Abstract book - ESTRO meets Asia

S21 ESTRO meets Asia 2018

II(54.4%) disease with clinical T2(31.5%), N0(42.5%) or pathological T2(54.3%), N0(58.8%) disease.Most (97.9%) of them had invasive ductal carcinoma. Most (98.4%) underwent surgery, mostly modified radical mastectomy (83.5%), and the rest underwent BCS (16.5%). Chemotherapy was received by 93% of them, mainly as adjuvant (70%) and only 30% got neoadjuvant chemotherapy.70.2% received both anthracycline and taxane based regimen and 24.4% received only anthracycline based chemotherapy. Pathological complete response rates in breast only and both breast and axilla were 31% and 22.6%, respectively.Adjuvant radiotherapy(RT) was indicated in 75% of them.Of these,88.8% received RT(one fourth with hypo fractionated regimen and the rest with conventional regimen). One fifth of the patients relapsed (21.3%), mainly at distant sites (74%), and the single most common site was brain(30%).The LRR for 4 years was 18% .The 3 yr OS for the study group was 84.1%(SE=1.4%) and the 3 yr DFS was 79.5%(SE=1.6%).The median time to relapse and the time from relapse to death was 20 and 6 months, respectively. Univariate analysis showed that advanced tumor stage, nodal stage and composite stages, neoadjuvant chemotherapy, use of anthracycline alone based regimen, not achieving a pathological complete response (breast alone or both breast and axilla) to neoadjuvant chemotherapy, not receiving adjuvant radiotherapy and first relapse as brain metastases, were associated with poor survival outcomes.In multivariate analysis, only T4 and N3 cancers showed poor survival and the use of anthracycline and taxane based regimen was associated with better survival. Conclusion TNBC has higher chance for distant visceral relapses, at shorter time intervals after treatment and a more aggressive course following relapse than other breast cancer subtypes. The survival rates for TNBC in this study are comparable to reported rates in literature. Longer follow up is required to further assess patterns of failure. OC-053 A prognostic model for non-lung-cancer death in old patients treated with SBRT for lung cancer Y. Matsuo 1 , T. Mitsuyoshi 1 , T. Shintani 1 , T. Mizowaki 1 1 Kyoto University- Graduate School of Medicine, Department of Radiation Oncology and Image- applied Therapy, Kyoto, Japan Purpose or Objective Stereotactic body radiotherapy (SBRT) is an important treatment option for early-stage non-small-cell lung cancer (NSCLC). Non-lung-cancer (non-LC) death becomes an issue in old patients after such an effective treatment. The objective was to create a prognostic model of non-LC deaths in old patients who received SBRT. Material and Methods Patients who met the following criteria were enrolled into the present study: (1) 65 years or older, (2) SBRT done for early-stage NSCLC during 1998 and 2015, and (3) pre- treatment body mass index (BMI) available. Non-LC death was defined as death of other causes than lung cancer, or death of unknown causes without any evidence of lung cancer recurrence. Incidence of non-LC death was estimated using the cumulative incidence function considering a competing risk of lung cancer death. Age, sex, performance status (PS), BMI, Charlson comorbidity index (CCI), tumor diameter, and histology were evaluated as potential prognostic factors for non-LC death. Results We identified 353 patients eligible to the study with a median potential follow-up period of 6.5 years. The study cohort consisted of 259 males and 94 females with a median age of 78 years (range, 65–93). Pre-treatment PS

was 0, 1, 2 and 3 in 166, 154, 29 and 4 patients, respectively. Most of the patients were treated with 48 Gy in 4 fractions for peripheral tumors (n = 234), and 60 Gy in 8 fractions for central tumors (n = 39). The median survival was 4.5 years (95% confidence interval [CI], 3.7–5.1 years). At the time of data cut-off, 120 and 80 patients died of lung cancer and non-LC causes, respectively. The non-LC causes included 32 respiratory failure, 12 other malignancies, 9 cardiac failure, 6 cerebral stroke, 8 other causes, and 13 unknown causes. Multivariate regression analysis revealed that age, PS, BMI and CCI contributed to non-LC death. Based on coefficients in the regression model, the following scores were assigned: age≥75 years, 1.5 points; PS≥2, 1.5 points; BMI≤18.4 kg/m 2 , 1.0 point; and CCI of 1–2 and ≥3, 2.5 and 3.0 points, respectively. The patients were stratified into the following 3 risk groups of non-LC death according to sum of the scores: 0– 3.0 points, low risk (n = 113); 3.5–4.0 points, moderate risk (n = 130); and 4.5–7.0 points, high risk (n = 110). Cumulative incidence of non-LC death at 5 years (95% CI) were 6.8% (2.7–13.5%), 23.1% (15.8–31.3%) and 40.2% (29.4–50.8%) in the low, moderate and high-risk groups, respectively (P<0.001, Figure). Whereas, cumulative incidence of lung-cancer death was not significantly different between the groups (29.6%, 37.5% and 27.5% at 5 years, respectively; P=0.421).

Conclusion A prognostic model based on age, PS, BMI and CCI for non- LC deaths in old patients treated with SBRT for NSCLC was proposed. Future studies to validate the prognostic model are warranted. OC-054 Improving lung cancer outcome by reducing normal lung tissue toxicity L. Giuranno 1 , C. Wansleeben 1 , L. Barbeau 1 , M. Vooijs 1 1 Maastricht Radiation Oncology MAASTRO, Radiotherapy, Maastricht, The Netherlands Purpose or Objective Lung cancer is the leading cause of cancer death in western countries. The current standard of care includes surgery , chemotherapy and radiotherapy. While significant progress has been made in terms of treatment modality radiotherapy is limited by dose-limiting side-effects which negatively affect tumour control and patient's quality of life. Reducing side-effects may improve tumor control by dose-escalation and treatment-time. The Notch signaling pathway plays an important role in lung cell differentiation and regeneration of the airway epithelium Abstract withdrawn