Forsteo ® (teriparatide)

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Can patients with a history of radiation therapy use Forsteo® (teriparatide)?

Forsteo is contraindicated in patients with prior external beam or implant radiation therapy to the skeleton and should not be prescribed.


Why is teriparatide contraindicated after prior radiation?

Radiation-induced osteosarcoma is a rare but well-recognized complication in human radiotherapy patients that was first reported in patients after treatment with ionizing radiation in the 1920s.1

In most radiotherapy protocols, high doses of therapeutic radiation are directed at the tumor tissue. Other tissues, including the skeleton and likely the entire body, can be exposed to comparatively low doses of unwanted radiation via scattering of radiation within the body and low level leakage from the treatment apparatus.2

Development of second malignant neoplasms (SMNs), including osteosarcoma, in tissues that are located in-field (in the path of the therapeutic beam) and out-of-field (outside the path of the therapeutic beam but affected by scatter) can occur years or decades after initial treatment.1,2

Forsteo is contraindicated in patients with prior external beam or implant radiation therapy to the skeleton.3

According to the US prescribing information, use of teriparatide should be avoided in patients with increased risk of osteosarcoma, including those who have had prior external beam or implant radiation therapy involving the skeleton.4

Examples of prior radiation therapy where teriparatide should not be used

Teriparatide should not be used if patient had exposure to 

  • therapeutic external beam radiation, including
    • radiation therapy for a soft tissue malignancy, such as breast cancer (such patients likely have experienced radiation affecting the skeleton around the breast [the sternum or ribs])5,6
  • any type of radiation implanted into the body, including
    • brachytherapy
    • interstitial radiation
    • intracavitary radiation,5,7 or
  • stereotactic radiation to the brain or other areas of the body, including
    • stereotactic radiosurgery
    • fractionated stereotactic radiotherapy
    • stereotactic body radiation therapy
    • Gamma Knife®
    • X-Knife®
    • CyberKnife®
    • Clinac®.5,8

Case reports of SMNs, including osteosarcoma, have been reported in patients receiving these therapies.9-11

Examples of prior radiation therapy where teriparatide may be considered

Teriparatide use may be considered in patients who had

  • radioactive iodine therapy
  • low doses of nonpenetrative radiation (Grenz radiation) used for treatment of skin conditions
  • diagnostic radiation, including
    • radiographs
    • computed tomography (CT) scans
    • radionuclide scans, or
  • non-radioactive forms of radiation, including
    • ultraviolet radiation
    • phototherapy.5


1Kalra S, Grimer RJ, Spooner D, et al. Radiation-induced sarcomas of bone: factors that affect outcome. J Bone Joint Surg Br. 2007;89-B(6):808-813.

2Newhauser WD, Durante M. Assessing the risk of second malignancies after modern radiotherapy. Nat Rev Cancer. 2011;11(6):438-448.

3Forsteo [summary of product characteristics]. Eli Lilly Nederland B.V., The Netherlands.

4Forteo [package insert]. Indianapolis, IN: Eli Lilly and Company; 2021.

5Data on file, Eli Lilly and Company and/or one of its subsidiaries.

6Benveniste MF, Gomez D, Carter BW, et al. Recognizing radiation therapy-related complications in the chest. Radiographics 2019;39(2):344-366.

7Getting internal radiation therapy (brachytherapy). American Cancer Society. Accessed August 16, 2022.

8Getting external beam radiation therapy. American Cancer Society. Accessed August 16, 2022.

9Sanno N, Hayashi S, Shimura T, et al. Intracranial osteosarcoma after radiosurgery. Neurol Med Chir (Tokyo). 2004;44(1):29-32.

10Abedalthagafi M, Bakhshwin A. Radiation-induced glioma following CyberKnife® treatment of metastatic renal cell carcinoma: a case report. J Med Case Rep. 2012;6:271.

11Balasubramaniam A, Shannon P, Hodaie M, et al. Glioblastoma multiforme after stereotactic radiotherapy for acoustic neuroma: case report and review of the literature. Neuro Oncology. 2007;9(4):447-453.

Date of Last Review: 16 August 2022

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