J.W. Snider

CyberKnife with Tumor Tracking: An Effective Treatment for High-Risk Surgical Patients with Single Peripheral Lung Metastases

Standard treatment for operable patients with single peripheral lung metastases is metastasectomy. We report mature CyberKnife outcomes for high-risk surgical patients with biopsy proven single peripheral lung metastases. Twenty-four patients (median age 73 years) with a mean maximum tumor diameter of 2.5 cm (range, 0.8–4.5 cm) were treated over a 6-year period extending from September 2004 to September 2010 and followed for a minimum of 1 year or until death. A mean dose of 52 Gy (range, 45–60 Gy) was delivered to the prescription isodose line in three fractions over a 3–11 day period (mean, 7 days). At a median follow-up of 20 months, the 2-year Kaplan–Meier local control and overall survival rates were 87 and 50%, respectively. CyberKnife with fiducial tracking is an effective treatment for high-risk surgical patients with single small peripheral lung metastases. Trials comparing CyberKnife with metastasectomy for operable patients are necessary to confirm equivalence.

Quantitative CT for volumetric analysis of medical images: initial results for liver tumors

Quantitative CT for volumetric analysis of medical images is increasingly being proposed for monitoring patient response during chemotherapy trials. An integrated MATLAB GUI has been developed for an oncology trial at Georgetown University Hospital. This GUI allows for the calculation and visualization of the volume of a lesion. The GUI provides an estimate of the volume of the tumor using a semi-automatic segmentation technique. This software package features a fixed parameter adaptive filter from the ITK toolkit and a tumor segmentation algorithm to reduce inter-user variability and to facilitate rapid volume measurements. The system also displays a 3D rendering of the segmented tumor, allowing the end user to have not only a quantitative measure of the tumor volume, but a qualitative view as well. As an initial validation test, several clinical cases were hand-segmented, and then compared against the results from the tool, showing good agreement.

Prophylactic cranial irradiation: recent outcomes and innovations

Brain metastases represent a frequent problem in several malignancies. They can shorten survival while causing significant morbidity and impairment in the patients quality of life. Prophylactic cranial irradiation (PCI) has become an integral part of the standard of care in small cell lung cancer (SCLC), yet its role in other malignancies remains the subject of significant discussion. Its role has been extensively investigated in non-small cell lung cancer and less so for breast cancer and other malignancies. Improvements in medical care as well as in whole brain radiotherapy (WBRT) techniques may improve the risk-benefit ratio of this therapy so as to expand its role in cancer care. The use of memantine in WBRT patients as well as the use of hippocampal avoidance techniques are of particular interest in this effort. Herein, we review the history of PCI, its current use, and areas of investigation in the application of PCI.

Advances in radiotherapy techniques and delivery for non-small cell lung cancer: benefits of intensity-modulated radiation therapy, proton therapy, and stereotactic body radiation therapy

The 21st century has seen several paradigm shifts in the treatment of non-small cell lung cancer (NSCLC) in early-stage inoperable disease, definitive locally advanced disease, and the postoperative setting. A key driver in improvement of local disease control has been the significant evolution of radiation therapy techniques in the last three decades, allowing for delivery of definitive radiation doses while limiting exposure of normal tissues. For patients with locally-advanced NSCLC, the advent of volumetric imaging techniques has allowed a shift from 2-dimensional approaches to 3-dimensional conformal radiation therapy (3DCRT). The next generation of 3DCRT, intensity-modulated radiation therapy and volumetric-modulated arc therapy (VMAT), have enabled even more conformal radiation delivery. Clinical evidence has shown that this can improve the quality of life for patients undergoing definitive management of lung cancer. In the early-stage setting, conventional fractionation led to poor outcomes. Evaluation of altered dose fractionation with the previously noted technology advances led to advent of stereotactic body radiation therapy (SBRT). This technique has dramatically improved local control and expanded treatment options for inoperable, early-stage patients. The recent development of proton therapy has opened new avenues for improving conformity and the therapeutic ratio. Evolution of newer proton therapy techniques, such as pencil-beam scanning (PBS), could improve tolerability and possibly allow reexamination of dose escalation. These new progresses, along with significant advances in systemic therapies, have improved survival for lung cancer patients across the spectrum of non-metastatic disease. They have also brought to light new challenges and avenues for further research and improvement.

Survival Outcomes of Patients Treated with Hypofractionated Stereotactic Body Radiation Therapy for Parotid Gland Tumors: a Retrospective Analysis

Background: to review a single-institution experience with the management of parotid malignancies treated by fractionated stereotactic body radiosurgery (SBRT). Findings: Between 2003 and 2011, 13 patients diagnosed with parotid malignancies were treated with adjuvant or definitive SBRT to a median dose of 33 Gy (range 25–40 Gy). There were 11 male and two female patients with a median age of 80. Ten patients declined conventional radiation treatment and three patients had received prior unrelated radiation therapy to neighboring structures with unavailable radiation records. Six patients were treated with definitive intent while seven patients were treated adjuvantly for adverse surgical or pathologic features. Five patients had clinical or pathologic evidence of lymph node disease. Conclusion: at a median follow-up of 14 months only one patient failed locally, and four failed distantly. The actuarial 2-year overall survival, progression-free survival, and local-regional control rates were 46, 84, and 47%, respectively. Statistical analysis revealed surgery as a positive predictor of overall survival while presence of gross disease was a negatively correlated factor (p < 0.05).

Hyperthermia and radiotherapy in bladder cancer

Abstract Hyperthermia represents a unique, safe, and advantageous methodology for improving therapeutic strategies in the management of bladder cancer. This modality has shown promise in contributing to treatment regimens for both superficial and muscle-invasive disease. Especially in conjunction with intravesical chemotherapy, systemic therapy, and radiotherapy, hyperthermia shows particular synergistic benefit. As such, it should be explored further through clinical use and clinical trial in conjunction with currently available techniques and emerging technologies. However, to conceptualise the way forward, it is particularly important to understand the current challenges to widespread use of non-invasive, bladder-sparing approaches and the current state of bladder cancer care. As such, in the following article, we have focused on not only the rationale for concurrent radiotherapy and hyperthermia, but also the clinical landscape in bladder cancer as a whole.

The use of stereotactic body radiation therapy for local control of glomangiomatosis: a case report

The vast majority of glomangiomas are small, benign neoplasms that can occur anywhere in the body but typically arise in the subcutaneous tissues of the extremities and are capable of causing extreme pain. Typically, these lesions are managed surgically with excellent rates of tumor control. On occasion, patients present with a variant of the glomangioma tumor consisting of numerous or recurrent nodules, a condition classified as glomangiomatosis. The authors present a case report of a young patient with multiply recurrent painful glomangiomas of the left foot, who was ultimately diagnosed with glomangiomatosis pedis. After multiple surgeries and surgical consultations, no surgery other than amputation was recommended. Therefore, the patient sought consultation with regard to stereotactic body radiation therapy (SBRT). In the absence of other options, and based on its effectiveness in treating glomus tumors of the head and neck which display similar natural history and histologic features, SBRT was offered. The patient underwent SBRT to the largest of his remaining tumors with excellent local control and significant reduction in pain at two and a half years follow-up.

Epidemiology, diagnosis, and optimal management of glioma in adolescents and young adults

Neoplasms of the central nervous system (CNS) are the most frequently encountered solid tumors of childhood, but are less common in adolescents and young adults (AYA), aged 15–39 years. Gliomas account for 29%–35% of the CNS tumors in AYA, with approximately two-thirds being low-grade glioma (LGG) and the remaining being high-grade glioma (HGG). We review the epidemiology, work-up, and management of LGG and HGG, focusing on the particular issues faced by the AYA population relative to pediatric and adult populations. Visual pathway glioma and brainstem glioma, which represent unique clinical entities, are only briefly discussed. As a general management approach for both LGG and HGG, maximal safe resection should be attempted. AYA with LGG who undergo gross total resection (GTR) may be safely observed. As age increases and the risk factors for recurrence accumulate, adjuvant therapy should be more strongly considered with a strong consideration of advanced radiation techniques such as proton beam therapy to reduce long-term radiation-related toxicity. Recent results also suggest survival advantage for adult patients with the use of adjuvant chemotherapy when radiation is indicated. Whenever possible, AYA patients with HGG should be enrolled in a clinical trial for the benefit of centralized genetic and molecular prognostic review and best clinical care. Chemoradiation should be offered to all World Health Organization grade IV patients with concurrent and adjuvant chemotherapy after maximal safe resection. Younger adolescents with GTR of grade III lesions may consider radiotherapy alone or sequential radiotherapy and chemotherapy if unable to tolerate concurrent treatment. A more comprehensive classification of gliomas integrating pathology and molecular data is emerging, and this integrative strategy offers the potential to be more accurate and reproducible in guiding diagnostic, prognostic, and management decisions.

Pencil beam scanning versus passively scattered proton therapy for unresectable pancreatic cancer

Background With an increasing number of proton centers capable of delivering pencil beam scanning (PBS), understanding the dosimetric differences in PBS compared to passively scattered proton therapy (PSPT) for pancreatic cancer is of interest. Methods Optimized PBS plans were retrospectively generated for 11 patients with locally advanced pancreatic cancer previously treated with PSPT to 59.4 Gy on a prospective trial. The primary tumor was targeted without elective nodal coverage. The same treatment couch, target coverage and normal tissue dose objectives were used for all plans. A Wilcoxon t-test was performed to compare various dosimetric points between the two plans for each patient. Results All target volume coverage goals were met in all PBS and passive scattering (PS) plans, except for the planning target volume (PTV) coverage goal (V100% >95%) which was not met in one PS plan (range, 81.8-98.9%). PBS was associated with a lower median relative dose (102.4% vs. 103.8%) to 10% of the PTV (P=0.001). PBS plans had a lower median duodenal V59.4 Gy (37.4% vs. 40.4%; P=0.014), lower small bowel median V59.4 Gy (0.11% vs. 0.37%; P=0.012), lower stomach median V59.4 Gy (0.01% vs. 0.1%; P=0.023), and lower median dose to 0.1 cc of the spinal cord {35.0 vs. 38.7 Gy [relative biological effectiveness (RBE)]; P=0.001}. Liver dose was higher in PBS plans for median V5 Gy (24.1% vs. 20.2%; P=0.032), V20 Gy (3.2% vs. 2.8%; P=0.010), and V25 Gy (2.6% vs. 2.2%; P=0.019). There was no difference in kidney dose between PBS and PS plans. Conclusions Proton therapy for locally advanced pancreatic cancer using PBS was not clearly associated with clinically meaningful reductions in normal tissue dose compared to PS. Some statistically significant improvements in PTV coverage were achieved using PBS. PBS may offer improved conformality for the treatment of irregular targets, and further evaluation of PBS and PS incorporating elective nodal irradiation should be considered.

Advances in the use of motion management and image guidance in radiation therapy treatment for lung cancer

The development of advanced radiation technologies, including intensity-modulated radiation therapy (IMRT), stereotactic body radiation therapy (SBRT) and proton therapy, has resulted in increasingly conformal radiation treatments. Recent evidence for the importance of minimizing dose to normal critical structures including the heart and lungs has led to incorporation of these advanced treatment modalities into radiation therapy (RT) for non-small cell lung cancer (NSCLC). While such technologies have allowed for improved dose delivery, implementation requires improved target accuracy with treatments, placing increasing importance on evaluating tumor motion at the time of planning and verifying tumor position at the time of treatment. In this review article, we describe issues and updates related both to motion management and image guidance in the treatment of NSCLC.