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Investigation of Cervical Cancer Recurrence Indicators Based On Multi-Modality Image Information

R Meerschaert

R Meerschaert*, S Miller , L Zhuang , Wayne State University School of Medicine, Detroit, MI


SU-E-605-4 (Sunday, July 30, 2017) 1:00 PM - 1:55 PM Room: 605

Purpose: To identify indicators for treatment response in cervical cancer radiotherapy patients based on multi-modality image information.

Methods: This study included 37 biopsy proven cervical cancer patients (stage IB-IVA) treated with combined external beam radiotherapy (EBRT) and high-dose-rate brachytherapy. Pre-EBRT FDG-PET/CT, EBRT planning CT, and post-EBRT MRI were analyzed for each patient. Overall, 8 patients experienced significant weight fluctuations (SWF) throughout EBRT leading to physician-initiated re-planning and 30 patients demonstrated significant tumor shrinkage (STS) on post-EBRT MRI. The clinical tumor volume (CTV) on EBRT CT was propagated to PET/CT through image fusion where a standardized uptake value (SUV) map was generated. Additionally, a cumulative intensity-volume histogram (IVH) was generated from the SUV map to extract Iₓ (minimum uptake to x% highest uptake volume) and Vₓ (volume having at least x% uptake) metrics. The gross tumor volume (GTV) was generated by applying a 40% maximum threshold to the CTV SUV map. Parameters extracted from CTV/GTV SUV maps and CTV/GTV IVH metrics were investigated as recurrence indicators through independent t-tests. Comparing groups were defined for patients with and without SWF and with and without STS. Kaplan-Meier (KM) curves were generated for comparing groups based on recurrence-free proportions and compared through Cox regression. Time of event was measured from final treatment to follow-up exam where recurrence occurred or patient was censored.

Results: At follow-up (median 12 months), 10 patients had recurrence. Compared to patients with SWF, patients without SWF had lower recurrence risk (p=0.025). Compared to patients with STS, patients without STS had higher recurrence risk (p=0.032). CTV SUV map minimum (p=0.004), in addition to I₁₀ (p=0.013), I₉₀ (p=0.007), and I₁₀-I₉₀ (p=0.014) from GTV IVH were found to be significant recurrence indicators.

Conclusion: The preliminary results from this study suggest information collected prior to, during, and post radiotherapy may indicate recurrence risk.

Funding Support, Disclosures, and Conflict of Interest: Funding Support: AAPM Graduate Fellowship

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