Port-Site Metastasis after Laparoscopic Surgery for Urological Malignancy: Forgotten or Missed

Purpose. Port-site metastasis has been a concern with the common use of laparoscopy in urologic oncology. We conducted this study to provide a review of port-site metastases reported after the laparoscopy in managing urologic malignancies, possible contributing factors and preventative measures. Materials and Methods. An electronic search of MEDLINE using the combined MESH key words “port-site metastasis” and “Urology”. Results. 51 articles addressing port-site metastasis after laparoscopic surgery for urolo¬gical malignancy were identified. Conclusion. Port-site metastasis after laparoscopic surgery for urolo¬gical malignancy is rare. The incidence is comparable to the rate for surgical wound metastases.


Introduction
In recent years, with the widespread use of laparoscopy to treat an ever-increasing number of urologic malignancies, questions have been raised about the oncologic safety of this surgical approach [1]. Currently, a large number of specialized centres around the world perform laparoscopy for urologic cancer [2,3]. Nevertheless, local recurrence and port-site metastasis remain a concern [4].
Port-site metastases, though rare, have been extensively documented for other gynaecological and GI malignancies. When they occur, they often do so in the presence of advanced disease, but it is not uncommon for them to occur in isolation [5,6]. Concern has been expressed that laparoscopic surgery might adversely affect the long-term outcomes by increasing the risk of port-site and peritoneal seeding.
The first known report of a port-site metastasis was by Dobronte and associates [7] in 1978. The authors reported implantation of malignant ovarian cystic adenoma in penetration sites of the pneumo-needle and trocar. Some specific procedures and tumors have been associated with a higher incidence of portsite metastasis or tumor seeding; however, the precise incidence of port-site metastasis and its aetiology and pathogenesis have not been well defined in urologic laparoscopy [8].
Port-site metastases is a multifactorial phenomenon with an as-yet undetermined incidence. Etiological factors include natural malignant disease behavior [9], host immune status [9], local wound factors [9], laparoscopy-related factors such as aerosolization of tumor cells (the use of gas, type of gas, insufflation and desufflation, and pneumoperitoneum) [9], and sufficient technical experience of the surgeons and operating team [9] (adequate laparoscopic equipment, skill, minimal handling of the tumor, surgical manipulation and wound contamination during instruments change, organ morcellation, and specimen removal) [9].

Materials and Methods
An electronic search of MEDLINE of the published literature up to 2010 was carried out using the combined MESH key words "port-site metastasis" and "Urology." Duplicate references, as well as repeated references to the same data sets, were removed. The articles and case reports directly addressing port-site metastasis after laparoscopic surgery for urological malignancy were reviewed.

Advances in Urology
Articles were selected and categorized by topic into incidence, aetiology, pathophysiology, and possible preventative measures. Table 1 showed the case reports found on MEDLINE search of the published literature up to 2010 recovered 51 for the MESH words "port-site metastasis" and "Urology." Etiological factor has been categorised in three main categories: tumour related, wound related, and surgical technique related. Surgical technique related factors have been categorised in two main categories: manipulation is the principal factor acting in tumour dissemination. Extraction of the surgical specimen is determined by the surgeon. The possible preventive measure has been categorised in two main categories: active measures and measures for reducing the risk of laparoscopic port-site metastasis in urological surgery.

Discussion
Laparoscopic surgery is rapidly gaining widespread acceptance among urologists, including extensive application in malignant conditions [9]. The incidence of tumour seeding in general laparoscopic surgery ranges from 0.8% to 21% (8,9). However, most authors report an incidence of 0.5%, comparable to the rate for surgical wound metastases (0.8%-1.6%) in conventional open methods [9][10][11]. In recent years, several reports of port-site metastasis and tumor seeding have been published. Tsivian and Sidi [9] alone reported nine cases of port-site metastases after urologic laparoscopy, and Rassweiler and colleagues [10] published eight local recurrences observed in 1098 laparoscopic procedures for urologic malignancies. Recently, in an international survey of 19 urologic laparoscopic centres performing a total of 18,750 laparoscopic procedures for urologic malignancies, tumour seeding was reported in 13 cases (0.1%) [8].
Various theories tried to explain metastasis development at laparoscopic port site [12]. Factors can be divided into three categories: tumor related, wound related, and surgical technique related [4].
Tumor-related factors [8][9][10]: biological aggressiveness of the tumor, represented by grade and stage, could play a decisive role in possible tumor seeding determination, explaining why grade 2 and 3 transitional cell carcinomas represent the majority of port-site metastases in urological procedures [8][9][10].
However, it is logical to assume that morcellation of the specimen increases tumor seeding [5,6,15]. The direct dissemination of tumor cells from contaminated material or from extraction with an unclosed bag is well documented [5,6,15]. The observance of a large number of tumor cells at excessively manipulated ports supports this hypothesis as well as observance of greater number of malignant cells at port sites used by the surgeon compared with those used by assistants [5,6,15].

Conclusion
Port-site metastasis in urological laparoscopic surgery is rare. Multiple factors have been associated with tumour seeding, but tumour grade and stage appear to play a major role. Multiple methods have been described to reduce the risk of port-site metastasis. The incidence is comparable to the rate for surgical wound metastases.