'Attractive' Option for Early Metastatic Seminoma

M. Alexander Otto

February 17, 2021

When early-stage seminoma metastasizes to one or two retroperitoneal lymph nodes, surgical excision is an "attractive" alternative to standard chemotherapy or radiation, according to an investigator from the phase 2 SEMS trial.

The trial enrolled 55 men with early-stage seminoma and isolated retroperitoneal disease, and all of them underwent retroperitoneal lymph node dissection (RPLND). At 2 years, the recurrence rate was 18%, the recurrence-free survival rate was 84%, and the overall survival rate was 100%. Surgical complications occurred in 13% of patients.

"The SEMS trial establishes RPLND as a first-line treatment alternative for testicular seminoma with isolated retroperitoneal lymphadenopathy up to 3 cm ... It’s an attractive option given the favorable long-term morbidity of RPLND," said co-principal investigator Siamak Daneshmand, MD, of the University of Southern California (USC), Los Angeles.

"The whole point is to offer an alternative treatment that will avoid long-term toxicity ... It makes no sense treating isolated retroperitoneal lymphadenopathy with strong chemotherapy that’s meant for more widely disseminated disease," Daneshmand said.

He presented results from the SEMS trial at the 2021 Genitourinary Cancers Symposium (Abstract 375).

Practice-Changing?

Daneshmand called the trial results "practice-changing" and noted that surgery "makes sense" to patients and providers, especially because RPLND is already an established option for early-stage non-seminoma testicular cancer. In fact, USC has continued to offer RPLND for early-stage seminoma since this trial ended 2 years ago, Daneshmand said.

Study discussant Pilar Laguna, MD, PhD, of Istanbul Medipol University in Turkey, offered a different viewpoint. She said the SEMS trial had an "excellent" design, but, due to the relatively short follow-up, she would recommend caution.

"We in Europe do not recommend primary retroperitoneal lymph node dissection in seminoma outside a trial or institutional study," Laguna said.

Still, she said the SEMS trial "establishes a solid base" for ongoing prospective trials of primary RPLND in early-stage seminoma.

Trial Details

The SEMS trial enrolled 55 patients with pure testicular seminoma. They had stage I disease with 1-3 cm relapse (25%) or stage IIA/B disease with no more than two lymph nodes in any dimension (75%). Imaging was done within 6 weeks of surgery to avoid under staging, and serum tumor markers could be no more than 1.5 times the upper limit of normal.

The majority of subjects were White, and the median age was 34 years (range, 21-64 years). Including USC, the trial was conducted at 12 North American sites.

Patients had open modified-template surgeries by surgeons who had performed at least eight open RPLNDs in 1 year or more than 24 in 3 years. Surgeries at USC used a midline approach, with a typical hospital stay of 1 day.

The median follow-up was 2 years. The overall recurrence rate was 18% (10/55), with a median time to recurrence of 8 months.

All 10 cases of recurrence were salvageable – 8 with chemotherapy and 2 with surgical resection. All of the recurrences were retroperitoneal.

"If you can cure 80% [of men] without radiation or chemotherapy, that’s very significant. These are young patients, and chemotherapy and radiation have long-term side effects. The important thing to remember is if men do recur, they are salvageable," Daneshmand said.

Seven patients (13%) had surgical complications that were largely minor. The exceptions were one case of pulmonary embolism and one case of chylous ascites that required drainage. There were no long-term complications, including retrograde ejaculation.

The SEMS study was funded by the Think Different Foundation. Daneshmand and Laguna said they have no relevant disclosures.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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