M.R. Kanakamedala

3D Image based Customized versus Standard Treatment Planning for Cervical Cancer High Dose Rate Brachytherapy with Tandem and Ovoids

Purpose and Objective(s): To investigate the advantages of volumetric treatment planning in HDR brachytherapy for cervical carcinoma compared to standardized loading based on 2-D planning techniques. Materials and Methods: Our institution uses volume-based 3-D planning for each tandem and ovoid (T&O) insertion for HDR brachytherapy in the treatment of advanced cervical carcinoma. Here, we attempt to define the benefits of this approach. We re-planned 48 CT-based treatment plans on 12 patients (treated in our facility between February, 2009 and February, 2010) using a commonly used 2-D standard HDR loading of the T&O. All patients had received 4 fractions of 6.5 Gy or 5 fractions of 5.5 Gy to point H or A. The following organs at risk (OARs) were contoured: rectum, bladder, sigmoid, and small bowel. Our customized planning approach required the adjustment of source dwell times and positions to keep doses to the OARs below 80% of the prescription dose. The standardized HDR planning, however, bases the loading time on the length of the tandem. The dwell time for each tandem source position is the same. The dwell time multipliers for the ovoids were 0.33, 0.665 and 1.0, proportionate to the 2 cm, 4 cm, and 6 cm tandem length, respectively. The dose to the highest 2 cc (D2cc) of the OARs were also determined and analyzed. Results: There was a marked change in the value and location of the D2cc for all OARs from one HDR session to the next in both the standard and customized plans. When the data for the 48 plans were analyzed together, there were no significant differences between the customized plans and the standardized plans. However, when data for the individual plans were analyzed, 35% of the 2-D based plans did not meet our treatment planning objectives. Conclusion: Using customized plans for HDR T&O brachytherapy did not always reduce the doses to the rectum, bladder, sigmoid, and small bowels compared to the standardized plans. The dose to the small bowel could be up to 15% higher than the dose to point H or A in the standard plans indicating that customized plans may be superior to the standardized ones for the treatment of patients where this dose is critical.

Radiation induced myelopathy in a patient with tongue cancer: a case report.

A 47-year-old male with no significant past medical history presented with a gradually progressive right neck mass over a period of 18 months. initial evaluation by an otolaryngolosit revealed a proliferative lesion of size 2 cm at the right base of tongue and a 3 cm to 4 cm right cervical lymph node which was non-tender and mobile involving level ii. He underwent flexible laryngoscopy that also showed a 2 cm proliferative lesion at the base of tongue, not crossing the midline, but no other additional findings. Biopsy from the base of tongue lesion reported poorly differentiated squamous cell carcinoma. A neck computed tomography scan with contrast confirmed a 2 cm enhancing lesion at the base of tongue and a 4 cm right cervical lymph node involving level iiA. The tumor was staged as a T1n2aM0 squamous cell carcinoma. He was treated with intensity modulated radiation therapy to a total dose of 70 Gy delivered in 5 fractions per week over seven weeks concurrently with weekly cisplatin of 40 mg/m2. Maximum spinal cord dose was limited to 44.8 Gy. He was immobilized using an S-frame, head, neck and shoulder mask. Daily set-up verification for radiation therapy was performed using on board KvCT volumetric imaging. Seven months after completion of chemoradiation therapy he presented with a recurrent right cervical lymphadenopathy and underwent right modified radical neck dissection. After surgery, he shortly developed sensory loss from the nipples down bilaterally, and over a twomonth period his symptoms worsened. in addition, he also developed bowel and bladder incontinence, gait instability, and mild weakness of all four extremities. His physical exam was remarkable with mild weakness in the upper extremities and decreased sensation to light touch, pin-prick, and temperature from the C4 down. Additionally, he had markedly reduced vibratory and position sense in all four extremities. He could walk, but his gait was widebased and required assistance. His laboratory studies including vitamin B12 level were unremarkable. His CSF revealed a negative cytology and no oligoclonal bands were detected. in addition, gram stain, fungal, and bacterial cultures, vZv, CMv, and EBv testing were negative from the CSF. Magnetic resonance imaging of his spinal cord revealed a T2 bright (Figure 1A) and T1 post-gadolinium enhancing lesion (Figure 1B) in the cervical spinal cord. He underwent a C2-C4 laminectomy for biopsy. He was eventually discharged to home with a percutaneous gastrotomy tube and continued physical therapy. The next month, he was hospitalized for right lower lobe pneumonia and methicillin resistant staphylococcus aureus (MRSA) bacteremia then unfortunately rapidly deteriorated and became unresponsive. He was not intubated in accordance with his prior decision, and he eventually expired. An autopsy was performed and the histopathology of the cervical spinal revealed significant damage particularly prominent in some areas of the lateral funiculi (Figure 2), which normally carry corticospinal, rubrospinal, spinocerebellar and reticulospinal fibers. The presence of spheroids (Figure 3A, circles) was indicative of an axonal type injury compatible with myelopathy. in addition, specific staining of myelin revealed demyelination in that area (Figure 3B). other important findings included vascular damage which was suggestive of radiation myelopathy. The small vessels had lost their endothelial lining, which was replaced by hyaline material (Figure 3C, arrows). The surrounding skeletal muscle also showed signs of damage from the radiation (Figure 3D). Radiation myelopathy (RM) mostly occurs between six months to three years after ionizing radiation therapy for tumors in the area in which some parts of the spinal cord are inevitably exposed. The clinical manifestation is usually variable and A ct a O nc ol D ow nl oa de d fr om in fo rm ah ea lth ca re .c om b y 99 .7 4. 21 7. 94 o n 12 /2 3/ 12

Machine-Specific Magnetic Resonance Imaging Quality Control Procedures for Stereotactic Radiosurgery Treatment Planning

Purpose Magnetic resonance (MR) images are necessary for accurate contouring of intracranial targets, determination of gross target volume and evaluation of organs at risk during stereotactic radiosurgery (SRS) treatment planning procedures. Many centers use magnetic resonance imaging (MRI) simulators or regular diagnostic MRI machines for SRS treatment planning; while both types of machine require two stages of quality control (QC), both machine- and patient-specific, before use for SRS, no accepted guidelines for such QC currently exist. This article describes appropriate machine-specific QC procedures for SRS applications. Methods and materials We describe the adaptation of American College of Radiology (ACR)-recommended QC tests using an ACR MRI phantom for SRS treatment planning. In addition, commercial Quasar MRID3D and Quasar GRID3D phantoms were used to evaluate the effects of static magnetic field (B0) inhomogeneity, gradient nonlinearity, and a Leksell G frame (SRS frame) and its accessories on geometrical distortion in MR images. Results QC procedures found in-plane distortions (Maximum = 3.5 mm, Mean = 0.91 mm, Standard deviation = 0.67 mm, >2.5 mm (%) = 2) in X-direction (Maximum = 2.51 mm, Mean = 0.52 mm, Standard deviation = 0.39 mm, > 2.5 mm (%) = 0) and in Y-direction (Maximum = 13. 1 mm , Mean = 2.38 mm, Standard deviation = 2.45 mm, > 2.5 mm (%) = 34) in Z-direction and < 1 mm distortion at a head-sized region of interest. MR images acquired using a Leksell G frame and localization devices showed a mean absolute deviation of 2.3 mm from isocenter. The results of modified ACR tests were all within recommended limits, and baseline measurements have been defined for regular weekly QC tests. Conclusions With appropriate QC procedures in place, it is possible to routinely obtain clinically useful MR images suitable for SRS treatment planning purposes. MRI examination for SRS planning can benefit from the improved localization and planning possible with the superior image quality and soft tissue contrast achieved under optimal conditions.

Stereotactic body radiation therapy in lung

Lung cancer is the leading cause of cancer death worldwide, in both men and women. Contrary to the improved survival outcomes for many other types of cancers, the prognosis for people diagnosed with lung cancer remains poor, with 5-year relative survival ranging 6-18%. Majority of lung cancers diagnosed at locally advanced stage, due to the lack of observable symptoms for early stage lung cancer. Recently Lung Cancer screening in high-risk population with low dose CT scan showed 20% reduction in relative death from cancer. Screening allows diagnosing the cancer at early stage. For early (local only) stage, lobectomy is he treatment of choice that offers best 5-year overall survival of 60%. But majority of these patients are unable to tolerate the surgery due to poor pulmonary reserve or medical co morbidity. With the advent of new technology, improvements in imaging and treatment delivery enable us to extend the stereotactic radiation therapy to extra cranial sites. Stereotactic radiation therapy to lung reported 5-year local control rates in excess of 90% and overall survival of 40%. In this review article, we discussed the rationale, evidence supporting stereotactic body radiation therapy (SBRT) in lung tumors, radiobiology of hypofractionation, mediastinal staging, the treatment planning, and delivery process and also the role of SBRT in metastatic setting.

Racial disparities in tumor features and outcomes of patients with squamous cell carcinoma of the tonsil: Racial Disparities in Tonsillar Cancer

To identify differences in 3‐year overall survival (OS) and disease‐free survival (DFS) based on race in patients with tonsillar squamous cell carcinoma.

Outcomes utilizing intensity-modulated radiotherapy in oropharyngeal cancers: Tonsils versus base of tongue

The purpose of this study was to present the outcomes of oropharyngeal cancers treated with intensity‐modulated radiotherapy (IMRT) especially the differences between tonsillar and base of tongue (BOT) primaries.

Saving the hand: role of multimodality therapy for Ewing's sarcoma family tumor of the palm

The Ewing’s sarcoma family of tumors (EFTs) are a rare subtype of tumor that include primitive neuroectodermal tumors (PNETs), typical Ewing’s sarcoma, and atypical Ewing sarcoma. EFTs of the hand are extremely rare, and none have been reported to our knowledge beyond the fifth decade of life. EFTs present most frequently in the second decade of life and have a male predominance. Multimodality therapy is typically used to treat patients. We present a case that is unique for several reasons. First, this patient presented in the sixth decade of life, which is later than most cases. Second, treatment included an amputation-sparing resection followed by adjuvant radiation therapy with electron beams. The patient was left with complete functionality of the hand and remained free of recurrent disease 4 years later.

Adjuvant treatment of meningioma with stereotactic radiation surgery and hypofractionated stereotactic radiation surgery: Patterns of care and survival in a large, hospital database

Objectives Stereotactic radiation surgery (SRS) and hypofractionated stereotactic radiation surgery (HF-SRS) have become an alternative to external beam radiation therapy (EBRT) in the adjuvant treatment of meningiomas. The purpose of this study was to identify national treatment patterns and survival outcomes for meningiomas on the basis of radiation treatment modality in the adjuvant setting. Methods and materials The National Cancer Database was queried for patients with meningioma diagnosed between 2010 and 2012. World Health Organization grade I disease with subtotal resection and all cases of grade II disease regardless of the extent of the resection were included. Logistic regression was used to determine factors that were associated with receipt of SRS/HF-SRS compared with EBRT. Cox regression was used to determine covariables associated with differences in overall survival (OS). Results A total of 802 patients met the inclusion criteria of which 173 patients received SRS/HF-SRS (22%) and 629 patients (78%) received EBRT. The 3-year OS rate was 97.3% for the SRS/HF-SRS group and 93.4% for the EBRT group (P = .018). On subgroup analysis by grade, for grade I the 3-year OS rate was 98.3% for the SRS/HF-SRS group versus 96.7% for the EBRT group (P = .117). For grade II disease, the 3-year OS rate was 94.4% in the SRS/HF-SRS group versus 92.4% in the EBRT group (P = .199). On multivariable analysis, World Health Organization grade II histology (odds ratio [OR]: 0.34; 95% confidence interval [CI], 0.21-0.56; P < .001) and gross total resection (OR: 0.29; 95% CI, 0.15-0.57; P < .001) were associated with a decreased likelihood of receiving SRS/HF-SRS but private insurance (OR: 8.89; 95% CI, 1.15-68.47; P = .036) and Medicare (OR: 10.03; 95% CI, 1.28-78.69; P = .028) were associated with an increased likelihood of receiving SRS/HF-SRS. Year of diagnosis was not associated with receipt of SRS/HF-SRS. The multivariable Cox regression demonstrated a trend toward improved OS for treatment with SRS/HF-SRS (hazard ratio: 0.24; 95% CI, 0.06-1.03; P = .055). Conclusions SRS and HF-SRS are associated with similar survival as EBRT; however, SRS/HF-SRS is used infrequently and usage has not increased over time.

Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer: A Retrospective, Single-Center Study of 55 Patients.

Purpose/Objective(s): Stereotactic body radiation therapy (SBRT) is an effective treatment for patients with early-stage non-small cell lung cancer (NSCLC) who are not surgical candidates or who refuse surgical management. In this study, we report on our clinical outcomes and toxicity in the treatment of early-stage NSCLC with SBRT. Methods and Materials: Fifty-five patients with 59 T1-2N0M0 NSCLC lesions were treated at our institution between December 2009 and August 2014. The majority of the patients [38 (69%)] were treated with 50 Gy in 5 fractions, 7 patients (13%) with 48 Gy in 4 fractions, 8 patients (14%) with 60 Gy in 3 fractions, 1 patient (2%) with 62.5 Gy in 10 fractions, and 1 patient (2%) with 54 Gy in 3 fractions. Tumor response was evaluated using RECIST 1.1, and toxicity was graded using the CTCAE (Common Terminology Criteria for Adverse Events) version 3.0. The primary endpoints of this retrospective review included rates of overall survival, disease-free and progression-free survival, local failure, regional failure, and distant failure. A secondary endpoint included radiation-related toxicities. Results: The median follow-up was 23.8 months (range 1.1-57.6). The 3-year local control, progression-free survival, and overall survival rates were 91, 55, and 71%, respectively. The median age at diagnosis was 67.9 years (range 51.4-87.1). There were a total of 54 T1N0 tumors (92%) and 5 T2N0 lesions (8%). Adenocarcinoma was the most common pathology, comprising 54% of the lesions. A total of 16 of the patients (29%) failed. Among these, 5 local (9%), 14 regional (25%), and 4 distant failures (7%) were observed. On follow-up, one patient had grade 2 and another had grade 5 pneumonitis. Three patients experienced grade 2 chest wall tenderness. Two patients had grade 1 rib fractures, one of which could not be discerned from radiation-induced toxicity versus a traumatic fall. Conclusion: The University of Mississippi Medical Center SBRT experience has shown that SBRT provides satisfactory local control and overall survival rates with minimal toxicity in early-stage NSCLC patients.

SU‐E‐T‐414: TG‐129 Implementation On BrachyvisionTM

PURPOSE To outline the steps taken to clinically implement TG-129 on Brachyvision™ Treatment Planning System and to show the dosimetric differences that can be expected from the original COMS Eye Plaque model. METHODS The original COMS-Eye Plaque protocol was based on the following simplification: point source model in infinite water medium, 1D geometric function, 1D radial dose function and no anisotropy. Recently, AAPM Task Group 129 had made two specific recommendations: 1> Upgrade to TG-43U1 line source model; and 2> Report the heterogeneity corrected dose. Upgrading to line TG-43U1 line source model was done by a creating a seed collection in Brachyvision (version 11) for each plaque size. For each seed in the collection, both end coordinates had to be entered into the software. Full line source model was followed to compute the homogeneous dose at the prescription point. This homogeneous dose was converted to heterogeneous dose using a conversion table. Dose to prescription points for five different plaque sizes, including one customized notched plaque, was calculated using the implemented TG-129 model and compared against actual COMS derived doses from previously treated patient plans. Conversion to heterogeneous doses was done based on table 2 of TG-129 report. RESULTS As expected, dose difference between COMS and TG-129 was relatively minor, ranging from -0.15% to 1.91% at the prescription point. On the other hand, heterogeneous dose, which should be used for reporting purpose only, can be up to ∼17% lower than the corresponding homogeneous dose. CONCLUSION Conversion to TG-129 can be rapidly accomplished in 1-2 weeks. The initial time investment can be quickly recouped since the TPS plans created can be modified for different patient cases. Dosimetric difference between TG-129 and the original COMS model is small, generally less than 2%.