Jennifer Zook

Stereotactic body radiotherapy for primary hepatocellular carcinoma.

PURPOSE To evaluate the safety and efficacy of stereotactic body radiotherapy (SBRT) for the treatment of primary hepatocellular carcinoma (HCC). METHODS AND MATERIALS From 2005 to 2009, 60 patients with liver-confined HCC were treated with SBRT at the Indiana University Simon Cancer Center: 36 Child-Turcotte-Pugh (CTP) Class A and 24 CTP Class B. The median number of fractions, dose per fraction, and total dose, was 3, 14 Gy, and 44 Gy, respectively, for those with CTP Class A cirrhosis and 5, 8 Gy, and 40 Gy, respectively, for those with CTP Class B. Treatment was delivered via 6 to 12 beams and in nearly all cases was prescribed to the 80% isodose line. The records of all patients were reviewed, and treatment response was scored according to Response Evaluation Criteria in Solid Tumors v1.1. Toxicity was graded according to the Common Terminology Criteria for Adverse Events v4.0. Local control (LC), time to progression (TTP), progression-free survival (PFS), and overall survival (OS) were calculated according to the method of Kaplan and Meier. RESULTS The median follow-up time was 27 months, and the median tumor diameter was 3.2 cm. The 2-year LC, PFS, and OS were 90%, 48%, and 67%, respectively, with median TTP of 47.8 months. Subsequently, 23 patients underwent transplant, with a median time to transplant of 7 months. There were no ≥Grade 3 nonhematologic toxicities. Thirteen percent of patients experienced an increase in hematologic/hepatic dysfunction greater than 1 grade, and 20% experienced progression in CTP class within 3 months of treatment. CONCLUSIONS SBRT is a safe, effective, noninvasive option for patients with HCC ≤6 cm. As such, SBRT should be considered when bridging to transplant or as definitive therapy for those ineligible for transplant.

Evaluation of superficial dosimetry between treatment planning system and measurement for several breast cancer treatment techniques

PURPOSE Dosimetric accuracy in radiation treatment of breast cancer is critical for the evaluation of cosmetic outcomes and survival. It is often considered that treatment planning systems (TPS) may not be able to provide accurate dosimetry in the buildup region. This was investigated in various treatment techniques such as tangential wedges, field-in-field (FF), electronic compensator (eComp), and intensity-modulated radiotherapy (IMRT). METHODS Under Institutional Review Board (IRB) exemption, radiotherapy treatment plans of 111 cases were retrospectively analyzed. The distance between skin surface and 95% isodose line was measured. For measurements, Gafchromic EBT2 films were used on a humanoid unsliced phantom. Multiple layers of variable thickness of superflab bolus were placed on the breast phantom and CT scanned for planning. Treatment plans were generated using four techniques with two different grid sizes (1 × 1 and 2.5 × 2.5 mm(2)) to provide optimum dose distribution. Films were placed at different depths and exposed with the selected techniques. A calibration curve for dose versus pixel values was also generated on the same day as the phantom measurement was conducted. The DICOM RT image, dose, and plan data were imported to the in-house software. On axial plane of CT slices, curves were drawn at the position where EBT2 films were placed, and the dose profiles on the lines were acquired. The calculated and measured dose profiles were separated by check points which were marked on the films before irradiation. The segments of calculated profiles were stretched to match their resolutions to that of film dosimetry. RESULTS On review of treatment plans, the distance between skin and 95% prescribed dose was up to 8 mm for plans of 27 patients. The film measurement revealed that the medial region of phantom surface received a mere 45%-50% of prescribed dose. For wedges, FF, and eComp techniques, region around the nipple received approximately 80% of prescribed dose, although only IMRT showed inhomogeneous dose profile. At deeper depths mainly (6-11 mm depths), film dosimetry showed good agreement with the TPS calculation. In contrast, the measured dose at a 3-mm depth was higher than TPS calculation by 15%-30% for all techniques. For the tangential and IMRT techniques, 1 × 1 mm(2) grid size showed a smaller difference than that with a 2.5 × 2.5 mm(2) grid size compared to the measurements. CONCLUSIONS In general, TPS even with advanced algorithms do not provide accurate dosimetry in the buildup region, as verified by EBT2 film for all treatment techniques. For all cases, TPS and measured doses were in agreement from 6 mm in depth but differed at shallower depths. Grid size plays an important role in dose calculation. For accurate dosimetry small grid size should be used where differences are lower between TPS and measurements.

ACR Appropriateness Criteria® Resectable Rectal Cancer

The management of resectable rectal cancer continues to be guided by clinical trials and advances in technique. Although surgical advances including total mesorectal excision continue to decrease rates of local recurrence, the management of locally advanced disease (T3-T4 or N+) benefits from a multimodality approach including neoadjuvant concomitant chemotherapy and radiation. Circumferential resection margin, which can be determined preoperatively via MRI, is prognostic. Toxicity associated with radiation therapy is decreased by placing the patient in the prone position on a belly board, however for patients who cannot tolerate prone positioning, IMRT decreases the volume of normal tissue irradiated. The use of IMRT requires knowledge of the patterns of spreads and anatomy. Clinical trials demonstrate high variability in target delineation without specific guidance demonstrating the need for peer review and the use of a consensus atlas. Concomitant with radiation, fluorouracil based chemotherapy remains the standard, and although toxicity is decreased with continuous infusion fluorouracil, oral capecitabine is non-inferior to the continuous infusion regimen. Additional chemotherapeutic agents, including oxaliplatin, continue to be investigated, however currently should only be utilized on clinical trials as increased toxicity and no definitive benefit has been demonstrated in clinical trials.The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Imaging changes after stereotactic body radiation therapy for lung and liver tumors.

Stereotactic body radiation therapy (SBRT) is gaining wide acceptance as a treatment modality for lung and liver tumors, and it is crucial to make an accurate evaluation of the local effects of ablative doses of radiation in terms of local tumor control and normal tissue reaction or damage. The very complex radiation dose distribution of SBRT, the use of a large number of non-opposing and noncoplanar beams, and the delivery of individual ablative doses of radiation may cause substantially different radiographic appearance on diagnostic imaging compared with conventional radiation therapy. Different patterns of radiographic changes have been observed in the lung and liver after SBRT. This article reviews the post-SBRT imaging changes in the lung and liver. Since computed tomography and PET are the most commonly used diagnostic imaging tools for monitoring lung tumor and computed tomography for liver tumors, this article will focus on the changes observed on those imaging modalities.

ACR Appropriateness Criteria®: Local Excision in Early-Stage Rectal Cancer

Low anterior resection or abdominoperineal resection is considered standard treatment for early rectal cancer. These procedures, however, carry a risk of morbidity and mortality that may not be warranted for early distal lesions, which may be treated with local excision. Emerging data has investigated the efficacy of local excision in patients with early stage rectal cancers. An expert panel designated by the American College of Radiology has reviewed supporting data, from a few prospective multi-institutional trials and a number of single-institution, retrospective reviews. The consensus recognizes the importance of accurate staging to identify patients who may be candidates for a local excision approach. Optimal candidates for local excision alone include small, low-lying T1 tumors, without adverse pathologic features. A number of procedures may be safely used including transanal, posterior trans-sphincteric, posterior proctotomy, transanal excision, or transanal microsurgery. It is important to note that none of these include lymph node evaluation, and depending on the risk of lymph node metastases, adjuvant radiation with or without chemotherapy may be warranted. Patients with positive margins or T3 lesions are at high risk of local recurrence and should be offered immediate APR or LAR. However, patients with high-risk T1 tumors, T2 tumors, or those who are not amenable to more radical surgery may benefit from adjuvant treatment. Data have also reported excellent local control rates for neoadjuvant radiation +/- chemotherapy followed by local excision in higher risk patients, but it is not yet clear if this approach reduces recurrence rates over surgery alone.

ACR Appropriateness Criteria®: Rectal Cancer—Metastatic Disease at Presentation

In 2009, an estimated 40,870 new cases of rectal cancer will be diagnosed in the USA. After decades of treating metastatic colorectal cancer (CRC) with 5-fluorouracil alone, newer agents have resulted in significant improvements in disease-free and overall survival rates. These improvements stem from combinations of newer cytotoxic agents and targeted therapies. Based on performance status and burden of disease, metastatic CRC patients are generally treated with either a curative or palliative intent. Curative paradigm patients often have low burden liver or lung metastases which are technically resectable. Patients with resectable colorectal liver metastases and no evidence of any extrahepatic metastases have impressive 5-year survival rates of 30%-70% following resection. Unfortunately, only 20%-30% of patients with colorectal liver metastases are candidates for resection at initial presentation. Patients with unresectable liver or lung metastasis are candidates for local therapies including radioablation, chemoembolization, radioembolization, and stereotactic radiation therapy. In select patients with metastatic CRC, neoadjuvant or adjuvant pelvic chemoradiation (CRT) is indicated to prevent local recurrence. Patients who have resectable metastatic disease with symptomatic, obstructive, Stage T3-4 and N1, or low-lying (<or=5 cm) primary tumors should be considered for neoadjuvant CRT. This review summarizes the current literature on metastatic CRC and presents 4 simulated patient variants.

TH‐F‐211‐05: Evaluation of Superficial Dosimetry between Treatment Planning System and Measurement among Several Breast Cancer Treatment Techniques

Purpose: Accurate superficial dosimetry in breast cancer treatment is critical for the evaluation of the cosmetic and recurrence free survival. It is often believed that treatment planning systems (TPS) may not be able to provide accurate dosimetry in buildup region as it is not properly modeled in most TPS. Breast dosimetry in various treatment techniques; tangential, field‐in field, electronic compensator and IMRT are studied using EBT2 film and compared with TPS. Methods: A humanoid unsliced phantom was chosen for this study. Multiple layers of superflab bolus were placed on the breast for EBT2 film dosimetry. Treatment plans were generated using 4 techniques with 2 different grid sizes (1×1 and 2.5×2.5 mm2) to provide optimum dose distribution using AAA algorithm. Films were exposed with selected techniques and analyzed after 24 hrs. A calibration curve for dose versus pixel values was also generated at the same day as of the phantom measurement. The calculated dose and image data are imported to in‐house software developed using Visual C++, and the dose profiles on the film positions were collected. The calculated profiles were stretched to match their resolutions to that of film dosimetry.Results: At 6 mm and 11 mm depths, film dosimetry showed good agreement with the TPS calculation. On the other hand, the measured dose at 3 mm depth was higher than calculation by 15–30% for all techniques. For tangential and IMRT techniques, the calculation with 1×1 mm2 grid size showed smaller difference than 2.5×2.5 mm2 grid size. Conclusions: It is concluded that TPS do not provide accurate dosimetry in the buildup region as verified by EBT2 film for all treatment techniques. For all cases TPS and measured dose are in agreement from 6 mm in depths but differ at shallower depths. Grid size does play role in dose calculation. This work was supported by the JSPS Core‐to‐Core Program No. 23003.

Carcinoma of the Vagina

Primary vaginal cancer is a rare entity representing about 2% of all female genital neoplasias and only 0.1–0.2% of all cancers (Jemal et al. 59(4):225–249, 2009). Most carcinomas found in the vagina represent direct extension or metastasis from other primary gynecologic (cervix or vulva) and non-gynecologic sites, most commonly breast and gastrointestinal tract. There are a number of controversies in terms of epidemiology, staging, and diagnostic evaluation as well as in the management of vaginal cancer. Because of its rarity, there is a lack of prospective, randomized studies in patients with vaginal cancer, and therefore it is difficult to establish strong, evidence based-recommendations. Decisions regarding therapeutic options are for the most part, based on retrospective data and individual assessment using general principles derived from clinical experience in the cancer management in other sites. Most of the available data refer to the treatment of primary invasive SCC of the vagina, since this represents the most common histology.

Technical Aspects of Radiation Therapy in Endometrial Carcinoma

An estimated 43,470 new cases of EC are expected in the US in 2010 with 7,950 estimated deaths (American Cancer Society Cancer facts and figures 2010. American Cancer Society, Atlanta, 2010). Currently, EC is the fourth most common cancer in females, ranking behind breast, bowel, and lung cancer. In over 80% of the cases, the disease is confined to the uterus and cervix at the time of diagnosis, and uncorrected survival rates of 75% or greater are expected (Pecorelli Int J Gynaecol Obstet 105(2):103–104, 2009). In the last 25 years, the treatment of EC has evolved from almost routine use of preoperative radiotherapy (RT), generally intracavitary brachytherapy, followed by hysterectomy, to upfront surgical staging followed by tailored adjuvant therapy based on histopathological findings, as recommended by the International Federation of Gynecology and Obstetrics (FIGO Int J Gynecol Obstet 28:189–193, 1989). The purpose of this chapter is to review the role and technical aspects of external beam RT (EBRT) and brachytherapy in the management of EC as well as describing the radiotherapeutic approach as definitive therapy for medically inoperable patients and in the salvage setting for recurrent disease.