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  Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 54  |  Issue : 2  |  Page : 421-425
 

Utilization of pelvic lymph node dissection in patients undergoing robot-assisted radical prostatectomy in India versus the United States – A Vattikuti Collective Quality Initiative database analysis


1 Vattikuti Urology Institute, Henry Ford Hospital, Detroit, MI, USA
2 Department of Urology and Kidney Transplant, Fortis Escorts Kidney and Urology Institute, New Delhi, India
3 Department of Urology, University Medical Center, Hamburg-Eppendorf, Hamburg, Germany
4 Department of Urology, Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai, Maharashtra, India
5 Department of Urology, Medanta Kidney and Urology Institute, Gurgaon, Haryana, India

Date of Web Publication21-Feb-2018

Correspondence Address:
Dr. F Abdollah
Vattikuti Urology Institute, Henry Ford Hospital, Detroit, MI
USA
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijc.IJC_227_17

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 » Abstract 


BACKGROUND: The utilization and extent of pelvic lymph node dissection (PLND) varies depending on the disease and practice patterns. AIMS: This study compares practice patterns in utilization of PLND between Indian and United States (US) practices. SETTINGS AND DESIGN: We focused on 415 patients (204 India; 211 US) prostate cancer patients treated with robot-assisted radical prostatectomy, between 2015 and 2016, within the Vattikuti Collective Quality Initiative database. SUBJECTS AND METHODS: Utilization of PLND and number of nodes removed were evaluated for the entire cohort, and after stratifying for Country of treatment and D'Amico risk groups. Logistic regression tested the relationship between PLND and country of treatment, after adjusting for disease risk. RESULTS: Indian patients had a higher risk distribution (D'Amico high-risk 53.4% in India vs. 27% in the US; P< 0.001) compared to their US counterparts. Overall, 193/204 (94.6%) Indian patients underwent PLND versus 181/211 (85.8%) US patients (P = 0.003). When stratified based on disease risk, PLND was performed more frequently in Indian patients with low-risk disease (81.0% vs. 41.4%,P= 0.008), but not in those with intermediate and high-risk disease. On multivariable analysis, Indian patients had a 2.57-fold higher probability of undergoing PLND than their US counterparts (P = 0.02). The analysis of the number of lymph nodes removed showed similar trends. CONCLUSIONS: Indian patients are more likely to undergo PLND than US patients. This is, especially true for patients with low-risk disease, who are unlikely to benefit from this procedure. Efforts should focus on optimizing the utilization of PLND, and deliver it only when there is clinical indication.


Keywords: Database, pelvic lymph node dissection, practice patterns, robot-assisted prostatectomy, Vattikuti Collective Quality Initiative database


How to cite this article:
Abdollah F, Arora S, Jindal T, Gild P, Sood A, Yuvaraja T B, Ahlawat R K, Gupta N P, Bhandari M, Menon M. Utilization of pelvic lymph node dissection in patients undergoing robot-assisted radical prostatectomy in India versus the United States – A Vattikuti Collective Quality Initiative database analysis. Indian J Cancer 2017;54:421-5

How to cite this URL:
Abdollah F, Arora S, Jindal T, Gild P, Sood A, Yuvaraja T B, Ahlawat R K, Gupta N P, Bhandari M, Menon M. Utilization of pelvic lymph node dissection in patients undergoing robot-assisted radical prostatectomy in India versus the United States – A Vattikuti Collective Quality Initiative database analysis. Indian J Cancer [serial online] 2017 [cited 2019 Oct 19];54:421-5. Available from: http://www.indianjcancer.com/text.asp?2017/54/2/421/225794

Abdollah F and Arora S: These authors contributed equally to this work





 » Introduction Top


Pelvic lymph node dissection (PLND) is the gold standard for lymph node staging in prostate cancer patients treated surgically,[1] and has also been shown to be of therapeutic benefit.[2],[3] However, this procedure is associated with increased morbidity, longer operative time, and higher costs.[4],[5] Moreover, it has a low yield in patients presenting with nonaggressive clinical disease characteristics. The indications, extent and potential benefit of PLND have been subjects of long dispute and controversy in the urological community over the years. However, most contemporary guidelines recommend an extended PLND in patients with significant lymph node invasion risk based on preoperative risk stratification models.[1],[6],[7],[8]

Among this uncertainty, the utilization of PLND is far from being standardized. Previous reports have showed a wide variation in the delivery of PLND and its extent based on many factors, such as tumor risk characteristics, surgical technique (open vs. robotic), and the institution/country where the patient received treatment among others.[9],[10],[11] It is noteworthy that documenting and understanding the PLND practice for a specific country is key, to establish a benchmark on which improvement plans can be developed. This might, in turn, optimize the use of health care resources, and ensure the delivery of a superior quality of care. Virtually, all previous reports [9],[10],[11] have originated from the North American or European centers. As such, none of the previous reports is necessarily representative and generalizable to a developing health care system, such as the Indian one. The latter is peculiar given that Indian patients (in comparison to Caucasian patients) usually present with more aggressive disease characteristics,[12],[13] and might have a different genomic disease profile. To address this void, we set to examine the current utilization and extent of PLND in Indian patients, and compare it to patients treated in the United States of America (US).


 » Subjects and Methods Top


Data source

The Vattikuti Collective Quality Initiative is a collaboration of quality seeking medical institutions from worldwide with a focus on improving patient outcomes after robotic surgery for various indications. The Vattikuti Collective Quality Initiative database is a prospective, user-friendly, multiprocedural web-based platform, and is Health Insurance Portability and Accountability Act of 1996, US compliant. Ethical Committee clearance for data collection is obtained at each participant center, and the data from each participant center are monitored for its quality and timeliness by a central administrator and a data manager at each participant center.

Patient cohort

We included 415 consecutive patients who underwent robot-assisted radical prostatectomy between 2015 and 2016 at multiple centers in India and the US. Of these, 204 (49.2%) cases were treated in India, and 211 (50.8%) were treated in the US. Given the prospective nature of the database, and the continuous monitoring by administrative personnel to ensure quality, none of these patients had missing data.

Covariates definition

The variables used in this study were country of treatment, defined as the country where surgery was performed, age (patient's age in years on the date of surgery), preoperative prostate-specific antigen (PSA) (ng/mL), clinical stage (cT1 vs. cT2 vs. cT3/T4), and biopsy Gleason score (6 vs. 7 vs. >8–10). Patients were stratified based on D'Amico risk classification, as previously described.[14]

Endpoint definition

Two endpoints were used in this study. The first was the utilization of PLND in patients operated on for prostate cancer, which was a binary outcome with two values– PLND performed versus PLND not performed. The second outcome was the number of lymph nodes removed, as reported in the final histopathology, in patients who had a PLND. This variable was used as a proxy for the extent of PLND, as performed in previous reports.[9]

Statistical methods

Frequencies and proportions were reported for categorical variables, whereas medians and interquartile range (IQR) were reported for continuous variables. Chi-squared test and Mann–Whitney U-tests were used to compare the statistical significance of differences in categorical and continuous variables, respectively. Our statistical analysis included three main steps. First, the baseline characteristics were compared between Indian and the US cohorts. Second, PLND utilization and number of lymph nodes removed were compared between the two cohorts overall, and then after stratifying patients per D'Amico risk classification. Third, logistic regression analysis tested the relationship between country of treatment and PLND utilization, after adjusting for D'Amico risk category. All analyses were performed using SAS 9.4 (SAS Institute, Cary, NC, USA).


 » Results Top


Descriptive statistics of the entire cohort, and after stratification for the country of treatment are shown in [Table 1]. For the entire cohort, median (IQR) of age and PSA were 65 (59–69.5) years and 8.5 (5.65–15) ng/mL, respectively. Most patients had the clinical T1 disease (226; 54.4%) and a biopsy Gleason score of 7 (229; 55.2%). Low, intermediate, and high-risk disease were present in 50 (12%), 199 (48.0%), and 166 (40.0%) of the patients, respectively.
Table 1: Descriptive statistics of the entire cohort, and after stratification for the country of treatment in 415 patients with prostate cancer treated with robot assisted radical prostatectomy between 2015 and 2016, in the Vattikuti Collective Quality Initiative database

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Patients treated in India were older (median [IQR] 66 [61.8–70.0] vs. 63.0 [58.0–68.0] years old in US; P < 0.001), had a higher PSA value (median [IQR] 12.5 [8.1–25.0] in India vs. 6.0 [4.6–8.8] ng/ml in US; P < 0.001), higher clinical stage (≥ T2: 62.07% in India vs. 29.38% in US; P < 0.001), higher tumor grade (Gleason 8–10: 27.09% in India vs. 20.38% in US; P = 0.002), and a higher D'Amico risk profile (D'Amico high-risk 53.4% in India vs. 27% in the US; P < 0.001) [Table 1].

Overall, 374 (90.1%) patients underwent a PLND. This rate was 94.6% in India, and 85.8% in the US (P = 0.003). When stratified per D'Amico risk classification, a higher proportion of patients underwent PLND for low-risk in India (81% in India vs. 41.4% in the US; P = 0.008), whereas no significant difference existed for D'Amico intermediate and high-risk categories [Table 2].
Table 2: Utilization of pelvic lymph node dissection in the entire cohort, and after stratification by D'Amico risk category and country of treatment in 415 patients treated with robotic-assisted radical prostatectomy between 2015 and 2016 in the Vattikuti Collective Quality Initiative database

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For the entire cohort, a median of 12 (IQR 7–17) lymph nodes were removed. The total number of lymph nodes removed was higher in India (median [IQR] 13 (10–18) vs. 11 (8–17) nodes; P = 0.03). When patients were stratified per D'Amico risk classification, there was no difference in the number of nodes removed for D'Amico high-risk category (median [IQR] of nodes removed 14 [10–19] in India vs. 16 [11–19] in the US; P = 0.2), whereas a significantly higher number of nodes were removed in the low and intermediate-risk categories in India [Table 3].
Table 3: Number of lymph nodes removed in the entire cohort, and after stratification by D'Amico risk category and country of treatment in 415 patients treated with robotic-assisted radical prostatectomy between 2015 and 2016 in the Vattikuti Collective Quality Initiative database

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On multivariable analysis, country of treatment was an independent predictor of PLND utilization [Table 4]. Specifically, patients treated in India had a 2.57-fold (95% confidence intervals 1.16–5.70) higher odds of receiving PLND, when compared to their US counterparts (P = 0.02).
Table 4: Logistic regression analysis predicting the utilization of pelvic lymph node dissection in 415 patients treated with robotic-assisted radical prostatectomy between 2015 and 2016 in the Vattikuti Collective Quality Initiative database

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 » Discussion Top


Prostate cancer is the second most common cancer in India.[15] The incidence of prostate cancer in India has seen an increasing trend over the years.[16] This may be due to higher PSA screening and improved access to healthcare. The practice patterns of the utilization and extent of PLND remain heterogeneous, and the data on these practice patterns are lacking for Indian practice. The present study was carried out using the Vattikuti Collective Quality Initiative prospective multi-institutional database to compare the practice of PLND between India and the US. This study is the first of its kind in Indian patients.

This study showed several interesting findings. First, we found that 37.8% of Indian patients had clinically T1 disease, which is similar to the 37.69% reported by Yadav et al.[12] Noteworthy, the percentage of patients with T1 disease is significantly lower than the US (70.6%). Other clinical characteristics such as PSA, biopsy Gleason score, and D'Amico risk profile were also high in Indian patients. These differences in the disease at presentation in Indian patients have also been reported in previous studies.[12],[17],[18] Tewari et al. in a pathological analysis of radical prostatectomy specimens of Indian patients treated in the US found a higher incidence of extraprostatic extension, indicating presentation at a higher stage.[19] These findings may be attributed to several factors, such as differences in PSA screening, patient selection, and varying treatment protocols. This could also be possibly due to differences in the prostate cancer genomic profile between Indian and North American patients.

Second, a significantly higher number of patients underwent a PLND in the Indian cohort (94.6% vs. 85.8%; P = 0.003), It has previously been shown that a higher proportion of Indian patients have N1 disease.[12] Thus, it is expected that a higher number of patients would undergo PLND as compared to the US cohort, but the utilization of PLND in the present study is out-of-sync with disease risk. Surprisingly, these differences were due to higher utilization of PLND in the low-risk population in India. When stratified by risk groups, there was no statistical difference in utilization of PLND in the intermediate and high-risk groups between the Indian and US cohorts. On the other hand, 81% of the low-risk patients underwent a PLND in India as compared to only 41.4% in the US (P = 0.008).

These trends were observed in the number of lymph nodes as well. The total number of lymph nodes removed in Indian patients were higher (median [IQR] 13 [10–18] vs. 11 [8–17] nodes; P = 0.031), but when stratified by risk category, these differences were due to the higher number of nodes removed in the low-risk (median [IQR] 12 [10–14] vs. 5.5 [1.5–10] nodes; P = 0.004) and intermediate-risk (median [IQR] 14 [10.5–18] vs. 11 [7.75–16] nodes; P = 0.020) categories. There was no statistically significant difference in the high-risk category. When indicated, guidelines recommend doing an extended PLND [20] and removal of at least 20 nodes. The need for PLND in the low-risk group remains debatable, as it is associated with a higher risk of complications and worse functional outcomes.[21] The National Comprehensive Cancer Network guidelines recommend that PLND should not be done if the predicted risk of lymph node positivity is <2%.[20]

In the multivariate model, even after adjusting for disease risk, patients treated in India have a 2.57-fold increased probability of getting a PLND. Taken together, these findings imply that efforts should focus on improving the utilization of PLND in Indian patients by delivery of extended PLND to patients with aggressive tumor characteristics, and avoiding this procedure in low-risk patients, as indicated by most contemporary guidelines.[1],[7],[22]

The study has clinical implications as well. Overutilization of PLND will increase the morbidity of radical prostatectomy without clinical benefit in patients who are at low risk of node-positive disease. Avoiding PLND in very low-risk patients also reduces operative time, and potentially reduces the cost of surgery. Underutilization, on the other hand, will lead to an inaccurate staging of the disease, which might decrease the chance of cure in some patients, as PLND has been shown to be therapeutic in a subset of prostate cancer patients.[3]

Despite the quality of data that we used, our study has some limitations. First, there is a limited number of centers enrolled in the Vattikuti Collective Quality Initiative database, which might not be representative of the practice in India or the US. This limits the generalizability of our findings. Second, the variations in individual practice have not been accounted for, as the analysis was not stratified for individual centers. Finally, there was no central review of pathology slides, and the variation in reporting at individual centers in this multicenter data might affect the results of this study. Despite these limitations, the present study is an important insight into the current practice and might help in course correction, wherever applicable.


 » Conclusions Top


Our findings show that patients treated in India are more likely to undergo PLND and to have more lymph nodes removed than US patients. However, this seems to be derived mainly by the higher number of Indian patients with low-risk disease, who receive an extended PLND procedure. Given the very low risk of lymph node invasion in these individuals, an extended PLND is unlikely to be beneficial and might result in unnecessary side effects. Efforts should focus on optimizing the utilization of PLND in India and to deliver it only when there is a clinical indication.

Financial support and sponsorship

Nil.

Conflicts of interest

Firas Abdollah is consultant, Genome DX Biosciences. This is outside the scope of the present manuscript. Rest of the authors have no conflicts of interest.



 
 » References Top

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Seiler R, Studer UE, Tschan K, Bader P, Burkhard FC. Removal of limited nodal disease in patients undergoing radical prostatectomy: Long-term results confirm a chance for cure. J Urol 2014;191:1280-5.  Back to cited text no. 2
    
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Abdollah F, Gandaglia G, Suardi N, Capitanio U, Salonia A, Nini A, et al. More extensive pelvic lymph node dissection improves survival in patients with node-positive prostate cancer. Eur Urol 2015;67:212-9.  Back to cited text no. 3
    
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Briganti A, Chun FK, Salonia A, Suardi N, Gallina A, Da Pozzo LF, et al. Complications and other surgical outcomes associated with extended pelvic lymphadenectomy in men with localized prostate cancer. Eur Urol 2006;50:1006-13.  Back to cited text no. 4
    
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Abdollah F, Sun M, Thuret R, Budäus L, Jeldres C, Graefen M, et al. Decreasing rate and extent of lymph node staging in patients undergoing radical prostatectomy may undermine the rate of diagnosis of lymph node metastases in prostate cancer. Eur Urol 2010;58:882-92.  Back to cited text no. 9
    
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Suardi N, Larcher A, Haese A, Ficarra V, Govorov A, Buffi NM, et al. Indication for and extension of pelvic lymph node dissection during robot-assisted radical prostatectomy: An analysis of five European institutions. Eur Urol 2014;66:635-43.  Back to cited text no. 11
    
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D'Amico AV, Whittington R, Malkowicz SB, Schultz D, Blank K, Broderick GA, et al. Biochemical outcome after radical prostatectomy, external beam radiation therapy, or interstitial radiation therapy for clinically localized prostate cancer. JAMA 1998;280:969-74.  Back to cited text no. 14
    
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Sagalovich D, Calaway A, Srivastava A, Sooriakumaran P, Tewari AK. Assessment of required nodal yield in a high risk cohort undergoing extended pelvic lymphadenectomy in robotic-assisted radical prostatectomy and its impact on functional outcomes. BJU Int 2013;111:85-94.  Back to cited text no. 21
    
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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