Modified templates and retroperitoneal mapping studies

In 1988 Jewett and Torbey [31] stated that ''all modified dissections introduce a risk of incomplete resection of involved nodes.'' In general, ipsilateral lymph nodes are resected between the level of the renal vessels and the bifurcation of the common iliac artery, contralateral dissection is limited or omitted, and interartocaval nodes are variably resected for left-sided primary tumors [8]. All modified RPLND templates limit dissection in anatomic regions felt to be at reduced risk for metastatic disease based on anatomic mapping studies of retroperito-neal metastases by Ray and colleagues, Donohue and colleagues, and Weissbach and Boedefeld [10-12]. Unfortunately, the mapping studies have significant limitations that may have also contributed to underestimating the extent of retroperito-neal metastasis. First, the mapping studies lack adequate postoperative follow-up; therefore, the rate of extratemplate recurrence is unknown [1012]. Without clinical follow-up, sample error by the surgeon and/or pathologist cannot be assessed. There was no follow-up reported in the studies by Ray and colleagues [10] or Donohue and colleagues [11]. Weissbach and Boedefeld [12] reported a median follow-up of only 22 months for node-negative patients and noted three retroperitoneal relapses. Second, the Weissbach study was a multicenter study involving 46 centers and 50 surgeons introducing significant surgical variability [12]. Third, as stated previously, it is not possible to accurately assess additional potential sites of metastasis in patients who received postoperative chemotherapy. All patients with pathologic stage II B disease in the Weissbach study participated in a randomized adjuvant chemotherapy trial and received either two or four cycles of PVB (cisplatin, vinblastine, bleomycin) [12]. Fourth, although uncommon, the potential impact that renal and renovascular anatomic variants may have on testicular lympho-vascular drainage is not described. Furthermore, the variable insertion of the right gonadal vein(s) at various levels of the inferior vena cava (IVC) and/or right renal vein as well as additional branches to the pelvis and Gerota's fascia may influence potential sites of metastatic disease. Chang and colleagues [32] demonstrated that 5% of patients with retroperitoneal disease harbor disease in the spermatic cord specimen, either within the vessel or in the adjacent tissue, and that incomplete resection may result in paracolic recurrence.

Recently, Eggener and colleagues [20] evaluated 500 patients with CS I-IIA NSGCT who underwent primary RPLND at MSKCC and analyzed the incidence of extratemplate disease for five modified RPLND templates (Weissbach, MSKCC, Indiana, JHU, Innsbruck) in the 191 patients with positive nodes. Depending on the template, overall extratemplate disease ranged from 3% to 23%, including 1% to 11% for patients with low-volume retroperitoneal disease. The histologic distribution of extratemplate disease was not significantly different from in-tem-plate disease [20]. For right-sided modified templates, the most common sites of extratemplate disease were the para-aortic nodes (Weissbach, Indiana, Innsbruck, and JHU templates) and preaortic nodes (JHU) [20]. In 2002, Leibo-vich and colleagues [33] reported that 28 (5%) of 607 patients with right-sided NSGCT who underwent RPLND at Indiana University had positive nodes only in the preaortic or para-aortic region.

For left-sided modified templates that excluded the interaortocaval region, disease would have been unresected in 23 (88%) of 26 patients [20].

A similar analysis by Carver and colleagues [34] of 532 patients with advanced NSGCT who underwent post-chemotherapy RPLND (PC-RPLND) at MSKCC showed a significant number of patients with extratemplate disease. Of 269 patients with viable GCT or teratoma in the retroperitoneal specimen, 7% to 32% had evidence of extra template disease, depending on the limits of the modified template. Again, there was no difference in the histologic distribution of extratemplate disease compared with in-template disease [34].

The most common site(s) of recurrent or residual mass prompting reoperation following either 1° RPLND or PC- RPLND for both right-and left-sided tumors are the left para-aortic area and the left hilar region. In the MSKCC series [3], 34 (53%) of 64 retroperitoneal masses resected at reoperation involved recurrences in the left para-aortic and/or hilar region. Similarly, three (50%) of six retroperitoneal recurrences reported by Cespedes and Peretsman [23] occurred in the left peri-hilar area. There are two reasons for this. First, as previously noted, this region is excluded in many modified templates for right-sided primary tumors [3,20,34]. Second, there are increased technical demands required to obtain adequate exposure to be able to meticulously dissect the left renal vessels and completely resect the lymph nodes in this area. The technical aspects of adequate exposure, pancreatic mobilization, vascular control, and adequate dissection are beyond the scope of this article and are described elsewhere [3,8].

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