New therapeutic option for early metastatic seminoma

The phase 2 SEMS trial demonstrated encouraging outcomes from retroperitoneal lymph node dissection (RPLND) for early metastatic (i.e. stage 2) testicular seminoma. The 2-year recurrence-free survival (RFS) rate was 87% and the overall survival rate (OS) was 100% among patients who underwent the procedure.

The National Comprehensive Cancer Network Guidelines for management of stage 2A testicular seminoma remain unchanged for several decades, recommending chemotherapy and radiation therapy. Although these interventions are associated with excellent cure rates, they are also associated with long-term morbidity as well as secondary complications such as cardiac events, secondary cancers, metabolic syndrome, and lung disease. For this reason, investigators of the SEMS trial wished to explore other therapeutic options for young men with this cancer [1].

A seminoma will typically first spread to the retroperitoneal space. RPLND is commonly employed in testicular germ cell tumours. The researchers aimed to investigate whether RPLND might also be effective for early metastatic seminoma. The SEMS trial (NCT02537548) is a single-arm, multi-institutional, phase 2 trial that is studying outcomes after RPLND in stage 1–2A testicular seminoma. Enrolled are 55 patients (median age 34 years) with testicular seminoma and isolated retroperitoneal lymphadenopathy measuring 1–3 cm to receive RPLND. The primary endpoint is RFS at 2 years. Secondary outcome measures are short-term (up to 12 months) and long-term (up to 5 years) RPLND complication rates and 5-year RFS.

Of the 55 patients in the trial, 14 had initial stage 1 disease and 41 had stage 2A–B. At a median follow-up period of 24 months post-RPLND, 10 participants experienced recurrence, yielding a recurrence rate of 18%. The median recurrence time was 8 months. Of these 10 participants, 8 received chemotherapy (i.e. 6 received 3 cycles of bleomycin/etoposide/cisplatin, 1 received 4 cycles of combination etoposide plus cisplatin, and 1 received combination carboplatin plus etoposide), and 2 required additional surgery. The 2-year RFS was 87% and OS was 100%.

Within the first year of surgery, 7 surgical complications occurred; 5 were classified as Clavien-Dindo I-II complications and 2 as Clavien-Dindo III. No patients have reported any long-term complications.

At the time of ASCO GU 2021, principal investigator Prof. Siamak Daneshmand (University of Southern California, USA) reported that these 55 patients have now been followed for 5 years and all have survived. The outcomes achieved in this trial are similar to results for non-seminomatous germ cell tumours. Thus, Prof. Daneshmand concluded that RPLND offers an effective first-line treatment option for men with testicular seminoma with retroperitoneal lymphadenopathy. The decreased long-term morbidity associated with RPLND makes it a favourable alternative.

1. Daneshmand S. SEMS Trial: Result of a prospective, multi-institutional phase II clinical trial of surgery in early metastatic seminoma. Abstract 375, ASCO Genitourinary Cancers Symposium, 11–13 February 2021.

 

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Posted on 24 March 202118 March 2024