Abstract 78P
Background
Triplet regimens incorporating doxorubicin, cisplatin and ifosfamide/methotrexate may improve pathological response, but increase the toxicity and cost, with no data showing improved survival in adult osteosarcoma. Dose-dense schedules have not been evaluated in this population.
Methods
We conducted a retrospective study of adults receiving ddEP chemotherapy (epirubicin 90mg/m2 and cisplatin 70mg/m2 every 2 weeks for 12 weeks) for localised osteosarcoma from 2014 to 2022 at a tertiary referral center. 41 patients received ddEP and 13 patients received other regimens (control group) based on physician preference during the same period. Outcomes assessed included histopathological response to chemotherapy, recurrence-free survival (RFS), overall survival (OS) and toxicity.
Results
Of a total of 54 patients, 77.8% were male and the median age was 22.5 years (IQR 19-30). The distal femur was the commonest site. Out of 33 patients with baseline staging available, 48.5% had Stage IIB disease. 10 patients had lung metastases at presentation. 28 patients received ddEP preoperatively while 13 received it in the adjuvant setting. 20 out of 28 receiving neoadjuvant ddEP underwent surgery at our centre. Of the 8 patents who did not undergo surgery, 4 progressed on treatment, 1 died, 1 did not consent for surgery and 2 were lost to follow up. A good histological response (≥90% necrosis) was seen in 35% of patients receiving ddEP compared to 23.1% in the control group. At a median follow-up of 8.5 months for the ddEP group, RFS was 86.9%, and OS was 95%, while for the control, at a median follow-up of 18.3 months, the RFS was 55.6 % and OS 72.7%. At 10 months of median follow-up for the entire cohort, the RFS was comparable in both groups- 86.9% for the ddEP group and 83.3% for the control group. Grade 3 anemia was seen in 42.4% and 75.0%, grade 3/4 thrombocytopenia in 22.2% and 90.9%, and febrile neutropenia in 7.3% and 61.5% in the ddEP and control groups respectively. Completion of all planned cycles of treatment was similar at 77% in both groups. The total cost of this regimen using generic drugs is EUR 622 (USD 668).
Conclusions
ddEP may be a cost-effective alternative to current systemic regimens for osteosarcoma, producing a similar histological response and comparable survival with lower toxicity.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.