# Bone pain palliation from osteoblastic metastases

Source: https://nuclide.cc/indications/bone-pain-palliation/  
Nuclide record `bone-pain-palliation` (Indication). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

For cancer that has spread widely to bone and causes pain everywhere at once, a bone-seeking radioactive injection travels to every affected spot in the skeleton and delivers pain-relieving radiation from the inside, sparing a trip to radiotherapy for each site.

## Summary

Widespread osteoblastic (bone-forming) metastases, most often from prostate or breast cancer, can cause diffuse skeletal pain that is impractical to treat site-by-site with external beam radiotherapy. Systemically administered beta-emitting bone-seeking radiopharmaceuticals - strontium-89 chloride, samarium-153 lexidronam (153Sm-EDTMP) and, historically, phosphorus-32 sodium phosphate - concentrate at sites of increased osteoblastic turnover in proportion to bone remodelling activity, verified beforehand by a positive radionuclide bone scan, and deliver local beta radiation to relieve pain over one to a few weeks. The alpha-emitting radium-223 dichloride is a related but distinct case: as a calcium mimetic it also concentrates in osteoblastic bone lesions, but it is FDA- and EMA-approved specifically for castration-resistant prostate cancer with symptomatic bone metastases and no visceral disease, and, unlike the older beta emitters, it prolongs overall survival, not just pain.

The SNMMI/EANM procedure standard for these agents recommends 89Sr-chloride at roughly 148 MBq (or 1.5-2.2 MBq/kg), 153Sm-EDTMP at 37 MBq/kg, and 223Ra-dichloride at 55 kBq/kg every four weeks for six cycles; all three are given as a slow intravenous injection with attention to avoiding extravasation. Only 223Ra-dichloride has shown a survival benefit (from the ALSYMPCA trial); 89Sr and 153Sm are recommended solely for pain palliation and are not associated with any demonstrated survival advantage, and neither should be given to patients with a life expectancy under about four weeks because of a lag of days to weeks before pain relief.

Selection is straightforward but firm: patients need painful lesions that are osteoblastic (not lytic) and bone-scan-avid, adequate baseline blood counts because myelosuppression is the dose-limiting toxicity of the beta emitters in particular, and no impending spinal cord compression or pathological fracture risk, which need surgery or external beam radiotherapy instead. Concomitant bisphosphonates are not contraindicated. Weekly complete blood counts are recommended for eight weeks after treatment, or until recovery from the nadir, given the risk of cytopenias.

## Fields

- Kind: Indication
- Last checked: 2026-09-22
- Tags: palliative care; bone metastases; alpha therapy; beta emitter
- Group: palliative care
- Burden: Bone metastases occur in a large majority of men who die of prostate cancer and a majority of women with metastatic breast cancer, and painful skeletal metastases are one of the most common causes of cancer-related pain requiring systemic, rather than site-specific, treatment.

## Standard of care

- Diffuse painful osteoblastic bone metastases from any solid tumour, confirmed osteoblastic on bone scan: Strontium-89 chloride or samarium-153-EDTMP for pain palliation; no proven survival benefit, and inappropriate if life expectancy is under about four weeks. ([ALSYMPCA](https://nuclide.cc/trials/alsympca/))
- Castration-resistant prostate cancer with symptomatic bone metastases and no visceral disease: Radium-223 dichloride, six cycles at 55 kBq/kg every four weeks, chosen over the older beta emitters because it also improves overall survival and delays symptomatic skeletal events. ([ALSYMPCA](https://nuclide.cc/trials/alsympca/))
- Before any bone-seeking radiopharmaceutical: Confirm osteoblastic, bone-scan-avid lesions and adequate blood counts; exclude impending cord compression or pathological fracture, which need surgery or external beam radiotherapy instead.

## State of the art

- The SNMMI Procedure Standard/EANM Practice Guideline for radionuclide therapy of painful bone metastases (updated version discussed in 2023 SNMMI technologist literature) sets current dosing, patient selection and monitoring practice for 89Sr, 153Sm-EDTMP and 223Ra-dichloride, and notes that 32P sodium phosphate is no longer available for this use in the United States.
- Radium-223's approval, based on the phase 3 ALSYMPCA trial (median overall survival 14.9 vs 11.3 months for placebo), remains the only agent in this class with a demonstrated survival benefit; its US label is currently restricted to castration-resistant prostate cancer with symptomatic bone metastases and no visceral disease.
- About 60% of patients receiving radium-223 experience meaningful pain reduction, with an estimated 3-4 month survival extension reported across analyses of the pivotal trial population.

## Open problems

- Strontium-89 and samarium-153 remain palliative only, with no survival benefit shown in any trial, and their future use may narrow further as radium-223 and lutetium-177-based radioligand therapies increasingly address the same castration-resistant prostate cancer population earlier in the disease course.
- Myelosuppression from the beta emitters can delay or preclude subsequent chemotherapy, an important sequencing consideration in patients who may still be candidates for later systemic therapy.
- Selecting between radium-223, PSMA-targeted lutetium-177 radioligand therapy and standard therapies in castration-resistant prostate cancer with bone-only disease is an active area of clinical judgement rather than settled guideline, particularly regarding sequencing and combination.

## Sources

- SNMMI Procedure Standard/EANM Practice Guideline for radionuclide therapy of painful bone metastases: https://tech.snmjournals.org/content/51/3/176
- EANM guidelines for radionuclide therapy of bone metastases with beta-emitting radionuclides: https://pmc.ncbi.nlm.nih.gov/articles/PMC5978928/
- FDA medical review: radium Ra 223 dichloride (Xofigo), NDA 203971: https://www.accessdata.fda.gov/drugsatfda_docs/nda/2013/203971Orig1s000MedR.pdf

## Connected records

- isotopes: [Phosphorus-32](https://nuclide.cc/isotopes/p-32/), [Radium-223](https://nuclide.cc/isotopes/ra-223/), [Samarium-153](https://nuclide.cc/isotopes/sm-153/), [Strontium-89](https://nuclide.cc/isotopes/sr-89/)
- drugs: [Phosphorus-32 (radiophosphorus)](https://nuclide.cc/drugs/phosphorus-32/), [Radium-223 dichloride](https://nuclide.cc/drugs/radium-223/), [Samarium-153 lexidronam](https://nuclide.cc/drugs/samarium-153-lexidronam/)
- trials: [ALSYMPCA](https://nuclide.cc/trials/alsympca/)
- key papers: [ALSYMPCA: alpha emitter radium-223 and survival in metastatic prostate cancer with bone metastases](https://nuclide.cc/key-papers/paper-alsympca-radium-223-nejm-2013/)

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