3802 - A Prospective Study of FDG-PET based Simultaneous Integrated Boost for Node Positive Cervical Cancer
Presenter(s)
R. Mishra1, H. Mishra1, S. Singh2, A. Pandey3, P. Sen1, A. Mandal1, and S. Sachan1; 1Institute of Medical Sciences, Banaras Hindu University, Varanasi, India, Varanasi, India, 2Institute of Medical Sciences, Banaras Hindu University,, Varanasi, India, 3Department of Radiotherapy and Radiation Medicine, Banaras Hindu University, Varanasi, India
Purpose/Objective(s):: Volumetric arc therapy (VMAT) with Simultaneous Integrated Boost (SIB) allows radiotherapy dose escalation to involved nodes in cervical cancer. However, treatment related early and late toxicities remain a major concern with SIB. The incorporation of PET-CT in the cervical cancer leads to higher accuracy in the detection of pelvic and para-aortic lymph node metastases [1,2]. Aim of this study was to incorporate 18FDG PET-CT in planning SIB to the positive lymph nodes in pelvic and/or para-aortic regions in cervical cancer; also to evaluate the efficacy and toxicity of treatment.
Materials/Methods: Histologically proven cases of squamous cell carcinoma of cervix having Positron emission tomography (PET) positive pelvic/para-aortic nodes were included from September 2021 to July 2024. All patients were treated by VMAT with SIB technique to the dose of 50.4Gy to whole pelvis and 58.8Gy to PET positive nodes in 28 fractions followed by HDR brachytherapy boost of 7Gy in three fractions with Concurrent cisplatin at the dose of 40mg/m2 on weekly basis. Post treatment response was assessed by clinical examination and PET-CT/CECT scans at 3months.Statistical analysis was done on SPSS version 26.0.Kaplan Meyer analysis was done to evaluate survival. Log rank test was done to identify prognostic factors.
Results: A total of 45 patients were enrolled in the study. Median age was 55 years (range 35-70). The median tumor size was 5.3cm (range 2.1-9.5) with 86.7% patients having disease more than 4cm. Median Standardized uptake value(SUV) maximum in PET at primary tumor and LN was 15.1 and 7 respectively. Pelvic node only was seen in 29(64.4%) patients while Para-aortic node was involved in 16(35.6%).The parametrial involvement was seen in 33 patients, Median number of positive nodes were five with median volume being 11.5cc. At median follow-up of 30 months, 3-year OS was 67.2%. The factors adversely affecting the outcome (3-year OS) were tumor size>4cm(p=0.05), largest node size>2cm(p=0.04) and volume>5cc(p=0.06), median number of concurrent cisplatin <5cycles(p=0.03), EBRT duration>6weeks(p=0.07) and SUVmax in node>7(p=0.05).The most common acute toxicity was skin grade I(60%) ,hematological grade I(35.5%), followed by Gastro-intestinal grade II(33%) ,the highest grade reported was hematological grade III in two patients. Maximum grade of late toxicity in skin was grade I whereas grade II in gastrointestinal (17.7%), and genitourinary (4.4%).
Conclusion: VMAT with dose escalated SIB to involved nodes results in effective loco-regional control with acceptable toxicities. Further dose escalation/de-escalation depending on the node size can be attempted to improve outcome.