Perioperative,Oncological,and Functional Outcomes after Retroperitoneal Laparoscopic Partial Nephrectomy in Elderly Patients: A Propensity Score Matching Analysis

Abstract

Purpose:

We aimed to assess the perioperative, oncological, and functional outcomes of patients aged 70 years or older following retroperitoneal laparoscopic partial nephrectomy (LPN) and compare their results with younger patients.

Materials and Methods:

A retrospective review of our prospectively maintained database identified 329 patients who underwent retroperitoneal LPN from January 2013 to October 2022. The patients divided into 2 groups defined by age ≥70 or <70 years at the time of surgery. A propensity score matching analysis was conducted to obtain two balanced groups. The groups were compared for safety (perioperative outcomes) and efficacy (oncological and functional outcomes).

Results:

After matching, all variables were well balanced with no differences between the two cohorts. No significant differences were found in perioperative outcomes, including operative time, warm ischemia time, blood loss, hospital stay, and complications (P values >.05). Concerning functional outcomes, postoperative glomerular filtration rate and decrease in glomerular filtration rate were significantly better in the younger group compared with the elderly groups (P = .003 and P = .001, respectively). Although margin, ischemia, complications rates were similar between the cohorts (P = .068), Pentafecta rates were lower in the elderly patients (P = .029). In terms of oncological outcomes, recurrence-free survival and cancer-specific survival were comparable between the groups.

Conclusion:

Retroperitoneal LPN can be performed safely and with adequate oncological efficacy in elderly patients.

Introduction

Kidney cancer is one of the most common cancers with a rate of 2.2% among all cancers.¹ Renal cell carcinoma (RCC) is the most common type of kidney tumor and is the most lethal among genitourinary cancers. The incidence of RCC has increased due to the increment utilization of cross-sectional imaging for unrelated reasons.² Partial nephrectomy (PN) is strongly recommended as a standard approach for localized RCC, as it offers a better preservation of renal function and an equivalent oncological outcome compared with radical nephrectomy radical nephrectomy (RN).³ Minimally invasive techniques such as laparoscopic partial nephrectomy (LPN) and robot-assisted PN have benefits, including shorter hospital stay, less blood loss, and fewer complications.⁴

The proportion of elderly people in the world population is increasing. Life expectancy for the U.S. population in 2021 was 76.4 years.⁵ Most RCC cases have been observed in patients older than 70 years, with an incidence rate of 31.2%.⁶ Given the increase in life expectancy and incidence of RCC, the treatment of RCC in elderly patients has become more essential. The data specifically addressing the outcomes of PN in the elderly are sparse. Therefore, we aimed to report on the safety and efficacy of LPNs in elderly patients with a comparison to a younger cohort.

Materials and Methods

After the local institutional review board approval, a retrospective review of our prospectively collected database identified 353 patients who underwent retroperitoneal LPN for a suspicious renal mass between January 2013 and October 2022. Exclusion criteria were as follows: (a) solitary kidney (n = 2); (b) history of ablation therapy (n = 1); (c) use of anticoagulants (n = 11); and (d) missing data (n = 10).

Before the surgery, all participants underwent a contrast-enhanced computed tomography (CT) or magnetic resonance imaging to determine the tumor characteristics and clinical TNM staging. The RENAL (radius; exophytic/endophytic; nearness; anterior/posterior; location) nephrometry scores were calculated by a radiologist according to the protocol described.⁷

Patient demographic variables and clinical information included age, gender, body mass index, American Society of Anesthesiologists (ASA) score, comorbidities (diabetes and hypertension), estimated glomerular filtration rate (eGFR), tumor size, RENAL nephrometry score, and clinical stage. Perioperative outcomes, including operative time (OT), warm ischemia time (WIT), estimated blood loss (EBL), changes in hematocrit values hematocrit (Htc), length of hospital stay (LOS), pathological stage, surgical margin, and complications, were recorded. Complications were classified using the Clavien–Dindo system.⁸ The renal function was evaluated preoperatively and 1 year after operation by serum creatinine levels and eGFR. Estimated GFR was calculated by the Chronic Kidney Disease Epidemiology Collaboration equation. Serum creatinine levels were measured for 3–10 days before the surgery and 1 year after the surgery. Absolute change in eGFR was calculated based on the difference between the preoperative and postoperative levels.

All LPNs were performed by a senior surgeon (M.A.) with previous long-lasting experience in laparoscopic surgery via retroperitoneal approach. We previously described our surgical technique in detail.⁹ Patients older than 70 years were determined for the elderly cohort, while patients <70 years old were selected for a control cohort of younger patients.

Lastly, both the margin, ischemia, complications (MIC) criteria and Pentafecta were applied to investigate the accomplishment of optimal outcomes of LPNs. The achievement of MIC was defined as the simultaneous fulfillment of the following factors: negative surgical margins, WIT< 20 minutes, and no major complications (Clavien III/IV). Patients with the absence of grade ≥3 Clavien–Dindo complications, WIT < 20 minutes, ≤10% postoperative eGFR decrease, negative surgical margins, and no upgrading of chronic kidney disease until 12 months after LPN were reported to achieve Pentafecta outcomes.

Statistical analysis

Descriptive statistical data were presented as mean (standard deviation) and median (interquartile range [IQR]) for continuous variables, and frequency (%) for categorical variables. Student-t and Mann–Whitney U tests were used to compare continuous variables, depending on the suitability for the given normal distribution. Pearson chi-square test was used to compare categorical data. Propensity score match analysis was applied to eliminate the differences in preoperative data between groups. The Kaplan–Meier analysis was used to demonstrate recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS); and the log-rank test was used to evaluate the differences. Data analysis was done using SPSS 22.0 (IBM corp., Armonk, NY) program. P < .05 was considered statistically significant.

Results

Population characteristics

A total of 353 patients were included in the study. Following exclusion, 63 patients (19.1%) were aged ≥70 years, and 266 patients (80.9%) were aged <70 years. After matching, the elderly cohort consisted of 59 patients, whereas the younger cohort consisted of 52 patients (Fig. 1). The mean follow-up time was 61.3 ± 12.1 months for the younger cohort, while the mean follow-up time was 59.4 ± 11.3 months for the elderly cohort.

FIG. 1.

Patient selection flowchart.

Before matching, a significant difference between elderly and younger patients was found in age, ASA score, hypertension, GFR value, tumor size, and clinical T stage. After propensity score matching, the patients’ demographics and tumor characteristics of both groups were comparable (Table 1).

Table 1.

The Comparison of Elderly and Younger Cohorts in Terms of Preoperative Variables Before and After Matching

	Unmatched comparisons		P	Matched comparisons		P
Variables	Elderly cohort	Younger cohort	P	Elderly cohort	Younger cohort	P
Age, years, mean ± SD	73.23 ± 2.6	54.76 ± 8.88	<.001	73.19 ± 2.58	57.33 ± 6.59	.001
Gender, n (%)			.953			.658
Male	45 (71.4%)	189 (71.1%)		42 (71.2%)	35 (67.3%)
Female	18 (28.6%)	77 (28.9%)		17 (28.8%)	17 (32.7%)
BMI, kg/m², mean ± S.D	28.50 ± 2.83	28.98 ± 3.64	.260	28.55 ± 2.90	28.83 ± 4.16	.685
ASA score, n (%)			<.001			.497
1	0	41 (15.4%)		0 (0%)	1 (1.9%)
2	39 (61.9%)	205 (77.1%)		39 (66.1%)	36 (69.2%)
3	24 (38.1%)	20 (7.5%)		20 (33.9%)	15 (28.8%)
Hypertension, n (%)			.001			.340
Yes	30 (47.6%)	71 (26.7%)		28 (47.5%)	20 (38.5%)
No	33 (52.4%)	195 (73.3%)		31 (52.5%)	32 (61.5%)
Smoking, n (%)			.579			.826
Yes	30 (47.6%)	137 (51.5%)		26 (44.1%)	24 (46.2%)
No	33 (52.4%)	129 (48.5%)		33 (55.9%)	28 (53.8%)
GFR, mL/min/1.73 m², mean ± SD	85.62 ± 17.51	94.91 ± 16.13	<.001	86.65 ± 16.87	92.59 ± 16.17	.063
RENAL score, median, IQR	5.21 ± 1.14	5.57 ± 1.48	.104	5.19 ± 1.17	5.29 ± 1.23	.654
Tumor size, cm, mean ± SD	3.40 ± 1.5	4.2 ± 1.5	<.001	3.40 ± 1.61	3.57 ± 1.40	.534
Clinical T stage, n (%)			<.001			.105
cT1a	48 (76.2%)	137 (51,5%)		45 (76.3%)	36 (69.2)
cT1b	12 (19%)	117 (44,0%)		11 (18.6%)	16 (30.8%)
cT2a	3 (4,8%)	12 (4,5%)		3 (5.1%)	0 (0%)

ASA, American Society of Anesthesiologists; BMI, body mass index; GFR, glomerular filtration rate.

Statistically significant values are indicated in bold.

Perioperative outcomes

None of the retroperitoneal LPNs was transferred to the open procedure. OT and WIT were not significantly different between the age ≥70 and age <70 (P = .062 and P = .596, respectively). There was no difference between the groups regarding EBL, LOS, drain removal time, and Htc drop (Table 2). No significant differences were found in overall complications (P = .459). Most of the complications (n = 16, 88.9%) were classified as Clavien–Dindo Grade 1–2 (fever, transient elevation of serum creatinine, blood transfusion). One patient in each group required Double J stent placement due to urine extravasation (Clavien–Dindo Grade 3).

Table 2.

Comparison of Perioperative and Functional Outcomes According to Groups

Variables	Elderly cohort (n = 59)	Younger cohort (n = 52)	P
Operative time, min, mean ± SD	80.37 ± 7.67	83.23 ± 8.26	.062
Warm ischemia time, min, mean ± SD	13.36 ± 8.85	14.30 ± 8.14	.596
Ischemia technique, n (%)			.277
Warm ischemia	41 (69.5%)	31 (59.6%)
Off-clamp	18 (30.5%)	21 (40.4%)
Estimated blood loss, mL, mean ± SD	194.23 ± 92.17	194.23 ± 92.17	.071
Length of hospital stay, day, mean ± SD	3.03 ± .18	3.09 ± .29	.195
Drain removal time, day, mean ± SD	2.03 ± .18	2.10 ± .30	.195
Htc drop, %, mean ± SD	4.80 ± 3.21	4.92 ± 2.97	.847
Complications within 30 days, n (%)			.459
None	48 (81.4%)	45 (86.5%)
Yes	11 (18.6%)	7 (13.5%)
Postoperative GFR, mL/min/1.73 m², mean ± SD	77.48 ± 14.79	86.04 ± 15.12	.003
Δ GFR, mL/min/1.73 m², mean ± SD	10.34 ± 6.59	6.59 ± 5.46	.001
Achieved MIC, n (%)	44 (74.6%)	44 (84.6%)	.068
Achieved Pentafecta, n (%)	30 (50.8%)	37 (71.2%)	.029
Recurrence at follow-up, n (%)			.495
No	55 (93.2%)	50 (96.2%)
Yes	4 (6.8%)	2 (3.8%)

GFR, glomerular filtration rate; MIC, margin, ischemia, complications.

Statistically significant values are indicated in bold.

Functional outcomes

The postoperative eGFR value was significantly lower in the elderly cohort (77.48 ± 14.79 mL/min/1.73m²) than in the younger cohort (86.04 ± 15.12 mL/min/1.73m²) (P = .003). The mean absolute change in eGFR at 1 year was 10.34 ± 6.59 mL/min/1.73m² in the elderly group and 6.59 ± 5.46 mL/min/1.73m² in the younger group (P = .001). The rate of MIC was similar among the groups (P = .068), however, the rate of Pentafecta was significantly higher in the younger cohort (P = .029) (Table 2).

Oncological outcomes

The recurrence was present in 6.8% of the age ≥70 group and in 3.8% of the age <70 group (P = .495). Both groups did not demonstrate a significant difference in either the RFS or the CSS (P = .430, and P = .873, respectively, Fig. 2A-2B). Compared with the younger cohort, the elderly cohort resulted in similar OS (P = .972, Fig. 2C).

FIG. 2.

Recurrence-free survival, cancer-specific survival, and overall survival curves according to age groups.

Discussion

It is now a fact that as the elderly population is increasing around the world, most urologists may confront the complexity of treating older patients who have renal tumors. The management of this condition in the elderly lacks clear recommendations, and safety concerns arise due to the presence of comorbidities. Accordingly, we aimed to perform a comparative analysis of the younger cohort versus elderly cohort after retroperitoneal LPN in terms of the complications, the oncological and the functional outcomes. Our data confirmed that retroperitoneal LPN was a safe and an effective treatment option in the elderly population regarding perioperative and oncological outcomes. The functional outcomes may be worse in older patients compared with younger patients.

After it was shown that the oncological results of PN were similar to RN, nephron-sparing approaches became more preferred due to the higher risk of developing chronic kidney disease and the cardiac sequelae of RN. Ablative therapies and PN are current options for nephron-sparing intervention. The usage of both methods in the treatment of renal masses has increased over the years.¹⁰ Nevertheless, PN remained the most applied treatment modality.^10,11 PN had a higher risk of complications while there was a higher rate of recurrence and the need for re-intervention in ablative therapies.¹² Similarly, a meta-analysis by Kunkle et al. reported that compared with PN, there was an increased risk of local progression after ablative therapies.¹³ In the study conducted by Bertolo et al. comparing cryoablation and robotic PN in elderly patients, although the rate of minor complications, blood loss, OT, and LOS, was significantly higher in PN, RFS favored PN. Major complications were similar between both groups.¹⁴ Based on these concerns, it is important to determine elderly patients who would benefit more from PN. We believe that retroperitoneal LPN is a safe and an effective treatment alternative with satisfying oncological results in experienced hands to treat the elderly population.

Previous studies comparing older and younger patients undergoing PN showed that PN was safe in older patients regarding perioperative outcomes. In the study by Sandberg et al., when stratified by age <70 and age ≥70, there were no significant differences in perioperative metrics such as OT, EBL, WIT, transfusion, LOS, and complications.¹⁵ Similarly, in a matched analysis, the intraoperative outcomes and complications were similar in younger and elderly patients.¹⁶ In a study of patients who underwent LPN, EBL and LOS were significantly higher in octogenarians. However, complications were found to be comparable among the two groups.¹⁷ Our findings are congruent with those studies’ perioperative outcomes and complications are not significantly different between the older and younger groups.

Previous studies proved that GFRs decline with aging process.¹⁸ Regarding renal functional outcomes, we matched the groups in terms of GFR. However, it was difficult to match this variable perfectly. As expected, eGFR values were lower in the elderly cohort than the younger cohort preoperatively (P = .063). Postoperative GFRs were significantly lower in the elderly patients. Similarly, Thomas et al.¹⁷ found that preoperative and postoperative GFRs were inferior in the elderly patients. In the most recently published study, preoperative GFRs were worse in the very old patients. However, change in GFRs was comparable among groups.¹⁹ Moreover, Sandberg et al.¹⁵ and Hillyer et al.¹⁶ demonstrated that there were no differences with respect to decrease in GFR between the elderly and younger patients. In our study, the decline in GFRs was greater, maybe partially attributed to the longer follow-up.

In terms of oncological outcomes, there are few researches investigating survival outcomes in studies comparing younger and elderly patients who underwent PN. A previous study showed that the tumor recurrence was similar between both groups.¹⁵ In this study, no significant differences were found in RFS, CSS, and OS between the groups. A recent retrospective study suggested that OS was worse in the octogenarian group compared with the younger group and CSS was similar.²⁰ However, more than half of the patients in this study underwent RN. Therefore, it would not be correct to generalize this study to PN outcomes.

The objective of PN is to achieve a satisfactory oncological outcome and minimize complications while preserving renal function to the extent possible. MIC, Trifecta, and Pentafecta reflect best the provision of these conditions. A study comparing patients aged <70 and aged ≥70 who underwent robotic PN, found no differences for Trifecta.²¹ Similarly, our study also showed similar MIC rates between the two groups. However, Pentafecta was lower in the elderly cohort. REnal SURGery in Elderly (RESURGE) Group²² demonstrated that PN in elderly patients can be performed with acceptable Trifecta outcomes.

LPN can be performed both transperitoneally and retroperitoneally. Although the retroperitoneal approach has a more restricted working area and difficulty reaching the medial part of the kidney, it has advantages in terms of immediate access to the renal vessels and without the excessive mobilization of the kidney. A benefit of retroperitoneal LPN is no need for lysis of adhesions in patients with prior abdominal surgery. Furthermore, avoiding bowel mobilization results in earlier bowel recovery postoperatively.²³ It is important, especially for elderly patients. Numerous studies have compared the results of transperitoneal and retroperitoneal approaches. A previous meta-analysis demonstrated that both techniques were reported to be safe and effective. Retroperitoneal LPN outperformed transperitoneal LPN in terms of OT and LOS.²⁴ The short hospital stay and short operation time in the retroperitoneal approach constitute an important treatment alternative for elderly patients.

Our study has several limitations. First, our database is prospectively recorded, however, the analysis was carried out retrospectively. Second, the cohort was relatively small within a single center, although the follow-up period was sufficiently long. Last, surgeries were performed by a senior surgeon with extensive experience with retroperitoneal LPNs. Our single-center data may not necessarily be generalizable to all practices.

Conclusion

There has been a consistent increase in the prevalence of renal tumors in the elderly. Which treatment option to perform in elderly patients with renal tumors can be challenging. To our knowledge, this is the first study comparing younger and elderly patients who underwent LPN via the retroperitoneal route. Retroperitoneal LPN represents an adequate and safe technique with satisfying oncological results for the treatment of elderly patients with renal tumors.

Authors’ Contributions

K.K.: Conceptualization, methodology, and writing—original draft. H.A.: Formal analysis, investigation, software, and validation. A.Y.: Data curation, resources, and supervision. A.G.: Formal analysis, methodology, and visualization. S.A.: Data curation, investigation, and validation. M.A.: Resources and writing—review and editing.

Ethics Approval and Consent to Participate

This study was approved by the Ethics Committee of Okan University (approval number: 2023–987). The committee also waived written informed consent for this retrospective study.

Footnotes

Disclosure Statement

The authors declare that they have no conflict of interest.

Funding Information

No funding was received for this article.

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