Emma C. Fields

Consensus Guidelines for Delineation of Clinical Target Volumes for Intensity Modulated Radiation Therapy for Intact Cervical Cancer: An Update

Accurate target delineation is essential when using intensity modulated radiation therapy for intact cervical cancer. In 2011, the Radiation Therapy Oncology Group published a consensus guideline using magnetic resonance imaging (MRI). The current project expands on the previous atlas by including computed tomography (CT)-based contours, contours with MRI and positron emission tomography (PET) registrations, the addition of common and complex scenarios, and incorporating information on simulation and treatment planning techniques. Twenty-eight experts in gynecologic radiation oncology contoured 3 cases, first on a noncontrast CT simulation scan and then with registered diagnostic scans. The cases included (1) International Federation of Gynecology and Obstetrics (FIGO) IIIC1 with a bulky tumor and vaginal metastasis, (2) FIGO IIB with calcified uterine fibromas, and (3) FIGO IIIC2 with large lymph nodes. The contours on all 6 data sets (3 CT simulations without diagnostic images and 3 with registered images) were analyzed for consistency of delineation using an expectation-maximization algorithm for simultaneous truth and performance level estimation with kappa statistics as a measure of agreement. The contours were reviewed, discussed, and edited in a group meeting prior to finalizing. Contours showed considerable agreement among experts in each of the cases, with kappa statistics from 0.67 to 0.72. For each case, diagnostic PET ± MRI was associated with an increase in volume. The largest increase was the clinical target volume (CTV) primary for case 2, with a 20% increase in volume and a 54% increase in simultaneous truth and performance level estimation volume, which may be due to variance in registration priorities. For the third case, 92.9% increased their CTVs based on the addition of the diagnostic PET scan. The main areas of variance were in determining the superior extent of CTV coverage, coverage of the mesorectum, and simulation and planning protocols. This study shows the value and the challenges of using coregistered diagnostic imaging, with an average increase in volumes when incorporating MRI and PET.

Tipping the Balance: Adding Resources for Cervical Cancer Brachytherapy

Utilizing a novel hybrid brachytherapy technique FINITO (Freehand Interstitial Needles in addition to Tandem and Ovoid) for locally advanced cervical cancer

We aimed to assess the clinical feasibility and advantages of using a novel hybrid brachytherapy technique by placing Freehand Interstitial Needles in addition to the Tandem and Ovoid applicator (FINITO) for the treatment of locally advanced cervical cancer (LAC). A retrospective analysis was performed on two cohorts of patients with LACC treated at our institution: 29 patients in the FINITO group and 17 patients in the control group using T&O only approach. Clinical outcomes of interest included local control (LC), progression-free survival (PFS), overall survival (OS), and rates of acute and late toxicities. Kaplan-Meier methodology was used to estimate OS, PFS, and LC. Wilcoxon signed-rank test was used to compare the median values for dosimetry parameters. A p-value of ≤ 0.05 was considered statistically significant. All statistical analyses were performed using RStudio. At a median of 2 years there was no difference in rates of OS, PFS or LC between the FINITO and the control group of patients. The 2-year OS, PFS, and LC for the FINITO group were 59% (95% CI 34%-100%), 58% (95% CI 38%-89%), and 84% (95% CI 69%-100%), respectively. Late toxicities were significantly lower in the FINITO group for both gastrointestinal and genitourinary symptoms (p = 0.001 and 0.01, respectively) as compared to the T&O group. Based on the equivalent LC rate and lower toxicity profile, our FINITO technique appears to be an excellent alternative to the standard intracavitary brachytherapy in patients with advanced disease, especially in resource-limited settings.