323P The role of SUVmax in 18F-FDG PET/CT for assessing radiation therapy response for cervical cancer

Abstract

Background We assessed the relationship between primary tumor18F-fluorodeoxyglucose (FDG) uptake expressed as the maximum standardized uptake value (SUV max), primary tumor response, and survival in patients with cervical cancer on pretreatment and posttreatment positron emission tomography-computed tomography (PET-CT). Methods We conducted a retrospective review of 35 cervical cancer patients (stage I-II: n = 19; stage III-IV: n = 16) treated with radiation therapy with or without chemotherapy. All patients (median age, 58.5 years; range, 37~81 years) had FDG PET- CT scans performed before and after radiation therapy (pre- and post-RT). The SUV max were recorded from PET-CT scans performed pre-and post-RT. The correlation between SUV max and treatment response was evaluated and analyzed. Measurement of primary tumor volumes (pTV) for the treatment response evaluation was performed by the diagnostic radiologist using magnetic resonance imaging or abdominopelvic CT. Results The median duration of follow-up was 42 months (range 5-72 months). The median SUVmax of cervical cancer pre- and post-RT were 10.1 (range: 4.31~28.5) and 2.51 (range: 1.65~5.91), respectively. After treatment for cervical cancer, the reduction of SUVmax (median 7.4 (range: 0.05~25.85)) was significant (p < 0.001). There was a significant correlation between post-RT SUVmax and post-RT pTV (r=0.470, p=0.004). There was also a significant correlation between SUVmax reduction rate and pTV reduction rate (r=0.447, p=0.007). A significant correlation was observed between post-RT SUV max and the pTV reduction rate after RT (r=-0.534, p=0.001). Conclusions The SUVmax was significantly reduced after RT for cervical cancer. This study showed that the SUVmax after RT in patients with cervical cancer was significantly correlated with the primary tumor response. Legal entity responsible for the study Gachon University Gil Medical Center Funding Gachon University Gil Medical Center Disclosure All authors have declared no conflicts of interest.