treatment options for PCa is the impact on QOL [5
]. Ideally a patient would select a treatment modality that maximizes both survival and QOL. Evolving treatment options make such choices more complex. Because rates of tumor control appear to be remarkably similar across treatment approaches, studies comparing QOL outcomes are of great importance [15
One hundred fifteen articles focused on IMRT were identified using the National Library of Medicine data-base http://www.pubmed.com
; however, few studies focused on QOL in patients receiving IMRT for prostate cancer. Kupelian and colleagues [16
] studied QOL of 51 prostate cancer patients treated with IMRT using the Expanded Prostate Cancer Index Composite to evaluate QOL. No other variables were measured; thus, predictors of QOL were not addressed. The objective of this article is to report physical and psychosocial predictors of QOL variables in men who are diagnosed with prostate cancer and receive radiation treatments including IMRT + HDR or IMRT + seed implantation. Figure describes proposed relationships among study variables. The main research question is: What proportion of the variance in each dimension of quality of life (physical function, role performance-physical, role performance-emotional, bodily pain, vitality, social function, mental health and general health) is predicted by demographic variables, physical symptoms, coping style, perceived stress, anxiety, and self-efficacy in men receiving IMRT + HDR or IMRT + seed implantation?