MRI-based IMRT planning for MR-linac: comparison between CT- and MRI-based plans for pancreatic and prostate cancers.

The treatment planning in radiation therapy (RT) can be arranged to combine benefits of computed tomography (CT) and magnetic resonance imaging (MRI) together to maintain dose calculation accuracy and improved target delineation. Our aim is study the dosimetric impact of uniform relative electron density assignment on IMRT treatment planning with additional consideration given to the effect of a 1.5 T transverse magnetic field (TMF) in MR-Linac. A series of intensity modulated RT (IMRT) plans were generated for two representative tumor sites, pancreas and prostate, using CT and MRI datasets. Representative CT-based IMRT plans were generated to assess the impact of different electron density (ED) assignment on plan quality using CT without the presence of a 1.5 T TMF. The relative ED (rED) values used were taken from the ICRU report 46. Four types of rED assignment in the organs at risk (OARs), the planning target volumes (PTV) and in the non-specified tissue (NST) were considered. Dose was recalculated (no optimization) using a Monaco 5.09.07a research planning system employing Monte Carlo calculations with an option to include TMF. To investigate the dosimetric effect of different rED assignment, the dose-volume parameters (DVPs) obtained from these specific rED plans were compared to those obtained from the original plans based on CT. Overall, we found that uniform rED assignment results in differences in DVPs within 3% for the PTV and 5% for OAR. The presence of 1.5 T TMF on IMRT DVPs resulted in differences that were generally within 3% of the Gold St for both the pancreas and prostate. The combination of uniform rED assignment and TMF produced differences in DVPs that were within 4-5% of the Gold St. Larger differences in DVPs were observed for OARs on T2-based plans. The effects of using different rED assignments and the presence of 1.5 T TMF for pancreas and prostate IMRT plans are generally within 3% and 5% of PTV and OAR Gold St values. There are noticeable dosimetric differences between the CT- and MRI-based IMRT plans caused by a combination of anatomical changes between the two image acquisition times, uniform rED assignment and 1.5 T TMF.

The use of radiation therapy in the management of selected patients with atypical lipomas.

Background and Objectives. Atypical lipomas are uncommon, slow-growing benign tumors. While surgery has been the primary treatment modality, we have managed some patients with radiation (RT) as a component of the treatment and have reported their outcomes in this study. Methods. A retrospective review of all cases of extremity and trunk atypical lipomas in The Sarcoma Database at the study institution was conducted. Results. Thirteen patients were identified. All patients underwent surgical resection at initial presentation and received pre- or postoperative radiation for subtotal resection (n = 2), local recurrence (n = 8), or progressive disease (n = 3). The median total radiation dose was 50 Gy. Median followup was 65.1 months. All patients treated with RT remained free of disease at the last followup. No grade 3 or higher late toxicity from radiation was observed. No cases of tumor dedifferentiation occurred. Conclusion. For recurrent or residual atypical lipomas, a combination of reexcision and RT can provide long-term local control with acceptable morbidity. For recurrent tumors, pre-op RT of 50 Gy appears to be an effective and well-tolerated management approach.

Recurrent invasive lobular carcinoma presenting as a ruptured breast implant.

BACKGROUND: For years, the treatment for invasive lobular carcinoma (ILC) has been mastectomy secondary to the lack of studies investigating the efficacy of breast conservation therapy on patients afflicted with ILC and due to the lack of long-term follow up investigating locoregional recurrence in this patient population. In this article we report the clinical course of a patient diagnosed with ILC. CASE REPORT: We describe the case of a 50-year-old woman with stage IIB (T2N1M0) ER/PR positive right breast ILC who underwent a right modified radical mastectomy, postoperative chemotherapy, a prophylactic left simple mastectomy with bilateral breast reconstruction and tamoxifen. Approximately 12 years later, she presented with a deflated breast implant and recurrent breast cancer with metastatic spread. She received palliative radiotherapy then palliative chemotherapy. Unfortunately, she succumbed to the cancer less than a year after being diagnosed with metastatic disease. CONCLUSIONS: This may be the first case report of a ruptured breast implant presenting at the same time as the diagnosis of recurrent breast cancer.

Preoperative CA 19-9 level is an important prognostic factor in patients with pancreatic adenocarcinoma treated with surgical resection and adjuvant concurrent chemoradiotherapy.

OBJECTIVES: To evaluate preoperative CA 19-9 level as a prognostic factor in patients with resected adenocarcinoma of the pancreas. METHODS: We retrospectively reviewed the cases of consecutive patients with pancreatic adenocarcinoma who had CA 19-9 measured preoperatively and underwent potentially curative resection at Mayo Clinic from September 1995 to January 2005. Patients who died within 30 days of resection were excluded. RESULTS: Search of our database identified 226 consecutive patients who met all the inclusion criteria. Adjuvant therapy was concurrent chemoradiotherapy (CCRT) in 122 patients, CCRT followed by chemotherapy in 23 patients, chemotherapy alone in 6 patients, and none in 69 patients. Median follow-up for surviving patients was 2.1 years. Median survival in all patients was 1.6 years. Patients with a high preoperative CA 19-9 level (defined as ≥180 U/mL) had a greater chance of having pathologic T3-T4 disease (P=0.03), positive lymph nodes (P=0.01), and histologic grade 3 or 4 (P=0.02). In multivariate analysis, a high preoperative CA 19-9 level (P=0.006) and R1-R2 margin status (P=0.03) were associated with decreased survival. Overall survival was increased for patients who received adjuvant CCRT (vs. those who did not; P=0.002) and for patients with high preoperative CA 19-9 level who received adjuvant CCRT (vs. those who did not; P<0.001). CONCLUSIONS: In patients with resected adenocarcinoma of the pancreas, high preoperative CA 19-9 level was associated with adverse pathologic features and poorer survival. Adjuvant CCRT was associated with a significant survival benefit in patients with high preoperative CA 19-9 but not in those with low CA 19-9.

Radiotherapy for marginally resected, unresectable or recurrent giant cell tumor of the bone: a rare cancer network study.

The role of radiotherapy for local control of marginally resected, unresectable, and recurrent giant cell tumors of bone (GCToB) has not been well defined. The number of patients affected by this rare disease is low. We present a series of 58 patients with biopsy proven GCToB who were treated with radiation therapy. A retrospective review of the role of radiotherapy in the treatment of GCToB was conducted in participating institutions of the Rare Cancer Network. Eligibility criteria consisted of the use of radiotherapy for marginally resected, unresectable, and recurrent GCToB. Fifty-eight patients with biopsy proven GCToB were analyzed from 9 participating North American and European institutions. Forty-five patients had a primary tumor and 13 patients had a recurrent tumor. Median radiation dose was 50 Gy in a median of 25 fractions. Indication for radiation therapy was marginal resection in 33 patients, unresectable tumor in 13 patients, recurrence in 9 patients and palliation in 2 patients. Median tumor size was 7.0 cm. A significant proportion of the tumors involved critical structures. Median follow-up was 8.0 years. Five year local control was 85% . Of the 7 local failures, 3 were treated successfully with salvage surgery. All patients who received palliation achieved symptom relief. Five year overall survival was 94%. None of the patients experienced grade 3 or higher acute toxicity. This study reports a large published experience in the treatment of GCToB with radiotherapy. Radiotherapy can provide excellent local control for incompletely resected, unresectable or recurrent GCToB with acceptable morbidity.

Fixation of atmospheric carbon dioxide by a cadmium(II) macrocyclic complex.

A crystal structure showing an unusual trinuclear Cd(II) cluster bridged in mu3 fashion by a carbonate ligand is reported. The carbonate ion is formed by fixation of atmospheric carbon dioxide from the corresponding cadmium mononuclear complex containing an aza crown ether.