Volume 80, Issue 4 , Pages 1080-1086, 15 July 2011
External Beam Radiotherapy for Prostate Cancer: Urinary Outcomes for Men With High International Prostate Symptom Scores (IPSS)
Article Outline
- Abstract
- Introduction
- Methods and Materials
- Results
- Discussion
- Conclusion
- Acknowledgment
- References
- Copyright
Purpose
To report the urinary outcome of men treated for prostate cancer with external beam radiotherapy (EBRT) who have pretreatment obstructive urinary symptoms (International Prostate Symptom Score [IPSS] ≥15).
Methods and Materials
We treated 368 patients with EBRT for localized prostate cancer, and pre- and post-radiotherapy (RT) IPSSs were recorded. In total, 80 men had an IPSS ≥15, 48% of whom were taking genitourinary (GU) medications before RT. The IPSS was followed over time and analyzed as a pretreatment factor against Radiation Therapy Oncology Group acute and late GU toxicity.
Results
The median follow-up was 44 months. Among men with a pre-RT IPSS ≥15, the median IPSS at baseline, first follow-up, and last follow-up was 18 (range, 15 to 34), 17 (range, 0 to 32), and 13 (range, 0 to 34), respectively. The mean patient declines in IPSS from baseline to first and last follow-up were −3.6 points (p < 0.0004) and −6.9 points (p < 0.0001), respectively. At last follow-up, 43 men (54%) took GU medications. Pre-RT IPSS ≥15 vs. ≤14 was associated with a higher incidence of Grade ≥2 acute GU toxicity (64% vs. 42%, p = 0.0005), and 4-year freedom from Grade ≥2 late GU toxicity was 38% vs. 64% (p < 0.0001). There was no greatly increased risk of Grade ≥3 late GU toxicity for men with IPSS ≥15 (4-year freedom from Grade ≥3 late GU toxicity of 90% vs. 96%, p = 0.0964).
Conclusions
Although the improvement is not immediate, men with moderate to severe obstructive GU symptoms can have improvement in urinary function after EBRT, without significant risk for severe morbidity.
IPSS, External beam radiotherapy, Genitourinary toxicity
Introduction
The International Prostate Symptom Score (IPSS) was first developed in 1992 by the American Urological Association (AUA) as a validated tool to assess symptomatic relief after radical prostatectomy for benign prostatic hypertrophy (1). Seven domains, evaluating incomplete emptying, frequency, weak stream, intermittency, urgency, straining, and nocturia, assess the frequency of urinary symptoms, each on a 0 to 5 scale. A separate quality-of-life score rates patient satisfaction with regard to these symptoms. The role of the pretreatment IPSS in predicting post-treatment urinary morbidity has been studied widely in localized prostate cancer patients undergoing brachytherapy. Higher rates of postimplant catheterization 2, 3, 4 and late urinary morbidity (5) are associated with a higher pretreatment IPSS. Because urinary symptom scores may require approximately 1 year to return to baseline 5, 6, 7, such patients with poor baseline urinary function are typically not candidates for brachytherapy (8).
For prostate cancer patients who have lower urinary tract symptoms, it is appropriate to primarily consider a surgical approach for relief of severe obstructive-type symptoms 9, 10, 11. However, radical prostatectomy carries an increased risk of urinary incontinence and pad use 10, 12, 13, 14, 15 compared with other radical therapies such as external beam radiotherapy (EBRT) and brachytherapy. In addition, not every man diagnosed with prostate cancer who has obstructive urinary symptoms is an appropriate operative candidate.
In contrast to numerous reports of brachytherapy data reporting how pretreatment function can influence urinary outcome 2, 3, 4, 5, 7, limited data exist for EBRT-treated men. The goal of this study was to characterize the nature and severity of post-EBRT urinary function for prostate cancer patients with moderate to severe obstructive urinary symptoms (IPSS ≥15). It is of interest to describe whether such men can expect eventual relief or whether they are at significantly higher risk for short- or long-term morbidity compared with men without obstructive uropathy. Furthermore, the results of this study would have potential implications in the initial evaluation and counseling of these patients regarding two primary considerations for curative therapy: radical prostatectomy and EBRT.
Methods and Materials
Patients
This study was a retrospective review of men treated at the University of Chicago Hospitals (Pritzker School of Medicine campus) with definitive radiotherapy (RT) for localized adenocarcinoma of the prostate. Patients were excluded if they underwent prior surgery for prostate cancer or brachytherapy as a component of their care. A total of 368 consecutive patients were treated with EBRT between 1998 and 2007 (minimum 2 years' potential follow-up) and had pretreatment and post-treatment IPSS available for review. Men with moderate to poor baseline urinary function were defined a priori as those having an IPSS ≥15. This cutoff was used based on brachytherapy data associating higher rates of urinary toxicity at or above this pretreatment IPSS 2, 4, 7. Of the men, 80 (22%) had an IPSS ≥15 and 288 had an IPSS ≤14. Baseline scores were obtained at consultation before the initiation of any therapy (i.e., RT or androgen-deprivation therapy [ADT]).
The median age of the 368 men was 69 years (range, 44 to 83 years). Patient and disease characteristics are detailed in Table 1. National Comprehensive Cancer Network risk classification (16) showed 113 men (31%) with low-risk disease, 166 men (45%) with intermediate-risk disease, and 86 men (24%) with high-risk disease. The median prostate volume (by computed tomography planning) was 39 cm3 (range, 12 to 186 cm3). Neoadjuvant and/or concurrent ADT was administered in 186 patients (51%) and consisted of a gonadotropin-releasing analog with or without an antiandrogen. The median ADT duration was 4 months (range, 2 to 83 months). During this time period, the administration of ADT was based on risk classification and not based on gland size or obstructive symptoms.
Table 1. Patient and treatment characteristics
| IPSS ≥15 (n = 80) | IPSS ≤14 (n = 288) | p value | |
|---|---|---|---|
| Median age (y) | 69 (range, 47–83) | 69 (range, 44–83) | 0.2344 |
| Race | 0.8990 | ||
 Caucasian | 29 (36%) | 102 (35%) | |
| African American | 49 (61%) | 173 (60%) | |
| Other/unknown | 2 (3%) | 10 (3%) | |
| Median pre-RT PSA level (ng/mL) | 7.9 (range, 0.97–155) | 7.9 (range, 1.09–242) | 0.6006 |
| PSA level | 0.6438 | ||
| 0–4 ng/mL | 5 (6%) | 24 (8%) | |
| 4–10 ng/mL | 43 (54%) | 148 (51%) | |
| 10–20 ng/mL | 17 (21%) | 73 (25%) | |
| >20 ng/mL | 15 (18%) | 41 (14%) | |
| Clinical T stage | 0.8482 | ||
| T1–T2a | 68 (85%) | 249 (86%) | |
| T2b–T2c | 8 (10%) | 23 (8%) | |
| T3 | 4 (5%) | 13 (5%) | |
| T4 | 0 (0%) | 0 (0%) | |
| Gleason sum | 0.3815 | ||
| 2–6 | 43 (54%) | 134 (47%) | |
| 7 | 31 (39%) | 119 (41%) | |
| 8–10 | 6 (8%) | 34 (12%) | |
| Median EBRT dose (Gy) | 75.6 (range, 71–76.4) | 75.6 (range, 68.5–76.4) | 0.5992 |
| Intensity-modulated RT | 65 (82%) | 246 (85%) | 0.4566 |
| Median prostate volume (mL)∗ | 42 (range, 15–186) | 38 (range, 12–133) | 0.2165 |
| Whole-pelvic RT | 10 (13%) | 27 (9%) | 0.4237 |
| TURP | 7 (9%) | 24 (8%) | 0.8183 |
| ADT | 36 (45%) | 150 (52%) | 0.2502 |
| Neoadjuvant ADT | 35 (44%) | 148 (51%) | 0.1874 |
| Median ADT duration (mo) | 4 (range, 2–38) | 4 (range, 2–83) | 0.3062 |
| ADT duration | |||
| 1–6 mo | 26 (74%) | 119 (81%) | |
| >6–12 mo | 5 (14%) | 18 (12%) | |
| >12 mo | 4 (11%) | 14 (8%) | |
| Median follow-up (mo) | 40 (range, 1–108) | 44 (range, 2–113) | 0.5589 |
∗Pre-RT and post-neoadjuvant ADT. |
Treatment
All patients underwent computed tomography planning and were treated to a median dose of 75.6 Gy (range, 68.5 to 76.4 Gy), prescribed to the planning target volume (PTV). Whole-pelvic radiotherapy (WPRT) was administered to 37 men (10%), whereas the remaining patients received initial treatment to the prostate and seminal vesicles alone (50–50.4 Gy) followed by a prostatic boost. The typical PTV expansion for the study time period was 1 cm on the clinical target volume (prostate with or without inclusion of proximal seminal vesicles). Intensity-modulated radiotherapy (IMRT) was delivered in 311 men (85%) (17). Patients were set up for treatment according to bony anatomy until April 2003, after which transabdominal ultrasound was introduced to localize the prostate before daily treatment.
Follow-up and IPSS assessment
Patients were followed up 1 month after EBRT and then every 6 months for 2 years. Gradually, follow-up was extended to annual visits after 5 years. At each follow-up, history and physical information, IPSS, prostate-specific antigen values, ADT, and medication use were collected. In addition, Radiation Therapy Oncology Group (RTOG) acute and late toxicity scores were collected during treatment and at each follow-up visit. Late genitourinary (GU) toxicity was defined as toxicity documented 90 days after the last radiation treatment.
For men with moderate to poor baseline urinary function, IPSS subset and urinary quality-of-life scores were collected in addition to total IPSS at baseline, first follow-up, and last follow-up. Common Terminology Criteria for Adverse Events version 3.0 (CTCAE v3.0) (18) was also collected during RT and at each follow-up in patients with a pre-RT IPSS ≥15. Freedom from biochemical failure was determined according to the Phoenix definition (nadir + 2 ng/mL) (19).
Changes in IPSS at first and last follow-up were analyzed by the paired t test. Baseline IPSS was analyzed against acute GU toxicity by chi-square analysis. All analysis of GU toxicity was performed against RTOG toxicity. Time to late Grade 2 or 3 toxicity was determined by the Kaplan-Meier method and was analyzed according to IPSS by the log-rank test. Multivariate analysis was performed by use of the Cox proportional hazards model with predetermined covariates including pre-RT IPSS, prostate volume, history of transurethral resection of prostate (TURP), radiation dose, and use of ADT, WPRT, and IMRT. Tests were performed by use of dichotomous variables and were two sided. Statistical significance was set at p < 0.05.
Results
The median follow-up was 40 months for patients with an IPSS ≥15 and 44 months for patients with an IPSS ≤14 (p = 0.5589). Overall, 4-year freedom from biochemical failure was similar (86% vs. 92%, p = 0.1077) for patients with a pretreatment IPSS ≥15 vs. those with a pretreatment IPSS ≤14. Baseline patient characteristics are listed in Table 1. There were no differences in demographic characteristics according to pretreatment IPSS. Treatment-related factors were also similar between the two groups including median EBRT dose, IMRT use, WPRT use, history of TURP, and ADT institution and duration.
Use and duration of GU medications
Among the 80 patients with an IPSS ≥15, 38 men (48%) were taking GU medications before treatment. Alpha-blockers accounted for 96% of GU medications, whereas the remaining agents included bladder antispasmodics. Of these 38 patients taking pre-RT medications, 15 (39%) required a dose increase during treatment because of lower urinary tract symptoms. Of 42 patients not taking GU medications at baseline, 31 men (74%) started treatment medications during or after RT. However, only about half of the overall cohort (n = 43 of 80, 54%) continued to take GU medications at last follow-up. Of these 43 men, 28 (65%) had been taking GU medications before RT. In 11 patients (14%), medications were never used before, during, or after RT.
The median duration of medication use in 31 patients who started taking GU agents after the initiation of RT was 15.2 months (range, 0 to 100 months). Medication duration was less than 6 months in 9 patients (29%), 6 to 11.9 months in 4 patients (13%), 12 to 23.9 months in 6 patients (19%), and at least 24 months in 12 patients (39%). Nearly a quarter of patients (9 of 38) who were taking medications before RT had discontinued use by their last follow-up visit.
Trends in IPSS after RT
At baseline, the median IPSS among our 80-patient cohort was 18 (range, 15 to 34) vs. a median score of 6 (range, 0 to 14) among the 288 men without poor baseline urinary function. Trends in IPSS at first and last follow-up for this cohort and for individual patients are displayed in Figs. 1A and 1B, respectively. At first follow-up (median of 5 weeks after EBRT), the median IPSS for patients with a baseline IPSS ≥15 was 17 points. The individual patient IPSS dropped by a mean of −3.6 points (95% confidence interval [CI], −5.5 to −1.7; p < 0.0004) and median of −2 points (range, −32 to 14). The quality-of-life score for the entire cohort, however, did not significantly change from baseline.
Fig. 1
(A) Trend in International Prostate Symptom Score (IPSS) for the entire cohort of men with pre–radiotherapy (RT) IPSS ≥15 at first follow-up (F/U) (median, 5 weeks) and last follow-up (median, 40 months). Blue, black, and red lines represent 75% quartile scores, median scores, and 25% quartile scores, respectively. Dotted lines represent range of IPSS. (B) Patient declines in IPSS at first follow-up (median, 5 weeks) and last follow-up (median, 40 months) compared with pre-RT IPSS. Blue, black, and red lines represent 75% quartile scores, median scores, and 25% quartile scores, respectively. Dotted lines represent range of values. Mean change from baseline to first follow-up, −3.6 points (95% confidence interval, −5.5 to −1.7; p < 0.0004); mean change from baseline to last follow-up, −6.9 points (95% confidence interval, −8.9 to −4.9; p < 0.0001).
At last follow-up (median, 40 months), the median IPSS for patients with a pre-RT IPSS ≥15 was 13 (range, 0 to 34) vs. 5 (range, 0 to 31) for the 288 men with a pre-RT IPSS ≤14 (p < 0.0001). The individual patient IPSS in men with a pretreatment IPSS ≥15 dropped by a mean of −6.9 points (95% CI, −8.9 to −4.9; p < 0.0001) and a median of −7 points (range, −29 to 13). This drop in IPSS was seen across all seven subset domains. Overall, 62 men (79%) had an IPSS decline by last follow-up out of the 78 men with a post-RT IPSS available. Forty-six men (59%) had a 5-point decline or greater and 29 (37%) had a 10-point decline or greater from baseline IPSS. A rise in IPSS developed from pretreatment baseline to last follow-up in only 16 men (21%); in these men, the median IPSS rise was 3.5 points (range, 1 to 13). Patient quality-of-life scores also dropped by a mean of −0.7 points (95% CI, −1.0 to −0.3; p = 0.0003) and a median of −1 point (range, −3 to 4). For men with a pretreatment IPSS ≤14, there was a minor, albeit statistically significant, rise in patient IPSS from baseline to last follow-up. The mean and median patient IPSS inclines for this group were 1 point (95% CI, 0.3 to 1.7; p = 0.0039) and 0.5 points (range, −13 to 29), respectively.
For patients with a pre-RT IPSS ≤14, there was no statistically significant difference in the magnitude of IPSS declines from baseline to last follow-up according to ADT use (data not shown). Men with a pre-RT IPSS ≥15 had a statistically significant IPSS decline from baseline to last follow-up whether they received ADT or not, although the magnitude of this decline was influenced by ADT use (p = 0.0259). The mean and median patient IPSS declines were −9.3 points (95% CI, −12.2 to −6.4) and −9 points (range, −29 to 13), respectively, for men treated with ADT, whereas the median and mean declines were −4.9 points (95% CI, −7.5 to −2.3) and −5 points (range, −24 to 11), respectively, for men treated without ADT.
Analysis by AUA symptom score classification (1), whereby baseline IPSSs of 0 to 7, 8 to 19, and 20 to 35 represent mild, moderate, and severe symptoms, respectively, are shown in Fig. 2. Declines in IPSS from baseline to last follow-up occurred only in men with moderate and severe symptoms before RT. The mean and median declines were −1.8 points (95% CI, −3.0 to −0.6; p = 0.0032) and −2 points (range, −17 to 17), respectively, for men with moderate baseline symptoms and −10.4 points (95% CI, −14.1 to −6.7; p < 0.0001) and −11 points (range, −29 to 13), respectively, for men with severe baseline symptoms. However, men with mild symptoms at baseline had a minor detriment in scores at last follow-up; the mean and median score inclines were 1.7 points (95% CI, 1.0 to 2.4; p < 0.0001) and 1 point (range, −8 to 29), respectively.
Fig. 2
American Urological Association (AUA) symptom classification impacts the change in International Prostate Symptom Score (IPSS) from baseline to last follow-up. RT = radiotherapy. Blue, black, and red lines represent 75% quartile scores, median scores, and 25% quartile scores, respectively. Dotted lines represent range of values.
Acute and late toxicity
Acute GU RTOG toxicity was analyzed by IPSS and showed 50 men (64%) with a pre-RT IPSS ≥15 in whom Grade ≥2 acute GU toxicity developed vs. 118 men (42%) with a pre-RT IPSS ≤14 (p = 0.0005). Acute Grade ≥3 GU toxicity, however, was rare and no different between the two groups, occurring in 8 men (3%) with a pre-RT IPSS ≤14 vs. 2 patients (3%) with a pre-RT IPSS ≥15 (p = 0.8958).
Late Grade ≥2 GU toxicity was also more prevalent in patients with a pre-RT IPSS ≥15. Four-year freedom from Grade ≥2 late RTOG GU toxicity among patients with a pre-RT IPSS ≥15 was 38% vs. 64% in men with a pre-RT IPSS ≤14 (p < 0.0001) (Fig. 3A). Grade ≥3 late RTOG GU toxicity was more common in men with a pre-RT IPSS ≥15, but this difference was not statistically significant. Grade ≥3 toxicity developed in 5 of 80 patients with a baseline IPSS ≥15 vs. 8 of 288 patients with a pretreatment IPSS ≤14, resulting in a 4-year freedom from Grade ≥3 toxicity of 90% vs. 96%, (p = 0.0964) (Fig. 3B). Grade 3 events were predominantly related to bleeding and cystitis, with only 4 patients (1%) overall having obstruction.
Fig. 3
(A) Men with a baseline International Prostate Symptom Score (IPSS) ≥15 have a statistically significant difference in freedom from Grade ≥2 Late Radiation Therapy Oncology Group (RTOG) genitourinary (GU) toxicity after external beam radiotherapy (EBRT) vs. men with a baseline IPSS ≤14. (B) Men with a baseline IPSS ≥15 have no statistically significant difference in freedom from Grade ≥3 Late RTOG GU toxicity after EBRT vs. men with a baseline IPSS ≤14.
By Common Terminology Criteria (CTC) scoring, among men with a pre-RT IPSS ≥15, acute Grade ≥2 GU toxicity (assessable in 77 men) was observed in 15 (19%), whereas Grade ≥3 acute GU toxicity developed in 2 (3%). Four-year freedom from Grade ≥2 late CTC GU toxicity was 69%, whereas four-year freedom from late Grade ≥3 CTC toxicity was 93%. This large difference in CTC Grade 2 toxicity compared with RTOG Grade 2 toxicity is attributable to the scoring of Grade 2 RTOG toxicity for any patient managed with a new or increased dose of GU medication at any time point after completion of RT.
On univariate analysis, ADT use (p = 0.2785), prior TURP (p = 0.3754), median prostate volume (p = 0.2160), minimum PTV dose (p = 0.8688), WPRT (p = 0.2327), and IMRT (p = 0.8694) were not associated with late Grade ≥2 GU toxicity, but pretreatment IPSS score (≥15 vs. ≤14) was (p < 0.0001). Univariate analysis for late Grade ≥3 GU toxicity showed no covariates associated with outcome. Multivariate analysis showed that IPSS ≥15 was associated with Grade ≥2 late GU toxicity (p = 0.0001) whereas ADT use (p = 0.2471), prostate volume (p = 0.2064), dose (p = 0.6028), WPRT (p = 0.8960), and IMRT (p = 0.4248) were not. A man with a pretreatment IPSS ≥15 was 2.3 times more likely to have Grade ≥2 late GU toxicity. However, neither pretreatment IPSS (p = 0.1070) nor any other covariates were associated with Grade ≥3 late GU events on multivariate analysis (data not shown).
Discussion
Urinary toxicity after EBRT is associated with pretreatment factors such as diabetes 20, 21, prostate volume (22), and pre-RT TURP 23, 24, as well as treatment-related factors such as RT dosimetry 22, 25, 26, 27 and ADT use 21, 24, 28. Few series, however, have analyzed the influence of pre-EBRT urinary symptoms on urinary function 21, 24, 26, 29, 30. Pretreatment GU symptoms were an independent risk factor for Grade ≥2 acute and late RTOG GU toxicity in men treated in a Dutch multicenter dose-escalation trial (24), whereas prostatism, in conjunction with neoadjuvant ADT, increased urinary morbidity rates by 4-fold in dose-escalation trial RTOG 94-06 (26).
In this study it was our objective to characterize the post-EBRT urinary outcome for patients with moderate to poor baseline urinary function, defined a priori as an IPSS ≥15. We found modest IPSS declines after EBRT at first follow-up and more notable improvements at last follow-up. Heightened use of GU medications was not the primary factor accountable for IPSS declines, because nearly the same percentage of men with a pre-RT IPSS ≥15 were taking GU medications before EBRT (48%) as those at last follow-up (54%). Moreover, there did not appear to be a long-term dependence on GU medications initiated during or after RT because the median duration of use was 15.2 months.
Of particular interest in this study was whether the presence of pretreatment symptoms exacerbated late GU toxicity, particularly Grade 3 obstruction-related side effects. Although a 2.3-fold increase occurred in Grade ≥2 toxicity for men with a pre-RT IPSS ≥15 over those with an IPSS ≤14, there was no statistically significant difference in the rates of Grade ≥3 urinary toxicity. This difference in Grade 2 toxicity was likely to be primarily because of GU medication use during follow-up.
Our results are concordant with a recent quality-of-life study in which men with localized prostate carcinoma were analyzed according to pretreatment function (9). Although patients with poor pretreatment GU function had the greatest symptom resolution after surgery, men treated with RT also gained improvements in baseline obstructive and irritative symptoms at 36 months.
Potential mechanisms for urinary symptom improvement over time may be related to (1) prostate cytoreduction from neoadjuvant ADT and/or RT, (2) GU medication use, (3) reduction in disease burden, and (4) patient bias. Nearly half of men with a baseline IPSS ≥15 received ADT with a median therapy duration of 4 months. Although few studies have reported increased rates of urinary morbidity with ADT use 21, 24, 28, the cytoreductive effect of ADT may have reduced lower urinary tract symptoms. Whereas our results show that ADT influenced the magnitude of IPSS declines from baseline to last follow-up in our subset of patients with a pre-RT IPSS ≥15, two separate analyses showed that the most significant reduction in prostate size occurs within the first 3 months of ADT with no significant volume reductions beyond 6 to 9 months 31, 32. Prostate RT may also induce prostate shrinkage and thus result in symptom improvement long term (33).
The efficacy of GU medications bears significance to the results of this study. Of patients with an IPSS ≥15, 86% had GU medication use before, during, or after EBRT. The efficacy of alpha-blockers was shown in a retrospective series of 275 EBRT-treated men with acute Grade 2 GU symptoms in which 43% were prescribed alpha-blockers (34). Of these men, 66% had complete or near complete resolution of their symptoms, and another 22% had partial improvement. Interestingly, a prior history of obstructive urinary symptoms had no impact on the response to alpha-blocker therapy.
A potential additional mechanism to explain urinary symptom resolution over time, particularly with longer follow-up, is the reduction in disease burden after definitive therapy. Significant differences in AUA symptom scores were observed in 265 men with localized prostate cancer according to clinical disease stage (35). Although we did not observe a difference in clinical disease stage between patients with a pre-RT IPSS ≥15 vs. ≤14, limited data have shown radiologic evidence of disease reduction after EBRT. An ultrasound study showed that prostate and hypoechoic nodule reduction occurs after EBRT with corresponding reductions in prostate-specific antigen values (36). If disease burden has some reflection on IPSS, then tumor reduction may further improve IPSS.
Although this report adds valuable information toward the understanding of post-EBRT urinary function in men with moderate to poor baseline function, there are certainly limitations of this analysis. A diligent attempt was made to determine the nature of urinary toxicity and GU medication use and dose adjustments over time; however, these observations were made retrospectively, and GU medications were not administered by a standard policy. Patients may have started taking medications with varying levels of urinary symptoms, with preference given to those patients with higher pretreatment IPSS. This lack of a prospective policy of prescribing medications may have accounted in part for the higher rate of RTOG Grade 2 GU toxicity in this group. A bias may also have been present in patient IPSS reporting, which may reflect patients' satisfaction with their treatment outcomes rather than a true assessment of urinary symptoms. Although we compared patients with pretreatment IPSS ≥15 with a larger cohort of patients with IPSS ≤14, the 80-patient cohort, which served as the main focus of study, represents a relatively small number of patients. Thus the results of the univariate and especially multivariate analysis have limited statistical certainty. Nevertheless, the outcomes of this study offer some guidance to clinicians in an area where data are relatively lacking and show that EBRT tends to improve obstructive urinary symptoms without greatly increasing the risk of severe GU toxicity.
Conclusion
After EBRT, patients with IPSS ≥15 can have modest improvement in their baseline urinary function over time. Although such patients are more likely to have Grade ≥2 late GU toxicity, they are not at significantly increased risk of severe GU toxicity or obstructive uropathy compared with patients with lower pretreatment IPSS. Patients with moderate to severe urinary obstructive symptoms may have more immediate relief with a surgical approach; however, these patients may also be managed well with a primary EBRT approach.
Acknowledgment
The authors thank David Correa for his administrative support.
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Note—An online CME test for this article can be taken at http://astro.org/MOC.
Conflict of interest: none.
PII: S0360-3016(10)00525-0
doi:10.1016/j.ijrobp.2010.03.040
© 2011 Elsevier Inc. All rights reserved.
Volume 80, Issue 4 , Pages 1080-1086, 15 July 2011