medwireNews: De-escalating chemoradiotherapy may be a feasible strategy for some patients with stage IIA or IIB classic seminoma, suggest the SAKK 01/10 trial investigators.
“Despite the fact that the primary endpoint was not met, we observed favourable 3-year progression-free survival [PFS] with single-dose carboplatin area under the curve 7 and involved-node radiotherapy, with minimal toxic effects,” write Alexandros Papachristofilou, from University Hospital Basel in Switzerland, and co-authors.
“Our findings might warrant discussion with patients about the SAKK 01/10 regimen as an alternative to standard-of-care treatment, but more research on this strategy is needed,” they say.
As described in The Lancet Oncology, 116 patients with treatment-naïve or relapsed seminoma were treated with one cycle of carboplatin to an area under the curve of 7. Stage IIA patients (n=46) were then given 30 Gy of radiation over 15 fractions while the stage IIB patients (n=70) received 36 Gy over 18 fractions.
The patients had a median of two lymph nodes affected and the median duration of follow-up was 4.5 years.
The overall 3-year rate of PFS for the patients was 93.7%; the lower limit of the two-sided 90% confidence interval was 88.5% and therefore the rate did not meet the primary endpoint criterion.
However, the researchers emphasize that the achieved PFS rate was “favorable” and “similar” to that achieved by the standard of care regimens.
The 3-year rates were 95.3% for the stage IIA cohort and 92.6% for the stage IIB cohort, and all relapses occurred in patients with de novo disease. The 3-year PFS rate for patients with stage IIA or IIB disease after active surveillance was 100% versus 90.3% for those with de novo disease.
Progression occurred after a median follow-up of 16.7 months from start of treatment, with six of the seven relapses occurring in the first 3 years. “All patients who relapsed were successfully treated with salvage standard-dose cisplatin-based chemotherapy,” report Papachristofilou and co-authors.
The 3-year overall survival rate was 99.3%, with one death in a patient with a history of alcohol abuse and chronic hepatitis B and C disease who developed a second primary cancer of the liver.
Safety analysis showed that grade 3 or more severe treatment-related adverse events were mostly related to chemotherapy, such as neutropenia (4%), thrombocytopenia (3%), and vomiting (1%). One patient experienced a grade 4 platelet count decrease and one patient developed a serious adverse event, namely transient creatinine elevation.
In an accompanying comment, Patrizia Giannatempo and Nicola Nicolai, both from the Foundation IRCCS National Cancer Institute in Milan, Italy, say that a “positive treatment effect” was found despite the regimen having a “substantial reduction” in radiation volume, and note that all but one of the relapses were found “outside the boundaries of a traditional dog-leg radiation field.”
Nevertheless, the commentators say that the follow-up so far is too short to show “a potential advantage in reducing treatment sequelae” but the regimen “could be a benchmark for further investigation.”
Recognizing that de-escalation strategies for stage IIA and IIB seminoma are “a current unmet clinical need,” they conclude that further improvements might include use of proton therapy or “more precise biomarkers, such as miRNA clusters.”
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