Systemic Cisplatin Does Not Affect the Bone Regeneration Process in a Critical Size Defect Murine Model

Osteosarcoma (OS) is the most common primary malignant bone tumor, and the current standard of care for OS includes neoadjuvant chemotherapy, followed by an R0 surgical resection of the primary tumor, and then postsurgical adjuvant chemotherapy. Bone reconstruction following OS resection is particularly challenging due to the size of the bone voids and because patients are treated with adjuvant and neoadjuvant systemic chemotherapy, which theoretically could impact bone formation. We hypothesized that an osteogenic material could be used in order to induce bone regeneration when adjuvant or neoadjuvant chemotherapy is given. We utilized a biomimetic, biodegradable magnesium-doped hydroxyapatite/type I collagen composite material (MHA/Coll) to promote bone regeneration in the presence of systemic chemotherapy in a murine critical size defect model. We found that in the presence of neoadjuvant or adjuvant chemotherapy, MHA/Coll is able to enhance and increase bone formation in a murine critical size defect model (11.16 ± 2.55 or 13.80 ± 3.18 versus 8.70 ± 0.81 mm³) for pre-op cisplatin + MHA/Coll (p-value = 0.1639) and MHA/Coll + post-op cisplatin (p-value = 0.1538), respectively, at 12 weeks. These findings indicate that neoadjuvant and adjuvant chemotherapy will not affect the ability of a biomimetic scaffold to regenerate bone to repair bone voids in OS patients. This preliminary data demonstrates that bone regeneration can occur in the presence of chemotherapy, suggesting that there may not be a necessity to modify the current standard of care concerning neoadjuvant and adjuvant chemotherapy for the treatment of metastatic sites or micrometastases.