Feasibility report of image guided stereotactic body radiotherapy (IG-SBRT) with tomotherapy for early stage medically inoperable lung cancer using extreme hypofractionation.
We report on the technical feasibility, dosimetric aspects, and daily image-guidance capability with megavoltage CT (MVCT) of stereotactic body radiotherapy (SBRT) using helical tomotherapy for medically inoperable T1/2 N0 M0 non-small cell lung cancer. Nine patients underwent treatment planning with 4D-CT in a double vacuum based immobilization system to minimize tumor motion and to define a lesion-specific 4D-motion envelope. Patients received 60 Gy in 5 fractions within 10 days to a PTV defined by a motion envelope plus a 6 mm expansion for microscopic extension and setup error using tomotherapy, with daily pretreatment MVCT image guidance. The primary endpoint was technical feasibility. Secondary endpoints were defining the acute and sub-acute toxicities and tumor response. Forty three of 45 fractions were successfully delivered, with an average delivery time of 22 minutes. MVCT provided excellent tumor visualization for daily image guidance. No significant tumor regression was observed on MVCT in any patient during therapy. Median mean normalized total doses were: tumor 117 Gy10; residual lung 9 Gy3. Maximum fraction-size equivalent dose values were: esophagus 5 Gy39; cord 7 Gy36. No patient experienced > or = grade 2 pulmonary toxicity. 3 complete, 4 partial and 2 stable responses were observed, with <3 months median follow-up. The mean tumor regression is 72%. SBRT using tomotherapy proved to be feasible, safe and free of major technical limitations or acute toxicities. Daily pretreatment MVCT imaging allows for precise daily tumor targeting with the patient in the actual treatment position, and therefore provides for precise image guidance.
Hodge
Wes
W
Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
Tomé
Wolfgang A
WA
Jaradat
Hazim A
HA
Orton
Nigel P
NP
Khuntia
Deepak
D
Traynor
Anne
A
Weigel
Tracey
T
Mehta
Minesh P
MP
D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D003131:Combined Modality Therapy; D019583:Dose Fractionation, Radiation; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010865:Pilot Projects; D016634:Radiosurgery / Q000379:methods*; D011878:Radiotherapy / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden / Q000528:radiation effects