Quality of life after high-dose-rate brachytherapy monotherapy for prostate cancer.

PURPOSE: There is little information in the literature on health-related quality of life (HRQOL) changes due to high-dose-rate (HDR) brachytherapy monotherapy for prostate cancer.
MATERIALS AND METHODS: We conducted a prospective study of HRQOL changes due to HDR brachytherapy monotherapy for low risk or favorable intermediate risk prostate cancer. Sixty-four of 84 (76 %) patients who were treated between February 2011 and April 2013 completed 50 questions comprising the Expanded Prostate Cancer Index Composite (EPIC) before treatment and 6 and/or 12 months after treatment.
RESULTS: Six months after treatment, there was a significant decrease (p <0.05) in EPIC urinary, bowel, and sexual scores, including urinary overall, urinary function, urinary bother, urinary irritative, bowel overall, bowel bother, sexual overall, and sexual bother scores. By one year after treatment, EPIC urinary, bowel, and sexual scores had increased and only the bowel overall and bowel bother scores remained significantly below baseline values.
CONCLUSIONS: HDR brachytherapy monotherapy is well-tolerated in patients with low and favorable intermediate risk prostate cancer. EPIC urinary and sexual domain scores returned to close to baseline 12 months after HDR brachytherapy.

INTRODUCTION

Management options for patients with low or intermediate risk prostate cancer and a life expectancy of less than 10 years include active surveillance (1), radical prostatectomy (2), external beam radiation therapy (EBRT), low-dose rate (LDR) brachytherapy monotherapy (3, 4), or high-dose-rate (HDR) brachytherapy (5, 6). Since cure rates are similar among these treatment options (7), health-related quality of life (HRQOL) is an important factor in a patient’s decision-making process (8).

In prostate cancer patients, physician-assessed HRQOL changes do not correlate with patient-assessed changes. Physicians under-estimate HRQOL changes and over-estimate improvement in symptoms relative to patients (9). Discrepancies are particularly large for symptoms like pain and fatigue (9). As a result, it is important to measure patient-assessed HRQOL. The Expanded Prostate Cancer Index Composite (EPIC) is a validated questionnaire used to assess HRQOL in prostate cancer patients. EPIC includes 4 domains: urinary, bowel, sexual, and hormonal (10). There are summary (i.e., overall) scores and function and bother subscale scores for each of the 4 domains. The urinary domain has 2 additional subscales: incontinence and irritative/obstructive. Domains and subscales are scored using a 0-100 grading system, with a higher score indicating a higher quality of life.

HRQOL changes in prostate cancer patients undergoing radical prostatectomy, LDR brachytherapy monotherapy or EBRT vary significantly between treatment modalities (11). There has been only one prior report on HRQOL changes due to HDR brachytherapy monotherapy for prostate cancer (12). As a result, we studied HRQOL changes in this select group of patients.

MATERIALS AND METHODS

Recurrence risk was defined according to the National Comprehensive Cancer Network (NCCN) guidelines (13). Low recurrence risk was defined as patients with clinical T1-T2a disease, prostate-specific antigen (PSA) <10 ng/mL, and a Gleason score ≤6. Intermediate recurrence risk patients were those with clinical T2b-T2c disease, PSA=10-20 ng/mL, or a Gleason score =7. Intermediate risk patients were subdivided into “favorable” and “unfavorable” groups. Favorable intermediate risk patients were defined as those with a Gleason score of 3+4=7, ≤cT2b disease, and ≤50% positive core biopsies (5). Low risk and favorable intermediate risk patients may be treated with HDR brachytherapy monotherapy (5, 6, 12, 14). Unfavorable intermediate risk patients had a Gleason score of 4+3=7, cT2c disease, or >50% positive core biopsies (15, 16). Patients with unfavorable intermediate risk prostate cancer and patients who received intensity modulated radiation therapy (IMRT) or androgen deprivation therapy were excluded from this study.

After obtaining institutional review board approval, we treated 84 low risk and favorable intermediate risk prostate cancer patients with HDR brachytherapy monotherapy at the H. Lee Moffitt Cancer Center & Research Institute between February 2011 and April 2013. After providing informed consent, patients underwent HDR brachytherapy monotherapy to the prostate to 2,700-2,800 cGy in two 1,350-1,400 cGy fractions separated by 2-3 weeks. Over a one-year period following HDR brachytherapy, approximately half of the patients were placed on phosphodiesterase-5 inhibitors such as one sildenafil 50 mg tablet by mouth three times per week for erectile dysfunction. Use of phosphodiesterase-5 inhibitors was based upon patient preference.

HRQOL was assessed using the most recent version of EPIC. Sixty-four of 84 (76%) patients completed the 50-question form prior to HDR brachytherapy monotherapy, i.e., at baseline, and 6 and/or 12 months after treatment. Characteristics of these 64 patients are presented in Table 1. Patients who failed to complete the 50-question EPIC questionnaire commonly stated that it was too long. Mean follow-up was 9 months.

Table 1

Patient characteristics.

Number of Patients	64
Mean Follow-up	9 months
Age at Diagnosis, mean (range)	65 years (48-83)
BMI, kg/m2, mean (range)	29.5 (22.0-43.0)
PSA, ng/mL, median (range)	5.3 (1.0 – 16.1)
Prostate Size, cc, median (range)	54 (24-108)
AJCC Clinical T Stage
T1c	58
T2a	5
T2b	1
Gleason Score
3+3=6	43
3+4=7	21
NCCN Recurrence Risk Group
Low	39
Intermediate	25

AJCC= American Joint Committee on Cancer; cc:cubic centimeters; NCCN= National Comprehensive Cancer Network; PSA= prostate-specific antigen.

In accordance with prior reports (12, 17, 18), we calculated mean EPIC scores for each time point. Pre-treatment EPIC scores were compared to scores obtained 6 months and 12 months after treatment using a Student’s t-test. Linear regression was used to analyze the relationship between patient characteristics (body mass index (BMI), age, prostate volume, PSA, Gleason score, and recurrence risk group) and EPIC scores.

RESULTS

Pre-treatment urinary overall, function, bother, incontinence, and irritative/obstructive scores were 87, 91, 85, 87, and 85, respectively (Figure 1). Six months after treatment, urinary overall, function, bother, incontinence, and irritative scores decreased to 76, 79, 75, 76, and 75 respectively (p<0.01). Twelve months after treatment, all urinary scores had increased and were not significantly different from baseline values.

Figure 1

EPIC urinary overall, function, bother, incontinence, and irritative/obstructive scores before HDR brachytherapy monotherapy and 6 and 12 months after treatment.

Pre-treatment bowel overall, function, and bother scores were 95, 90, and 95, respectively (Figure 2). Six months after treatment, there was a significant decrease in bowel overall, function, and bother scores to 86, 84, and 86 respectively (p<0.001). Twelve months after treatment, bowel overall and bother scores increased to 88 and the bowel function score had increased to 86. These scores remained statistically below baseline values.

Figure 2

EPIC bowel overall, function, and bother scores before HDR brachytherapy monotherapy and 6 and 12 months after treatment.

Pre-treatment sexual overall, function, and bother scores were 46, 43, and 53, respectively (Figure 3). Six months after treatment, there was a significant decrease in sexual overall and bother scores to 34 and 42, respectively. Twelve months after treatment, sexual overall and bother scores increased and were not statistically different from baseline values.

Figure 3

EPIC sexual overall, function, and bother scores before HDR brachytherapy monotherapy and 6 and 12 months after treatment.

Pre-treatment hormonal overall, function, and bother scores were 91, 88, and 92, respectively (Figure 4). Six months after treatment, there was a non-significant decrease in sexual hormonal scores. Twelve months after treatment, hormonal scores had decreased further. However, they were not significantly below baseline.

Figure 4

EPIC hormonal overall, function, and bother scores before HDR brachytherapy monotherapy and 6 and 12 months after treatment.

There was no association between patient characteristics and EPIC scores.

DISCUSSION

Morton et al. (19) reported HRQOL changes in intermediate risk prostate cancer patients who received EBRT and an HDR brachytherapy boost without androgen deprivation therapy. Patients experienced clinically significant decreases in EPIC urinary, bowel, and sexual overall scores 12 months and 24 months after treatment. In contrast, the EPIC hormonal overall score did not change significantly due to radiotherapy. Similarly, in this study, the EPIC bowel overall score remained significantly below baseline 12 months after radiotherapy (Figure-2); however, the decrease in the EPIC hormonal overall score was not statistically significant (Figure-4).

To date, only one study has reported patient-assessed HRQOL changes in prostate cancer patients treated with HDR brachytherapy monotherapy. Barkati et al. (12) treated 79 low and intermediate risk prostate cancer patients with HDR brachytherapy monotherapy. Seven patients also received neoadjuvant androgen deprivation therapy. They observed a decline in EPIC scores across all 4 domains as early as one month after treatment. Urinary, bowel, and hormonal scores recovered 3 months after HDR brachytherapy monotherapy. This compares favorably with our findings, where EPIC urinary and sexual scores did not improve until 12 months after HDR brachytherapy (Figures 1 and 3). EPIC scores may have taken longer to improve after HDR brachytherapy in this report because we delivered a higher biologically effective dose of radiotherapy (14). Barkati et al. observed that urinary, bowel, and hormonal scores remained stable 3-48 months after treatment. Also, they reported a decline in sexual overall scores as early as one month after treatment with no recovery thereafter. Patients’ ages were similar to this study. However, baseline sexual overall scores were lower in this report. As in the report by Barkati et al., baseline sexual scores in this study were considerably lower than urinary, bowel, and hormonal scores (Figures 1-4). Like Barkati et al., we observed a significant decrease in sexual overall and bother scores at 6 months (Figure-3). However, in this report, there was improvement in sexual scores at 12 months. This was probably due to early use of a phosphodiesterase-5 inhibitor after brachytherapy in approximately half of our patients (20).

Marina et al. (21) used the Common Terminology Criteria for Adverse Events v4 grading system to determine incidence rates of erectile dysfunction 3 years after HDR brachytherapy monotherapy vs. IMRT. Rates of erectile dysfunction requiring medical intervention for both HDR brachytherapy monotherapy and IMRT were low and equivalent.

In this study, 64/84 (76%) prostate cancer patients treated with HDR brachytherapy monotherapy completed 50 questions comprising the most recent version of the EPIC questionnaire. Similarly, others have reported 36-78% compliance rates (12, 22). Since men who did not complete the form commonly stated that it was too long, we have switched to a 26-item, short-form version of EPIC in an effort to improve patient compliance (23, 24).

CONCLUSIONS

HDR brachytherapy monotherapy is well-tolerated in patients with low and favorable intermediate risk prostate cancer. EPIC urinary and sexual domain HRQOL scores returned to close to baseline 12 months after treatment.