Abstract Book

S781

ESTRO 37

1 Tri-Service General Hospital, radiation oncology, Taipei, Taiwan Purpose or Objective To evaluate i) the effectiveness of transarterial chemoembolization (TACE) and stereotactic body radiotherapy (SBRT) in patients with medium-sized hepatocellular carcinoma (HCC) and ii) the post-therapy survival of these patients. Material and Methods We enrolled patients who were diagnosed with HCC, with tumours sized 3–8 cm, and were receiving primary treatment with TACE or SBRT in Tri Service General Hospital (Taipei, Taiwan). The diagnosis of HCC was based on histological data or on radiological criteria. Those who underwent prior radiotherapy to the liver were excluded. The date of enrolment was defined as the date when the patient received primary treatment (TACE or SBRT). The endpoints of the study were overall survival (OS) and infield failure-free survival (IFFS). OS was defined as the number of months from the start of primary therapy to the last follow-up day. IFFS was defined as the number of months from the start of primary therapy to the date of infield failure or the last follow-up day. Kaplan–Meier and Cox regression analyses were used to evaluate the prognostic factors of HCC and correct for confounding factors. Results There were 49 patients in the SBRT group and 27 patients in the TACE group. Compared to the SBRT arm, patients in the TACE group presented with smaller tumour sizes, and less advanced American Joint Committee on Cancer (AJCC) and Barcelona Clinic Liver Cancer (BCLC) stages. The 2-year IFFS rates of the SBRT and TACE groups were 82.7% and 70.6%, respectively. The 5-year IFFS rates of the SBRT and TACE groups were 81.0% and 67.9% (p = 0.246), respectively. There were no statistically significant factors associated with the IFFS rate.

Results Fifty-six patients with invasive cancer, 23 patients (41.1%) achieved pCR and 33 patients had non-pCR (58.9%) following preoperative CRT. The average age was 62 years (±9.1), and most patients were males (83.9%). Histological types included squamous cell carcinoma (75%) and adenocarcinoma (25%). The total radiation dose was 45 Gy in 76.8% of the patients and 50.4 Gy in 23.2%. The median overall survival (OS) of the entire group was 3.5 years ±1.2, and the 5-year OS rate was 38%, while the median disease-free survival (DFS) was 2.1 years ±0.4 and the 5-year DFS rate was 33%. The patients who achieved pCR had significantly higher 5-year OS and 5-year DFS rates; 47% and 48% compared to 27% and 21% for the non- pCR patients respectively (P=0.4, 0.4). The median time of local recurrence was 11.01 months ±3.1 in pCR group and 9.4 months ±1.1 in non-pCR group (P=0.1), while the median time of distant metastases in pCR group was 12.6 months ±5.5 and 12.1 months ±1.9 in non-pCR group (P=0.6).

Conclusion Complete pathological response predicts significantly higher rates of OS and DFS in patients with esophageal cancer treated with neoadjuvant chemoradiotherapy followed by surgery. EP-1437 Comparison of stereotactic radiotherapy and transarterial embolization for hepatocellular carcinoma P.C. Shen 1 , W.Y. Huang 1 , C.H. Lo 1 , J.F. Yang 1 , C.S. Lin 1 , H.L. Chao 1

The 2-year OS rates of the SBRT and TACE groups were 66.5% and 68.2%, respectively. The 5-year OS rates of the SBRT and TACE groups were 18.7% and 16.2% (p = 0.852), respectively. Upon univariate analysis, tumour size (hazard ratio [HR] = 1.85, p = 0.046 for >5 cm vs. ≤5 cm), AJCC stage (HR = 2.56, p = 0.003 for stage IIIA/IV vs. stage I/II), BCLC stage (HR = 2.62, p = 0.002 for BCLC >2 vs. ≤2), and Eastern Cooperative Oncology Group (ECOG)