PD 15 - GYN 2 - Poster Discussion
1132 - Changes on Mid-Treatment FDG-PET/CT for Cervical Cancer Treated With Chemoradiotherapy Are Associated With Prognosis
Wednesday, October 24
11:36 AM - 11:42 AM
Location: Room 217 A/B
Changes on Mid-Treatment FDG-PET/CT for Cervical Cancer Treated With Chemoradiotherapy Are Associated With Prognosis
C. D. Jacobs, D. J. Carpenter, and J. P. Chino; Duke University Medical Center, Durham, NC
Purpose/Objective(s): To assess whether radiographic/metabolic changes on mid-chemoradiation (CRT) FDG-PET/CT for cervical cancer predict outcome.
Materials/Methods: Thirty women with FIGO stage IB1-IVB cervical cancer treated with concurrent cisplatin-based CRT and brachytherapy (BT) were prospectively enrolled between Feb 2012 and Jun 2016. FDG-PET/CT was obtained pre-CRT and ~3 weeks intra-CRT. Max and mean standard uptake values (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for the primary tumor and clinically involved lymph nodes (LN+) from the pre-CRT and intra-CRT FDG-PET/CT were recorded. Clinical endpoints analyzed include overall survival (OS), disease-free survival (DFS), and rates of cervical recurrence (CR), nodal recurrence (NR), and distant metastasis (DM). FDG-PET/CT variables and other prognostic factors associated with clinical endpoints were identified via univariate Cox proportional hazards modeling, with multivariate modeling performed for PET-derived variables where p<0.1.
Results: Median patient age was 41 (interquartile range 37-51), most common FIGO stage was IIB (40%), 24 (80%) women had pelvic LN+, 8 (27%) women had para-aortic LN+, and 2 (7%) had IVB disease due to supraclavicular LN+. Median dose to the elective volume, pelvic sidewall, and LN+ were 45 Gy, 55 Gy, and 65 Gy, respectively. Median BT dose was 27.5 Gy in 5 fractions. All received concurrent cisplatin and 3 women with small cell histology also received etoposide. After a median follow up of 22 months for living patients, 2 year rates of CR, NR, DM, DFS, and OS were 11% (95% confidence interval [CI] 0-22%), 21% (95% CI 4-38%), 45% (95% CI 25-65%), 44% (95% CI 26-63%), and 72% (95% CI 55-89%), respectively. While several PET metrics were associated with individual clinical endpoints, TLG was more consistently associated across endpoints on univariate analysis. Intra-CRT TLG was associated with NR (HR 1.40, 95% CI 1.09-1.76; p=0.016), DFS (HR 1.19, 95% CI 1.03-1.34; p=0.018), and OS (HR 1.33, 95% CI 1.13-1.54; p=0.002), with a trend for DM (HR 1.20, 95% CI 0.99-1.40; p=0.053). Relative change in TLG was associated with CR (p=0.021) and NR (p=0.035). Pre-CRT TLG was significantly associated with DM (HR 1.06, 95% CI 1.001-1.12; p=0.031), with a trend for DFS (HR 1.05, 95% CI 0.999-1.10; p=0.059) and OS (HR 1.06, 95% CI 0.98-1.12; p=0.057). On multivariate analysis, DFS was significantly associated with the difference in pre- to intra-CRT SUVmean (HR 3.00, 95% CI 1.09-12.7; p=0.031) with a trend for intra-CRT SUVmean (HR 2.11, 95% CI 0.90-4.92; p=0.064), while controlling for age, FIGO, grade, and LN+.
Conclusion: In this group of high-risk cervical cancer patients treated with CRT+BT, TLG on mid-treatment FDG-PET/CT was associated with recurrence and OS, while the difference in SUVmean between pre- and mid-CRT scans was independently associated with DFS. These metrics may provide an early signal for selective treatment intensification, with either dose escalation or adjuvant chemotherapy.
Author Disclosure: C.D. Jacobs: None. D.J. Carpenter: None. J.P. Chino: Partner; Duke University Cancer Center. Stock; NanoScint. Co-Founder/Owner; NanoScint.