Outpatient template-guided permanent interstitial brachytherapy using (131)Cs in gynecologic malignancies: Initial report.

Optimal curative intent brachytherapy for certain gynecologic cancers requires interstitial brachytherapy, often using template-guided techniques such as a Syed-Neblett implant. Whether high or low dose rate (LDR), these procedures pose significant risks to patients, partly attributable to the prolonged period of bed rest. Published results of free-handed permanent interstitial brachytherapy (PIB) with 131Cs demonstrate it to be an effective modality for the management of small volume gynecologic cancers. This report is the first to describe a permanent template-guided interstitial technique using 131Cs for gynecologic cancers, performed as an LDR outpatient procedure. Five sequential patients with recurrent or primary gynecologic malignancies underwent template-guided PIB using 131Cs. A posttreatment planning CT was obtained immediately after the procedure and again 3-4 weeks later. Both CT data sets were fused and the relative positions compared to assess for migration in the x, y, and z planes. Seed positions as well as dosimetric parameters including D90, D100, V100, and the dose to 2 cc of rectum and bladder were compared to quantify migration of sources and the resulting effect, if any, on the treatment. The median age was 69 years (range 64-85). All patients received a template-guided 131Cs PIB implant to treat gross disease. All 5 patients had significant medical comorbidities that limited treatment options. Considering all 5 patients, a total of 40 interstitial needles were placed. Ten needles carried only Vicryl-stranded sources, and 30 needles carried a combination of stranded 131Cs seeds and free seeds. Needle count was between 6 and 10 needles per patient, with active lengths of 4-10 cm. The median dose was 30 Gy (range 25-55 Gy) to permanent decay, enabling a cumulative median biological effective dose 91.5 Gy (range 60.9-92.1 Gy) and equivalent dose at 2 Gy per fraction 75.9 Gy (range 50.7-76.8 Gy). All implants were performed as outpatient procedures with only the first patient admitted for 23-hour observation. All calculated median migration distances were less than 1 cm in the axial, sagittal, or coronal planes. In 69.2% cases, the individual seed migration was <5 mm. Strand migration appeared directly related to peripheral placement and the use of stranded sources. The median D90, D100, and V100 were compared between study sets, and no significant differences were identified. No Grade 3 or higher complications occurred. Permanent LDR template-guided PIB using 131Cs can be safely performed on an outpatient basis. Compared to currently used template-guided techniques, the use of 131Cs avoids prolonged bed rest and hospitalization, significantly lowers cost, and enables a higher cumulative dose. Seed migration is minimal with this technique. Early experience suggests that the technique is safe and merits further study.

Feddock J ，Aryal P ，Steber C ，Edwards J ，Cheek D ，Randall M ... -  《-》

Implementation and early clinical results utilizing Cs-131 permanent interstitial implants for gynecologic malignancies.

Permanent interstitial brachytherapy is an ideal yet underutilized treatment modality for accessible, small volume gynecological malignancies. We present early clinical results utilizing a new permanent isotope, Cs-131. A retrospective review was performed evaluating patients treated with Cs-131 permanent interstitial radiation at our institution from July 2011 through June 2013. Doses were most commonly prescribed and calculated to a depth of 5mm using Paterson-Parker planar implant rules for Au-198. This activity was converted to air-kerma strength (U). A conversion factor of 1.1 was applied based on RBE calculations, clinical observation and experience. 14 patients were identified among whom 17 Cs-131 implants were performed. Seven patients were implanted as sole therapy, and a median dose of 50 Gy was delivered. Ten implants were performed as boost within a more extensive radiation treatment plan. In these patients, a median implant dose of 27.5 Gy was used and the median total dose delivered in combination was 78.25 Gy. After a median follow up of 12 months, the actuarial local control rate was 84.4%. A very low level of grade 1-3 reactions was observed with no fistula formations or other severe side effects. Permanent interstitial brachytherapy with Cs-131 was well tolerated with favorable early results compared to other series. Cs-131 has multiple favorable properties, including minimal radiation exposure to treating staff, and should be considered as a therapeutic option in appropriately selected patients. A methodology for dose prescription, calculation of radioactivity required and distribution of the isotope is also presented.

Wooten CE ，Randall M ，Edwards J ，Aryal P ，Luo W ，Feddock J ... -  《-》

Image and laparoscopic guided interstitial brachytherapy for locally advanced primary or recurrent gynaecological cancer using the adaptive GEC ESTRO target concept.

To retrospectively assess treatment outcome of image and laparoscopic guided interstitial pulsed dose rate brachytherapy (PDR-BT) for locally advanced gynaecological cancer using the adaptive GEC ESTRO target concept. Between June 2005 and December 2010, 28 consecutive patients were treated for locally advanced primary vaginal (nine), recurrent endometrial (12) or recurrent cervical cancer (seven) with combined external beam radiotherapy (EBRT) and interstitial PDR-BT. Treatment was initiated with whole pelvic EBRT to a median dose of 45 Gy followed by PDR-BT using the Martinez Universal Perineal Interstitial Template (MUPIT). All implants were virtually preplanned using MRI of the pelvis with a dummy MUPIT in situ. The GEC ESTRO high risk clinical target volume (HR CTV), intermediate risk clinical target volume (IR CTV) and the organs at risk (OAR) were contoured and a preplan for implantation was generated (BrachyVision, Varian). The subsequent implantation was performed under laparoscopic visualisation. Final contouring and treatment planning were done using a post-implant CT. Planning aim of PDR-BT was to deliver 30 Gy in 50 hourly pulses to HR CTV. Manual dose optimisation was performed with the aim of reaching a D90>80 Gy in the HR CTV calculated as the total biologically equivalent to 2 Gy fractions of EBRT and BT (EQD2). Dose to the OAR were evaluated using dose volume constraints for D(2cc) of 90 Gy for bladder and 70 Gy for rectum and sigmoid. For HR CTV the median volume was 26 cm(3) (7-91 cm(3)). Coverage of the HR CTV was 97% (90-100%) and D90 was 82 Gy (77-88 Gy). The D(2cc) for bladder, rectum, and sigmoid were 65 Gy (47-81 Gy), 61 Gy (50-77 Gy), and 52 Gy (44-68 Gy), respectively. Median follow up was 18 months (6-61 months). The actuarial 2 years local control rate was 92% (SE 5), while disease-free survival and overall survival were 59% (SE 11) and 74%, respectively (SE 10). No complications to the laparoscopic guided implantation were encountered. Late grade 2 (CTC v 3.0) complications were recorded in nine (32%) patients. One patient had a grade 3 vaginal complication. No grade 4-5 complications have been recorded so far. Image and laparoscopic guided interstitial PDR-BT using the GEC ESTRO target concept is applicable for locally advanced primary vaginal or recurrent endometrial and cervical cancer resulting in an excellent local control rate and limited morbidity.

Fokdal L ，Tanderup K ，Nielsen SK ，Christensen HK ，Røhl L ，Pedersen EM ，Schønemann NK ，Lindegaard JC ... -  《-》

A new technique for performing Syed-Neblett template interstitial implants for gynecologic malignancies using transrectal-ultrasound guidance.

Stock RG ，Chan K ，Terk M ，Dewyngaert JK ，Stone NN ，Dottino P ... -  《-》

Predictors of toxicity after image-guided high-dose-rate interstitial brachytherapy for gynecologic cancer.

To identify predictors of grade 3-4 complications and grade 2-4 rectal toxicity after three-dimensional image-guided high-dose-rate (HDR) interstitial brachytherapy for gynecologic cancer. Records were reviewed for 51 women (22 with primary disease and 29 with recurrence) treated with HDR interstitial brachytherapy. A single interstitial insertion was performed with image guidance by computed tomography (n = 43) or magnetic resonance imaging (n = 8). The median delivered dose in equivalent 2-Gy fractions was 72.0 Gy (45 Gy for external-beam radiation therapy and 24 Gy for brachytherapy). Toxicity was reported according to the Common Toxicity Criteria for Adverse Events. Actuarial toxicity estimates were calculated by the Kaplan-Meier method. At diagnosis, the median patient age was 62 years and the median tumor size was 3.8 cm. The median D90 and V100 were 71.4 Gy and 89.5%; the median D2cc for the bladder, rectum, and sigmoid were 64.6 Gy, 61.0 Gy, and 52.7 Gy, respectively. The actuarial rates of all grade 3-4 complications at 2 years were 20% gastrointestinal, 9% vaginal, 6% skin, 3% musculoskeletal, and 2% lymphatic. There were no grade 3-4 genitourinary complications and no grade 5 toxicities. Grade 2-4 rectal toxicity was observed in 10 patients, and grade 3-4 complications in 4; all cases were proctitis with the exception of 1 rectal fistula. D2cc for rectum was higher for patients with grade 2-4 (68 Gy vs 57 Gy for grade 0-1, P=.03) and grade 3-4 (73 Gy vs 58 Gy for grade 0-2, P=.02) rectal toxicity. The estimated dose that resulted in a 10% risk of grade 2-4 rectal toxicity was 61.8 Gy (95% confidence interval, 51.5-72.2 Gy). Image-guided HDR interstitial brachytherapy results in acceptable toxicity for women with primary or recurrent gynecologic cancer. D2cc for the rectum is a reliable predictor of late rectal complications. Three-dimensional-based treatment planning should be performed to ensure adequate tumor coverage while minimizing the D2cc to the rectum.

Lee LJ ，Viswanathan AN 《-》