Palliative treatment of bone metastases with samarium-153

Transcription

1 APPROVED BY: Z. Yang Page 1 of 5 Palliative treatment of bone metastases with samarium-153 Primary Indications: Rationale: To treat bone pain resulting from osteoblastic metastases as defined by bone scan. Samarium 153 (Quardramet): is indicated for the treatment of bone pain resulting from a metastatic malignancy that has involved multiple skeletal sites and has evoked an osteoblastic response on bone scintigraphy. The radioactive material in the samarium treatment goes into the cancer cells. It does not go into healthy bones or tissues. Left over drug is passed out of the body through the urine. Where there is danger of either spinal cord compression from vertebral metastases or pathologic fracture in the extremities, Samarium 153 therapy should be only used in conjunction with other forms of management directed at these complications and after management of the acute presentation. Interfering Conditions: Patient Preparation: Patient Scheduling: Hypercalcemia should not deter Samarium 153 treatment unless accompanied by renal failure. Recent administration of etidronate or other bisphosphonates may decrease the uptake of Samarium 153 at the tumor site and, consequently, decrease the effectiveness of pain palliation. If bisphosphonates have been administered within 2 weeks before the planned therapy, a bone scan should be considered to confirm adequate uptake at the tumor site. Bisphosphonate therapy probably should not be given for at least 48 hrs after Samarium 153 therapy. Do not need NPO. The patient should remain well hydrated before, during, and after the procedure. Referring physician needs to complete Checklist for Palliative Treatment of Painful Bone Metastases for this procedure (Please see the check list). The following is the detailed explanations for the check list: 1. The patient should have had recent bone scintigraphy (less than 8 wk) documenting increased osteoblastic activity in the painful sites. Bone scintigraphic abnormalities should be correlated with appropriate physical

2 APPROVED BY: Z. Yang Page 2 of 5 examination and imaging studies to ascertain that osseous or soft-tissue abnormalities, which might cause cord or other nerve compression or pathologic fracture in an extremity, are not present. 2. Patient should not have received long-acting myelosuppressive chemotherapy (e.g., nitrosoureas) for 6 8 wk, and full doses of other forms of myelosuppressive chemotherapy or systemic radioisotope ther-apy for approximately 4 wk before administration of Samarium 153 and for about 12 wk after administration of Samarium 153 because of the potential for severe leukopenia or thrombocytopenia. Caution should be used if Samarium 153 is used in conjunction with myelosuppressive chemotherapy. 3. The patient should not have received external beam hemibody radiation within 2 3 mo before administration of Samarium 153 to reduce the probability of combined myelotoxicity from the external and internally distributed radiopharmaceuticals during this period, except for radiotherapy to local areas performed to prevent fracture or spinal compression. 4. Complete blood counts should be obtained, preferably on the day of, and not more than 7 days before, administration of Samarium 153. The patient s platelet count should probably exceed 60000/uL and preferably 100,000/uL; the leukocyte count should probably exceed 2,400 3,000/ul and preferably 5,000/uL; the absolute granulocyte count should exceed 2,000/uL; and the hemoglobin count should be more than 10g/dL. Results below these blood count levels are not absolute contraindications to treatment but raise the chance of infection or bleeding. Practitioners should be aware of counts over the preceding weeks; a rapid recent fall without signs of recovery should be considered a probable contraindication. 5. Active disseminated intravascular coagulation (DIC) may be a risk factor for severe thrombocytopenia post-therapy. Deaths have been reported in patients with DIC after therapy with β-emitting radiopharmaceuticals, and this potential risk must be sought and carefully considered before administering Samarium 153 in the presence of DIC, especially if a rapid recent fall in platelet count has occurred. 6. Hospitalization is not required for the administration of Samarium 153

3 APPROVED BY: Z. Yang Page 3 of 5 7. A patient who has a life expectancy of less than 4 6 weeks is unlikely to benefit from Samarium The procedure may be repeated 12 or more weeks after the first injection if blood counts are at the suggested levels. The response rate after the second treatment is about 50% and may occur even if there was no response to the first treatment. A few patients who have failed to respond to the first Samarium 153 injection have had pain reduction with a second injection 12 weeks later. Radiopharmaceutical: Quardramet: Samarium 153 EDTMP (ethylenediaminetetra methylenephosphonic acid), 153 Sm lexidronam Half-life Onset of action in patients who respond Emission Excretion Penetration Quadramet Samarium SM-153 Lexidronam Injection 1.93 d 1 wk Beta: Avg. 233 kev (0.810 Mev maximum) Gamma: 103 kev 100% urinary 1.7 mm in bone 3.1 mm in soft tissue Adult Dose: Samarium 153 (Quardramet): 1.0 mci/kg up to 75 mci The procedure may be repeated 12 or more weeks after the first injection if blood counts are at the suggested levels. Patients have responded to up to 7 dosages of radiotracer if needed, but the risk of marrow toxicity rises with each subsequent dosage.

4 APPROVED BY: Z. Yang Page 4 of 5 Radiation Dosimetry: 153 Sm Radiation Dosimetry Organ mgy / MBq Rad / mci Bone surface Red Bone Marrow Lower Bowel Wall Bladder Wall Testes Ovaries Kidneys Route of Administration: Equipment Setup: Patient Positioning: Intravenous, The radiopharmaceutical should be administered slowly through an intravenous catheter or a running intravenous line to avoid infiltration, to reduce the hand dose to the injecting technologist, and to permit flushing of the syringe so that all of the Samarium 153 injected. A plastic syringe shield or equivalent is suggested for administration of the radiopharmaceutical. Flush the syringe and intravenous line from the syringe to the patient with saline from the running intravenous line or a saline-filled syringe attached to a 3-way stopcock. Gamma Camera: Whole-body, LFOV Collimator: Whole-body and spot-view planar imaging: LEAP or high-resolution collimator Energy Window: 103 kev with 20% window Routine whole-body imaging: supine with arms at side (supinated)

5 APPROVED BY: Z. Yang Page 5 of 5 Procedure: Routine whole body imaging: 24 hours imaging after injection of Samarium 153 including SPECT/CT from the vertex to the proximal thighs and planar imaging of the lower extremities with a dual-head whole-body camera. Review and Approval Date Initials: Date: Medical Director Tech Director/Supervisor