Evaluating the potential benefit of reduced planning target volume margins for low and intermediate risk patients with prostate cancer using real-time electromagnetic tracking.

PURPOSE: The aim of this study is to quantify and describe the feasibility, clinical outcomes, and patient-reported outcomes of reduced planning target volume (PTV) margins for prostate cancer treatment using real-time, continuous, intrafraction monitoring with implanted radiation frequency transponder beacons. METHODS AND MATERIALS: For this prospective, nonrandomized trial, the Calypso localization system was used for intrafraction target localization in 31 patients with a PTV margin reduced to 2 mm in all directions. A total of 1333 fractions were analyzed with respect to movement of the prostate, pauses and interruptions, and dosimetric data. Pre- and posttreatment quality-of-life scores were tracked at baseline, during treatment, and up to 24 months after treatment. RESULTS: The mean time of daily treatment was 10 minutes, with 96.1% of all treatments falling within a 20-minute treatment window standard. On average, beacon motion exceeded 3 mm during active treatment only 1.76% of the time. The average length of treatment interruption was 34.2 seconds, with an average of 1 interruption every 3.39 fractions. The displacement or excursion of the prostate was the greatest in the superior or inferior dimension (0.11 mm and 0.09 mm, respectively) and anterior or posterior dimension (0.07 mm and 0.13 mm, respectively), followed by the left or right dimension (0.05 mm and 0.06 mm, respectively). At 6 months, patients demonstrated a smaller change in Expanded Prostate Cancer Index Composite scores than the ProtecT comparator group (decreased short-term morbidity). However, in the Bowel and Urinary domains at 12 and 24 months, there was no significant difference. CONCLUSIONS: Our data confirm and support that the use of Calypso tracking with intensity modulated radiation therapy reliably provides minimal disruption to daily treatments and overall time of treatment, with the PTV only moving outside of a 3-mm margin < 2% of the time. The use of a 3-mm PTV margin provides adequate dosimetric coverage while minimizing genitourinary and gastrointestinal toxicity.

Successful treatment of melanoma metastatic to the left atrium using external beam radiation therapy.

The successful treatment of a patient with primary nasal melanoma metastatic to the lung, pulmonary vein, and left atrium using radiation therapy is described. The patient was effectively treated with a conventional external beam radiation fractionation scheme (rather than a more commonly used hypofractioned regimen) that was utilized to minimize risk of arterial embolus of the tumor or rupture of a vessel wall. A post-treatment CT demonstrated a significant decrease in the caliber of the right pulmonary vein and tumor thrombus. The patient never developed cardiac valvular dysfunction or acute life-threatening massive embolism of tumor from the atrium. Unfortunately, the patient experienced clinical decline secondary to the massive progression of intra-abdominal disease and subsequently died from multiple liver metastases and liver failure. Numerous studies and this case report demonstrate that radiation therapy can be very effective in the treatment of malignant melanoma, especially when only small volumes of disease need to be treated and adequate total doses are used. Therefore, radiation therapy appears to play an important yet underutilized role in the treatment of metastatic melanomas.

Colorectal complications of external beam radiation versus brachytherapy for prostate cancer.

BACKGROUND: Although radiation therapy plays a central role in the management of prostate cancer, complications remain a troubling byproduct. We sought to determine the prevalence and significance of colorectal complications after external beam radiation (EBRT) versus brachytherapy (BT) for prostate cancer. METHODS: We performed a retrospective review of all patients undergoing EBRT or BT for prostate cancer from January 1999 to October 2005. Toxicities were graded using the Radiation Therapy Oncology Group scoring system or the modified Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer grading criteria. RESULTS: A total of 183 patients underwent EBRT and 50 patients underwent BT with a mean follow-up period of 39 months. BT was associated with significantly less acute (6% vs 43.5%) and late toxicities (2% vs 21.8%; both P < .001). Among patients receiving EBRT, acute grade 3 toxicity was experienced by 1 (.5%) patient, and grade 2 toxicity was experienced by 79 (43%) patients. Increased stool frequency was the most common manifestation (62%), followed by rectal pain and urgency (30%) and rectal bleeding (21%). Late toxicity included 34 (18.6%) patients with grade 2 toxicity (bleeding, 68%; frequent stools, 26%; pain and urgency, 18%), and 5 patients (2.7%) with grade 3 toxicity (bleeding requiring multiple cauterizations, 3; small-bowel obstruction requiring surgery, 1; anal stenosis requiring repeat dilations, 1). BT was relatively well tolerated, with only 3 patients (6%) experiencing grade 2 acute toxicity symptoms of pain and urgency. One BT patient suffered late grade 2 toxicity of bleeding requiring intervention. One patient developed rectal cancer 20 years after EBRT. CONCLUSIONS: Despite its relative safety, radiation therapy for prostate cancer has a significant incidence of colorectal complications. Overall, BT has a significantly lower incidence of acute and late toxicities than EBRT.