Problems in treating cancer patients include not only the cancer itself, but also the quality of life and psychological problems of patients. Anxiety and depression are the most common psychological disorders in patients with cancer [17
]. It has been reported that the level of anxiety and depression is higher in prostate cancer patients than in healthy men. The MAXPC is a valid and reliable method for identifying anxiety related to prostate cancer [19
]. In this study, the mean MAXPC score was 10.47±4.64. Similar results were reported by Van den Bergh et al. [20
], who found a mean MAX-PC score of 9.3±6.8. The analysis of the relationship between prostate cancer stage and anxiety scores showed a significant difference in the mean MAX-PC score (P
=0.0001) between the early-stage prostate cancer group (8.32±3.65) and the advanced-stage prostate cancer group (12.61±4.56). Vodermaier et al. [16
] reported the same findings that anxiety symptoms were more commonly found in metastatic prostate cancer patients than in nonmetastatic prostate cancer patients.
Another study by Bill-Axelson et al. [21
] suggested that the hospitalization rate related to psychiatric symptoms (anxiety) will increase along with the diagnosis of prostate cancer. In patients with advanced-stage cancer, there would be more treatment for anxiety with a relative risk of 2.28 (95% confidence interval, 1.45–3.57) compared with early-stage cancer [21
]. The most common metastatic site of prostate cancer is bone. In prostate cancer, bone metastatic lesions result in localized pain [22
]. In our study, the pain score (VAS) in patients with advanced-stage prostate cancer was significantly higher than that in patients with early-stage prostate cancer. In this study, there were some confounding variables significantly related to the MAX-PC score (P
<0.05). These were the level of pain (VAS score), PSA value, and number of bone metastatic lesions. The VAS score was significantly correlated with the anxiety level (MAX-PC score). Cancer pain in prostate cancer patients was considered to have a major effect on anxiety level (r
<0.001); therefore, the proper management of pain is important.
The high level of anxiety could affect patient decision making in determining the treatment of choice [19
]. A study by Latini et al. [24
] showed that early-stage prostate cancer patients who have a high level of anxiety tend to make an early decision for more aggressive therapy compared with undergoing active surveillance. The existence of this anxiety disorder along with depression would interfere in daily activities, reduce the quality of life, and increase the incidence of suicide of prostate cancer patients [3
]. Factors that could increase the risk of anxiety in cancer patients are advanced stage of cancer, previous history of anxiety, lack of family support, activity limitations due to cancer, other comorbidities, and unresolved cancer pain [23
]. In the National Comprehensive Cancer Network distress guideline version 2.2013, an indication for referring a cancer patient to mental health services or social work and counseling services is a Distress Thermometer value of 4 or more with social, family, physical, emotional, and other medical problems. In assessing prostate cancer–related anxiety, we have not yet found a cutoff score on the MAX-PC for referral to mental health services (psychiatry). Despite some research on the psychological needs of men with prostate cancer in Asian countries, it is difficult to draw clear conclusions about the impacts of prostate cancer on the psychological health of Asian men with prostate cancer [15
]. Further investigations are required to determine the cutoff score on the MAX-PC questionnaire for referral to mental health services.
The limitations of this study were the relatively small number of study subjects (34 patients in each group) and the lack of guidelines in terms of psychiatric treatment for patients with high levels of anxiety. This study also did not examine the effect of the high level of anxiety on patient quality of life and their therapy selection. Future studies should be conducted to determine the cutoff value of MAX-PC score for referral by use of the MAX-PC instrument in combination with a psychiatric diagnostic instrument, such as the Mini-International Neuropsychiatric Interview for The Diagnostic and Statistical Manual of Mental Disorders (MINI, DSM-IV). The MINI is a short, structured diagnostic interview developed in 1990 by psychiatrists and clinicians in the United States and Europe for DSM-IV and International Statistical Classification of Diseases-10th revision psychiatric disorders [25
In conclusion, advanced-stage prostate cancer was significantly related to a high level of anxiety (MAX-PC score). Furthermore, VAS scores, PSA value, and the number of bone metastatic lesions might affect the anxiety (MAX-PC score) of patients with prostate cancer. Study of larger populations should be done to acquire a cutoff value of the MAX-PC score for better management of mental health issues in prostate cancer patients.