Few new compounds are available for relapsed osteosarcoma. We retrospectively evaluated the activity of gemcitabine (G) plus docetaxel (D) in patients with relapsed high-grade osteosarcoma and high-grade spindle cell sarcoma of bone (HGS). Patients receiving G 900 mg/m2 d 1, 8; D 75 mg/m2 d 8, every 21 days were eligible. Primary end-point: progression-free survival (PFS) at 4 months; secondary end-point: overall survival (OS) and response rate. Fifty-one patients were included, with a median age of 17 years (8–71), 26 (51 %) were pediatric patients. GD line of treatment: 2nd in 14 patients, ≥3rd in 37. 25 (49 %) patients had metastases limited to lungs, 26 (51 %) multiple sites. Histology: 40 (78 %) osteosarcoma, 11 (22 %) HGS. Eight (16 %) patients achieved surgical complete response (sCR2) after GD. Four-month PFS rate was 46 %, and significantly better for patients with ECOG 0 (ECOG 0: 54 % vs ECOG 1: 43 % vs ECOG 2: 0 %; p = 0.003), for patients undergoing metastasectomy after GD (sCR2 75 % vs no-sCR2 40 %, p = 0.02) and for osteosarcoma (osteosarcoma 56 % vs HGS 18 %; p = 0.05), with no differences according to age, line of treatment, and pattern of metastases. Forty-six cases had RECIST measurable disease: 6 (13 %) patients had a partial response (PR), 20 (43 %) had stable disease (SD) and 20 (43 %) had progressive disease (PD). The 1-year OS was 30 %: 67 % for PR, 54 % for SD and 20 % for PD (p = 0.005). GD is an active treatment for relapsed high-grade osteosarcoma, especially for ECOG 0 patients, and should be included in the therapeutic armamentarium of metastatic osteosarcoma.

Background: The evidence on high-dose ifosfamide (HD-IFO) use in patients with relapsed osteosarcoma is limited. We performed a retrospective study to analyze HD-IFO activity. Methods: Patients with osteosarcoma relapsed after standard treatment [methotrexate, doxorubicin, cisplatin +/− ifosfamide (MAP+/−I)] with measurable disease according to RECIST1.1 were eligible to ifosfamide (3 g/m²/day) continuous infusion (c.i.) days 1–5 q21d. RECIST1.1 overall response rate (ORR) (complete response (CR) + partial response (PR)), progression-free survival at 6-month (6m-PFS), duration of response (DOR), and 2-year overall survival (2y-OS) were assessed. PARP1 expression and gene mutations were tested by immunohistochemistry and next-generation sequencing. Results: 51 patients were included. ORR was 20% (1 CR + 9 PR). Median DOR was 5 months (95%CI 2–7). Median PFS, 6m-PFS, OS, and 2y-OS were 6 months (95%CI 4–9), 51%, 15 months (10–19), and 30%, respectively. A second surgical complete remission (CR2) was achieved in 26 (51%) patients. After multivariate analysis, previous use of ifosfamide (HR 2.007, p = 0.034) and CR2 (HR 0.126, p < 0.001) showed a significant correlation with PFS and OS, respectively. No significant correlation was found between outcomes and PARP1 or gene mutations. Conclusions: HD-IFO should be considered as the standard first-line treatment option in relapsed osteosarcoma and control arm of future trial in this setting.

In patients with relapsed osteosarcoma, the surgical excision of all metastases, defined as second complete remission (CR-2), is the factor that mainly influences post-relapse survival (PRS). Currently a validated follow-up policy for osteosarcoma is not available, both chest X-ray and computed tomography (CT) are suggested for lung surveillance. The purpose of this study is to evaluate whether the type of imaging technique used for chest surveillance, chest X-ray or CT, influenced the rate of CR-2 and prognosis in patients with recurrent osteosarcoma. Patients up to 40 years with extremity osteosarcoma enrolled in consecutive clinical trials and treated at the Rizzoli Institute from 1986 to 2009 were identified. Only patients who had lung metastases alone as first pattern of recurrence were considered for the analysis. The rate of CR-2, overall survival (OS) and PRS were the end-points of the study. The median follow-up was 47 months (1–300), 215 patients were eligible. Lung metastases were detected by chest X-ray in 100 (47%) patients, by CT in 112 (52%) and by symptoms in 3 (1%). CR-2 rate was 60% for patients followed by X-rays and 88% for those followed by CT (p < .0001). 5-year PRS was 30% (95% CI 21–39) in the X-ray group and 49% (95% CI 39–59) in the CT group (p = .0004). 5-year OS was 35% (95% CI 26–44) in the X-ray group and 60% (95% CI 51–70) in the CT group (p = .004). A follow-up strategy with chest CT leads to a higher rate of CR-2 and significantly improves PRS and OS in osteosarcoma, compared to chest X-ray.

High-grade foci (grade 3 according to Broder’s grading system) are sometimes detected in low-grade (grade 1 and 2) central osteosarcoma. The aim of this study was to retrospectively evaluate the clinical outcome in patients upgraded to high grade (grade 3) after a first diagnosis of low-grade osteosarcoma, following the detection of high-grade areas (grade 3) in the resected specimen. Of the 132 patients with a diagnosis of low-grade central osteosarcoma at surgical biopsy at our Institute, 33 patients were considered eligible for the study. Median age was 37 (range 13–58 years). Location was in an extremity in 29 patients (88 %). Post-operative chemotherapy was given in 22 (67 %) patients. Follow-up data were available for all patients, with a median observation time of 115 months (range 4–322 months). After histological revision, areas of high-grade (grade 3) osteosarcoma accounting for less than 50 % of the tumor were found in 20 (61 %) patients, whereas the majority of the tumor was composed of a high-grade (grade 3) component in 13 (39 %) patients. In the 20 cases of low-grade osteosarcoma with high-grade foci (grade 3) in less than 50 % of the tumor, 9 patients did not receive adjuvant chemotherapy; only one of them died, of unrelated causes. In the adjuvant chemotherapy group (11 out of 20 patients), one patient developed multiple lung metastases and died of disease 39 months after the first diagnosis. In the other 13 cases of low-grade osteosarcoma with high-grade foci (grade 3) in more than 50 % of the tumor, 12 patients received adjuvant chemotherapy: 2 had recurrence, 4 developed multiple lung metastases and 3 died of disease. The only patient who did not receive chemotherapy is alive without disease 232 months after complete surgical remission. Our data indicate that patients with a diagnosis of low-grade osteosarcoma where the high-grade (grade 3) component is lower than 50 % of the resected specimen, may not require chemotherapy, achieving high survival rates by means of complete surgical resection only.

PURPOSE: Outcome of patients with localized osteosarcoma is challenging. The role of mifamurtide is still a matter of debate. Two prospective trials were carried out in Italy (ISG/OS-2) and Spain (GEIS-33) with mifamurtide in ABCB1/P-glycoprotein (Pgp)–positive patients. PATIENTS AND METHODS: Patients age ≤40 years with localized extremity high-grade osteosarcoma were eligible. Analysis of Pgp expression from diagnostic biopsy was centralized. Patients received two cycles of preoperative methotrexate, doxorubicin, and cisplatinum (MAP) before surgery. Postoperatively, in case of Pgp overexpression (Pgp-positive), mifamurtide was added, combined with doxorubicin (one cycle) and four consecutive cycles of high-dose ifosfamide (HDIFO) for patients with poor histologic response, or with MAP in case of good response. Patients who were Pgp-negative received MAP postoperatively. We present the merged analysis of ISG/OS-2 and GEIS-33 trial, an observational study with same inclusion criteria and treatment of ISG/OS-2. The primary endpoint was 5-year event-free survival (EFS) according to the use of mifamurtide. Secondary endpoint was overall survival (OS). RESULTS: From March 2013 to April 2018, 398 patients were analyzed. The median age was 14 years (range, 4-40), male/female: 238/160 (1.48/1.0); 211 of 398 (53%) tumors were Pgp-positive, and 204 of 398 (51.3%) patients received mifamurtide. With a median follow-up of 70 months (IQR, 49-90 months), the 5-year EFS and OS were 65.2% (95% CI, 60.1 to 69.8) and 74.8% (95% CI, 69.8 to 79.0), respectively, with superior EFS for patients undergoing mifamurtide and chemotherapy as compared with EFS of patients undergoing chemotherapy alone (5-year EFS 71.4% v 58.3%; P = .0139) not confirmed at multivariable analysis ( P = .0593). CONCLUSION: In this merged analysis with a risk-adapted strategy for nonmetastatic osteosarcoma, the group with unfavorable prognoses, identified by Pgp expression, performed well when mifamurtide, combined with HDIFO in case of poor response, was administered after surgery.