Introduction/Background The first cases of radiation-induced cancers were published five years following the discovery of radioactivity. The rates might exceed 5% and even exceed 20% in some series.

Methodology We report two cases of radio-induced occurring to prophylactic pulmonary irradiation on two patients treated for osteosarcoma.

Results Case 1 pertained to a 43-year-old female patient that had been treated for non-metastatic right lower limb osteosarcoma at the age of 12. The treatment consisted of neoadjuvant chemotherapy (NCT) followed by a non-conservative surgery and then a prophylactic bilateral pulmonary irradiation. Eighteen years later, the patient developed an infiltrating ductal left breast carcinoma ranked T4bN0M0. NCT was performed followed by mastectomy and locoregional radiotherapy (LRRT). Estrogen and progesterone receptors were negative. Five years later, the patient developed her second contralateral cancer which was classified as T4bN1M0. NCT was prescribed followed by radical surgery, adjuvant CT, and LRRT. Six years after her second breast cancer, the patient was alive with local relapse and lung metastases. Case 2 revealed a 52-year-old-female that had been treated for non-metastatic right tibia osteosarcoma at the age of 13. The patient was treated with non-conservative surgery followed by CT and a prophylactic bilateral pulmonary irradiation. At the age of 36, left breast cancer was discovered and it was classified as T1N0M0, luminal B. The treatment consisted of conservative surgery, adjuvant CT, hormonotherapy (HT), and RT. Sixteen years later, the patient developed her second breast cancer which was treated with zonectomy and then was classified as pT1N0M0, Luminal B. RT, and HT were prescribed. Actually, the patient is in complete remission.

Conclusion These two cases highlight the importance of full pretreatment discussion and properly documented ’informed consent’ before treatment and of close follow-up of all patients whose therapy includes ionizing irradiation.

Disclosures This publication adds to several previous publications the probably radio-induced bilateral breast cancer occurred after prophylactic bilateral pulmonary in the treatment of osteosarcoma. A brief review of relevant literature is presented.