Role of Radiation Therapy in the Multidisciplinary Management of Uterine Carcinosarcoma.

OBJECTIVES: This study aimed to evaluate the impact of radiation therapy on outcomes for patients with uterine carcinosarcoma (UC). METHODS/MATERIALS: We retrospectively reviewed the records of 155 women with stage I (98), II (11), or III (46) UC who underwent total abdominal hysterectomy/bilateral salpingo-oophorectomy at our institution between 1990 and 2011. Survival rates were assessed using the Kaplan-Meier method and log-rank test. Univariate and multivariate Cox regression analyses were performed. RESULTS: Seventy-six patients (49%) received radiation therapy: 38 (50%) had vaginal cuff brachytherapy (VBT) alone and 38 had external beam radiation therapy (EBRT) ± VBT. Seventy patients (45%) received chemotherapy (12 concurrent, 49 adjuvant, 9 both). The 5-year overall survival rate was 48.6% (stage I, 53.8%; II, 30.0%; and III, 42.5%). The disease-specific survival (DSS) rate was 57.2% (stage I, 60.9%; II, 44.4%; and III, 51.8%). Patients treated with EBRT had a higher 5-year pelvic disease control rate (88.3%) than did patients treated with VBT only (67.4%) or no radiation (71.2%; P = 0.04). In stage III patients, EBRT was associated with higher 5-year pelvic disease control (90.0% vs 55.5%, P = 0.046), DSS (64.6% vs 46.4%, P = 0.13), and overall survival (64.6% vs 34.0%, P = 0.04) rates. For all 155 patients, age at least 65 years, cervical involvement, and lymph vascular space invasion were correlated with lower DSS on univariate and multivariate analyses. In addition, treatment with concurrent chemoradiation therapy was independently associated with a higher DSS rate on multivariate analysis. CONCLUSIONS: Patients with UC have a high rate of relapse in the regional nodes and distant sites. External beam radiation therapy improves locoregional control in all stages and may improve survival in stage III patients who are at the highest risk of pelvic relapse.

Creation of a Prognostic Index for Spine Metastasis to Stratify Survival in Patients Treated With Spinal Stereotactic Radiosurgery: Secondary Analysis of Mature Prospective Trials.

PURPOSE: There exists uncertainty in the prognosis of patients following spinal metastasis treatment. We sought to create a scoring system that stratifies patients based on overall survival. METHODS AND MATERIALS: Patients enrolled in 2 prospective trials investigating stereotactic spine radiation surgery (SSRS) for spinal metastasis with ≥ 3-year follow-up were analyzed. A multivariate Cox regression model was used to create a survival model. Pretreatment variables included were race, sex, age, performance status, tumor histology, extent of vertebrae involvement, previous therapy at the SSRS site, disease burden, and timing of diagnosis and metastasis. Four survival groups were generated based on the model-derived survival score. RESULTS: Median follow-up in the 206 patients included in this analysis was 70 months (range: 37-133 months). Seven variables were selected: female sex (hazard ratio [HR] = 0.7, P=.02), Karnofsky performance score (HR = 0.8 per 10-point increase above 60, P = .007), previous surgery at the SSRS site (HR = 0.7, P=.02), previous radiation at the SSRS site (HR = 1.8, P=.001), the SSRS site as the only site of metastatic disease (HR = 0.5, P=.01), number of organ systems involved outside of bone (HR = 1.4 per involved system, P<.001), and >5 year interval from initial diagnosis to detection of spine metastasis (HR = 0.5, P < .001). The median survival among all patients was 25.5 months and was significantly different among survival groups (in group 1 [excellent prognosis], median survival was not reached; group 2 reached 32.4 months; group 3 reached 22.2 months; and group 4 [poor prognosis] reached 9.1 months; P < .001). Pretreatment symptom burden was significantly higher in the patient group with poor survival than in the group with excellent survival (all metrics, P < .05). CONCLUSIONS: We developed the prognostic index for spinal metastases (PRISM) model, a new model that identified patient subgroups with poor and excellent prognoses.

Outcomes for Spine Stereotactic Body Radiation Therapy and an Analysis of Predictors of Local Recurrence.

PURPOSE: To investigate local control, survival outcomes, and predictors of local relapse for patients treated with spine stereotactic body radiation therapy. METHODS AND MATERIALS: We reviewed the records of 332 spinal metastases consecutively treated with stereotactic body radiation therapy between 2002 and 2012. The median follow-up for all living patients was 33 months (range, 0-111 months). Endpoints were overall survival and local control (LC); recurrences were classified as either in-field or marginal. RESULTS: The 1-year actuarial LC and overall survival rates were 88% and 64%, respectively. Patients with local relapses had poorer dosimetric coverage of the gross tumor volume (GTV) compared with patients without recurrence (minimum dose [Dmin] biologically equivalent dose [BED] 23.9 vs 35.1 Gy, P<.001; D98 BED 41.8 vs 48.1 Gy, P=.001; D95 BED 47.2 vs 50.5 Gy, P=.004). Furthermore, patients with marginal recurrences had poorer prescription coverage of the GTV (86% vs 93%, P=.01) compared with those with in-field recurrences, potentially because of more upfront spinal canal disease (78% vs 24%, P=.001). Using a Cox regression univariate analysis, patients with a GTV BED Dmin ≥33.4 Gy (median dose) (equivalent to 14 Gy in 1 fraction) had a significantly higher 1-year LC rate (94% vs 80%, P=.001) compared with patients with a lower GTV BED Dmin; this factor was the only significant variable on multivariate Cox analysis associated with LC (P=.001, hazard ratio 0.29, 95% confidence interval 0.14-0.60) and also was the only variable significant in a separate competing risk multivariate model (P=.001, hazard ratio 0.30, 95% confidence interval 0.15-0.62). CONCLUSIONS: Stereotactic body radiation therapy offers durable control for spinal metastases, but there is a subset of patients that recur locally. Patients with local relapse had significantly poorer tumor coverage, which was likely attributable to treatment planning directives that prioritized the spinal cord constraints over tumor coverage. When possible, we recommend maintaining a GTV Dmin above 14 Gy in 1 fraction and 21 Gy in 3 fractions.

Variable impact of intracavitary brachytherapy fractionation schedule on biologically effective dose to organs at risk in patients with cervical cancer.

PURPOSE: To determine the effect of intracavitary brachytherapy (ICBT) fractionation schedule on biologically effective dose to organs at risk. METHODS AND MATERIALS: We reviewed records from 26 patients who had CT imaging during ICBT for International Federation of Gynecology and Obstetrics stage IB2-IVA cervical cancer. Using α/ß=10, we calculated hypothetical nominal doses to achieve a biologically effective dose at 2 Gy per fraction (EQD2α/ß=10) of 40 Gy to Point A for high-dose-rate ICBT with 1-15 fractions. Corresponding minimum EQD2α/ß=3s to the maximally irradiated 2 cc of rectum, bladder, and sigmoid were calculated for each fractionation scheme and added to EQD2α/ß=3 from external beam radiotherapy. Total EQD2α/ß=3s were compared with American Brachytherapy Society suggested dose constraints (rectum/sigmoid, ≤75 Gy; bladder, ≤90 Gy). RESULTS: Except for rectal EQD2α/ß=3 in three patients, the rectal, bladder, and sigmoid EQD2α/ß=3s decreased with increasing fractionation in all patients. Although the total rectal EQD2α/ß=3s were less than the American Brachytherapy Society rectal dose constraint in all patients at all fractionation schedules, the total bladder EQD2α/ß=3s routinely exceeded the bladder dose constraint, even at maximum fractionation. By contrast, increasing fractionation decreased the number of patients with doses exceeding the sigmoid dose constraint by 48%. CONCLUSIONS: The relationship between ICBT fractionation schedule and relative EQD2α/ß=3s to rectum, bladder, and sigmoid depends on individual anatomy. Fractionation optimization can improve therapeutic ratios by minimizing the risk or severity of toxic effects. For patients in whom many fractions optimize the therapeutic ratio, low-dose-rate or pulsed-dose-rate brachytherapy may be preferred.

Improving prostate brachytherapy quality assurance with MRI-CT fusion-based sector analysis in a phase II prospective trial of men with intermediate-risk prostate cancer.

PURPOSE: We combined sector analysis with MRI-CT fusion to comprehensively assess postimplant dosimetry after prostate brachytherapy. METHODS AND MATERIALS: Subjects were 50 men with intermediate-risk prostate cancer treated with (125)I brachytherapy in a prospective phase II clinical trial. On Day 30 after the implantation, dosimetry was evaluated in the prostate base, midgland, and apex regions on fused MRI-CT scans and CT scans. Volumes of each sector receiving 100% of the prescribed dose (V100) and doses to 90% of each sector (D90) were also calculated on the ultrasonogram used for treatment planning and compared with values derived from CT and fused MRI-CT scans. RESULTS: Fused MRI-CT scans revealed lower-than-expected doses for the whole prostate (V100=91.3%, D90=152.9Gy) compared with CT scans (98.5% and 183.6Gy, p<0.0001) and lower doses to the prostate base (V100=79%, D90=130Gy) vs. CT (96% and 170Gy, p<0.0001). However, lower doses to the prostate base did not adversely affect biochemical outcomes in men with biopsy-proven disease at the base. At a median followup time of 42 months, the mean prostate-specific antigen level for all patients was 0.3ng/mL, and no patient had experienced biochemical or clinical progression or recurrence. CONCLUSIONS: MRI-CT fusion-based sector analysis was feasible and revealed significantly lower doses to the prostate base than doses estimated from CT alone, although this did not affect biochemical outcomes. MRI-CT fusion-based sector analysis may be useful for developing MRI-based dosimetric markers to predict disease outcomes and treatment-related morbidity.

Probing the interaction between the coiled coil leucine zipper of cGMP-dependent protein kinase Ialpha and the C terminus of the myosin binding subunit of the myosin light chain phosphatase.

Nitric oxide and nitrovasodilators induce vascular smooth muscle cell relaxation in part by cGMP-dependent protein kinase I (PKG-Ialpha)-mediated activation of myosin phosphatase (MLCP). Mechanistically it has been proposed that protein-protein interactions between the N-terminal leucine zipper (LZ) domain of PKG-Ialpha ((PKG-Ialpha(1-59)) and the LZ and/or coiled coil (CC) domain of the myosin binding subunit (MBS) of MLCP are localized in the C terminus of MBS. Although recent studies have supported these interactions, the critical amino acids responsible for these interactions have not been identified. Here we present structural and biophysical data identifying that the LZ domain of PKG-Ialpha(1-59) interacts with a well defined 42-residue CC motif (MBS(CT42)) within the C terminus of MBS. Using glutathione S-transferase pulldown experiments, chemical cross-linking, size exclusion chromatography, circular dichroism, and isothermal titration calorimetry we identified a weak dimer-dimer interaction between PKG-Ialpha(1-59) and this C-terminal CC domain of MBS. The K(d) of this non-covalent complex is 178.0+/-1.5 microm. Furthermore our (1)H-(15)N heteronuclear single quantum correlation NMR data illustrate that this interaction is mediated by several PKG-Ialpha residues that are on the a, d, e, and g hydrophobic and electrostatic interface of the C-terminal heptad layers 2, 4, and 5 of PKG-Ialpha. Taken together these data support a role for the LZ domain of PKG-Ialpha and the CC domain of MBS in this requisite contractile complex.

Cyclic GMP-dependent protein kinase Ialpha inhibits thrombin receptor-mediated calcium mobilization in vascular smooth muscle cells.

Vascular smooth muscle contractile state is regulated by intracellular calcium levels. Nitric oxide causes vascular relaxation by stimulating production of cyclic GMP, which activates type I cGMP-dependent protein kinase (PKGI) in vascular smooth muscle cells (VSMC), inhibiting agonist-induced intracellular Ca2+ mobilization ([Ca2+]i). The relative roles of the two PKGI isozymes, PKGIalpha and PKGIbeta, in cyclic GMP-mediated inhibition of [Ca2+]i in VSMCs are unclear. Here we have investigated the ability of PKGI isoforms to inhibit [Ca2+]i in response to VSMC activation. Stable Chinese hamster ovary cell lines expressing PKGIalpha or PKGIbeta were created, and the ability of PKGI isoforms to inhibit [Ca2+]i in response to thrombin receptor stimulation was examined. In Chinese hamster ovary cells stably expressing PKGIalpha or PKGIbeta, 8-Br-cGMP activation suppressed [Ca2+]i by thrombin receptor activation peptide (TRAP) by 98 +/- 1 versus 42 +/- 5%, respectively (p <0.002). Immunoblotting studies of cultured human VSMC cells from multiple sites using PKGIalpha- and PKGIbeta-specific antibodies showed PKGIalpha is the predominant VSMC PKGI isoform. [Ca2+]i following thrombin receptor stimulation was examined in the absence or presence of cyclic GMP in human coronary VSMC cells (Co403). 8-Br-cGMP significantly inhibited TRAP-induced [Ca2+]i in Co403, causing a 4-fold increase in the EC50 for [Ca2+]i. In the absence of 8-Br-cGMP, suppression of PKGIalpha levels by RNA interference (RNAi) led to a significantly greater TRAP-stimulated rise in [Ca2+]i as compared with control RNAi-treated Co403 cells. In the presence of 8-Br-cGMP, the suppression of PKGIalpha expression by RNAi led to the complete loss of cGMP-mediated inhibition of [Ca2+]i. Adenoviral overexpression of PKGIbeta in Co403 cells was unable to alter TRAP-stimulated Ca2+ mobilization either before or after suppression of PKGIalpha expression by RNAi. These results support that PKGIalpha is the principal cGMP-dependent protein kinase isoform mediating inhibition of VSMC activation by the nitric oxide/cyclic GMP pathway.