Sea S. Chen

Cost of radiotherapy versus NSAID administration for prevention of heterotopic ossification after total hip arthroplasty.

PURPOSE Heterotopic ossification (HO), or abnormal bone formation, is a common sequela of total hip arthroplasty. This abnormal bone can impair joint function and must be surgically removed to restore mobility. HO can be prevented by postoperative nonsteroidal anti-inflammatory drug (NSAID) use or radiotherapy (RT). NSAIDs are associated with multiple toxicities, including gastrointestinal bleeding. Although RT has been shown to be more efficacious than NSAIDs at preventing HO, its cost-effectiveness has been questioned. METHODS AND MATERIALS We performed an analysis of the cost of postoperative RT to the hip compared with NSAID administration, taking into account the costs of surgery for HO formation, treatment-induced morbidity, and productivity loss from missed work. The costs of RT, surgical revision, and treatment of gastrointestinal bleeding were estimated using the 2007 Medicare Fee Schedule and inpatient diagnosis-related group codes. The cost of lost wages was estimated using the 2006 median salary data from the U.S. Census Bureau. RESULTS The cost of administering RT was estimated at

Radiation recall reaction with docetaxel administration after accelerated partial breast irradiation with electronic brachytherapy

899 vs.

A dosimetric analysis comparing treatment of low-risk prostate cancer with TomoTherapy versus static field intensity modulated radiation therapy.

20 for NSAID use. After accounting for the additional costs associated with revision total hip arthroplasty and gastrointestinal bleeding, the corresponding estimated costs were

A dosimetric analysis comparing electron beam with the MammoSite brachytherapy applicator for intact breast boost

1,208 vs.

Upright 3D treatment planning using a vertical CT.

930. CONCLUSION If the costs associated with treatment failure and treatment-induced morbidity are considered, the cost of NSAIDs approaches that of RT. Other NSAID morbidities and quality-of-life differences that are difficult to quantify add to the cost of NSAIDs. These considerations have led us to recommend RT as the preferred modality for use in prophylaxis against HO after total hip arthroplasty, even when the cost is considered.

VARIATION IN POST-SURGICAL LUMPECTOMY CAVITY VOLUME WITH DELAY IN INITIATION OF BREAST IRRADIATION BECAUSE OF CHEMOTHERAPY

PURPOSE Accelerated partial breast irradiation (APBI) offers several advantages over whole breast irradiation. Electronic brachytherapy may further reduce barriers to breast conserving therapy by making APBI more available. However, its toxicity profile is not well characterized. METHODS AND MATERIALS A 60-year-old woman was treated with APBI using Axxent (Xoft, Sunnyvale, CA) electronic brachytherapy. One month after APBI, a cycle of docetaxel and cyclophosphamide was given. Within 3 weeks, the patient developed an ulcerative radiation recall reaction in the skin overlying the lumpectomy cavity. To investigate this toxicity, the skin dose from electronic brachytherapy was compared with the dose that would have been delivered by an iridium-192 ((192)Ir) source. Additionally, a dose equivalent was estimated by adjusting for the increased relative biologic effectiveness (RBE) of low energy photons generated by the electronic source. RESULTS Using electronic brachytherapy, the skin dose was 537cGy per fraction compared with 470cGy for an (192)Ir source. Given an RBE for a 40kV source of 1.28 compared with (192)Ir, the equivalent dose at the skin for an electronic source was 687cGy-equivalents, a 46% increase. CONCLUSIONS We present a case of an ulcerative radiation recall reaction in a patient receiving APBI with electronic brachytherapy followed by chemotherapy. Our analysis shows that the use of electronic brachytherapy resulted in the deposition of significantly higher equivalent dose at the skin compared with (192)Ir. These findings suggest that standard guidelines (e.g., surface-to-skin distance) that apply to (192)Ir-based balloon brachytherapy may not be applicable to electronic brachytherapy.

Cost-Benefit Analysis of Post-Lumpectomy Treatment in Elderly Women.

Objectives:Static field intensity modulated radiation therapy (IMRT) has demonstrated dosimetric and clinical benefits over 3-dimensional conformal radiation therapy. TomoTherapy is a unique form of IMRT that may offer further improvements. Methods:The study population consisted of 15 patients with low-risk prostate cancer treated at Rush University with TomoTherapy (n = 7) or IMRT (n = 8). For each patient, both a TomoTherapy plan and an IMRT plan were generated using identical planning objectives. The planning target volume (PTV) was defined as the prostate and proximal seminal vesicles plus a margin. The prescription dose was 7740 cGy in 43 fractions. Radiation Therapy Oncology Group (RTOG) normal tissue guidelines were used as constraints, and the PTV coverage was made equivalent for the paired plans by equalizing the PTV V100. RTOG benchmark DVH values for the rectum and bladder and mean dose to the penile bulb were recorded. The volume of PTV receiving ≥105% of the prescription dose was measured. Results:The mean DVH values for each of the RTOG constraints for rectum and bladder were significantly improved using TomoTherapy. The volume of the PTV that received at least 105% of the dose was higher with IMRT (11.7% vs. 0.2%, <0.001). The mean dose to the penile bulb was higher with TomoTherapy (40.4 Gy vs. 27.4 Gy, P = 0.005). Conclusions:TomoTherapy offers a more favorable dose distribution to the bladder and rectum, as well as improved target homogeneity in comparison with IMRT.

A virtual matching technique for three-field breast irradiation using 3-D planning.

INTRODUCTION Electron beam radiation is the modality most often used to deliver an operative bed boost to breast cancer patients after completing whole breast radiation. However, electrons can potentially provide inadequate coverage. The MammoSite breast brachytherapy applicator may provide dosimetric advantages in the delivery of an operative bed boost and its role in this setting is not yet defined. MATERIALS AND METHODS The study population consisted of 15 patients with early stage breast cancer treated with partial breast irradiation (PBI) using the MammoSite device. For each patient, a theoretical boost plan using electrons and a second theoretical boost plan using the MammoSite applicator were created. To assess the adequacy of each boost plan, the PTV V90, PTV V95, and PTV V100 were calculated. To assess dose to normal tissues, the ipsilateral breast V50, ipsilateral lung V30, and heart V20 were calculated. RESULTS The mean PTV V100 for the MammoSite boost was 95.5%, compared to 77.4% for the electron boost (p<0.001). The mean PTV V95 was 97.8%, compared to 93.3% for the electron boost (p=0.02). The mean PTV V90, mean breast V50, mean lung V30, and mean heart V20 were not statistically different for MammoSite compared to electrons. CONCLUSIONS A tumor bed boost using the MammoSite breast brachytherapy applicator provides superior target coverage and delivers similar doses to the ipsilateral breast and lung compared to a boost delivered with electrons. More investigation into the role of balloon brachytherapy in the delivery of a breast boost is warranted.

CASE REPORT AND DOSIMETRIC ANALYSIS OF AN AXILLARY RECURRENCE AFTER PARTIAL BREAST IRRADIATION WITH MAMMOSITE CATHETER

In this report, we describe a novel technique used to plan and administer external beam radiation therapy to a patient in the upright position. A patient required reirradiation for thymic carcinoma but was unable to tolerate the supine position due to bilateral phrenic nerve injury and paralysis of the diaphragm. Computed tomography (CT) images in the upright position were acquired at the Northern Illinois University Institute for Neutron Therapy at Fermilab. The CT data were imported into a standard 3-dimensional (3D) treatment planning system. Treatment was designed to deliver 24 Gy to the target volume while respecting normal tissue tolerances. A custom chair that locked into the treatment table indexing system was constructed for immobilization, and port films verified the reproducibility of setup. Radiation was administered using mixed photon and electron AP fields.

TU-E-ValB-03: Simultaneous Integrated Boost Utilizing IMRT for the Treatment of Breast Cancer

PURPOSE The addition of a radiotherapy boost has been shown to improve local control in breast conservation therapy. Three dimensional planning provides more accurate targeting of the operative bed than clinical setup using the lumpectomy scar. However, contraction of the lumpectomy cavity over time may have implications for the volume of tissue included in the boost field. METHODS AND MATERIALS The clinical variables and treatment planning volumes for patients receiving whole-breast radiotherapy at a single institution between July 1, 2006, and December 31, 2007 were analyzed retrospectively. RESULTS Of the 93 patients identified, 29 received chemotherapy (CTX) and 64 did not; CTX was sequenced before radiotherapy in all patients. Patients receiving CTX were more likely to have higher T and N stage and a longer interval between definitive breast surgery and radiation. The lumpectomy specimens of women receiving CTX trended toward being larger than those of women not receiving CTX (113.4 cm(3) vs. 74.6 cm(3), p = 0.08). Despite this, the volume of the lumpectomy cavity measured on computed tomography was smaller in patients receiving CTX (9.1cm(3) vs. 16.8 cm(3), p = 0.02), as was the volume of the planning target volume (56.6 cm(3) vs. 79.9 cm(3), p = 0.02). CONCLUSIONS Patients receiving CTX were at higher risk for local recurrence. However, as a result of lumpectomy bed contraction, these patients received a boost to a smaller volume than patients not receiving CTX. This finding is counterintuitive and supports re-evaluation of the optimal size of the boost field. In addition, these results may have implications for patients treated with partial breast irradiation.