PD-111 Predicting the risk of symptomatic radiation pneumonitis by clinical and dosimetric parameter in lung cancer patients treated with 3-D conformal radiation therapy

Poster Discussions / Radio therapy

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QOL assessment tools and correlation with serum markers for normal tissue injury

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clinical Implementstlon of respiratory gated Intensity modulated radiotherapy

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Patterns of local/regional failure after high dose radiation In petlente with Inoperable/unresblctable non-small cell lung cancer

E Kong ~. I. Chetty I . P Crenin 2. C. Mam 2. D. TalzoI . J. Hayman I . R. Ten

Haken ~ l Departmant of Radiation Oncotogy,, University or Michigan, Ann Arl,~r Mtch/gan, USA: 2Department ct Radiology, Untversity of Mtch/gan, USA

P Keall. S Vedam. R George. J Siebers. l- Chung Department ~Raclat]on

Oncdogy, Virginia Commonwaalth University, Richmond, Virginia, USA Background: The clinical use of respiratory gated raclethorapy and the applieatlon of intensity modulated racicthorapy (IMRT) to lung cancer are two relatively new modal~es Respiratory gating can reduce the deleterious effects of intrafractlen motion, and IMRT can concurrently increase tumor dose homogeneity and reduce dose to critical StTUctUreS including the lungs. spinal cord. esophagus and heart The aim of this work is to describe the implementation and in~]al clirlcal results from combining these two modalitles for the b-eatment of non small call lung cancar. Methods: Quality assurance procedures were created to quantify beth the dos~me1~e and positional accuracy of respiratory gated IMRT. Treatment planning procedures for respiratory gated IMRT. including the GTV CTV and CTVPTV margins were standardized, and beam arrangements and dose volume constraints wore consb-ucted. Both rim doslmetry and Monte Cado dose calculation techniques were developed for vedficatlen and validation of individual patient tTeatments Result,=: The dosimetTic (<1%) and positional (<2 mm) quality assurance tests indicated that respiratory gated IMRT could be delivered accurately With respiratory gating. 11 mm CTV4~TV margins were reduced to 8 mm As the delivery efficiency for beth respiratory gating and IMRT is less than conventional thoracic radiotherapy, the treatment time increases by 2 ,5 minutes per patient Respiratory gated IMRT is accepted by b-eatment staff and patients alike. To date over 25 patients have been treated vath this modality at our instltut]en. The initial clinical results are positrve, particularly for smaller tumors, with several complete responses and no untoward texic~os. Conclusions: When carefully implemented, respiratory gated IMRT is a practical altematrve to conventional therac~e radiotherapy. For mobile tumors. respiratory gated radiotherapy is used as the standard of care at our instraJt]on. Due to the increased workload, the choice of IMRT is tal~en on a case4)ycase basis, with approximately half of the non-small call lung cancer patients receiving respiratory gated IMRT We are currently avaluatlng whether superior tumor coverage and limited normal tissue dosing will lead to improvements in local contToI and survival in non-small cell lung cancer

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Predicting me risk of symptomatic radiation pneumonltls by clinical and doslmstdc parameter In lung cancer patients treated with 3-D conformal redlstlon therapy

Y. Kim ~. J. Park 2, J. Kang ~. Y. Kim I . J. Song2 . S. Lee2, H. Yoon2, S. Yoon~. S Chung ~. M Ryu ~ 1Catholic University or Korea, KangqVarn St Mary's

Hosptal, Seoul, South Korea: 2 Cathet/c Umvereity of Korea, St. Mary's Hosptal, Saoul, Korea Background: To identify factors that may predict for symptomatic raclation pneumonltis (RP). we reb-ospeotlvely reviewed clinical charaoterlstlos and DVH data of 104 patients of lung cancer. Methods: Medical records and DVH data of 104 lung cancer patients treated with curative raclatlon from August 2002 to July 2004 at St Mary's Hospital were analyzed All included patients were new diagnosed lung cancer with any of histology tTeated with ouratJve intent 34) cenformal RT ± chemotherapy. without evidence of distant metastasis and minimum follow-up duration was more than 6 months We analyzed the correlatlen with symptomatic RP and potential predctive factors (age. gender. Pistology. stage, pulmonary function variables, performance status, underlying lung disease, proportion of interstitial change in chest CT before R].. tumor Iocatlen. chemotherapy or not. chemotherapy regimen or timing, total radation dose. radation field size. fraction size. V10. V20. V30. V40. mean lung dose). Unlvarlate and multlvanate analysis were performed to assess the relation with RE Results: With the meclan FJ,,I of 13 months. RTOG grade 3 or higher RP was observed in 1,5 patients (14.4%). Among them ,5 patients were dead (grade ,5 RP) In the unlvadate analysis. FEVl <0 8. L. poor performance status, the propo~on of interstitial change in chest CT before RT. V40 or higher and mean lung dose were associated with grade 3 or higher RP (p range 0 05 0 001) Using multivanata analysis, the proportion of interst~al change in chest CT before RT. V40 or higher were significant risk factors (p 0 001. p 0 003) Neither other RT related factor nor combined chemotherapy were not predictor of RP Conclusions: Our data suggest that reducing high dose volume could reduce RP than corresponding reduction of low dose region in DVH. Diff~Jseinterst~]al disease significant impacted on RP occurrenca. Hopefully. future stuclos v~ll better identify nsk factor for RP and could select patients for better therapeutic ratio.

Purpose: To study the pattern of local failure for patients with non-small call lung cancer (NSCLC) treated with cenformal therapy Methods: TPis study included patients who failed locally and a matched group without failures after 3-D conformal radatlon per a radiation dose escalation thai. Radiation doses ranged from 65.1 to 102.9Gy in 2.1Gy fractions, originally computed using an equivalent path length algorithm. The recurrent gross target volumes (RGTV) were contoured. The original and recurrent planning target volume (PTV and RPTV) were generated by 1 crn uniform expansion from GTV. DMHs and generalized equivalent uniform doses (EUD {E I(dl)a}~la) were computed Marginal failures were defined for RGTVs covered by the original 10% to 90% isodose surfaces Results: There wore no significant differences between the failed and control groups with regard to average onginal GTV volumes. GTV and PTV doses. and minimum PTV doses. Of the 15 RGTVs. ,5 had marginal failure. 9 mostly within and one outside of the original PTV. The average EUDs were 60+30Gy and 49 +31Gy. for the RGTVs and RPTVs respectively, significantly below the prescribed doses (p = 0.03). EUDs were less than 66 Gy for 40% of the RGTVs and 60% of the RP]Vs. The RG]Vs were not encompassed by the original 90% isodose surfaces in 7 of the 15 cases The EUDs for these seven cases were only within 1%-63% of those for the odginal P1-Vs When the doses were recalculated using the Monte Cede algorithm, additional 10 20% dose reductions were found for patients who failed after high dose radiation Conclusions: Inadequate dose. marginal target misses, under-dosage from inaccurate dose caloulatlon and tumor motion are all likely to contribute to local failure after 3~3 conformal radiation therapy In add~on to dose escalation, further clinical thals should focus on margin definition accurate dose calculation, and motion compensation to improve the tumor control in NSCLC.

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Redlosurgery and fractionated stereotactlc radiotherapy In the treatment of patients with brain metastases from non small cell lung carolnorna

C. Mantovani ~. G. Bellzamo~. S. Zeme 2. R. Ragena ~. C. Fiandra ~. U. Rlcarcl I .

1D U Radiofarapta ospedale San Giovanni Batt]sta di Torino, Torino, Italy, 2Neuroc~turg/a ospedale San G/ovanm Ba~sta dt Tonno, Tonno, Italy Purpose: We prospectively analyzed the feasibility, toxicity and efficao/" of Radiosurgery (SRS) and Fractionated Stereota~c Radiotherapy (FSRT) in the tTeatment of patients with brain metastases from non small call lung carcinoma (NSCLC) and evaluated factors affecting tumor local control and long term patient survival Methods and material: From April 1998 to December 2004. 79 patients (58 male. 21 female; mean age 60; squamous (:ell carcinoma in 63 patients. adencoarclnoma in 10 patients, large cell carcinorna in 5 and mixed call carcinoma in one patient; RPA class I: 28 patients. RPA clams I1: 51patients) with 92 lesions underwent Stereotactic Radiotherapy at our Institution. Eligibility criteria for Stereotactlc Radiotherapy were: 1) Age > 18 years. 2) Karnofsk'y Performance Score >80.3) 1-3 brain metastases on MRI. 4) lesion diameter <3,5 cm According to Institute guidelines patients with radiograpPically welldefined lesions measuring 1 ,5 cm or less were candidates to SRS. while lesions adjacent to critical structure or with diameter >1 5 cm underwent FSRT We applied image fusion CT-RM technique for tTeatment planning in brain metastases when necessary for a better target definition SRS was delivered to 35 lesions, with a median dose of 18Gy (Range 16 24Gy) using an invasive storeetactic frame: 48. patients underwent FSRT with a meclan dose of 24Gy (Range 16-36 Gy) given in three fract]ens. Local tumor control was defined as no increase in the tumor's maximal clameter on axial plane imagos on MRI. Results: Meclan follow up period was 10 months in the SRS group and 13.5 months in the FSRT group. Actuarial 1year local conb'ol rate was 72% in the SRS group and 69% in the FSRT group. Median survival time was 630 days in the SRS group and 390 days in the FSRT group. All b'eatments wore well tolerated and no acute complications were soon. Mull~vadate analysis revealed that age and Karnofsk'y Performance Score are statistleally significant predictor of local tumor control Conclusions: Overall high local control and low morbility rates suggest that FSRT and SRS are an effective and safe modality in selected patients affected by NSCLC with brain metastases