Desmond A. O'Farrell

Sigmoid dose using 3D imaging in cervical-cancer brachytherapy ☆

BACKGROUND AND PURPOSE To evaluate the proximity, variance, predictors of dose, and complications to the sigmoid in cervical-cancer brachytherapy using 3D planning. MATERIALS AND METHODS Over 36 months, 50 patients were treated for cervical cancer with either low-dose-rate (LDR) or high-dose-rate (HDR) brachytherapy. The distance from the central tandem to the sigmoid, the D0.1 cc and the D2 cc to the sigmoid, rectum and bladder doses, and toxicity were analyzed. RESULTS The median sigmoid EQD2 D0.1 cc and D2 cc were 84 Gy and 68.3 Gy for HDR versus 71.1 Gy and 65.9 Gy for LDR (p=0.02 and 0.98, respectively). Twenty percent of the HDR fractions required manipulation of the superior dwell positions to decrease the sigmoid dose. The median distance from the sigmoid to the tandem was 1.7 cm (range [rg], 0.1-6.16 cm) for HDR and 2.7 cm (rg, 1.17-4.52 cm) for LDR; from the sigmoid to the 100% isodose region the median distances were -0.1 cm (rg, -1.4 to 2.5 cm) and 0.44 cm (rg. -0.73-5.2 cm), respectively. The proximity of the sigmoid to the tandem is significantly related to sigmoid dose (p<0.0001). Within-patient (among-fraction) variation in sigmoid-to-tandem distance during HDR was substantial (coefficient of variation =40%). No grade 3-4 sigmoid toxicity was seen after a median 31-month follow-up period. CONCLUSIONS 3D imaging in cervical-cancer brachytherapy shows the sigmoid in close proximity to the tandem. The sigmoid-to-tandem distance varies substantially between fractions, indicating the importance of sigmoid dose-volume evaluation with each fraction.

Dose volume histogram analysis of normal structures associated with accelerated partial breast irradiation delivered by high dose rate brachytherapy and comparison with whole breast external beam radiotherapy fields

PurposeTo assess the radiation dose delivered to the heart and ipsilateral lung during accelerated partial breast brachytherapy using a MammoSite™ applicator and compare to those produced by whole breast external beam radiotherapy (WBRT).Materials and methodsDosimetric analysis was conducted on patients receiving MammoSite breast brachytherapy following conservative surgery for invasive ductal carcinoma. Cardiac dose was evaluated for patients with left breast tumors with a CT scan encompassing the entire heart. Lung dose was evaluated for patients in whom the entire lung was scanned. The prescription dose of 3400 cGy was 1 cm from the balloon surface. MammoSite dosimetry was compared to simulated WBRT fields with and without radiobiological correction for the effects of dose and fractionation. Dose parameters such as the volume of the structure receiving 10 Gy or more (V10) and the dose received by 20 cc of the structure (D20), were calculated as well as the maximum and mean doses received.ResultsFifteen patients were studied, five had complete lung data and six had left-sided tumors with complete cardiac data. Ipsilateral lung volumes ranged from 925–1380 cc. Cardiac volumes ranged from 337–551 cc. MammoSite resulted in a significantly lower percentage lung V30 and lung and cardiac V20 than the WBRT fields, with and without radiobiological correction.ConclusionThis study gives low values for incidental radiation received by the heart and ipsilateral lung using the MammoSite applicator. The volume of heart and lung irradiated to clinically significant levels was significantly lower with the MammoSite applicator than using simulated WBRT fields of the same CT data sets.Trial registrationDana Farber Trial Registry number 03-179

Vaginal brachytherapy for early stage uterine papillary serous and clear cell endometrial cancer

OBJECTIVE To report clinical outcomes following adjuvant high-dose-rate (HDR) vaginal brachytherapy (VB) for early-stage uterine papillary serous (UPSC) and clear cell (CC) endometrial cancer. METHODS A retrospective study of Stage I and II papillary serous and clear cell endometrial cancer treated with post-operative HDR VB between October 2005 and May 2012 was performed. A total of 37 patients were identified, 26 with UPSC, 9 with CC and 2 with mixed UPSC/CC. After total hysterectomy and bilateral salpingo-oophorectomy, VB was administered without external-beam radiation with a dose of 24 Gy in 6 fractions prescribed to the vaginal surface. Chemotherapy was given to 30 patients (75%). RESULTS The median follow up time was 24.8 months (range, 2.0 to 71.5 months). Four patients relapsed, 2 with UPSC and 2 with CC. The initial site of relapse was concurrent vagina, pelvic/para-aortic nodes and abdominal wall (1), pelvic/para-aortic nodes (1) and para-aortic nodes alone (2). The 2-year vaginal-control rate was 96.8%. The pelvic-control rate including vaginal and nodal relapse was 93.5%. The 2-year disease-free and overall survival rates were 89.3% and 100%, respectively. CONCLUSION HDR VB as the sole adjuvant treatment modality for early-stage UPSC/CC is associated with a low rate of vaginal relapse and excellent survival outcomes. This novel low-dose regimen for VB is safe and effective.

Prospective Clinical Trial of Bladder Filling and Three-Dimensional Dosimetry in High-Dose-Rate Vaginal Cuff Brachytherapy

PURPOSE To investigate the effect of bladder filling on dosimetry and to determine the best bladder dosimetric parameter for vaginal cuff brachytherapy. METHODS AND MATERIALS In this prospective clinical trial, a total of 20 women underwent vaginal cylinder high-dose-rate brachytherapy. The bladder was full for Fraction 2 and empty for Fraction 3. Dose-volume histogram and dose-surface histogram values were generated for the bladder, rectum, and urethra. The midline maximal bladder point (MBP) and the midline maximal rectal point were recorded. Paired t tests, Pearson correlations, and regression analyses were performed. RESULTS The volume and surface area of the irradiated bladder were significantly smaller when the bladder was empty than when full. Of the several dose-volume histogram and dose-surface histogram parameters evaluated, the bladder maximal dose received by 2 cm(3) of tissue, volume of bladder receiving >/=50% of the dose, volume of bladder receiving >/=70% of the dose, and surface area of bladder receiving >/=50% of the dose significantly predicted for the difference between the empty vs. full filling state. The volume of bladder receiving >/=70% of the dose and the maximal dose received by 2 cm(3) of tissue correlated significantly with the MBP. Bladder filling did not alter the volume or surface area of the rectum irradiated. However, an empty bladder did result in the nearest point of bowel being significantly closer to the vaginal cylinder than when the bladder was full. CONCLUSIONS Patients undergoing vaginal cuff brachytherapy treated with an empty bladder have a lower bladder dose than those treated with a full bladder. The MBP correlated well with the volumetric assessments of bladder dose and provided a noninvasive method for reporting the MBP dose using three-dimensional imaging. The MBP can therefore be used as a surrogate for complex dosimetry in the clinic.

PERMANENT IODINE-125 INTERSTITIAL PLANAR SEED BRACHYTHERAPY FOR CLOSE OR POSITIVE MARGINS FOR THORACIC MALIGNANCIES

PURPOSE To assess toxicity and outcome following permanent iodine-125 seed implant as an adjunct to surgical resection in cases of advanced thoracic malignancy. METHODS AND MATERIALS An institutional review board-approved retrospective review was performed. Fifty-nine patients were identified as having undergone thoracic brachytherapy seed implantation between September 1999 and December 2006. Data for patient demographics, tumor details, and morbidity and mortality were recorded. RESULTS Fifty-nine patients received 64 implants. At a median follow-up of 17 months, 1-year and 2-year Kaplan-Meier rates of estimated overall survival were 94.1% and 82.0%, respectively. The 1-year and 2-year local control rates were 80.1% and 67.4%, respectively. The median time to develop local recurrence was 11 months. Grades 3 and 4 toxicity rates were 12% at 1 year. CONCLUSIONS This review shows relatively low toxicity for interstitial planar seed implantation after thoracic surgical resection. The high local control results suggest that an incomplete oncologic surgery plus a brachytherapy implant for treating advanced thoracic malignancy merit further investigation.

High-dose-rate brachytherapy for prostate cancer in a previously radiated patient with polyethylene glycol hydrogel spacing to reduce rectal dose: Case report and review of the literature

PURPOSE To describe the use of a temporary spacer to reduce rectal dose prior to prostate radiation in a man with prior pelvic radiotherapy and review the relevant literature. METHODS AND MATERIALS A healthy 57-year-old man presented with high-risk prostate cancer (Gleason score of 8, prostate-specific antigen level [PSA] 12.6 ng/mL, T3a by magnetic resonance imaging [MRI]), only 2.5 years after a low anterior resection followed by pelvic chemo-radiotherapy to 50.4 Gy for a locally advanced rectal cancer. Due to the prior radiation, he was not felt to be a candidate for surgery or external beam radiation, so he chose long-term androgen deprivation therapy (ADT) plus high-dose-rate brachytherapy to 36 Gy in 6 fractions. To reduce the radiation dose to the anterior rectal wall, 10 mL of a polyethylene glycol hydrogel spacer was injected between the prostate and rectum and created between 1.4 and 1.5 cm of separation along the length of the prostate. RESULTS Two randomized trials demonstrating that local therapy plus ADT improves overall survival compared to ADT alone provided the rationale for additional prostate radiotherapy in this otherwise healthy patient. Salvage brachytherapy is associated with a 3.4% rate of rectal fistula among the 251 cases reported in the literature from 2000-2007, with rates as high as 12% in one series. The spacer allowed the rectal dose constraint goals to be easily met. CONCLUSIONS Injecting an absorbable polyethylene glycol hydrogel to separate the prostate and rectum appears to be associated with decreased maximum and mean rectal doses, and may have particular utility in previously irradiated patients.

Use of a rectal spacer with low-dose-rate brachytherapy for treatment of prostate cancer in previously irradiated patients: Initial experience and short-term results.

BACKGROUND Salvage brachytherapy in patients with prior pelvic radiation carries a risk of rectal injury. Herein, we report our initial experience using a hydrogel spacer between the prostate and the rectum during salvage brachytherapy. METHODS AND MATERIALS A total of 11 patients with prostate cancer and prior radiotherapy (5 prostate brachytherapy, 2 prostate external beam radiation therapy [EBRT], and 4 rectal cancer EBRT) received (125)I brachytherapy after attempted placement of 10cc of a diluted hydrogel spacer between the prostate and rectum. RESULTS Spacing was achieved in 8 of the 11 (73%) patients but was not possible in 3 (1 prior brachytherapy and 2 prior EBRT) owing to fibrosis and adhesions. For the 8 patients in whom spacing was accomplished, the median space between the prostate and rectum was 10.9mm (prior EBRT) vs. 7.7mm (prior brachytherapy), p=0.048. Median followup was 15.7 months. One patient developed a prostato-rectal fistula requiring a diverting colostomy. The 16-month estimate of late Grade 3 or 4 gastrointestinal or genitourinary toxicity was 26%. One patient developed lymph node-positive recurrence. The 16-month prostate-specific antigen failure-free survival rate was 89%. Compared with baseline, Expanded Prostate Cancer Index Composite for Clinical Practice urinary quality of life (QoL) was significantly worse at 3 and 6 months but not significantly worse by 1 year. There were no significant changes throughout the study period in bowel or sexual QoL. CONCLUSION Hydrogel spacer placements may be feasible in most patients with prior pelvic radiation. Further followup is needed to determine whether spacer placement will produce long-term improvements in toxicity or QoL.

Treatment of Cutaneous Metastases of Merkel Cell Carcinoma With Surface-Mold Computer-Optimized High-Dose-Rate Brachytherapy

e19010 Background: Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma with great propensity for locoregional recurrence and distant metastases. Despite surgery and radiation therapy, lower extremity in-transit (and retrograde) cutaneous metastases are unfortunately common and present a therapeutic challenge. The often diffuse nature of lower extremity metastases renders negative margin excision unfeasible. Response to chemotherapy is limited and rarely durable. Although MCC is radiosensitive, radiation therapy is technically difficult for multifocal disease over the complex anatomic curvatures of the lower extremities. Methods: The Dana-Farber/Brigham and Womens Cancer Center has overcome these limitations with surface-mold computer-optimized high-dose rate brachytherapy (SMBT). Moldable applicators composed of a thermoplastic material and HDR treatment catheters are created for 3D conformal image-guided brachytherapy, which allows for the efficient and accurate targeting of ...

Redesign of process map to increase efficiency: Reducing procedure time in cervical cancer brachytherapy

PURPOSE To increase intraprocedural efficiency in the use of clinical resources and to decrease planning time for cervical cancer brachytherapy treatments through redesign of the procedures process map. METHODS AND MATERIALS A multidisciplinary team identified all tasks and associated resources involved in cervical cancer brachytherapy in our institution and arranged them in a process map. A redesign of the treatment planning component of the process map was conducted with the goal of minimizing planning time. Planning time was measured on 20 consecutive insertions, of which 10 were performed with standard procedures and 10 with the redesigned process map, and results were compared. Statistical significance (p < 0.05) was measured with a two-tailed t test. RESULTS Twelve tasks involved in cervical cancer brachytherapy treatments were identified. The process map showed that in standard procedures, the treatment planning tasks were performed sequentially. The process map was redesigned to specify that contouring and some planning tasks are performed concomitantly. Some quality assurance tasks were reorganized to minimize adverse effects of a possible error on procedure time. Test dry runs followed by live implementation confirmed the applicability of the new process map to clinical conditions. A 29% reduction in planning time (p < 0.01) was observed with the introduction of the redesigned process map. CONCLUSIONS A process map for cervical cancer brachytherapy was generated. The treatment planning component of the process map was redesigned, resulting in a 29% decrease in planning time and a streamlining of the quality assurance process.

American Brachytherapy Society consensus guidelines for thoracic brachytherapy for lung cancer

PURPOSE To update brachytherapy recommendations for pretreatment evaluation, treatment, and dosimetric issues for thoracic brachytherapy for lung cancer. METHODS AND MATERIALS Members of the American Brachytherapy Society with expertise in thoracic brachytherapy updated recommendations for thoracic brachytherapy based on literature review and clinical experience. RESULTS The American Brachytherapy Society consensus guidelines recommend the use of endobronchial brachytherapy for disease palliation in patients with central obstructing lesions, particularly in patients who have previously received external beam radiotherapy. The use of interstitial implants after incomplete resection may improve outcomes and provide enhanced palliation. Early reports support the use of CT-guided intratumoral volume implants within clinical studies. The use of brachytherapy routinely after sublobar resection is not generally recommended, unless within the confines of a clinical trial or a registry. CONCLUSIONS American Brachytherapy Society recommendations for thoracic brachytherapy are provided. Practitioners are encouraged to follow these guidelines and to develop further clinical trials to examine this treatment modality to increase the evidence base for its use.