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Whole Brain Radiation Therapy (WBRT) with Simultaneous Integrated Boost (SIB) to Brain Metastasis via Image Guided, Intensity Modulated Radiation Therapy (IG-IMRT): Dosimetric and Early Clinical Experience

2008; Elsevier BV; Volume: 72; Issue: 1 Linguagem: Inglês

10.1016/j.ijrobp.2008.06.624

1879-355X

Grant M. Clark, B Plants, J Mallah, P Raja, L Farinash, M. Harmon, Lewis Whaley, D Mihailidis,

Glioma Diagnosis and Treatment

Purpose/Objective(s)To present our early clinical experience with IG-IMRT for the treatment of single or multiple brain metastases using a SIB to visible tumor while delivering a prophylactic dose to WB with a single isocenter.Materials/MethodsEight patients were treated from 7/07 through 1/08 using IG-IMRT to deliver a SIB to tumor (GTV + 3mm = PTV) with WBRT to a lower "prophylactic" dose. The median patient age was 55.5 (range, 40-71) years. Primary cancers included lung (4), melanoma, biliary, uterine, and unknown primary. The median KPS was 60 (range, 40-80). The mean number of metastases was 3.75 (range, 1-13). All patients had uncontrolled systemic disease at the time of simulation and 4 were given concurrent radiation therapy to extracranial sites. No patient received prior WBRT.The CT images were fused with pretreatment MRIs for inverse treatment planning on Pinnacle v7.4f. A standard Aquaplast mask was used for immobilization. Frameless IGRT with BrainLAB's ExacTrac with body markers for infrared tracking was used to monitor intrafraction motion. A non-coplanar, 5-field beam arrangement was delivered using a Siemen's Primus linac. Optic structures, parotids, inner ear, and scalp were optimized to minimize toxicity.ResultsAll treatments were delivered within a 30-minute treatment slot. The median total PTV was 20.3 (range, 10.1-169.3) cm3. The median prescribed dose to tumor PTV was 45 (range, 40-45) Gy, median dose to WB (excluding metastasis) was 30 (range, 25-36) Gy, delivered over a median of 15 fractions (range, 10-15). The median PTV coverages were a maximum of 105% and a minimum of 91%.Acute toxicities included 2 patients with Grade 2 (G2) fatigue and 1 patient with G2 alopecia. Common G1 toxicities were rash/dermatitis (7/8) and alopecia (8/8). There were no toxicities >G2. One patient had G2 limb weakness prior to treatment that improved to G1. Two patients had G2 aphasia prior to RT: 1 improved to G1 and another showed complete resolution.Five patients underwent posttreatment MRI at a median time of 112 (range, 45-194) days after the start of treatment. Local brain control was achieved in 16 of 17 total metastatic sites. One of 5 patients had new brain mets. Response rate was partial in 3 patients, complete in 1, and stable in another. No patients had brain necrosis.ConclusionsLow-dose "prophylactic" WBRT can be safely delivered with SIB to brain metastases with minimal toxicity and local control that is comparable to sequential WBRT and stereotactic radiosurgery (SRS). This technique is convenient, non-invasive, and may combine the benefits of WBRT and SRS into one procedure. We are currently accruing patients to further assess toxicity and tumor control using this approach. Purpose/Objective(s)To present our early clinical experience with IG-IMRT for the treatment of single or multiple brain metastases using a SIB to visible tumor while delivering a prophylactic dose to WB with a single isocenter. To present our early clinical experience with IG-IMRT for the treatment of single or multiple brain metastases using a SIB to visible tumor while delivering a prophylactic dose to WB with a single isocenter. Materials/MethodsEight patients were treated from 7/07 through 1/08 using IG-IMRT to deliver a SIB to tumor (GTV + 3mm = PTV) with WBRT to a lower "prophylactic" dose. The median patient age was 55.5 (range, 40-71) years. Primary cancers included lung (4), melanoma, biliary, uterine, and unknown primary. The median KPS was 60 (range, 40-80). The mean number of metastases was 3.75 (range, 1-13). All patients had uncontrolled systemic disease at the time of simulation and 4 were given concurrent radiation therapy to extracranial sites. No patient received prior WBRT.The CT images were fused with pretreatment MRIs for inverse treatment planning on Pinnacle v7.4f. A standard Aquaplast mask was used for immobilization. Frameless IGRT with BrainLAB's ExacTrac with body markers for infrared tracking was used to monitor intrafraction motion. A non-coplanar, 5-field beam arrangement was delivered using a Siemen's Primus linac. Optic structures, parotids, inner ear, and scalp were optimized to minimize toxicity. Eight patients were treated from 7/07 through 1/08 using IG-IMRT to deliver a SIB to tumor (GTV + 3mm = PTV) with WBRT to a lower "prophylactic" dose. The median patient age was 55.5 (range, 40-71) years. Primary cancers included lung (4), melanoma, biliary, uterine, and unknown primary. The median KPS was 60 (range, 40-80). The mean number of metastases was 3.75 (range, 1-13). All patients had uncontrolled systemic disease at the time of simulation and 4 were given concurrent radiation therapy to extracranial sites. No patient received prior WBRT. The CT images were fused with pretreatment MRIs for inverse treatment planning on Pinnacle v7.4f. A standard Aquaplast mask was used for immobilization. Frameless IGRT with BrainLAB's ExacTrac with body markers for infrared tracking was used to monitor intrafraction motion. A non-coplanar, 5-field beam arrangement was delivered using a Siemen's Primus linac. Optic structures, parotids, inner ear, and scalp were optimized to minimize toxicity. ResultsAll treatments were delivered within a 30-minute treatment slot. The median total PTV was 20.3 (range, 10.1-169.3) cm3. The median prescribed dose to tumor PTV was 45 (range, 40-45) Gy, median dose to WB (excluding metastasis) was 30 (range, 25-36) Gy, delivered over a median of 15 fractions (range, 10-15). The median PTV coverages were a maximum of 105% and a minimum of 91%.Acute toxicities included 2 patients with Grade 2 (G2) fatigue and 1 patient with G2 alopecia. Common G1 toxicities were rash/dermatitis (7/8) and alopecia (8/8). There were no toxicities >G2. One patient had G2 limb weakness prior to treatment that improved to G1. Two patients had G2 aphasia prior to RT: 1 improved to G1 and another showed complete resolution.Five patients underwent posttreatment MRI at a median time of 112 (range, 45-194) days after the start of treatment. Local brain control was achieved in 16 of 17 total metastatic sites. One of 5 patients had new brain mets. Response rate was partial in 3 patients, complete in 1, and stable in another. No patients had brain necrosis. All treatments were delivered within a 30-minute treatment slot. The median total PTV was 20.3 (range, 10.1-169.3) cm3. The median prescribed dose to tumor PTV was 45 (range, 40-45) Gy, median dose to WB (excluding metastasis) was 30 (range, 25-36) Gy, delivered over a median of 15 fractions (range, 10-15). The median PTV coverages were a maximum of 105% and a minimum of 91%. Acute toxicities included 2 patients with Grade 2 (G2) fatigue and 1 patient with G2 alopecia. Common G1 toxicities were rash/dermatitis (7/8) and alopecia (8/8). There were no toxicities >G2. One patient had G2 limb weakness prior to treatment that improved to G1. Two patients had G2 aphasia prior to RT: 1 improved to G1 and another showed complete resolution. Five patients underwent posttreatment MRI at a median time of 112 (range, 45-194) days after the start of treatment. Local brain control was achieved in 16 of 17 total metastatic sites. One of 5 patients had new brain mets. Response rate was partial in 3 patients, complete in 1, and stable in another. No patients had brain necrosis. ConclusionsLow-dose "prophylactic" WBRT can be safely delivered with SIB to brain metastases with minimal toxicity and local control that is comparable to sequential WBRT and stereotactic radiosurgery (SRS). This technique is convenient, non-invasive, and may combine the benefits of WBRT and SRS into one procedure. We are currently accruing patients to further assess toxicity and tumor control using this approach. Low-dose "prophylactic" WBRT can be safely delivered with SIB to brain metastases with minimal toxicity and local control that is comparable to sequential WBRT and stereotactic radiosurgery (SRS). This technique is convenient, non-invasive, and may combine the benefits of WBRT and SRS into one procedure. We are currently accruing patients to further assess toxicity and tumor control using this approach.