Palliative Radiotherapy for Large Osteolytic Metastatic Tumors Involving the Iliac Bone: A Report of 16 Cases

Background/Aim: Among the bones that compose the pelvis, the ilium is the most commonly affected by metastatic tumors. The objective of our study was to describe the outcomes after palliative radiotherapy (PRT) of osteolytic metastatic tumors involving the iliac bone (OMTIB).

Patients and Methods: Sixteen symptomatic patients with OMTIB were treated with PRT during a six-year period. The mean maximum diameter of the pelvic bone lesions was 9.3 cm (range=3.4-16 cm). OMTIB affected the iliac bone alone (six patients), the adjacent pelvic bones or muscles (seven patients), or both structures (three patients). The irradiation dose-fractionation scheme was ≥30 Gy given in 10 to 15 fractions.

Results: Pain response rates were: good in 44% (7/16) of cases, fair in 25% (4/16), and poor in 31% (5/16). After treatment, mobility outcomes exhibited ambulation in 69% (9/13) and non-ambulation in 31% (4/13). During follow-up, the effects of PRT on OMTIB were reflected as stability in 28% (3/11), enlargement in 36% (4/11), and re-calcification in 36% (4/11). The overall survival rates at one and two years were 44% (7/16) and 19% (3/16), respectively; median survival was two months.

Conclusion: Although the prognosis of OMTIB is poor, PRT is an effective treatment for pain relief, improving mobility and promotion of bone repair.