Primary retroperitoneal lymph node dissection (RPLND) in seminoma stage IIA-IIC <= 3cm: Combined results of the SWENOTECA (Swedish Norwegian Testicular Cancer Group) and Cologne

Background: Chemotherapy or radiotherapy have been standard treatment for stage II seminomas with excellent survival but are associated with significant long-term treatment-related toxicities. Several prospective trials have shown primary retroperitoneal lymph node dissection (RPLND) to be an effective and safe alternative. The current SWENOTECA treatment program recommends primary RPLND in seminoma stage IIA to IIB ≤ 3 cm with 1-2 metastatic nodes as the standard treatment modality. We present preliminary results combined with data from Cologne. Methods: Within SWENOTECA, RPLND is centralized to 5 hospitals and Cologne is a tertiary centre for patients recruited from different parts of Germany. Both patients with recurrence after initial stage I disease and patients with primary stage IIA and IIB at diagnosis were included. We collected information on operation time, bleeding, peri- and postoperative complications. We also analyzed histologic outcome and whether adjuvant chemotherapy was given. We followed the patients for any recurrence of disease. Results: We have included 94 patients operated from May 2018 to November 2022. The number of operations per site varied from 4 to 28. The mean age of patients at time of RPLND was 41.8 years (range 21-79). Overall, 54 patients had recurrence after initial stage I disease and 40 patients had primary stage IIA/IIB disease at diagnosis (one missing data). At time of RPLND 62 patients had IIA-disease and 31 stage IIB-disease (one missing data). The histology from RPLND showed seminoma in 83 patients, benign/necrosis in eight patients, vital non-seminomatous GCT in one patient, teratoma only in one patient and lymphoma in one patient. Mean number of resected nodes was 19, and mean number of positive nodes were 1.5. Twenty-six patients (28%) were operated with robotic laparoscopic technique. Ten patients (10.6%) had a Clavien-Dindo postoperative complication > 2. Twenty-three of the patients were given adjuvant oncological treatment after RPLND, most of them one course of BEP. The patients have been followed for in median 18 months (range 2-59). Nine patients (9.6 %) have had recurrences, all but one in the first year after RPLND. Conclusions: Our early results of primary RPLND of seminomas IIA-IIB ≤ 3 cm are promising. Longer follow-up is required to ensure this as a safe treatment option.