Feasibility of outpatient hybrid brachytherapy for cervical cancer with minimal sedation: Results from a single-institutional protocol.

Purpose: Pain control techniques during high-dose-rate hybrid intracavitary-interstitial brachytherapy (HBT) for cervical cancer vary widely, with many centers opting for general anesthesia (GA) or conscious sedation (CS). Here, we describe a single-institutional series of patients treated with HBT and ASA-defined minimal sedation, utilizing oral analgesic and anxiolytic medications in substitution for GA or CS. Material and methods: The charts of patients who underwent HBT treatments for cervical cancer from June 2018 to May 2020 were retrospectively reviewed. Prior to HBT, all patients underwent an exam under anesthesia (EUA), and Smit sleeve placement under general anesthesia or deep sedation. Oral lorazepam and oxycodone/acetaminophen were administered between 30-90 minutes before HBT procedure for minimal sedation. HBT placement was performed on computed tomography (CT) table, with needle advancement under CT-guidance. Results: Treatments with minimal sedation were attempted in 63 patients. A total of 244 interstitial implants with 453 needles were placed via CT-guidance. Sixty-one patients (96.8%) tolerated the procedure without any additional intervention, while two patients (3.2%) required the use of epidural anesthesia. None of the patients in the series required a transition to general anesthesia for the procedure. Bleeding, which resolved with short-term vaginal packing, occurred in 22.1% of insertions. Conclusions: In our series, the treatment of HBT for cervical cancer with minimal sedation was feasible at a high percentage (96.8%). The ability to perform HBT without GA or CS could be a reasonable option to provide image-guided adaptive brachytherapy (IGABT) with limited resources, allowing for more widespread use. Further investigations using this technique are warranted.

Phase II trial of adjuvant pelvic radiation "sandwiched" between combination paclitaxel and carboplatin in women with uterine papillary serous carcinoma.

OBJECTIVE: To evaluate the safety and survival in women treated with adjuvant pelvic radiation "sandwiched" between six cycles of paclitaxel and carboplatin chemotherapy with completely resected UPSC. METHODS: Surgically staged women with UPSC (FIGO stage 1-4) and no visible residual disease were enrolled. Treatment involved paclitaxel (175 mg/m(2)) and carboplatin (AUC=6.0-7.5) every 21 days for 3 doses, followed by radiation therapy (RT), followed by an additional 3 cycles of paclitaxel and carboplatin (AUC=5-6). Survival analysis, using Kaplan-Meier methods, was performed on patients who completed at least 3 cycles of chemotherapy and RT. RESULTS: A total of 81 patients were enrolled, of which 72 patients completed the first 3 cycles of chemotherapy followed by prescribed RT. Median age was 67 years (range: 43-82 years). 59/72 (82%) had disease confined to the uterus and 13/72 (18%) had completely resected extra-uterine disease (stage 3 and 4). 65 (83%) completed the protocol. Overall PFS and OS for combined stage 1 and 2 patients was 65.5 ± 3.6 months and 76.5 ± 4.3 months, respectively. PFS and OS for combined stage 3 and 4 patients was 25.8 ± 3.0 and 35.9 ± 5.3 months, respectively. Three-year % survival probability for stage 1 and 2 patients was 84% and for stage 3 and 4 patients was 50%. Of the 435 chemotherapy cycles administered, there were 11(2.5%) G3/G4 non-hematologic toxicities. 26(6.0%) cycles had dose reductions and 37(8.5%) had dose delays. CONCLUSIONS: Compared to prior studies of single modality adjuvant therapy, RT "sandwiched" between paclitaxel and carboplatin chemotherapy is well-tolerated and highly efficacious in women with completely resected UPSC.

Phase II trial of adjuvant pelvic radiation "sandwiched" between ifosfamide or ifosfamide plus cisplatin in women with uterine carcinosarcoma.

OBJECTIVE: Uterine carcinosarcoma (CS) is a rare uterine tumor with an extremely poor prognosis. In the adjuvant setting, efficacy has been shown with radiotherapy (RT), systemic chemotherapy, or both. This is the first report describing the efficacy and toxicity of adjuvant ifosfamide or ifosfamide plus cisplatin "sandwiched" with RT in patients with surgically staged and completely resected uterine carcinosarcoma. METHODS: Women with surgically staged CS with no gross residual disease were initially administered ifosfamide (1.2 g/m(2)/day×5 days) with cisplatin (20 mg/m(2)/day×5 days) every 3 weeks for 3 cycles followed by pelvic external beam RT and brachytherapy followed by 3 additional cycles of ifosfamide (1.0 g/m2/day) with cisplatin (20 mg/m(2)/day×5 days) every 3 weeks. Similar to the GOG trial in recurrent CS (Sutton et al., 2000), the addition of cisplatin added toxicity without additional efficacy, so mid-study, the cisplatin was eliminated from the regimen. Toxicities were recorded and disease-free survival (DFS) was calculated with Kaplan-Meier statistical methods. RESULTS: In total, 12 patients received ifosfamide and cisplatin and 15 patients received ifosfamide alone, both 'sandwiched' with RT. The median follow up was 35.9 months (range 6-88). The 2 year DFS was similar in both the ifosfamide/cisplatin and ifosfamide groups (log-rank p=0.16), so they were combined for analysis. 19 patients (70%) completed the protocol. As expected, stage 1 patients had a better 2-year DFS (18.75 ± 1.12 months; log-rank p=0.008 when compared to stages 2, 3, 4). Also, in stages 2, 3 and 4 patients, the DFS was 15.81 ± 1.73 months. Grade 3/4 neutropenia, anemia and thrombocytopenia occurred in 18%, 4% and 4% of cycles, respectively. CONCLUSIONS: Ifosfamide "sandwiched" with RT appears to be an efficacious regimen for surgically staged CS patients with no residual disease, even in patients with advanced stage. The addition of cisplatin to the regimen added toxicity without improving efficacy. Even with ifosfamide alone, the efficacy of this 'sandwich' regimen comes with a moderate but tolerable toxicity profile.

Discordance in Perceptions of Barriers to Breast Cancer Treatment Between Hispanic Women and Their Providers.

Despite comparable screening and incidence rates that are 26% below that of non-Hispanic Whites, Hispanic women present with breast cancer at more advanced stages of disease, representing a continuing and troubling health disparity for this population. Reducing these disparities warrant more innovative research approaches to better understand perspectives of Hispanic patients regarding barriers to treatment and how these perspectives compare to those of their providers. A pilot qualitative study was conducted at a major urban cancer center in Arizona that measured both patient and provider perspectives regarding barriers to treatment. Through a multimethod qualitative analysis, researchers surveyed patients and providers to identify perceived barriers and discordance in shared understanding. Data collection and analysis consisted of surveying patients and providers, then performing inductive qualitative analysis. Results indicated the highest concordance, or shared understanding, between patients and providers was in recognizing barriers within delivery of care, such as cost of care and insurance coverage. The greatest discordance, or gaps in shared understanding, existed in upstream barriers of the health care system, such as emotional support and trust in systems. These results underscore the gap in shared understanding between patients and providers regarding upstream barriers to care as well as the nonclinical social determinants of health Hispanic patients face in accessing breast cancer treatment. More research is warranted using this approach as a tool to reduce health disparities.

Intraoperative seed placement for thoracic malignancy-A review of technique, indications, and published literature.

PURPOSE: This review examines the role of permanent radioactive seed implantation in thoracic malignancy. This technique can be used intraoperatively to provide additional highly localized radiation therapy in cases where optimal oncologic margins are unattainable or to palliate unresectable disease. METHODS AND MATERIALS: Relevant trials were identified through a systematic literature search using Pubmed. RESULTS: The intraoperative placement of brachytherapy seeds has been described after sublobar resection for non-small-cell lung cancer (NSCLC), where surgical margins are close or microscopically positive and in the presence of macroscopic residual disease. This brachytherapy technique is currently the focus of a randomized prospective trial in the USA in patients unfit for lobectomy for early-stage NSCLC. CONCLUSIONS: This review summarizes the methods of brachytherapy seed placement and the published experience of brachytherapy implants within the thorax, also examining radiation safety and postoperative dosimetry. This technique has the potential to improve local control with optimal sparing of normal tissue owing to its highly conformal radiotherapy delivery.

ICRU reference dose in an era of intensity-modulated radiation therapy clinical trials: correlation with planning target volume mean dose and suitability for intensity-modulated radiation therapy dose prescription.

BACKGROUND AND PURPOSE: IMRT clinical trials lack dose prescription and specification standards similar to ICRU standards for two- and three-dimensional external beam planning. In this study, we analyzed dose distributions for patients whose treatment plans incorporated IMRT, and compared the dose determined at the ICRU reference point to the PTV doses determined from dose-volume histograms. Additionally, we evaluated if ICRU reference type single-point dose prescriptions are suitable for IMRT dose prescriptions. MATERIALS AND METHODS: For this study, IMRT plans of 117 patients treated at our institution were randomly selected and analyzed. The treatment plans were clinically applied to the following disease sites: abdominal (11), anal (10), brain (11), gynecological (15), head and neck (25), lung (15), male pelvis (10) and prostate (20). The ICRU reference point was located in each treatment plan following ICRU Report 50 guidelines. The reference point was placed in the central part of the PTV and at or near the isocenter. In each case, the dose was calculated and recorded to this point. For each patient--volume and dose (PTV, PTV mean, median and modal) information was extracted from the planned dose-volume histogram. RESULTS: The ICRU reference dose vs PTV mean dose relationship in IMRT exhibited a weak positive association (Pearson correlation coefficient 0.63). In approximately 65% of the cases studied, dose at the ICRU reference point was greater than the corresponding PTV mean dose. The dose difference between ICRU reference and PTV mean doses was 2% in approximately 79% of the cases studied (average 1.21% (+/-1.55), range -4% to +4%). Paired t-test analyses showed that the ICRU reference doses and PTV median doses were statistically similar (p=0.42). The magnitude of PTV did not influence the difference between ICRU reference and PTV mean doses. CONCLUSIONS: The general relationship between ICRU reference and PTV mean doses in IMRT is similar to that in 3D CRT distributions. Point doses in IMRT are influenced by the degree of intensity modulation as well as calculation grid size utilized. Although the ICRU reference point type prescriptions conceptually may be extended for IMRT dose prescriptions and used as a representative of tumor dose, new universally acceptable dose prescription and specification standards for IMRT based on RTOG IMRT prescription model incorporating dose-volume specification would likely lead to greater consistency among treatment centers.

Point vs. volumetric bladder and rectal doses in combined intracavitary-interstitial high-dose-rate brachytherapy: correlation and comparison with published Vienna applicator data.

PURPOSE: We correlated rectal and bladder point and volumetric dose data in patients treated for advanced cervix cancers with combined intracavitary-interstitial high-dose-rate (HDR) brachytherapy (BT). The results are compared with published Vienna applicator data. METHODS AND MATERIALS: We retrospectively analyzed 30 individual combined intracavitary plus interstitial implants from 10 patients treated with external beam radiation therapy (EBRT) followed by HDR BT for locally advanced cervix carcinoma. EBRT consisted of 45 Gy to the pelvis followed by 9-14.4 Gy boost to involved parametria. BT consisted of a total dose of 21 Gy delivered in 7 Gy fraction. For each implant, CT-image-based simulation and image-guided BT treatment planning was performed. Bladder and rectal doses were evaluated and analyzed using both International commission on Radiation Units and Measurements (ICRU) reference points and dose-volume histograms. The cumulative doses to the rectum and bladder were calculated by combining contributions from external beam therapy and BT. To facilitate comparison with published literature, the total doses were normalized to equivalent dose in 2-Gy fractions (EQD2) using the equation EQD2total = EQD2EBRT + EQD2BT. RESULTS: For the patient population considered, the mean ICRU bladder dose was 75 (+/-4) Gy3 compared to bladder D0.1 cc and D2 cc doses of 84 (+/-4) and 78 (+/-3) Gy3, respectively. The mean ICRU rectal dose was 73 (+/-4) Gy3 compared to rectal D0.1 cc and D2 cc doses of 79 (+/-5) and 74 (+/-4) Gy3, respectively. For rectum, the mean dose ratios (D0.1 cc/D(ICRU)) and (D2 cc/D(ICRU)) were 1.08 and 1.01, respectively, compared to Vienna applicator study mean dose ratios of 1.08 and 0.93, respectively. ICRU rectal dose correlated with volumetric rectal doses and best with volumetric D2 cc dose (rS = 0.91, p = 0.0003); however, ICRU bladder dose did not correlate with volumetric bladder dose. CONCLUSIONS: Our study findings reveal a strong correlation between ICRU rectal reference dose and volumetric rectal D2 cc dose in combined intracavitary-interstitial HDR brachytherapy. This surrogate rectal-dose relationship is valuable in establishing rectal tolerance dose levels in transitioning from traditional two-dimensional to image-based three-dimensional dose planning.

Custom mold applicator high-dose-rate brachytherapy for nonmelanoma skin cancer-An analysis of 273 lesions.

PURPOSE: Nonmelanoma skin cancer is the most commonly diagnosed malignancy in the United States. A modern version of surface brachytherapy, "topographic applicator brachytherapy" (TAB), can be used to treat early-stage nonmelanoma skin cancer (ES-NMSC). The purpose of this study was to evaluate the acute toxicity, chronic toxicity, and recurrence rates of patients with ES-NMSC treated with TAB. METHODS AND MATERIALS: From 2010 to 2013, 172 patients with 273 ES-NMSC tumors were consecutively treated with TAB. A custom applicator was created using a thermoplastic mold with Harrison Anderson Mick applicators. Dose fractionation schemes included 40 Gy in eight fractions delivered twice per week or 48 Gy in 16 fractions delivered four times per week. RESULTS: Of the 273 tumors treated, 23.8% were located on the nose, 54.2% were basal cell carcinoma, 76.2% were Stage I, 89.3% were treated definitively, 98.9% completed treatment, and 75.5% received 40 Gy in eight fractions. Median followup was 25.0 months (0.5-71.0 months). Maximum acute toxicity was G0, 0.4%; G1, 33.3%; G2, 48.7%; G3, 12.1%; and G4, 5.1%. Local recurrence was 4.8% at 25 months, with median time to recurrence being 9 months. There was no regional or distant metastasis documented during the followup. Chronic toxicities included erythema (4.4%), chronic ulceration (4.0%), telangiectasia (2.6%), and pigmentation changes (2.2%). CONCLUSIONS: TAB was able to provide excellent local control (95.2%) with low rates of Grades 3 and 4 toxicities for treatment of ES-NMSC. TAB is a reasonable alternative to surgical resection when there is concern of poor cosmesis/wound healing.

Intensity-modulated radiotherapy with concurrent chemotherapy for previously irradiated, recurrent head and neck cancer.

PURPOSE: Primary treatment fails in >70% of locally advanced head and neck cancer patients. Salvage therapy has a 30-40% response rate, but few long-term survivors. Intensity-modulated radiotherapy (IMRT) has recently emerged as a new modality for salvage therapy. This retrospective study evaluated our experience using every-other-week IMRT with concurrent chemotherapy. METHODS AND MATERIALS: Between 2001 and 2006, 41 patients underwent IMRT as repeat RT with concurrent chemotherapy. All but 6 patients received 60 Gy at 2 Gy/fraction. RT was delivered on an alternating week schedule. RESULTS: With a median follow-up time of 14 months, the overall response rate was 75.6%, with a complete response and partial response rate of 58.5% and 17.1%, respectively. The Kaplan-Meier estimate of overall survival, disease-free survival, and progression-free survival at 24 months was 48.7%, 48.1%, and 38%, respectively. Patients who underwent surgery as a part of their salvage therapy had a mean estimated survival of 30.9 months compared with 22.8 months for patients who received only chemoradiotherapy (p = 0.126). Grade 3 or 4 acute toxicities occurred in 31.7% of patients, but all had resolved within 2 months of therapy completion. No deaths occurred during treatment, except for 1 patient, who died shortly after discontinuing treatment early because of previously undiagnosed metastatic disease; 6 patients had long-term complications. CONCLUSIONS: Concurrent chemotherapy with repeat radiotherapy with IMRT given every other week appears to be both well tolerated and feasible in patients treated with previous radiotherapy for recurrent head and neck cancer. IMRT represents a reasonable modality for reducing treatment-related toxicities in a repeat RT setting.

Severe toxicity after permanent radioactive seed implantation for mediastinal carcinoid tumors.

PURPOSE: Permanent implantation of 125I seeds may be used when uninvolved surgical margins are unobtainable or close. Two cases of mediastinal carcinoid tumors with prior chemoradiation had tumors adherent to esophageal muscularis. Both underwent intraoperative permanent seed implantation and developed esophageal fistulas requiring surgical correction. METHODS AND MATERIALS: Custom permanent 125I seed mesh implants were fashioned intraoperatively in a geometrically coherent pattern. The implants were directly sutured to the partially resected esophageal wall. The postimplant CT scans were fused with the postfistula scans to provide dosimetric information at the fistula site. Doses were calculated from time of insertion to time of fistula formation. Neither patient showed evidence of disease recurrence at the time of fistula repair. RESULTS: Patient 1 developed an esophageal-pleural fistula 83 days after seed implantation. Patient 2 developed a broncho-pleural fistula 300 days after seed implantation. CONCLUSIONS: These cases demonstrated that implantation in the setting of extensive subcarinal space dissection and partial esophageal wall resection could cause fistula formation and the need for additional surgery. The high mucosal dose, despite the relatively low activity implant, was due to lack of geometric sparing of the mucosa. We recommend that extensive subcarinal space dissection be considered a contraindication to permanent seed implantation.

Skin surface brachytherapy: A survey of contemporary practice patterns.

PURPOSE: The aim of this study was to define current patterns of care among radiation oncologists who use skin surface brachytherapy for the treatment of cutaneous squamous cell carcinoma (cSCC) and basal cell carcinoma (BCC) in academic and community settings. METHODS AND MATERIALS: A 30-question electronic survey was administered to clinician members of the American Brachytherapy Society. The respondents were asked to provide details regarding their clinical practice and their approach to skin surface brachytherapy. RESULTS: A total of 16 surveys were returned. Among the respondents, aggregate experience varied from 8 to 1800 cases. Most preferred brachytherapy over external beam radiation because of shorter treatment course, conformality of treatment for irregular or curved targets, and shallow dose deposition. Of the total, 60% of respondents routinely estimated lesion depth via ultrasound before initiating treatment. Treatment margin on gross disease varied widely (range, 3-15 mm; median, 5 mm). Hypofractionation was the preferred dose schedule. Prescribed doses ranged from 30 Gy in five fractions to 64 Gy in 32 fractions (EQD2, 40 Gy-65 Gy). There was a tendency to increase the number of fractions for larger targets, although some used the same fractionation regardless of anatomic location or lesion size. There was no consensus on dosimetric constraints, and some respondents reported cases of severe toxicity, particularly when treating the pretibial skin. CONCLUSIONS: This pattern of care study suggests that skin brachytherapy can be a convenient and safe tool for treatment of BCC and cSCC. Prospective trials and the development of expert consensus guidelines would be beneficial for optimizing skin surface brachytherapy and reducing practice variation.

Multiple dural-based hemangiopericytomas.

Here we report the case of a 57-year-old man who underwent resection of a dural-based hemangiopericytoma (HPC) in the left frontoparietal region. The patient was treated with radiation therapy and remained symptom-free for 10 years. At 67 years of age, he presented with a mass in the left frontal region near the same area as the first tumor, in addition to a separate smaller mass in the right middle cranial fossa. Resection of the larger left frontal mass revealed an HPC. Follow-up imaging 9 months later showed a significant increase in size of the right middle cranial fossa mass. This third mass was resected, and histological examination also demonstrated an HPC.

A new approach to reduce number of split fields in large field IMRT.

Intensity-modulated radiation therapy (IMRT) has been applied for treatments of primary head with neck nodes, lung with supraclavicular nodes, and high-risk prostate cancer with pelvis wall nodes, all of which require large fields. However, the design of the Varian multileaf collimator requires fields >14 cm in width to be split into 2 or more carriage movements. With the split-field technique, both the number of monitor units (MUs) and total treatment time are significantly increased. Although many different approaches have been investigated to reduce the MU, including introducing new leaf segmentation algorithms, none have resulted in widespread success. In addition, for most clinics, writing such algorithms is not a feasible solution, particularly with commercial treatment planning systems. We introduce a new approach that can minimize the number of split fields and reduce the total MUs, thereby reducing treatment time. The technique is demonstrated on the Eclipse planning system V7.3, but could be generalized to any other system.

A multidisciplinary approach to fertility-sparing therapy for a rare vulvar tumor.

OBJECTIVE: Case report of a young woman with a rare vulvar malignancy who received treatment with a personalized multidisciplinary approach to balance management of her malignancy without compromising survival with her desire for future pregnancy. DESIGN: Case report. SETTING: University hospital. PATIENT(S): A 33-year-old woman, gravida 2, para 1-0-1-1, who had a diagnosis of synovial cell sarcoma of the vulva and who desired future fertility. INTERVENTION(S): At multiple steps, treatment was planned to try to maximize fertility preservation without potentially affecting initial treatment, which included a radical hemivulvectomy with bilateral lymph node dissection, brachytherapy with interstitial needles (20 Gy), and external beam radiation therapy (50 Gy). MAIN OUTCOME MEASURE(S): Treatment and eradication of the malignancy and achievement of a successful subsequent pregnancy and live birth. RESULT(S): The patient had no evidence of disease for 2 years after treatment. During that time she received preconception counseling by both a perinatologist and a reproductive endocrinologist. She conceived with the use of ultrasound monitoring to time intercourse specifically with ovulation from the contralateral ovary and had an uncomplicated pregnancy with a term delivery. CONCLUSION(S): By using several disciplines and subspecialists, this patient received personalized treatment for a rare cancer, focused at curing her cancer and optimizing her future fertility.

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.

Change in seroma volume during whole-breast radiation therapy.

PURPOSE: After breast-conserving surgery, a seroma often forms in the surgical cavity. If not drained, it may affect the volume of tumor bed requiring a boost after whole-breast radiation therapy (WBRT). Our objective was to evaluate the change in seroma volume that occurs during WBRT, before boost planning. METHODS AND MATERIALS: A retrospective review was performed of women receiving breast-conserving therapy with evidence of seroma at the time of WBRT planning. Computed tomography (CT) simulation was performed before WBRT and before the tumor bed boost. All patients received either a hypofractionated (42.4 Gy/16 fraction + 9.6 Gy/4 fraction boost) or standard fractionated (50.4 Gy/28 fraction + 10 Gy/5 fraction boost) regimen. Seroma volumes were contoured and compared on CT at the time of WBRT simulation and tumor bed boost planning. RESULTS: Twenty-four patients with evidence of seroma were identified and all patients received WBRT without drainage of the seroma. Mean seroma volume before WBRT and at boost planning were significantly different at 65.7 cm(3) (SD, 50.5 cm(3)) and 35.6 cm(3) (SD, 24.8 cm(3)), respectively (p < 0.001). Mean and median reduction in seroma volume during radiation were 39.6% (SD, 23.8%) and 46.2% (range, 10.7-76.7%), respectively. Fractionation schedule was not correlated with change in seroma volume. Length of time from surgery to start of radiation therapy showed an inverse correlation with change in seroma volume (Pearson correlation r = -0.53, p < 0.01). CONCLUSIONS: The volume of seroma changes significantly during WBRT. Consequently, the accuracy of breast boost planning is likely affected, as is the volume of normal breast tissue irradiated. CT-based boost planning before boost irradiation is suggested to ensure appropriate coverage.

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.

PURPOSE: To 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 METHODS: Dosimetric 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. RESULTS: Fifteen 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. CONCLUSION: This 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.

Inherent change in MammoSite applicator three-dimensional geometry over time.

Accelerated partial breast irradiation is commonly done with the MammoSite applicator, which requires symmetry to treat the patient. This paper describes three cases that were asymmetric when initially placed and became symmetric over time, without manipulation.