When do you consider is too late after resection to offer adjuvant therapy for high grade osteosarcoma?

Regarding the time to resume chemotherapy post resection in osteosarcomas, I do not feel there is a strict cut-off time frame that would render one unlikely to benefit, however, there is well cited literature that shows that a delay of >21 days (3 weeks) leads to a higher risk of death (57%) compar...