PV QA 4 - Poster Viewing Q&A 4
TU_25_3568 - Medically Inoperable Early-Stage Lung Cancer Treated with Stereotactic Ablative Radiation Therapy (SABR): Multicenter Study of Turkish Radiation Oncology Group (TROG)
Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3
Medically Inoperable Early-Stage Lung Cancer Treated with Stereotactic Ablative Radiation Therapy (SABR): Multicenter Study of Turkish Radiation Oncology Group (TROG)
B. Atalar1, E. Kaytan Saglam2, Z. Akgun3, U. Abacioglu4, A. Arifoglu5, B. Şahin1, E. Ozyar1, G. Yaprak6, N. Ozseker7, E. Kocak8, S. Karaman9, S. Igdem10, U. Selek11, H. F. Dincbas12, M. Sengoz1, S. B. Yucel1, A. N. Demiral13, and S. Akyurek14; 1Acibadem University, Department of Radiation Oncology, Istanbul, Turkey, 2Istanbul University, Institute of Oncology ; Memorial Şişli Hospital, Department of Radiation Oncology, Istanbul, Turkey, 3Memorial Şişli Hospital, Department of Radiation Oncology, İstanbul, Turkey, 4Acibadem Altunizade Hospital, İstanbul, Turkey, 5Acibadem Altunizade Hospital, Istanbul, Turkey, 6Kartal Lutfi Kirdar Research and Training Hospital, Department of Radiation Oncology, İstanbul, Turkey, 7Kartal Lutfi Kirdar Training and Research Hospital, istanbul, Turkey, 8Medipol University, Department of Radiation Oncology, Istanbul, Turkey, 9Istanbul University, Department of Radiation Oncology, Istanbul, Turkey, 10Istanbul Bilim University, Gayrettepe Florence Nightingale Hospital, Istanbul, Turkey, 11MD Anderson Radiation Oncology Outreach Center at American Hospital, Istanbul, Turkey, 12Cerrahpasa School of Medicine, Department of Radiation Oncology, Istanbul, Turkey, 13Dokuz Eylul University, Department of Radiation Oncology, Izmir, Turkey, 14Ankara University, Department of Radiation Oncology, Ankara, Turkey
To review treatment outcomes for SABR in medically inoperable early stage lung cancer (NSCLC) patients treated by Turkish Radiation Oncology Group (TROG) member centers.
Between 2009 and 2017, a total of 386 patients with NSCLC treated with SABR in 12 TROG centers. Patient, disease, and treatment related prognostic factors were analyzed. Primary endpoints were, overall survival (OS), progression free survival (PFS), local control (LC) and regional control (RC) and radiation-related toxicities.
Median follow-up was 15 months. The median age at diagnosis was 72 years (43-93) and 79% were men. Median tumor size was 30 mm (5 - 78 mm). Seventy-two percent of the patients have histologically confirmed diagnosis whereas 28% of patients were treated with clinical and radiological findings only without pathological diagnosis. Staging was as follows; T1N0 in 215, T2N0 in 166, T3N0 in 2 and T4N0 in 3 patients because of bilaterally tumors. Median SABR dose was 54Gy (30-70Gy), corresponding to a biological equivalent dose (BED) of 112Gy (48 - 180Gy) administered in median 5 (1-10) fractions. Response evaluation was made either with PET/CT or CT in median 3 months after SABR and complete response, partial response, stable disease and progression rates were 48%, 36%, 5.7% and 0.5%, respectively. The cumulative locoregional failure rate was 15%. Among these, 23 were local (6%) and 35 regional (9%) failures. Distant failure was reported in 67 (17%) patients. One to 3 years LC and RC rates were 97%, 91% and 93%, 86%, respectively. One and 3 years PFS and OS were 88%, 72% and 90%, 65%, respectively. At their last follow up 271 patients (71%) were alive. Prognostic factors associated with LC, RC and OS were summarized in table 1. No severe acute side effects were observed. Overall 18 patients experienced ≥ grade 3 pneumonitis, 11 patients had chest wall pain and 1 patient had rib fracture.
The results of this retrospective study have shown that SABR is a promising technique with satisfactory LC and OS rates and minimal toxicity in patients with medically inoperabl NSCLC. Table 1:
Prognostic factors affecting overall survival and recurrence
| || Univariate || Multivariate |
| Local Control @ 3 years |
| BED10 ≥90Gy || BED10 ≥90, 92% BED10 <90, %71 p=0.003 || HR:3.6, 95% CI (1.3-9.9) p=0.011 |
| Tumor Size (17mm) || ≤17mm, 100% >17mm, 89% p=0.035 || p=0.98 |
| Histology (Squamous/Adeno) || Adeno, 96% Squamous, 88% p=0.006 || HR:2.2, 95% CI (1.2-4.0) p=0.008 |
| PET/CT Response (Complete/Partial) || CR, 96% PR, 74% p<0.0001 || HR:3.5, 95% CI (1.6-7.5) p=0.002 |
| Regional Control @ 3 years |
| Tumor Size (30mm) || ≤30mm, 95.5% >30mm, 77.5% p=0.025 || HR:2.1, 95% CI (1.1-4.2) p=0.028 |
| PET/CT Response (Complete/Partial) || CR, 87% PR, 62% p<0.033 || p=0.06 |
| Overall Survival @ 3 years |
| Tumor Size (28mm) || ≤28mm, 69,6% >28mm, 59,8% p=0.009 || HR:1.6;95% CI (1-2.5) p=0.03 |
, Biological Effective Dose; HR
,Hazard Ratio; CR
, Complete Response; PR
, Partial response
Author Disclosure: B. Atalar: None. E. Kaytan Saglam: None. Z. Akgun: None. U. Abacioglu: None. A. Arifoglu: None. N. Ozseker: None. U. Selek: Member of Board of Directors; Turkish Society for Radiation Oncology, Turkish Society of Lung Cancer.