Robotic Versus Laparoscopic Total Mesorectal Excision for Middle Rectal Cancer: Functional Results from a Randomized Pilot Study

Abstract

Introduction

Urinary and sexual dysfunctions are recognized as serious complications that affect patients' quality of life after mid-rectal cancer surgery; however, studies that focus on the urogenital function after robot-assisted compared to laparoscopic rectal cancer surgery are limited.

Objective

To compare functional outcomes between patients undergoing robotic and laparoscopic approaches for middle rectal cancer submitted to neoadjuvant chemoradiation.

Materials and Methods

Patients with mid-rectal cancer were prospectively enrolled in this phase-II randomized trial to robotic or laparoscopic total mesorectal excision (TME). After eligibility was confirmed and chemoradiation therapy was completed, patients underwent randomization in a 2:1 ratio (robotic: laparoscopic TME groups) with stratification according to gender (male or female) and body mass index (BMI) < 35 or ≥ 35. The assessment of urinary function was carried out using complete urodynamic study, urinary symptoms questionnaire (International Consultation on Incontinence Questionnaire – Short Form [ICIQ-SF]), and urinary continence questionnaire (International Prostate Symptom Score [I-PSS]). The complete urodynamic study and the questionnaires were carried out before the start of any treatment and after neoadjuvant therapy (before surgery) and was repeated in the 1st, 3rd, 6th, 12th, 18th and 24th postoperative months. The analysis of male sexual function was carried out using International Index of Erectile Function (IIEF-5) questionnaire. Female sexual function was analyzed using the specific Female Sexual Functiona Index (FSFI) questionnaire, and the Quality-of-Life Questionnaire Core 30 (QLQ-C30) and Quality-of-Life Questionnaire - Colorectal Cancer 29 (QLQ-CR29 were applied to patients at the same time as the sexual and urinary function assessment questionnaires.

Results

Between 2017 and 2022, 32 patients entered the trial, and 30 were eligible to participate (2 patients were excluded due to screening failure). Among them, only 21 were randomized to robotic or laparoscopic group. Only 9 (42.9%) and 12 patients (57.1%) underwent urodynamic testing at the 3^rd and 6^th month of postoperative follow-up, respectively. Eighteen (85.7%) and 16 patients (76.2%) completed both the ICIQ-SF and I-PSS questionnaires at the 3^rd and 6^th month of postoperative follow-up, respectively. Only 7 and 10 patients (33.3% and 47.6%, respectively) completed the IIEF-5 and FSFI at the 3rd month of postoperative follow-up. There was no significant difference in age, BMI, tumor location, neoadjuvant therapy, postoperative pathological results, and adjuvant therapy between the two groups. Our study did not identify any parameter that could suggest lower urinary tract dysfunction in both groups analyzed, either by evaluating maximum flow, postvoid residue and, mainly, by the results of detrusor pressure at maximum flow. On the other hand, the present study demonstrated better sexual function outcomes with robotic surgery in male patients as assessed by the IIEF-5 score. There was a slight advantage to robotic surgery at the 3-month follow-up (median score 18 for robotic versus 17 for laparoscopic). By 6 months, the difference became more pronounced in favor of the robotic group (median score 23 for robotic versus 15 for laparoscopic). Additionally, there was better sexual desire at 3 months in the robotic group according to the QLQ-C29 (median score 66.7 in the robotic group versus 16.6 in the laparoscopic group).

Conclusion

The robotic approach for TME was associated with potentially better male sexual function than the laparoscopic approach. More randomized studies with a larger number of patients are necessary to confirm our findings.

Keywords

robotic surgery - laparoscopic - rectal cancer - urogenital function

Introduction

Colorectal cancer is the third most common cancer type and the second most common cause of cancer-related death worldwide.[1] Rectal cancer accounts for approximately 30% of the total colorectal cancer incidence.[2] Total mesorectal excision (TME) is considered the cornerstone of rectal cancer treatment.[3] Several randomized trials and meta-analyses have showed that laparoscopic mesorectal excision has not only faster recovery but also long-term oncologic results comparable to those of open surgical mesorectal excision.[4] [5] However, laparoscopic approach in rectal cancer is very challenging due to restricted visual field of the pelvic cavity besides several limitations, including two-dimensional visualization, restricted dexterity of movement, amplification of hand tremors, and limited surgical field exposure. These downsides are associated with worse functional (sexual and urinary) outcomes when compared to the open approach.[6] [7]

To overcome the technical limitations of the traditional laparoscopic surgery for rectal cancer, robotic surgery was developed to offer several advantages over laparoscopic surgery, such as three-dimensional high-definition, endo-wrist motion, high-definition views of the operative field, and lower levels of physician fatigue. Therefore, theoretically, all these robotic skills would contribute to better TME dissection and nerve preservation and, consequently, improved sexual and urinary outcomes. Thus, robotic mesorectal excision has been widely performed for the treatment of rectal cancer. It has been reported that the robotic approach is safe and has better functional outcomes comparable to those of the laparoscopic approach. However, functional outcomes have only been reported in single studies with dissonant results due to diverse methodological and functional assessment tools.[8] [9] [10] [11] [12] [13] [14] [15] [16] [17] The present study aims to compare functional outcomes between patients undergoing the robotic and laparoscopic approaches for middle rectal cancer submitted to neoadjuvant chemoradiation.

Materials and Methods

Patients and Study Design

We conducted a randomized phase-II trial (ClinicalTrials.gov identifier: NCT03209076) at two Brazilian Cancer Centers Institutions (Instituto Nacional de Câncer [INCA] and Hospital de Amor). The trial was conducted in accordance with the principles of the Declaration of Helsinki and the International Council for Harmonisation's Good Clinical Practice guidelines and approved by the institutional review boards of each participating center. All participants provided written informed consent. We recruited patients 18 years of age or older who had untreated, pathologically confirmed, locally advanced mid-rectal cancer (extra-peritoneal rectal tumor: reachable lesion on digital rectal examination up to 12 to 15 cm from the anal verge, confirmed by endoscopic examination and magnetic resonance imaging) with the necessity to undergo neoadjuvant chemoradiation. Participants had to have an Eastern Cooperative Oncology Group (ECOG) performance-status score of 0, 1, or 2. The exclusion criteria were T4 tumors; M1 metastatic disease; abnormal laboratory measures; diabetes; central or peripheral neuropathies, proven or suspected, related to voiding disorders, such as Parkinson's disease, spinal trauma (at any spinal level), tropical spastic paraparesis, stroke, multiple sclerosis, and brain tumors, among others; use of alpha-blocker and 5-alpha-reductase enzyme inhibitor medications, and penile prosthesis wearers.

After eligibility was confirmed and chemoradiation therapy was completed, patients underwent randomization in a 2:1 ratio (robotic: laparoscopic TME group) on the basis of a dynamic randomization scheme (permuted blocks using the Microsoft Access software [Microsoft Corp.] and the R package [R Development Core Team, 2008]) with stratification according to gender (male or female) and body mass index (BMI < 35 or ≥ 35).

All patients received standard neoadjuvant chemoradiation, using either capecitabine (1,650 mg/m² for 5 days for 5 weeks) or bolus 5-FU/leucovorin (bolus 5-FU 350 mg/m² + leucovorin 20 mg/m² for 5 days on week 1 and 5) concomitant to long-course radiation therapy (50.4 Gy) on the rectum and adjacent lymph nodes.

Procedures

The assessment of urinary function was carried out using three instruments: complete urodynamic study, and urinary symptoms and urinary continence questionnaires. The complete urodynamic study was carried out in accordance with the standards proposed by the International Continence Society,[18] before the start of any treatment and after neoadjuvant therapy (before surgery). The urodynamic study was repeated in the 1st, 3rd, 6th, 12th, 18th and 24th postoperative months. After free urination for uroflowmetric evaluation, the patient underwent small-caliber double urethral catheterization (6 and 8 Fr.), under transurethral local anesthesia (lidocaine jelly 2%) and bladder filling with 0.9% saline solution for cystometric stage. Once bladder fullness was achieved, the patient was asked to urinate, with a single urethral catheter (6 Fr.) intraurethral, to diagnose possible bladder emptying dysfunctions (flow-pressure study). Postvoid residual measurement was performed after free uroflowmetry and the pressure-flow study.

To assess urinary continence and possible lower urinary tract symptoms, the International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF)[19] and International Prostate Symptom Score (I-PSS)[20] validated for the Portuguese language were used in the preoperative period, as well as in the 1st, 3rd, 6th, 12th, 18th and 24th months of postoperative follow-up.

The analysis of male sexual function was carried out using the summarized version (validated for the Portuguese language) of the International Index of Erectile Function Questionnaire (IIEF-5).[21] The possible scores for the IIEF-5 range from 5 to 25, and erectile dysfunction (ED) was classified into 5 categories based on the scores: severe (5–7), moderate (8–11), mild-to-moderate (12–16), mild (17–21), and no ED (22–25). Female sexual function was analyzed using the specific Female Sexual Function Index (FSFI) questionnaire.[22] The FSFI is a brief self-report measure of women's sexual function, which considers the multidimensional nature of sexual function. Its six subscales assess desire, arousal, lubrication, orgasm, satisfaction, and pain, by summing individual items that comprise the subscale and multiplying the sum by a factor. Lower scores on any of the subscales or on the overall FSFI indicate worse sexual function. The questionnaires were applied in the preoperative stage (before and after neoadjuvant treatment) and in the 1st, 3rd, 6th, 12th, 18th and 24th month of postoperative follow-up.

The Quality-of-Life Questionnaire Core 30 (QLQ-C30)[23] and Quality-of-Life Questionnaire - Colorectal Cancer 29 (QLQ-CR29)[24] were applied to patients at the same time as the sexual and urinary function assessment questionnaires, that is, before the start of any treatment, after neoadjuvant therapy (before surgery), and in the 1st, 3rd, 6th, 12th, 18th and 24th postoperative months. The QLQ-CR29 is a disease-specific module for colorectal cancer that includes items that address symptoms and side effects related to the different therapeutic modalities employed, body image, sexuality, and patients' perspectives on the future.

Robotic TME was performed as a fully robotic nerve-sparing TME procedure with the Da Vinci Si platform (Intuitive Surgical, Inc.). All procedures were performed by five experienced surgical oncology professionals. The robotic TME was standardized in order to allow a totally robotic intervention from the same position of the robotic cart, vessel ligation, splenic flexure mobilization, and the appropriate oncological dissection of the mesorectum. Laparoscopic TME followed the same oncological technical principles described above.

Sample Size Calculation

In order to obtain estimates for carrying out the sample calculation, the weighted mean and standard deviation of the results of the studies included in the meta-analysis published by Broholm et al.[25] The calculation was carried out based on the urinary dysfunction averages (I-PSS), since the sexual dysfunction indicator (IIEF-5) presents a greater difference in the average treatment scores and, consequently, would require a smaller sample. The calculation was then made for the smallest mean difference observed, thus obtaining a larger sample that correctly estimates both urinary and sexual dysfunction outcomes. The calculation was made for the I-PSS measured after 3 months of treatment and the one-sided t test was used to detect differences between the means. An increase of 20% was made in the sample calculation, taking into account a loss of 20%. The following parameters were used to calculate the sample size: Power of 80% and Alpha of 20%. Sample allocation 0.5 (2 robotic surgeries x 1 laparoscopic surgery) and difference between mean scores from 10.5 (laparoscopic) to 8.5 (robotic).

End Points

The primary objective was to determine whether robotic TME would be superior to laparoscopic TME with respect to functional outcomes (urinary and sexual). Secondary end points included short-term oncologic outcomes, conversion rate, and postoperative complications.

Statistical Analysis

Statistical analysis was conducted with the R package.[26] Descriptive statistics were calculated for all variables. Numerical variables are presented as median and interquartile range (IQR) and categorial variables are presented as absolute and relative numbers.

Results

Patient Characteristics

Thirty-two patients entered the trial between 2017 and 2022, and 30 were eligible to participate. Two patients were excluded due to screening failure. Among the 30 eligible participants, only 23 were randomized (7 participants were not randomized: 1 patient did not undergo urodynamic testing due to the pandemic, 4 withdrew the informed consent, 1 passed away, and 1 experienced distant disease progression before surgery. Among the 23 randomized, 2 patients did not continue in the trial as they refused to undergo urodynamic testing during the postoperative follow-up. Then, 21 participants were randomized to the robotic or laparoscopic group.

Details of patient characteristics, BMI, tumor, node, and metastasis (TNM) staging and operative procedures are given in [Table 1].

Table 1 Patients' characteristics

	Robotic arm	Laparoscopy arm	Total
Age (number) Median (range)	N = 13 52 years-old (47.9–60.7)	N = 8 56.2 (39.7–59.1)	N = 21 52.6 (45.9–60.7)
Gender Male Female	6 (46.2%) 7 (53.8%)	4 (50.0%) 4 (50.0%)	10 (47.6%) 11 (52.4%)
BMI (median, range)	28.0 (25.1–31.2)	26.7 (25.6–28.7)	27.6 (25.3–30.2)
Basal clinical stage (MRI) T3N0M0 T3N1M0 T4aN1M0	6 (46.2%) 7 (53.8%)	3 (37.5%) 4 (50.0%) 1 (12.5%)	9 (42.8%) 11 (52.4%) 1 (4.8%)
Comorbidity No Yes	7 (53.8%) 6 (46.2%)	6 (75.0%) 2 (25.0%)	13 (61.9%) 8 (38.1%)

Abbreviation: BMI, body mass index; MRI, magnetic resonance imaging.

Only 9 (42.9%) and 12 patients (57.1%) underwent urodynamic testing at the 3rd and 6th month of postoperative follow-up respectively. Eighteen (85.7%) and 16 patients (76.2%) completed both the ICIQ-SF and I-PSS questionnaires at the 3rd and 6th month of postoperative follow-up, respectively. Only 7 and 10 patients (33.3% and 47.6% respectively) completed the IIEF-5 and FSFI in the 3rd month of postoperative follow-up.

Bladder Function

Qmax

The maximum flow value (Qmax) remained within normal limits (> 12 mL/s)[27] in both groups for up to 6 months of follow-up, with a higher value among patients undergoing robotic surgery in the first 3 months (17 mL/s x 12 mL/s) and a favorable change to the laparoscopic arm after 6 months of surgery (15 mL/s x 21 mL/s) ([Table 2]).

Table 2 Urinary functional outcomes

	Robotic arm	Laparoscopy arm
Qmax at 3 months (mL/s) Median (range)	17 (14.5–19.5)	12 (11.5–24)
Qmax at 6 months (mL/s) Median (range)	15 (13–34)	21 (15.5–31)
Postvoiding residue at 3 months (mL) Median (range)	50 (23.8–147.5)	0 (0–15)
Postvoiding residue at 6 months (mL) Median (range)	20 (0–60)	10 (5–25)
Bladder sensitivity at 3 months (mL) Median (range)	215 (179.2–280)	150 (150–187.5)
Bladder sensitivity at 6 months (mL) Median (range)	178 (150–250)	180 (115–202.5)
Bladder compliance at 3 months (mL/cmH2O) Median (range)	49.5 (26.5–100.2)	60 (42.5–130)
Bladder compliance at 6 months (mL/cmH2O) Median (range)	31 (29–41)	50 (32–55)
Maximum bladder capacity at 3 months (mL) Median (range)	425 (332.5–455.2)	360 (330–380)
Maximum bladder capacity at 6 months (mL) Median (range)	400 (300–450)	300 (300–350)
Bladder stability at 3 months (number of involuntary contractions)	5	2
Bladder stability at 6 months (number of involuntary contractions)	5	2
PdetQmax at 3 months (cmH2O) Median (range)	20.5 (11.5–28)	67 (38.5–73.5)
PdetQmax at 6 months (cmH2O) Median (range)	23 (12–27)	43 (36.5–60.5)
ICIQ-SF score at 3 months Median (range)	0 (0–0)	0 (0–0)
ICIQ-SF score at 6 months Median (range)	0 (0–0)	0 (0–0)
IPSS score at 3 months Median (range)	10 (7.2–12.2)	7 (5.8–10.8)
IPSS score at 6 months Median (range)	6 (2.5–9)	6 (4–11)

Abbreviations: ICIQ-SF, International Consultation on Incontinence Questionnaire – Short Form; I-PSS, International Prostate Symptom Score; PdetQmax, detrusor pressure at maximum flow; Qmax, maximum flow value.

Postvoiding Residue

The values of residue present in the bladder after urination were compatible with bladder emptying within physiological conditions in both groups, with average values of 0 to 50 mL (3 months) and 10 to 20 mL (6 months) ([Table 2]).

Sensitivity, Compliance, and Capacity

The 3 parameters were within normal limits in both groups, at 3 and 6 months of follow-up. The average value of the 1st urges to void (indicator of bladder sensitivity)[27] was observed after filling 215 mL and 150 mL of saline, at 3 months, and 178 mL and 180 mL in the group undergoing robotics and laparoscopy, respectively.

Bladder compliance corresponds to its elastic capacity and must be greater than 12 mL/cmH2O[27] to allow this organ to accommodate urinary volumes under low pressure, preventing urine reflux to the kidneys. We observed mean values of 49.5 mL/cmH2O and 60 mL/cmH2O at 3 months, and 31 mL/cmH2O to 50 mL/cmH2O, at 6 months, in the robotic and laparoscopic groups, respectively.

Regarding maximum bladder capacity, we observed average values of 425 mL and 360 mL at 3 months, and 400 mL and 300 mL at 6 months, in patients who underwent robotic and laparoscopic procedures, respectively ([Table 2]).

Bladder Stability

Bladder stability corresponds to the bladder's ability to store volumes without involuntary contractions of its detrusor muscle.[27] We observed a higher incidence of patients with involuntary contractions at 3 and 6 months of follow-up in the robotic group (5) than in the laparoscopic group (2) ([Table 2]).

PdetQmax

Detrusor pressure at maximum flow (PdetQmax) is an important indicator of situations of infravesical obstruction or detrusor hypoactivity and must remain between 20 and 40 cmH2O.[27]

We observed higher PdetQmax values in the group undergoing laparoscopic surgery (67 cmH2O at 3 months and 43 cmH2O at 6 months) compared to robotic surgery (20.5 cmH2O at 3 months and 23 cmH2O at 6 months) ([Table 2]).

ICIQ-SF

The ICIQ-SF has been validated for the Portuguese language,[28] and it is used to evaluate complaints of urinary incontinence. When the sum of the questionnaire results is zero, we have no incontinence, and this was the result found in both groups 3 and 6 months after surgery ([Table 2]).

I-PSS

The I-PSS was used to evaluate the patient's perceived quality of life related to the lower urinary tract symptoms. Most participants (95.2%) answered the I-PSS questionnaire at 3 and 6 months. At 3 months, the laparoscopic group presented better functional outcomes (median score of 10 for robotics versus 7 for laparoscopy). At 6 months, there was no difference between the 2 groups (median score of 6 for each arm) ([Table 2]).

Sexual Function

Men

Eight male patients (80%) answered the IIEF-5 at 3 and 6 months posturgery. The robotics group showed slightly better functional outcomes at 3 months (median score of 18 for robotics versus 17 for laparoscopy). At 6 months, this difference became more pronounced (median score of 23 for robotics versus 15 for laparoscopy). At 6 months, the robotics group had no erectile dysfunction (median score 23), whereas the laparoscopic group had mild-to-moderate erectile dysfunction (median score 15) ([Table 3]).

Table 3 Sexual functional outcomes

	Robotic arm	Laparoscopy arm
IIEF-5 score at 3 months Median (range)	18 (17.2–18.2)	17 (12.5–19)
IIEF-5 score at 6 months Median (range)	23 (21–23.2)	15 (10–17)
FSFI score at 3 months Median (range)	3 (1.2–12.1)	19 (13.8–21.3)
FSFI score at 6 months Median (range)	2.4 (1.2–17.5)	19.3 (13.1–22.6)

Abbreviations: FSFI, Female Sexual Function Index; IIEF-5, International Index of Erectile Function.

Women

The FSFI was used to evaluate female sexual function. All 11 women answered the FSFI questionnaire at 3 and 6 months. The laparoscopic group showed better functional outcomes at 3 and 6 months (median score of 2.4 for robotics versus 19 for laparoscopy) ([Table 3]).

Quality of Life

The QLQ-C30, QLQ-CR29 and EuroQol-5 dimensions (EQ-5D) questionnaires were used to evaluate postoperative quality of life. Most participants (95.2%) answered the QLQ-C30 and QLQ-CR29 questionnaires at 3 and 6 months postsurgery. At 3 months, the laparoscopic group presented better quality of life (median QLQ-C30 summary score of 85.3 for the robotic arm versus 91.5 for the laparoscopic arm). On the other hand, at 6 months, the robotic group showed a slightly better quality of life (median QLQ-C30 summary score of 88.5 for the robotic arm versus 87.4 for the laparoscopic arm) ([Table 4]).

Table 4 Quality of life outcomes

	Robotic arm	Laparoscopy arm
QLQ-C30 summary score at 3 months Median (range)	85.3 (79.8–91.5)	91.5 (87.7–95.3)
QLQ-C30 summary score at 6 months Median (range)	88.5 (84.3–93.9)	87.4 (83.3–93.5)
QLQ-C29 male sexual desire score at 3 months Median (range)	66.7 (0–66.7)	16.6 (0–41.6)
QLQ-C29 male sexual desire score at 6 months Median (range)	33.3 (33.3–66.7)	33.3 (33.3–66.7)
QLQ-C29 female sexual desire score at 3 months Median (range)	100 (83.3–100)	50 (33.3–66.7)
QLQ-C29 female sexual desire score at 6 months Median (range)	83.3 (41.6–100)	33.3 (33.3–41.6)
QLQ-C29 urinary frequency score at 3 months Median (range)	33.3 (0–54.2)	58.4 (45.8–66.7)
QLQ-C29 urinary frequency score at 6 months Median (range)	33.3 (8.3–58.4)	33.3 (16.6–41.6)
EQ-5D score at 3 months Median (range)	75 (67.5–92.5)	90 (77.5–91.2)
EQ-5D score at 6 months Median (range)	80 (75–90)	80 (80–90)

Abbreviations: EQ-5D, European Quality of life-5 dimensions questionnaire; QLQ-C29, Quality of Life Questionnaire C29; QLQ-C30, Quality of Life Questionnaire C30.

Regarding the results of the QLQ-C29 questionnaire, the male sexual desire score at 3 months showed a better outcome in the robotic group (median score of 66.7 in the robotic group versus 16.6 in the laparoscopy group). However, at 6 months, the male sexual desire score was similar between the groups (median score of 33.3 in both groups). Regarding female sexual desire, a significantly better outcome was evidenced in the robotic group at 3 and 6 months (median score of 100 in the robotic group versus 50 in the laparoscopy group at 3 months and median score of 83.3 in the robotic group versus 33.3 in the laparoscopy group at 6 months). Regarding urinary frequency, there was a worse outcome in the laparoscopy group in 3 months (median score of 58.4 in the laparoscopy group versus 33.3 in the robotic group); however, in 6 months, the results were similar (median score of 33.3 in both groups) ([Table 4]).

The EQ-5D questionnaire assesses health-related quality of life across 5 main dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Additionally, it also includes a visual analog scale to evaluate overall self-rated health. Regarding the visual analog scale of the EQ-5D questionnaire (a scale that provides an overview of the individual's health and wellbeing), there was a better outcome in the laparoscopy group at 3 months, but they became similar at 6 months postsurgery ([Table 4]).

Surgical and Short-Term Oncological Outcomes

Surgical and short-term oncological outcomes are described in [Table 5].

Table 5 Surgical and short-term oncological outcomes

	Robotic arm	Laparoscopy arm	Total
Conversion to open surgery	0 (0.0%)	1 (12.5%)	1 (4.8%)
Operative time (minutes) median (range)	240.0 (210.0–270.0)	240.0 (221.2–375.0)	240.0 (210.0–300.0)
Blood Transfusion n (%)	1 (7.7%)	0 (0.0%)	1 (4.8%)
Median length of stay in days(range)	5.0 (4.0–8.0)	4.5 (3.8–5.0)	5.0 (4.0–5.0)
Readmission	0 (0.0%)	0 (0.0%)	0 (0.0%)
Reoperation	0 (0.0%)	0 (0.0%)	0 (0.0%)
30 days mortality	0 (0.0%)	0 (0.0%)	0 (0.0%)
VAS score on first day postsurgery 0 1 2 3 4 5 6 7 8 9 10	3 (23.1%) 2 (15.4%) 2 (15.4%) 1 (7.7%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 0 (0.0%) 1 (7.7%) 0 (0.0%) 0 (0.0%)	1 (12.5%) 0 (0.0%) 2 (25.0%) 0 (0.0%) 0 (0.0%) 1 (12.5%) 0 (0.0%) 1 (12.5%) 0 (0.0%) 1 (12.5%) 0 (0.0%)	4 (19.0%) 2 (9.5%) 4 (19.0%) 1 (4.8%) 0 (0.0%) 1 (4.8%) 0 (0.0%) 1 (4.8%) 1 (4.8%) 1 (4.8%) 0 (0.0%)
Local recurrence	3/13 23%	2/8 25%	5/21 23%
Circumferential margin < 1 mm > 1 mm	5 (38.5%) 8 (61.5%)	3 (37.5%) 5 (62.5%)	8 (38.1%) 13 (61.9%)
Lymph nodes retrieved Median (range)	12 (11–19)	14 (9–14)	13 (10–17)

Abbreviation: VAS, Visual Analogue Scale.

Discussion

It has been reported that the robotic approach is safe and has better functional outcomes, comparable to those of the laparoscopic approach. However, functional outcomes have only been reported in single studies with dissonant results due to diverse methodological and functional assessment tools.[8] [9] [10] [11] [12] [13] [14] [15] [16] [17] For that reason, we proposed the current randomized trial to compare functional results between the robotic and laparoscopic approached in middle rectal cancer patients submitted to neoadjuvant therapy.

The lower urinary tract dysfunctions most related to rectal resection surgeries are represented by urinary retention associated with the appearance of an underactive detrusor, generally resulting from injury to the pelvic plexus during manipulation of the rectum.[29] [30] In this context, urodynamic assessment gains importance as it is considered, to date, the only diagnostic tool capable of establishing this diagnosis of detrusor failure, in addition to also giving visibility to changes in the bladder-filling phase.[27] Adding the urodynamic assessment to the quality-of-life questionnaires would potentially enhance the accuracy of the urinary measure's outcomes. Most of the previous studies regarding this subject utilized only quality-of-life questionaries to compare both approaches.[8] [9] [10] [11] [12] [13] [14] [15] [16] [17]

Despite adding urodynamic assessment to measure the urinary outcomes, our study did not identify any parameter that could suggest lower urinary tract dysfunction in both groups analyzed, either by evaluating maximum flow, postvoid residue and, mainly, by the results of detrusor pressure at maximum flow. Another indirect sign of a possible bladder emptying dysfunction would be “overflow incontinence”, with manifestations such as nocturia, urinary frequency, and urgency incontinence, easily detected by the ICIQ-SF questionnaire. Likewise, we did not observe changes related to continence, due to the lack of scores in this questionnaire in both groups. We believe that the absence of urinary dysfunctions in this study may be due to the small sample size.

On the other hand, the present study demonstrated better sexual function outcomes with robotic surgery in male patients as assessed by the IIEF-5 score. There was a slight advantage for robotic surgery at 3 months postsurgery (median score 18 for robotic versus 17 for laparoscopic). By 6 months, the difference became more pronounced in favor of the robotic group (median score 23 for robotic versus 15 for laparoscopic). Additionally, there was better sexual desire at 3 months in the robotic group according to the QLQ-C29 quality of life questionnaire (median score 66.7 in the robotic group versus 16.6 in the laparoscopic group). However, by 6 months, sexual desire scores were similar between the groups in men (median score of 33.3 in both groups). Regarding the results in the female group, we found better female sexual function in the laparoscopy group according to the FSFI questionnaire. However, there was better female sexual desire in the robotic group at 3 and 6 months according to the QLQ-C29 questionnaire.

Regarding quality of life, a slightly better overall quality of life was observed in the robotic group at 6 months, probably related to sexual function, as there was no difference in urinary function (QLQ-C30). However, there was no difference in quality of life at 6 months between the groups according to the EQ-5D questionnaire.

One of the strengths of the present study is its prospective randomized design (most studies addressing this topic are represented by retrospective studies), which allows for the reduction of some biases compared to retrospective studies. Additionally, another strength was the inclusion of the urodynamic study, which aimed to improve the accuracy of urinary function assessment due to it providing a more precise measurement than the evaluation through quality-of-life questionnaires (most studies only used quality-of-life questionnaires to assess urinary function outcomes).

Regarding the weaknesses, we can highlight the low number of patients recruited for the study. The low recruitment was due to the coronavirus disease 2019 (COVID-19) pandemic, which forced us to interrupt recruitment throughout the pandemic period. Furthermore, we had some participants drop out during the follow-up due to the need to perform the urodynamic study as a method of assessing postoperative urinary function.

Despite all these weaknesses, we were able to demonstrate a potential advantage in sexual function in the male group that underwent robotic surgery. This result leads us to believe in the need for prospective random studies with a larger number of patients to confirm our findings.

Conflict of Interests

The authors have no conflict of interests to declare.

Authors' Contributions

MV: Conceptualization; Methodology; Investigation; Supervision; Writing – Original Draft; Writing – Review & Editing; RA: Data Curation; Formal Analysis; Investigation; Writing – Review & Editing; JAPC: Methodology; Resources; Investigation; Writing – Review & Editing; VJFM: Data Curation; Formal Analysis; Visualization; Writing – Review & Editing; EL: Resources; Investigation; Validation; Writing – Review & Editing; CV: Methodology; Resources; Investigation; Writing – Review & Editing; MD: Interpretation of Data; Writing – Review & Editing; FD: Resources; Data Curation; Visualization; Writing – Review & Editing; LR: Validation; Writing – Review & Editing.

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Publikationsverlauf

Eingereicht: 02. November 2024

Angenommen: 04. August 2025

Artikel online veröffentlicht:
29. Dezember 2025