Jennifer Croke

A prospective study of DWI, DCE-MRI and FDG PET imaging for target delineation in brachytherapy for cervical cancer.

BACKGROUND AND PURPOSEnWe examined the utility of dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted MRI (DWI), and FDG-PET imaging for brachytherapy target delineation in patients with locally advanced cervical cancer.nnnMATERIALS AND METHODSnTwenty-two patients had DWI, DCE-MRI, and FDG-PET/CT scans after brachytherapy applicator insertion, in addition to standard T2-weighted (T2w) 3T MRI. Gross tumor volume (GTVB) and high-risk clinical target volume (HRCTV) were contoured first on T2w images, and then modified if indicated upon review of DWI/DCE-MRI/FDG-PET images by two observers. The primary endpoint was utility, determined by the number of patients whose volumes were modified, and interobserver variability.nnnRESULTSnEleven patients T2w-GTVB were modified based on DWI/DCE-MRI/FDG-PET by observer 1, due to clearer demarcation (7) and residual disease not well visualized on T2w MRI (4). GTVB was modified in 17 patients by observer 2 (11 and 6, respectively). Incorporation of functional imaging improved the conformity index (CI) for GTVB from 0.54 (T2w alone) to 0.65 (P=0.003). HRCTV was modified in 3 and 8 patients by observers 1 and 2, respectively, with a trend toward higher CI using functional imaging (0.71 to 0.76, P=0.06).nnnCONCLUSIONSnDWI/DCE-MRI/FDG-PET imaging as a supplement to T2w MRI decreased interobserver variability in GTVB delineation.

Intermediate dose–volume parameters and the development of late rectal toxicity after MRI-guided brachytherapy for locally advanced cervix cancer

PURPOSEnThe dose delivered to the most exposed 2xa0cm3 [Formula: see text] of the rectum and bladder is predictive of late rectal and bladder toxicity in cervix cancer patients. We investigated the predictive value of intermediate doses to the rectum and bladder for late rectal/bladder toxicity after MRI-guided brachytherapy for patients with locally advanced cervix cancer.nnnMETHODS AND MATERIALSnToxicity was prospectively graded using Common Toxicity Criteria for Adverse Events v4.0 and retrospectively verified for women with Stage IB-IVA cervix cancer treated consecutively with MRI-guided brachytherapy between 2008 and 2013. The minimum equivalent dose in 2 Gy fractions delivered to 0.1, 1, 2, 5, and 10xa0cm3 of the rectum and bladder and the absolute volume of the rectum receiving 55, 60, 65, 70, and 75 Gy3 (V55-75) were collected. The association between dose-volume parameters and Grade 2+xa0rectal/bladder toxicity was examined using logistic regression.nnnRESULTSnWith a median followup of 44xa0months, cumulative incidences of Grade 2+xa0rectal and bladder toxicity among the 106 patients were 29% and 15% at 3xa0years, respectively. All the dose-volume parameters were significantly associated with late Grade 2+xa0rectal and bladder toxicity (pxa0<xa00.05), except for bladder [Formula: see text] . On multivariable logistic regression, both [Formula: see text] xa0>xa070 Gy3 and V55xa0>xa011xa0cm3 (pxa0<xa00.05) were predictive of late Grade 2+xa0rectal toxicity, with improved model fitting and higher area under the curve compared with the model with [Formula: see text] xa0>xa070 Gy3 alone.nnnCONCLUSIONSnIn this study, V55 was predictive of late Grade 2+xa0rectal toxicity. Adding V55 toxa0 [Formula: see text] improved prediction accuracy.

Radiation Therapy Quality of Care Indicators for Locally Advanced Cervical Cancer: A Consensus Guideline

PURPOSEnRadiation therapy plays an important curative role for patients with locally advanced cervical cancer (LACC). There are no standards to define best practice. The purpose of this study was to develop a suite of radiation therapy key quality-of-care indicators (KQIs) for the curative management of LACC based on expert consensus.nnnMETHODS AND MATERIALSnA modified Delphi method was used after identifying candidate KQIs. Round 1 involved surveying all Canadian gynecology radiation oncologists. The current and anticipated future (5 years) importance and current achievability of each KQI was ranked. Round 2 consisted of a facilitated face-to-face meeting with a smaller expert panel to discuss, revise, and develop consensus on the KQIs.nnnRESULTSnThe literature review identified 83 candidate KQIs. Survey response was 71%. Round 2 yielded a final suite of 40 KQIs in the following categories: pretreatment assessment, external beam radiation therapy, brachytherapy, follow-up, and expertise/workload. A prominent theme was the importance of having KQIs to measure the current state, evolution, and future uptake of magnetic resonance-guided brachytherapy.nnnCONCLUSIONSnTo our knowledge, this is the first study establishing radiation therapy KQIs in LACC based on expert consensus. These KQIs should be used to guide programmatic direction and resource allocation to assure consistent and optimal patient care.

Comparison of dosimetric parameters derived from whole organ and wall contours for bladder and rectum in cervical cancer patients treated with intracavitary and interstitial brachytherapy

For volumes up to 2u202fcm3 of the bladder and possibly up to 5u202fcm3 of the rectum, doses computed from the whole organ were good estimates of the doses in the wall in cervix brachytherapy, and there were no significant differences between patients treated with or without interstitial needles.

Circulating Human Papillomavirus DNA as a Biomarker of Response in Patients With Locally Advanced Cervical Cancer Treated With Definitive Chemoradiation

PurposeTo determine whether plasma human papillomavirus (HPV) DNA predates clinical recurrence and compare its accuracy with 3-month fluorodeoxyglucose positron emission tomography (FDG-PET) in locally advanced cervical cancer.MethodsThis prospective multicenter study accrued 23 women with stage IB to IVA cervical cancer planned for definitive chemoradiation therapy (CRT). Plasma HPV DNA was measured serially by digital polymerase chain reaction, and FDG-PET was performed at 3 months post-CRT.ResultsOf the 19 women with HPV+ cervical cancer included in this analysis, 32% were stage IB, 58% IIB, and 10% IIIB/IVA. Median follow-up was 24 months (range, 18 to 30 months). All patients had detectable plasma HPV DNA before treatment. Six patients had detectable plasma HPV DNA at the end of CRT, and three of them developed metastases at 3 months. Of the 13 patients with undetectable plasma HPV DNA at end of CRT, to date, only one has developed recurrence. Six of those 13 patients had a positive 3-month FDG-PET w...

Technique adaptation, strategic replanning, and team learning during implementation of MR-guided brachytherapy for cervical cancer

PURPOSEnMR-guided brachytherapy (MRgBT) with interstitial needles is associated with improved outcomes in cervical cancer patients. However, there are implementation barriers, including magnetic resonance (MR) access, practitioner familiarity/comfort, and efficiency. This study explores a graded MRgBT implementation strategy that included the adaptive use of needles, strategic use of MR imaging/planning, and team learning.nnnMETHODS AND MATERIALSnTwenty patients with cervical cancer were treated with high-dose-rate MRgBT (28xa0Gy in four fractions, two insertions, daily MR imaging/planning). A tandem/ring applicator alone was used for the first insertion in most patients. Needles were added for the second insertion based on evaluation of the initial dosimetry. An interdisciplinary expert team reviewed and discussed the MR images and treatment plans.nnnRESULTSnDosimetry-trigger technique adaptation with the addition of needles for the second insertion improved target coverage in all patients with suboptimal dosimetry initially without compromising organ-at-risk (OAR) sparing. Target and OAR planning objectives were achieved in most patients. There were small or no systematic differences in tumor or OAR dosimetry between imaging/planning once per insertion vs. daily and only small random variations. Peer review and discussion of images, contours, and plans promoted learning and process development.nnnCONCLUSIONSnTechnique adaptation based on the initial dosimetry is an efficient approach to implementing MRgBT while gaining comfort with the use of needles. MR imaging and planning once per insertion is safe in most patients as long as applicator shifts, and large anatomical changes are excluded. Team learning is essential to building individual and programmatic competencies.