Radiation for Bone Metastases

Radiation Therapy for Bone Metastases

External beam irradiation is commonly used to treat painful bone metastases, often given in 10 treatments (commonly 300cGy x 10) with slower and higher doses for more destructive lesions (particularly over the spine) e.g. 4000cGy in 20 fractions. For some areas in patients with very advanced disease a single fraction (e.g. 600 or 800cGy) may be all that is needed. (see literature review of single versus multiple fractions here and here. See more of the RTOG bone met data: table1 and table2.) For wide spread metastases it's also possible to treat half the body in one shot (celled hemibody radiation) or to inject radioisotopes (e.g. strontium or metastron.) Common ranges of response rates are as note:

External Beam	80 - 90%
Hemibody	75 - 77%
Strontium 89	72 - 91%

**RTOG Trial for Bone Metastases**
RTOG 7402 (multiple fractions, external beam) 90% response 54% complete response RTOG 7801 (800cGy Hemibody) 73% response 20% complete

**Hemibody Irradiation**
600cGy (upper) or 800cGy (lower) Pretreatment with hydration, antiemetics, steroids Lower toxicity in lower body Palliation sustained until death in 82% (upper) 67% (lower)

**Single Fraction of Radiation for Bone Mets**
Dose	Response	Complete
600cGy	89%	39%
Conventional	75-90%	27 - 54%

**Metastron or Strontium-89 (Sr-89)**
Response rate of 67 - 80% Relief begins in 7 - 20 days Duration for 6 months, may be repeated after 90 days Delays need for XRT from 5.8 mos to 12.8 mos Depression of wbc (20%) platelets (30%)

**Literature Review on Isotopes for Bone Mets**
(*Sem Rad Onc 2000;10:103)*
Isotope	Response Rate	Duration	Time to Respond	Thrombocytopenia	Flare
Samarium-153	70 - 75%	2 - 3 months	5- 10 days	mild-mod	10%
Strontium-89	60 - 80%	3 - 4 months	10 - 20 days	moderate	5 - 10%

A systematic overview of radiation therapy effects in skeletal metastases.

Falkmer U, Acta Oncol. 2003;42(5-6):620-33

A systematic review of radiation therapy trials in several tumour types was performed by The Swedish Council of Technology Assessment in Health Care (SBU). The procedures for evaluation of the scientific literature are described separately (Acta Oncol 2003; 42: 357-365). This synthesis of the literature on radiation therapy for skeletal metastases is based on data from 16 randomized trials. Moreover, data from 20 prospective studies, 5 retrospective studies and 22 other articles were used. A total of 63 scientific articles are included, involving 8051 patients. The results were compared with those of a similar overview from 1996 including 13,054 patients. The conclusions reached can be summarized as follows: Irradiation of skeletal metastases is, with few exceptions, a palliative treatment. There is strong evidence that radiotherapy of skeletal metastases gives an overall (complete and partial pain relief) in more than 80% of patients. There is strong evidence that the duration of pain relief in at least 50% of patients lasts for > or = 6 months. There is convincing evidence that pain relief, in terms of degree and duration, does not depend on the fractionation schedules applied. Irrespective of the fractionation schedule used at irradiation, the number of later complications, such as spinal cord compression or pathological fractures, at the index fields are low. There are some data showing that the difference in cost between single and multifraction treatment is small. However, these data do not permit any firm conclusions to be drawn. Several reports indicate that early diagnosis and early therapy of spinal cord compression are the two most important predictors of a favourable clinical outcome after radiotherapy. However, no controlled studies have been undertaken. When the diagnosis of spinal cord compression is late, a favourable outcome might depend on the radio-responsiveness of the tumour. The documentation is weak and no conclusions can be drawn. There is some evidence that a small proportion of totally paralytic patients can regain walking function after radiotherapy. There is strong evidence that the radionuclides 89Sr and 153Sm are efficient when they are used as a systemic treatment of generalized bone pain due to metastasis from carcinomas of the prostate and breast. Overall bone pain relief occurs in about 60-80% of patients with a median response duration of 2-4 months. There is strong evidence that intravenous treatment with bisphosphonates in patients with myeloma and osteolytic bone metastasis due to carcinoma of the breast significantly decreases the number of skeleton-related events and bone pain.