ESTRO 38 Abstract book

S467 ESTRO 38

Adenocarcinoma was the most frequent histological subtype, detected in 18 pts, undifferentiated in 3, squamous cells in 8; in 13 cases histological confirmation was not available and diagnosis was made on the evidence of pathological uptake recorded on PET scan. SBRT was performed with Helical Tomotherapy delivering 60-70 Gy in 8-10 fractions for peripheral lesions and 50-60 Gy in 10 fractions for central and ultra-central lesions. Acute and late toxicity assessment was conducted using CTCAE v4.0 scale; for the first year after RT, follow-up was based on quarterly chest CT scans and PET scans if needed. Any clinical correlation was evaluated with Fisher’s exact test and Kaplan-Meier method and log-rank test were performed for Local Control (LC) and Overall Survival (OS) estimates. Results Median CCI and G8 scores were 6 (4-11) and 14 (12-17). Median treatment time was 15 days (10-24), with 29 patients treated daily, and 13 every other day. BED10≥100Gy schedules were administered in 53% (n=22) of cases, for a median BED 10 =105 Gy (75-119). With a median follow-up of 14 months (3-37) we observed 3 cases of acute G2 radiation pneumonitis, resolved after steroids therapy. As regards late toxicity, we reported only one case of G2 non-cardiac chest pain and one case of G2 radiation pneumonitis treated with steroids. At statistical analysis, G8 scores≤14 were significantly associated with late toxicity rates (p=0.049), no other statistical correlation was found. At the time of the analysis, we detected 4 local failures resulting in 1- and 2-yrs LC rates of 91% and 86%. 12 patients out of 42 died, 6 for non- cancer related causes, resulting in 1- and 2-yrs OS rates of 93% and 80%. Conclusion In our experience the use of the G8 screening tool, for the pre-treatment evaluation of elderly patients candidate to SBRT for es-NSCLC, revealed a predictive power for late toxicity patterns, suggesting its implementation for a more tailored approach. PO-0886 Partial tumor irradiation exploiting immuno- mediated effects: tumor microenvironment as a new oar. S. Tubin 1 1 KABEG Klinikum- Landeskrankenhaus, Strahlentherapie und Radioonkologie, Klagenfurt, Austria Purpose or Objective In a pre-clinical phase of this translational oncology research, it was proved for the first time that the hypoxic tumor cells show higher potential for induction of the bystander (BE) and abscopal effects (AE) than the normoxic cells: single high-dose irradiation of the hypoxic tumor exclusively resulted in significantly stronger radiation-hypoxia-induced BE and AE . These finding were translated to a clinic. Since BE and AE are mediated by the immune-system cells, we hypothesized that high- dose partial tumor irradiation (PTI), targeting exclusively the hypoxic tumor segment, and leaving the tumor microenvironment intact, would generate an effective tumor-abscopal signaling and antigen release leading to immune-mediated regression of whole partially-irradiated tumor (due to BE) but also of unirradiated metastases (due to AE). Primary endpoint included BE and AE response rates. Secondary endpoints included assessment of toxicity, overall (OS) and disease-specific survival (DSS). Material and Methods Clinical study involved 32 patients whose bulky tumors of the lung, H&N, pancreas, kidney, skin and adrenal glands were partially irradiated. “Bystander Tumor Volume (BTV)” (hypoxic segment) was defined using PET-CT, as a Poster: Clinical track: Other

Conclusion A linear prediction model was built to predict 30-day mortality for palliative RT patients with advanced cancer. An AUC of 0.84 was obtained (0.15 higher than TEACHH) proving that the problem is well characterized by the features selected. This encourages us to prospectively validate the model with the hope that it can be informative in the physician/patient decision process.

Poster: Clinical track: Elderly

PO-0885 Comprehensive geriatric assessment tools for elderly patients with early NSCLC treated with SBRT F. Cuccia 1 , A. Donofrio 1 , V. Valenti 1 , A. Tripoli 1 , N. Luca 1 , A. Palmeri 1 , G. Terranova 1 , E. Quartuccio 1 , G. Napoli 1 , G. De Gregorio 1 , D. Cespuglio 2 , G. Mortellaro 2 , G. Ferrera 2 , A. Lo Casto 3 1 Radiation Oncology School - University of Palermo, Radiotherapy Department - ARNAS Civico Hospital, Palermo, Italy ; 2 ARNAS Civico Hospital, Radiotherapy Department, Palermo, Italy ; 3 Radiation Oncology School - University of Palermo, Section of Radiological Sciences - DIBIMED, Palermo, Italy Purpose or Objective The constant increase of life expectancy is associated to a higher incidence of cancer diagnosis in the elderly population. For aged patients with early stage Non Small Cell Lung Cancer (es-NSCLC), surgery is not often proposable, so Stereotactic Body Radiotherapy (SBRT) represents an attractive option for elderly subjects unfit or refusing resection, leading to a reduced percentage of untreated patients. In the effort to offer the best tailored approach to this subset of more vulnerable patients, several authors suggest the use of geriatric comprehensive assessment tools in order to facilitate a more customized treatment. Here we report our single-center experience of SBRT for es-NSCLC in ≥65 years patients, who were evaluated in the pre-treatment setting using G8 screening tool and Charlson Comorbidity Index (CCI). Material and Methods From March 2014 to June 2018 we retrospectively evaluated 42 patients ≥65-years with es-NSCLC who were assessed with G8 screening tool and CCI. Median age was 74 years (range, 65-91), 38 were stage I and 4 stage II.