| OBJECTIVE This research aims to compare the curative effects of laparoscopic inguinal lymphadenectomy and open inguinal lymphadenectomy as a way to provide the basis for clinical treatment of penile cancer. The prognostic impacts on patients with penile cancer going through bilateral metastasis and extra nodal extensionwere was exerted with the status of lymph nodes. At last, the value of the 7th edition of AJCC N-staging of penile cancer in predicting the prognosis of penile cancer was verified.METHODS After a review and sifting of 38 medical records of patients undergoing the bilateral inguinal lymph node dissection operated in Guangxi Medical University Cancer Hospital from January 2002 to December 2015, a shallow comparative analysis of the clinical data and postoperative complications respectively from 19 cases of laparoscopic surgery and 19 cases of open surgery was carried out. The research of the disease was conducted by the disease-specific survival or DSS analysis using Kanlan-Meier method, and the differences between the different groups were compared using the Log-rank test. The ROC curve was applied to calculate the best critical point of prognosis by the use of continuous variable ratio of positive lymph nodes. Relationship between the total number of lymph nodes and that of positive ones was analyzed by the locally weighted regression scatterplot smoothing or LOWESS analysis. Univariate COX proportional hazards model was used to evaluate the relevant risk factors associated with prognosis of patients with positive penile cancer. Then statistically significant variables in the univariate COX analysis were included in the multivariate COX proportional hazards regression model to calculate the risk factors related to the prognosis of penile cancer. Finally, Logistic Model was applied to predict the accuracy of penile cancer prognosis by the use of 6th or 7th edition of AJCC pN-staging.RESULTS1. Among 38 cases of bilateral inguinal lymph node dissection,19 of which were cases of laparoscopic surgery and the rest was open surgery, each accounting for 50%.12.63±5.92 lymph nodes were removed in the open surgery group, while 29.16±16.78 lymph nodes were dissected in the laparoscopic surgery group. That meant the total number of lymph nodes cleared in the laparoscopic surgery group was more than that in the open surgery group (P<0.001). The average time of open surgery group was 4.29±1.57 hours, while that of laparoscopic surgery group was 8.13±3.12 hours. That indicated the average time of laparoscopic surgery group was longer than that of open surgery group (P<0.001). Among the cases of inguinal lymphadenectomy operated in the same period of time, the average time of laparoscopic surgery group was 7.90±2.77 hours, while that of open surgery group cost 3.72±0.92 hours. That turned out that there was no statistical significance in the difference between the two sample groups (P=0.05). Among the cases of total penectomy and inguinal lymphadenectomy operated in the same period of time, the average time of laparoscopic surgery group was 6.63±3.82 hours, while that of open surgery group was 4.70±1.56 hours. That revealed there was no statistical significance in the difference between the two sample groups (P=0.55). Among the cases of partial penectomy and inguinal lymphadenectomy operated in the same period of time, the average time of laparoscopic surgery group was 8.76±3.08 hours, while that of open surgery group was 4.53±1.87 hours. That showed the average time of laparoscopic surgery group was longer than that of open surgery group (P<0.01). The average time of drainage tube indwelling in open surgery group was 10.90±4.97 days, while that in laparoscopic surgery group was 15.67±6.45 days. That proved the average time of drainage tube indwelling in laparoscopic surgery group was longer than that in open surgery group (P=0.02). The occurrence rate of flap necrosis was 47.37%(9 out of 19 cases) in the open surgery group, while that was 10.53%(2 out of 19 cases) in the laparoscopic surgery group, which meant the occurrence rate of flap necrosis in the laparoscopic surgery group was lower than that in the open surgery group (P=0.01). The occurrence rate of lymphorrhagia in the open surgery group referred to 42.11%(8 out of 19 cases), compared to 10.53% in the laparoscopic surgery group (2 out of 19 cases), which manifested that the occurrence rate of lymphorrhagia in the laparoscopic surgery group was lower than that in the open surgery group (P=0.03). No deep vein thrombosis, lower extremity edema, seroma or paresthesia occurred in the inpatients receiving both the open surgery and laparoscopic surgery. There were 2 out of 38 cases of lymphocele (5.26%), each surgery group accounting for 1 case (5.26%). No clear difference was found between the open surgery and laparoscopic surgery in terms of postoperative mortality, the number of positive lymph nodes, length of hospital stays, blood loss during the operation and the occurrence rate of incision infection (P>0.05 in all).2. Apart from 2 cases in which patients had been taken preoperative neoadjuvant chemotherapy, the average age of the patients in the rest cases was 49.53±13.68 years (25-77years), with an average follow-up time of 50.71±41.95 months (ranging from 5.1 to 159.5 months), and an average survival time of 63.15±4.74 months. There were 8 death cases, occupying 22.22%, due to the tumor itself. There were 22 out of 36 cases (61.11%) in which pathologically confirmed lymph nodes became positive, and 6 out of 22 cases (27.27%) in which patients died. There were 14 out of 36 cases (38.89%) in which pathologically confirmed lymph nodes became negative, and 2 out of 14 cases (14.29%) in which patients died. Different clinical features might be statistically significant on a different number of positive lymph nodes in the findings from the research of 36 patients’general survival rate (P=0.03), the distribution of positive lymph nodes in different places (P=0.03), whether lymph nodes had extranodal extension (P=0.02), and different survival rate resulting from different pNstagings according to the 7th edition (p=0.04).3. Defined value of the total number of inguinal lymph nodes in the inguinal lymph node dissection with reference to NCCN melanoma, among all patients, the boundary in the total number of lymph nodes removed was set at 16. The 5-year DSS rate of 16 lymph nodes and more dissected was 67.11%, compared to a rate of 71.43% in less than 16 lymph nodes removed, which showed that such difference was not statistically significant (P=0.60). Among all patients with positive lymph nodes, the 5-year DSS rate of 16 lymph nodes and more dissected was 55.56%, compared to a rate of 62.50% in less than 16 lymph nodes removed, which meant that such difference was not statistically significant (P=0.57). Among all patients with negative lymph nodes, the 5-year DSS rate of 16 lymph nodes and more dissected was 100.00%, compared to a rate of 83.33% in less than 16 lymph nodes removed, which meant that such difference was not statistically significant (P=0.52). Among 22 cases in which patients had positive lymph nodes, the application of LOWESS showed that the total number of lymph nodes as well as that of the positive ones was on the rise, with the number of positive lymph nodes reaching a peak as the total number of lymph nodes ranged from 30 to 40. The use of ROC curve in calculating the density of positive lymph nodes through prognostic prediction of penile cancer demonstrated that its optimal threshold reached 12.5%. The 5-year DSS rate of patients whose lymph node density or LND was lower than 12.5% is 80.00%, while the 5-year DSS rate of patients whose LND was 12.5% and more was 40.91%. Log-rank test showed that there was no statistical significance in the difference between two sample groups in terms of overall survival rate (P=0.08).4. Among the relevant risk factors, which affected the prognosis of patients with positive penile cancer, investigated by the univariate and multivariate COX research model, results from univariate COX proportional hazard model showed that the relevant risk factors associated with poor prognosis included a large number of positive lymph nodes (HR=2.68; 95%CI:1.05-6.84;P=0.04), bilateral inguinal positive lymph nodes (HR=5.71;95%CI:1.03-31.66;P=0.04), extranodal extension of positive lymph nodes (HR=6.14; 95% CI:1.17-32.25;P=0.03). The multivariate COX analysis showed that more positive lymph nodes remained as the risk factors related to penile cancer associated with poor prognosis (HR=7.57; 95% CI:1.12-51.19; P=0.04).5. According to the 7th edition of pN-staging,1 patient whose pNl in the 6th edition rose to pN3, and 6 patients whose pN2 in the 6th edition were up to pN3. The 5-year DSS rate of patients with pNl, pN2 and pN3 in the 6th edition was 83.33%,24.24% and 50.00% respectively, with no statistical difference found between sample groups (.P=0.09), while the 5-year DSS rate of patients with pNl, pN2 and pN3 in the 7th edition was 83.33%,50.00% and 25.93% respectively, with a statistical difference found between sample groups (P=0.04). Parameters from the prediction model showed that HR of the 7th edition of pN-staging reached 2.05, higher than the 6th edition of 1.89 and LR of the 7th edition of pN-staging was topped at 5.42, higher than the 6th edition of 3.39.CONCLUSIONS1.The laparoscopic inguinal lymphadenectomy for penile cancer is proven better than the open inguinal lymphadenectomy in terms of postoperative complications such as lymphorrhagia and flap necrosis and the total number of lymph nodes acquired. It is worth applying and promoting in the treatment of patients with penile cancer as it is conducive to reducing the occurrence rate of postoperative complications while ensuring the effect of tumor control.2. Within an appropriate range of lymph nodes dissection, a best prognosis can be obtained as the total number of lymph nodes removed reaches a certain range instead of removing lymph nodes without control in order to achieve the desired prognosis. This might require the help of a doctor from pathology department during the operation. Such practice might contribute to reducing the length of operation and avoiding the occurrence of anesthetic accidents and postoperative complications, though enormous researches of the bulk of cases are still needed.3. Our results indicate that compared to the 6th edition of pN-staging, the 7th edition one is better as it involves such factors as extranodal extension.4. Whether lymph nodes have gone through bilateral metastasis or not, the number of positive lymph nodes, and whether positive lymph nodes have extranodal extension or not are regarded as the risk factors related to the prognosis of patients with penile cancer. |
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