www.oncologyeducation.ca radiotherapy versus carboplatin for stage i seminoma: updated analysis of...
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Radiotherapy versus carboplatin for stage I seminoma: Updated analysis of the
MRC/EORTC randomized trial
Authors: Oliver et al, ASCO 2008.
Abstract: 1
Date posted: July 2008
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BACKGROUND
• Stage I seminoma is the most common testicular cancer presentation
• Treatment options:
• Radiation therapy: 4% relapse rate
• Surveillance: 15-20% relapse rate
• Chemotherapy with Carboplatin
• Cure rate should be 99%
• Case series suggest Carboplatin x 1 is as good as RT
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Treatment A:
Carboplatin x 17 x (GFR + 25) by EDTA or creatinine clearance(not Cockcroft)
Treatment B:
Radiotherapy20-30 Gy
Stage I Seminoma
Randomization 3C:5RT
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DESIGN
• Non-inferiority
• Powered to exclude an increase in 2 year relapse rate of 3% with chemotherapy
• Accrual: 1996-2001
• Planned accrual n=1200
• Actual accrual n=1447
• First presented ASCO 2004 and published Lancet 2005;366:293
• Updated analyses planned 5 years after last patient entry
• Median follow-up = 6.5 years
• 78% with follow-up 5 years
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TOXICITY
Carbo RT p-value
All Grade 3/4 All Grade 3/4
Thrombocytopenia 21% 9% 2% 0% 0.001
Dyspepsia 8% 17% 0.001
Unable to Work
– Week 4 19% 38% 0.001
– Week 12 10% 14% NS
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Results
Carbo RT p-value
n 573 904
Total Relapses 29 (5%) 37 (4%)
New Primary 7 (1.1%) 25 (2.8%)
– GCT 2 (0.3%) 15 (1.7%)
– Other 5 (0.8%) 10 (1.1%)
Total Deaths 6 (1.0%) 10 (1.1%)
– From Seminoma 0 1
5y Relapse-free 94.7% (92.5-96.3) 96% (94.5-97.1) 0.37
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STUDY COMMENTARY
• Carboplatin x1 (AUC of 7) is safe and is not inferior to radiation for stage I seminoma with relapse rate of 5.3% (RT=4%)
• Carboplatin dosing is important and need an AUC 7
• Will take 20 years to determine the cardiovascular toxicity and secondary malignancy rates with this treatment
• Still remains to be seen whether Carboplatin x1 simply delays the relapse vs. prevents it – longer follow-up than 6.5 years may be needed
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BOTTOM LINE FOR CANADIAN MEDICAL ONCOLOGISTS
• Stage I seminoma treatment options include surveillance, Carboplatin and radiation
• Carboplatin and RT over-treat 80% of patients
• Carboplatin and RT still require long-term follow-up including CT scan imaging
• Carboplatin may have cardiovascular morbidity
• Therefore, surveillance makes the most sense for the majority of men after a full discussion has taken place
• If treatment wanted/needed, the:
• Known short-term and long-term risks of radiation
• Known short-term and unknown long-term risks of Carboplatin need to be discussed with patients