ESTRO 2022 - Abstract Book

S1153

Abstract book

ESTRO 2022

progression 1.2 times higher than the patient with a lower value (HR 1.20; 95% CI 0.49–2.95, p = 0.700) (Figure 1). A statistically significant mean difference (p=0.012) was found for NLR between patients who had a complete response and those who did not.

Conclusion In our study, higher values of NLR were associated with a lower response to FSRT and higher probability of disease progression. Pre-treatment immune markers of systemic inflammation have been reported as independent prognostic factors; however, the landscape is multifaceted and further validation are needed to reach the clinic. NLR is an easily measurable, available, cost-effective parameter, useful in treatment response prediction with consequent therapeutic and follow-up strategy customization.

PO-1359 Cancer stem cell biomarkers SOX2 and Oct4 in cervical cancer patients undergoing radiotherapy

D. Chakrabarti 1 , S. Qayoom 2 , D. Kukreja 1 , M.M. Goel 2 , U. Singh 2 , M. Verma 1 , K. Srivastava 1 , M.L. Bhatt 1

1 King George's Medical University, Radiotherapy, Lucknow, India; 2 King George's Medical University, Pathology, Lucknow, India Purpose or Objective Cancer stem cells(CSCs) are a subpopulation of tumour cells that account for radioresistance. SRY(sex-determining region Y)-box 2(SOX2) and octamer-binding transcription factor 4(Oct4) are transcription factors that have been proposed as biomarkers to identify CSCs in cervical cancers. Data about their clinical implications are limited and contradictory. Materials and Methods This study included patients of cervical squamous cell carcinoma(FIGO stage IB2-IVA) who received definitive chemoradiotherapy(EBRT with concurrent cisplatin and intracavitary brachytherapy, ICBT) in the year 2017 and were on regular follow-up. Patient particulars were recorded. Tissue biopsy specimens were evaluated for SOX2 and Oct4 expression by immunohistochemistry, quantified by a combined score, product of proportion score(1-<10%positive tumour cells, 2-10- 50% cells, 3->50% cells) and intensity score (0-no staining,1-weak,2-moderate, 3-strong). Scores ≤ 4 were considered low expression, while ≥ 6 was high expression. Results 59 patients were included. Their baseline details were: median age 50 years, most commonly FIGO IIB(64%), moderately- differentiated(81%), keratinising(59%), with necrosis(37%), LVSI(12%), PNI(14%), and tumour infiltrating lymphocytes(TIL)(90%). Most patients (95%) had ≥ FIGO stage IIB disease. The common dose schedule was EBRT of 50Gy followed by 3 ICBT fractions of 7Gy each. The median(IQR) cycles of chemotherapy administered was 4(3–5). Acute reactions were: haematological-49%(Grade III-2%), gastrointestinal-41%(Grade III-3%), genitourinary-7%. Chronic reactions and vaginal stenosis were present in 17%. SOX2 expression(high:low 21:38 patients) and Oct4 expression(high:low 4:55 patients) had a