West Asia Organization for Cancer Prevention (WAOCP), APOCP's West Asia Chapter. Asian Pacific Journal of Cancer Prevention 1513-7368 26 9 2025 09 01 Survival and Prognostic Determinants after IMRT and 3D Radiotherapy in Metachronus Bone – Only Spinal Metastasis of Breast Cancer: A Prospective Phase II Trial 3423 3429 91847 10.31557/APJCP.2025.26.9.3423 EN Ayatallah Youssif Radiotherapy and Nuclear Medicine, South Egypt Cancer Institute, Assiut University, Assuit, Egypt. Asmaa Abdellah Lecture of Clinical Oncology, Assuit University, Assuit, Egypt. Summar El-Morshidy Lecture of Clinical Oncology, Assuit University, Assuit, Egypt. Asmaa Hasaballah Radiotherapy and Nuclear Medicine, South Egypt Cancer Institute, Assiut University, Assuit, Egypt. Journal Article 2025 03 18 Objectives: Oligometastasis is a distinctive subset of osseous metastatic breast cancer, represented by single or few detectable metastatic osseous lesions. A more advanced radiotherapy approach can be considered in those bone-only diseases. We analysed different predictive factors affecting the 5-year survival after palliative radiotherapy in patients with bone-only metastatic breast cancer. Methods: This prospective multicentre phase II study included 60 breast cancer patients with metachronus osseous oligometastasis in the period from January 2019 to January 2024. Result: The mean age of our patients was 49.55±6.39 (40-67), and the median follow-up time was 45 months. The mean survival time from metastasis and radiotherapy was 41.11 (36.33-45.89), and 49.64 (44.11-55.16), respectively. The three-year bone survival rate was 81.7% and the five-year survival rate was 79%. In the univariate analysis, the significant prognostic factors that were associated with poor OS were: age more than 50 years old,  multiple metastasis, higher level of LDH , anemic patients,  triple negative disease, 3D planning and dose less than 3000/10GY. Multivariate analysis confirmed 2 independent prognostic factors for longer survival: triple-positive histology (p=0.0001), and intended radiation dose more than or equal 30 Gy (p=0.028). Conclusion: Prolonged radiotherapy fractionation schedules improve survival in triple positive bone-only metastatic breast cancer with controlled primary. Simple blood tests should not be routinely done in those patients. https://journal.waocp.org/article_91847_be325e5bc4d33e8900b47435a976cd27.pdf