Comparing Patient-reported Functional Outcomes After Radical Prostatectomy in Historical and Contemporary Practice

Abstract

Purpose:

Modifications to surgical technique, particularly the widespread adoption of robotic surgery, have been proposed to improve functional recovery after prostate cancer surgery. However, rigorous comparison of men in historical vs contemporary practice to evaluate the cumulative effect of these changes on urinary and sexual function after radical prostatectomy is lacking.

Materials and Methods:

We compared prospectively collected patient-reported urinary and sexual function from historical (PROSTQA [Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment study], n = 235) and contemporary (MUSIC-PRO [Michigan Urological Surgery Improvement Collaborative Patient Reported Outcome] registry, n = 1,215) cohorts at the University of Michigan to understand whether modern techniques have resulted in functional improvements for men undergoing prostate cancer surgery.

Results:

We found significant differences in baseline function, with better urinary (median [IQR]; 100 [93.8–100] vs 93.8 [85.5–100], P < .001) and sexual scores (median [IQR]; 83.3 [66.7–100] vs 74.4 [44.2–87.5], P < .001) prior to treatment in PROSTQA compared to MUSIC-PRO patients, respectively. There was no statistically significant difference in the pattern of urinary incontinence recovery after surgery from 6–24 months between groups (P = .14). However, men in the contemporary MUSIC-PRO group did have significantly better recovery of sexual function compared to men in the historical PROSTQA group (P < .0001). Further, we found that contemporary practice consists of men with more unfavorable demographic and clinical characteristics compared to historical practice.

Conclusions:

Our results demonstrate that the widespread alterations in prostate cancer surgery over the past 2 decades have yielded improvements in sexual, but not urinary, function recovery.

THE universal integration of robotic approaches for the surgical management of prostate cancer (PCa) has led to the perception of substantial gains in PCa outcomes with minimally invasive compared to open radical prostatectomy (RP). Despite multiple studies comparing those undergoing open vs robotic surgery, limited data exist to suggest considerable functional or oncologic benefit from a robotic approach to RP.^1–3 Other continued modifications to surgical technique, such as anterior urethral suspension, limiting cautery and traction on neurovascular bundles, and limiting anatomical dissection, have been proposed to improve PCa functional recovery after RP.^4,5 Studies evaluating the impact of these measures on urinary incontinence and sexual function (SF) have shown mixed results and are largely limited to individual surgeon experiences or evaluate a single specific technique.^5–9 A comparison of historical and contemporary RP cohorts to understand the cumulative effect of these dynamic changes in surgical practice on long-term, real-world functional outcomes is lacking. Therefore, we compared patient-reported urinary and SF recovery from a contemporary, prospectively collected PCa registry with those from a historical, prospectively collected longitudinal cohort to better understand whether modern changes in surgical practice, including the use of robotic surgery or evolving surgical technique for RP, have led to functional improvements.

MATERIALS AND METHODS

We evaluated University of Michigan data from the prospective, longitudinal Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment (PROSTQA) study, comprising men with previously untreated PCa who had elected RP (open or robotic) as primary treatment.¹⁰ These data were compared to University of Michigan data from the contemporary Michigan Urological Surgery Improvement Collaborative Patient Reported Outcome (MUSIC-PRO) registry. Patient-reported outcome (PRO) measures, including urinary incontinence (UIN) and SF, were collected in both cohorts using EPIC-26 (Expanded Prostate Cancer Index Composite)¹¹ at baseline (presurgery) and 6, 12, and 24 months after treatment. We included men with fully available PRO data from PROSTQA (2003–2006) and MUSIC-PRO (2016–2018).

Patient characteristics were compared between the PROSTQA and MUSIC-PRO groups, including age, race, BMI, prostate gland volume, baseline (presurgery) PSA, Gleason grade, clinical stage, proportion of biopsy cores positive, National Comprehensive Cancer Network (NCCN) risk group, and baseline patient-reported UIN and SF. The Wilcoxon rank-sum test was used to compare continuous outcomes (age, gland volume, percent cores positive, UIN, SF). For categorical variables, the general χ² test was used for unordered/binary variables (race, clinical stage) and the Mantel-Haenszel χ² test was used for ordered variables (BMI, PSA, GG, NCCN risk). Linear mixed regression models were used to test for differences between PROSTQA and MUSIC-PRO in the quadratic recovery curves for quality of life (QOL) between 6 and 24 months postsurgery. Models were fit for the difference in postoperative QOL from baseline, with primary exposure variables consisting of a binary indicator of cohort (MUSIC vs PROSTQA), linear and quadratic time variables to account for the plateauing of the recovery over time, and 2-way interaction variables between cohort and the time variables, adjusted for fixed effects for each of the patient characteristics listed and baseline QOL value as well as random effects to account for within-patient correlation. To answer the primary clinical question of whether the recovery curves differ by cohort, we need to simultaneously test the 2 interaction variables in each model, which was performed with a contrast statement and approximated t-test.

RESULTS

We identified 1,015 men in MUSIC-PRO and 235 men in PROSTQA who met the inclusion criteria and were included in the analysis (see Table). In PROSTQA, 60% underwent open RP and 40% underwent a robotic approach, whereas 98% of men in MUSIC underwent a robotic approach (Supplementary Table 1, https://www.jurology.com). Men in MUSIC-PRO had worse demographics and disease characteristics than their counterparts in PROSTQA, being older and more overweight with greater baseline PSA and higher-grade disease. Similarly, men in MUSIC-PRO had poorer baseline QOL (both UIN and SF) than men in PROSTQA.

Table.

Baseline Characteristics of Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment Study and Michigan Urological Surgery Improvement Collaborative Patients

Variable	ProstQA (2003–2006) n = 235		MUSIC (2014–2019) n = 1,015		P value
Age, median (IQR), y	59	(56–63)	64	(57–68)	< .001
Race, No. (%) White	217	(93)	876	(89)	.15
Black	13	(5.6)	90	(9.1)
Asian	0		9	(0.9)
Other	3	(1.4)	11	(1)
BMI, No. (%), kg/m2					< .001
<25	45	(19)	145	(14)
25–<30	123	(52)	410	(41)
30–<35	51	(22)	293	(29)
35+	16	(7)	160	(16)
Prostate gland volume, median (IQR), mL	40	(31–54)	40	(29–52)	.15
PSA, No. (%), ng/mL					.001
<4	34	(14.5)	119	(12)
4–10	167	(71)	631	(62)
>10	34	(14.5)	263	(26)
GG, No. (%) 1	123	(52)	155	(15)	< .001
2	73	(31)	456	(45)
3	30	(13)	199	(20)
4	4	(1.8)	96	(9)
5	5	(2.2)	109	(11)
Clinical stage, No. (%)					.15
T1	193	(82)	773	(78)
T2	42	(18)	220	(22)
Median % biopsy cores positive (IQR)	25	(17–50)	40	(25–58)	< .001
NCCN risk					< .001
Low	97	(41)	125	(13)
Intermediate	126	(54)	621	(62)
High	12	(5)	249	(25)
Baseline QoL
Urinary incontinence, median (IQR)	100	(93.8–100)	93.8	(85.5–100)	< .001
Sexual function, median (IQR)	83.3	(66.7–100)	74.4	(44.2–87.5)	< .001

Abbreviations: BMI, body mass index; GG, Grade Group; IQR, interquartile range; MUSIC, Michigan Urological Surgery Improvement Collaborative; NCCN, National Comprehensive Cancer Network; ProstQA, Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment Study; PSA, prostate-specific antigen; QoL, quality of life.

All patients experienced initial declines in patient-reported urinary function and SF after treatment, with recovery up to 24 months. For UIN, there were no statistical differences in either the levels (P = .14) or the recovery pattern (P = .2) between the MUSIC and PROSTQA groups, after adjusting for demographic and disease-related parameters (part A of Figure and Supplementary Table 2, https://www.jurology.com). The adjusted SF values were better in MUSIC than the corresponding values for PROSTQA at each postsurgical time point (P < .001), though the recovery patterns were similar (P = .4), indicating that the adjusted group differences that presented at 6 months held steady through the later follow-up time points (part B of Figure and Supplementary Table 2, https://www.jurology.com). There was no difference in QOL outcomes between the PROSTQA open and robotic cohorts from baseline to 24 months for SF, but those who underwent robotic surgery in the PROSTQA cohort had significantly better reported UIN at 12 months, compared to those who underwent open surgery (Supplementary Table 3, https://www.jurology.com).

Figure.

Adjusted patient-reported urinary incontinence (A) and sexual function (B) in the historical (Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment [PQA] study) and contemporary (Michigan Urological Surgery Improvement Collaborative [MUSIC] registry) groups from 0–24 months after radical prostatectomy.

DISCUSSION

In this study, we investigated if collective modifications to RP technique have resulted in improvements in patient-reported UIN and SF. We evaluated prospectively collected historical and contemporary cohorts to capture the combined dynamic changes that have occurred in PCa surgery over the past 2 decades. Similar to previous reports, our results show that men in contemporary practice experience similar patterns of decline and recovery of postprostatectomy UIN to their historical counterparts.¹ However, men in the contemporary era had significantly improved SF at 6, 12, and 24 months postprostatectomy despite lower baseline scores in contemporary practice. Interestingly, we also noted substantial differences in patient demographics for men undergoing surgery for PCa between the 2 cohorts. Compared to historical practice, RP in current practice includes men with more unfavorable patient (age, obesity) and disease (baseline PSA, Gleason grade, percent positive biopsy cores, NCCN risk) characteristics.

The historical population in our analysis consists of a large proportion of men who underwent open prostatectomy. With regard to urinary function, a comparison of open vs robotic prostatectomy has suggested no difference in outcomes, consistent with our findings.^2,12–16 These relationships with regard to SF, however, are more variable. For example, previous population-based comparisons of men undergoing robotic vs open approaches in the Comparative Effectiveness Analysis of Surgery and Radiation (CEASAR) and Prostate Cancer Outcomes Study (PCOS) have demonstrated a potential benefit for robotic surgery with regard to SF, which was again demonstrated in the Swedish multicenter prospective trial.^15,16 It is possible our finding of improved SF in the contemporary cohort is reflective of the distribution of open surgery in the historical (PROSTQA) cohort (see Table). However, this would not entirely explain this result given the substantial proportion of patients who also underwent robotic surgery within PROSTQA. Nonetheless, our objective was not to compare open vs robotic surgery, but instead to determine if combined changes among different surgical eras led to differences in PROs.

Strengths of this study include the large representative cohort with complete PRO information and prospective data collection over a period of 2 decades. Further, we report longer patient-reported follow-up to 24 months after surgery. While isolated prior reports have shown continued improvement in function with longer follow-up,^17,18 the majority have suggested little to no improvement beyond 24 months.^19–21 Potential limitations include the single-center nature of this study, including lower number of patients analyzed in the historical cohort, and the potential for masking in the analysis of patient-reported data. For example, clinically relevant improvements in urinary function may not be captured or could be variably reported by individuals. However, the current differences between groups meet previously published criteria for minimally important differences for the EPIC SF domain.²² Additional considerations include variability at the level of the surgeon, which poses a challenge when assessing improvements in large-scale functional outcomes over time, as well as differences in diagnostic method (ie, use of MRI) or subjectivity associated with risk stratification (ie, Gleason grading) that may differ among separate eras.²³ Further, data regarding intraoperative techniques (ie, nerve sparing) or postoperative adjunctive therapies (ie, adjuvant or salvage radiation, hormones, pelvic floor physical therapy, penile rehabilitation) were not included, which have shown variable influence with regard to patient-reported urinary function and SF.^1,24,25 Data regarding the individual surgeons or their associated volume among the PROSTQA (historical) cohort were not available. Further, surgeon volume and its association with outcomes within the MUSIC cohort has been previously published. Given the absence of individual surgeon-level data in the PROSTQA cohort, it is not possible to make comparisons with regard to surgeon volume with the MUSIC population.²³ Lastly, despite performing adjustment for various disease and demographic variables between the historical and contemporary cohorts in our analysis, the differences in baseline characteristics suggest the possibility of the existence of unmeasured confounders that may have influenced our findings.

Nevertheless, using our approach, we attempted to understand whether combined dynamic changes between surgical eras have resulted in improved patient outcomes. Using prospectively collected data from historical and contemporary cohorts, we theoretically capture and assess the multitude of changes that occur in surgical or perioperative techniques over time. Our results should provide a continued basis for preoperative counseling and treatment selection for men with PCa.

CONCLUSIONS

Collectively, these results demonstrate that the past 2 decades have provided improvements in sexual, but not urinary, functional outcomes for men after PCa surgery. However, the etiology of this difference, whether it be new surgical techniques, technological advances, changes in perioperative care, surgeon experience, or differences in method of diagnosis, remains to be investigated.

Data Availability:

The data sets generated during the current study are not publicly available as they are institutional but are available from the corresponding author on reasonable request.