Impact of Accidental Tumor Incision During Laparoscopic Partial Nephrectomy on the Oncologic and Clinical Outcomes

Abstract

Background

To investigate the impact of accidental tumor incision (ATI) during laparoscopic partial nephrectomy (LPN) on the treatment outcome of LPN and to determine the predictive factors for ATI.

Patients and Methods

Consecutive 156 patients with renal tumors suspicious of renal cell carcinoma cT1N0M0 undergoing laparoscopic partial nephrectomy at Yokohama City University between May 2003 and November 2014 were retrospectively evaluated. The analyzed clinical factors included maximum tumor diameter, the R.E.N.A.L. Nephrometry Score, occurrence of ATI during surgery, and the postoperative pathological findings including the presence of a pseudocapsule. Port site metastasis, tumor seeding, and local recurrence were investigated by routine follow-up computed tomography during the postoperative period.

Results

Among enrolled 156 procedures, 12 (7.7%) showed ATI during surgery. Positive surgical margin and local tumor recurrence were observed in 5 and 1 cases in the non-ATI group, respectively, as compared with in no cases in the ATI group. Port site metastasis or tumor seeding was not observed in either group. Multivariate analysis indicated that pseudocapsule formation significantly correlated with ATI (P = .022) and that maximum tumor diameter was a possible predictor of ATI (P = .054).

Conclusion

To our knowledge, there are no previous studies to evaluate the impact of ATI, and we here, for the first time, report that the risk of ATI is influenced by the presence of a pseudocapsule, and, to some degree, by the tumor size. Moreover, we also show that ATI during laparoscopic partial nephrectomy is not necessarily associated with poor outcomes such as local tumor recurrence.

Introduction

In the last 2 decades, partial nephrectomy (PN) has emerged as an oncologically equivalent treatment¹ to radical nephrectomy in most cases of localized renal cell carcinoma (RCC) in terms of the cancer-specific survival2, 3 and overall survival.³ Therefore, initially open and later on laparoscopic PN (LPN) has been widely accepted as one of the standard treatment options for these tumors.4, 5, 6 With improvements of the surgical devices, laparoscopic surgeries have resulted in improved visualization of the resection margin. In turn, this contributes to the decision regarding the optimal surgical incision line for removing the tumor completely with appropriate surgical margins. Although complete tumor removal is an oncologic principle of paramount importance, inappropriate surgical incisions are still observed in the clinical field, and may lead to accidental tumor incision (ATI) and pathologically positive surgical margin (PSM), and consequently to eventually residual malignancy induced by the incomplete resection.

A complete resection of the renal mass, avoiding ATI and PSM, along with the potential risks of disseminated cancer cells such as port site metastasis, tumor seeding, and local tumor recurrence, is essential in LPN. Previous reports showed that the factors related to tumor seeding and port site metastases can be divided into three categories, namely tumor-, wound-, and operation-related factors7, 8; among these, the most significant issue has been reported to be the surgical technique used.⁷ Curet showed that tumor manipulation increased the risk of tumor metastasis in both open and laparoscopic surgeries.⁷ Additionally, some previous studies have suggested that avoidance of tumor boundary violation and traumatic manipulation were important to prevent urologic tumor seeding and port site metastasis.8, 9 Furthermore, a previous animal model indicated that crushing of a subcapsular splenic tumor during laparoscopic exploration increased the incidence of port site metastasis.¹⁰ Therefore, it has been well established that the tumor boundaries must be respected in order to perform oncologically safe procedures and that traumatic tumor manipulation should be avoided during surgery to prevent dissemination of cancer cells.7, 8, 9 Recently, the impact of PSM in RCC during laparoscopic surgery on the treatment outcomes, including tumor recurrence, has been well-evaluated, and several reports have indicated that there is no large clinical impact of PSM11, 12, 13; however, a few reports have indicated that PSM might correlate with tumoral recurrence in high-grade tumors.¹⁴ On the other hand, the impact of ATI during LPN has not been fully investigated, even though, principally, ATI is considered to be associated with a potential risk of disseminated cancer cells during surgery.

In the present study, we aimed to investigate the risks of port site metastasis, tumor seeding, local recurrence, and cancer-specific survival in patients with ATI, and to reveal the impact of ATI on the treatment outcomes of LPN. Furthermore, we attempted to determine the predictive factors for the occurrence of ATI during LPN.