Evaluation of normal tissue exposure in patients receiving radiotherapy for pancreatic cancer based on RTOG 0848.

BACKGROUND: Pancreatic cancer is a highly aggressive malignancy. Chemoradiotherapy (CRT) is utilized in many cases to improve locoregional control; however, toxicities associated with radiation can be significant given the location of the pancreas. RTOG 0848 seeks to evaluate chemoradiation using either intensity-modulated radiation therapy (IMRT) or 3D conformal photon radiotherapy (3DCRT) modalities as an adjuvant treatment. The purpose of this study is to quantify the dosimetric changes seen when using IMRT or 3D CRT photon modalities, as well as proton radiotherapy, in patients receiving CRT for cancer of the pancreas treated per RTOG 0848 guidelines. MATERIALS: Ten patients with pancreatic head adenocarcinoma treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using IMRT and 3DCRT as well as proton radiotherapy were created for each patient. All planning volumes were created per RTOG 0848 protocol. Dose-volume histograms (DVH) were calculated and analyzed in order to compare plans between the three modalities. The organs at risk (OAR) evaluated in this study are the kidneys, liver, small bowel, and spinal cord. RESULTS: There was no difference between the IMRT and 3DCRT plans in dose delivered to the kidneys, liver, or bowel. The proton radiotherapy plans were found to deliver lower mean total kidney doses, mean liver doses, and liver D1/3 compared to the IMRT plans. The proton plans also gave less mean liver dose, liver D1/3, bowel V15, and bowel V50 in comparison to the 3DCRT. CONCLUSIONS: For patients receiving radiotherapy per ongoing RTOG 0848 for pancreatic cancer, there was no significant difference in normal tissue sparing between IMRT and 3DCRT treatment planning. Therefore, the choice between the two modalities should not be a confounding factor in this study. The proton plans also demonstrated improved OAR sparing compared to both IMRT and 3DCRT treatment plans.

Analysis of Intensity-Modulated Radiation Therapy (IMRT), Proton and 3D Conformal Radiotherapy (3D-CRT) for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients.

Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of Intensity-Modulated Radiation Therapy (IMRT), proton and 3D conformal radiotherapy (3D-CRT) with regard to reducing perioperative cardiopulmonary complications in esophageal cancer patients. Materials. Ten patients with esophageal cancer treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using proton radiotherapy, IMRT, and 3D-CRT modalities were created for each patient. Dose-volume histograms were calculated and analyzed to compare plans between the three modalities. The organs at risk (OAR) being evaluated in this study are the heart, lungs, and spinal cord. To determine statistical significance, ANOVA and two-tailed paired t-tests were performed for all data parameters. Results. The proton plans showed decreased dose to various volumes of the heart and lungs in comparison to both the IMRT and 3D-CRT plans. There was no difference between the IMRT and 3D-CRT plans in dose delivered to the lung or heart. This finding was seen consistently across the parameters analyzed in this study. Conclusions. In patients receiving radiation therapy for esophageal cancer, proton plans are technically feasible while achieving adequate coverage with lower doses delivered to the lungs and cardiac structures. This may result in decreased cardiopulmonary toxicity and less morbidity to esophageal cancer patients.

Palliative radiation therapy for primary gastric melanoma.

INTRODUCTION: Primary gastric melanoma is an exceedingly rare cause of upper gastrointestinal bleeding (GI bleeding). Prior reports of primary gastric melanoma have mostly been treated with surgery with utilization of radiation therapy being unreported. Radiation therapy has been used to palliate bleeding of other cancers including lung, bladder, cervix, and more recently primary gastric cancers. CASE PRESENTATION: This case documents an 87-year-old male who presented with fatigue and melena, and was found to have severe anemia. Endoscopy with biopsy revealed an isolated focus of melanoma. After discharge, he presented two days later and was found to have continued bleeding. Because he was deemed a poor surgical candidate he elected to undergo palliative radiation therapy for bleeding control. DISCUSSION: The diagnosis of primary verses metastatic melanoma is a topic of debate. Case reports of patients with no known extra-gastric primary have undergone surgical treatment with varying outcomes. Patients with metastatic gastric melanoma have relied on chemotherapy and radiation in addition to surgery, with radiation being used in the palliative setting. The use of radiation to control bleeding in other cancers including primary gastric adenocarcinoma has been previously studied. This case documents the utilization of radiation therapy in bleeding due to primary gastric melanoma. CONCLUSIONS: Radiation therapy can provide adequate bleeding palliation in patients with primary gastric melanoma.

Surgical and radiation therapy management of recurrent anal melanoma.

BACKGROUND: Melanoma of the anorectal mucosa is a rare but highly aggressive tumor. Its presenting symptoms are frequently confused with hemorrhoids, thereby causing a delay in diagnosis. Anorectal melanoma carries with it a very poor prognosis. There is a paucity of data investigating management options for anorectal melanoma, and even fewer data reporting recurrent or refractory cases. CASE PRESENTATION: This case documents a 41-year-old female with a long history of hemorrhoids presenting with anorectal discharge. She was incidentally found have anorectal melanoma following surgical resection. Systemic diagnostic work-up demonstrated PET-avid lymphadenopathy in her right groin. She underwent right groin dissection. However, seven months later she recurred in her right groin and a new recurrent mass was found in her pelvis. She underwent a second groin dissection and resection of the pelvic recurrence. This was followed by a course of hypofractionated radiation therapy then systemic immunotherapy. DISCUSSION: Surgery has been the mainstay of treatment. However, the extent of surgery has been the topic of investigation. Historically, radical resections have been performed but they result in high rates of post-operative morbidity. Newer studies have compared radical resection with wide local excisions and found comparable outcomes. Anorectal melanoma is frequently a systemic disease. The ideal systemic therapy regimen has not yet been determined but numerous studies show a benefit to multi-agent treatments. Radiation therapy is typically given in the post-operative or palliative setting. CONCLUSIONS: Anorectal mucosal melanoma is a very rare but aggressive disease with a poor prognosis. The overall treatment goal should strive to optimize quality of life and tumor control while minimizing treatment-related morbidities.

Proton therapy for hepatocellular carcinoma.

Proton radiotherapy has seen an increasing role in the treatment of hepatocellular carcinoma (HCC). Historically, external beam radiotherapy has played a very limited role in HCC due to a high incidence of toxicity to surrounding normal structures. The ability to deliver a high dose of radiation to the tumor is a key factor in improving outcomes in HCC. Advances in photon radiotherapy have improved dose conformity and allowed dose escalation to the tumor. However, despite these advances there is still a large volume of normal liver that receives a considerable radiation dose during treatment. Proton beams do not have an exit dose along the beam path once they enter the body. The inherent physical attributes of proton radiotherapy offer a way to maximize tumor control via dose escalation while avoiding excessive radiation to the remaining liver, thus increasing biological effectiveness. In this review we discuss the physical attributes and rationale for proton radiotherapy in HCC. We also review recent literature regarding clinical outcomes of using proton radiotherapy for the treatment of HCC.