Intensity-modulated Radiotherapy For Definitive Treatment Of Cervical Cancer

Part1. Establishment of Intensity-modulated radiotherapy for the definitive treatment of cervical cancerObjectives:To establish the methods of intensity-modulated radiotherapy for the definitive treatment of cenvical cancer and taget volume delineation.To compare the dose of organs at risk recieved between conventional four fields whole pelvis radiotherapy(4F-WPRT) plan and intensity-modulated WPRT(IM-WPRT) planMarerials and methods:Between2009and2011,10patients with stage IIA-IIIB cervical cancer were selected for the dosimetric study.Delineated the GTV, CTV of cervical cancer and compared the treatment plan for IM-WPRT and4F-WPRT. Dose-volume histograms for target and OAR were compared for each patient with paried t-tests. Compared the volume of cervix and uterine between fist CT and second CT after radiotherapy of40-45Gy with15patients who needed boost9-14.4Gy to local tumor with IMRT.Results:There was no significant difference between the planning of7—field and9—field of IMRT,5—feield is little inferior. Intensity—modulated radiotherapy (IMRT) was associated with a significant reduction in the dose of OAR at the V40, V45. The reduction of GTV and CTV after40-45Gy radiotherapy was40%and25%, respectively.A new boost planning of IMRT is necessaryConlusions:IMRT of whole pelvic and boost leads to a reduction in the dose to OAR without compromising target coverage. Part2. The application of FDG Positron Emission Tomography in intesity-modulated radiotherapy of cervical cancerObjectives:To evaluate the role of positron emission tomography (PET) using F-18-fluorodeoxyglucose(FDG) in diagonsis and treatment optimazation in cervical cancer.Marerials and methods:Between2010and2011,25newly diagnosed patients with locally advanced cervical cancer were performed PET/CT scans prior to treatment in our institute. PET/CT were repeated in15patients after radiotherapy. The maximum diameter and SUVmax for the most FDG-avid pelvic lymph nodes(SUVpln) and SUVmax of the primary cervical tumor(SUVcervix) were recorded definitely.Results:All primary tumors of cervix were diagnosed with FDG-PET/CT and the mean SUVcervix was11. Nine patients were found with pelvic lymph node metastasis and the mean SUVpln was3.8, in whom3patients presented with synchronous para-aortic lymph node metastasis.24patients were received PET-guided target delineration of GTV and21patients revised target.15patients diminished the volume of GTV while other6patients had enlarged volume of GTV. The GTV-CT was associated with significanly larger mean volume compared with GTV-PET/CT (P=0.04), with the mean volume of280.4±131.2cc and259.7±96.2cc, respectively.Conlusions:PET-CT has advantage in the dignosis and treatment optimization of cervical cancer, especially in the target delineation when patients reveived radiotherapy. Part3. Clinical outcomes of intesity-modulated radiation therapy for patients with locally advanced cervical cancerObsectives:Concurrent chemoradiotherapy (CCRT) is the mainstay treatment for locally advanced cervical cancer. The purpose of this study was to investigate the treatment outcome and toxicity of definitive intensity-modulated radiotherapy(IMRT) with concurrent chemotherapy for patients with locaaly advanced cervical cancer.Marerials and methods:Between november2009and october2011,57patients with stage IB2-ⅢB cervical cancer treated with IMRT and concurrent chemotherapy were evaluated in our institute. PET guide or MRI guide with IMRT plans were designed to deliver40-45Gy in1.8Gy daily fractions to the planning target volume wile minimizing dose to the bowel, bladder, and rectum and with IMRT boost of9-14.4Gy. High dose rate brachytherapy of20—31.3Gy was prescribed to point A as a local boost. The endpoints were overall survival(OS) and disease free survival(DFS).Patients were assessed for acute toxicitie according to the National Cancer Instituts Common toxicity for Adverse Events, version3.0. All late toxicities were scored with Radiation Therapy Oncology Group late toxicity score.Results:The median follow up time was13.5months (5—28months). The1-year OS and DFS were98.2%and84.2%, respectively. One (1.8%) patient developed grade3acute gastrointestinal (GI) and15(26.3%) patients developed grade3or greater hemotological toxicity.One (1.8%) patient developed grade3chronic GI toxicity and no patients developed grade3or greater acute or chronic genitourinary system toxicity.Conlusions:The use of IMRT concurrent with chemotherapy showed favorable outcomes in the treatment of patients with locally advanced cervical cancer, with low rate of acute and late toxicities.