Timothy N. Showalter

Parallelized patient-specific quality assurance for high-dose-rate image-guided brachytherapy in an integrated computed tomography–on-rails brachytherapy suite

PURPOSEnTo describe a parallelized patient-specific quality assurance (QA) program designed to ensure safety and quality in image-guided high-dose-rate brachytherapy in an integrated computed tomography (CT)-on-rails brachytherapy suite.nnnMATERIALS AND METHODSnA patient-specific QA program has been modified for the image-guided brachytherapy (IGBT) program in an integrated CT-on-rails brachytherapy suite. In the modification of the QA procedures of Task Group-59, the additional patient-specific QA procedures are included to improve rapid IGBT workflow with applicator placement, imaging, planning, treatment, and applicator removal taking place in one room.nnnRESULTSnThe IGBT workflow is partitioned into two groups of tasks that can be performed in parallel by two or more staff members. One of the unique components of our implemented workflow is that groups work together to perform QA steps in parallel and in series during treatment planning and contouring. Coordinating efforts in this systematic way enable rapid and safe brachytherapy treatment while incorporating 3-dimensional anatomic variations between treatment days.nnnCONCLUSIONSnImplementation of these patient-specific QA procedures in an integrated CT-on-rails brachytherapy suite ensures confidence that a rapid workflow IGBT program can be implemented without sacrificing patient safety or quality and deliver highly-conformal dose to target volumes. These patient-specific QA components may be adapted to other IGBT environments that seek to provide rapid workflow while ensuring quality.

Breast Brachytherapy and Clinical Appendix

Breast brachytherapy delivers partial breast irradiation after breast-conserving surgery. The goal is to reduce local recurrence while minimizing dose to normal tissue. The majority of ipsilateral breast tumor recurrences occur within the index quadrant. It provides options for shorter treatment duration compared to traditional whole breast external beam radiation therapy (5 days vs. 5 weeks). Guidelines from several groups exist with recommendations for selecting appropriate patients. Multiple imaging modalities may be used to identify the lumpectomy cavity and confirm applicator placement. Cross-sectional imaging allows for evaluation of the implant (confirms placement, adjustment, manipulation). HDR or LDR can be utilized to deliver dose: 34 Gy in 10 fractions over 5 days (HDR), 32 Gy in 8 fractions over 4 days (HDR), 10 Gy in 2 fractions over 1–2 days (HDR boost), 45–50 Gy/0.50 Gy per hour (LDR), or 15–20 Gy/0.50 Gy per hour (LDR boost). NSABP B-39/RTOG 0413 will allow for comparison of treatment-related toxicity and cosmesis between accelerated partial breast irradiation and whole breast irradiation (results pending). Good to excellent cosmetic and high treatment-related satisfaction have been reported in many series.

Fractionation trends in breast cancer and implications in partial breast irradiation

Purpose/objectivesThe aim of this study is to analyze the national trends in breast radiotherapy fractionation over the past decade.Methods/materialsThe National Cancer Database was queried for women with pTis-pT3pN0, cM0 breast carcinoma (ductal or lobular) treated with breast conserving surgery and radiotherapy (RT) from 1998 to 2012. Patients were grouped by number of radiotherapy fractions into four groups: conventional fractionation (ConvFx, 25–33 fractions), hypofractionation (HypoFx, 15–24 fractions), accelerated partial breast RT (APBI, 10 fractions), and intraoperative RT (IORT, 1 fraction on the day of surgery). Patients with alternative schedules were excluded. Trends were analyzed graphically, and univariable and multivariable (MVA) analyses were performed to investigate factors associated with the receipt of APBI or IORT.ResultsA total of 371,145 patients met inclusion criteria. Trends analysis demonstrates a clear increase in APBI from 1998 to 2008, at which point hypofractionation became increasingly popular and APBI stabilized. Among APBI patients (nxa0=xa05787), the predominant RT modality was HDR brachytherapy (71%). On MVA, several factors were associated with APBI over other fractionations (all pxa0<xa00.001): later year of diagnosis, older age, ductal histology, smaller tumors, estrogen receptor positivity, lower grade, and increased patient distance from treating facility (OR 2.16 if over 100xa0mi). Similar factors were associated with the receipt of IORT, including patients living a further distance from the hospital (OR 8.18 if over 100xa0mi).ConclusionsWhile APBI utilization increased sharply from 2000 to 2008, the use of APBI has stabilized since 2008 with a concomitant increase in use of hypofractionation. The causes of these trends are unknown but should be the focus of future research.