Biomedical subjects

Charles N Catton

Publications and source records attributed to Charles N Catton.

15 recordsLinked to original sources

PubMed2006

Radiation planning comparison for superficial tissue avoidance in radiotherapy for soft tissue sarcoma of the lower extremity.

PURPOSE: Three types of preoperative radiotherapy (RT) plans for extremity soft tissue sarcoma were compared to determine the amount of dose reduction possible to the planned surgical skin flaps required for tumor resection and wound closure, without compromising target coverage. METHODS AND MATERIALS: Twenty-four untreated patients with large, deep, lower extremity STS treated with preoperative RT and limb salvage surgery had their original conventional treatment plans re-created. The same clinical target volume was used for all three plans. The future surgical skin flaps were created virtually through contouring by the treating surgeon and regarded as an organ at risk. The original, conformal, and intensity-modulated RT (IMRT) plans were created to deliver 50 Gy in 25 fractions to the clinical target volume. Clinical target volume and organ-at-risk dose-volume histograms were calculated and the plans compared for conformality, target coverage, and dose sparing. RESULTS: The mean dose to the planned skin flaps was 42.62 Gy (range, 30.24-48.65 Gy) for the original plans compared with 40.12 Gy (range, 24.24-47.26 Gy) for the conformal plans and 26.71 Gy (range, 22.31-31.91 Gy) for the IMRT plans (p = 0.0008). An average of 86.4% (range, 53.2-97.4%) of the planned skin flaps received >or=30 Gy in the original plans compared with 83.4% (range, 36.2-96.2%) in the conformal plans and only 34.0% (range, 22.5-53.3%) in the IMRT plans (p = 0.0001). IMRT improved target conformality compared with the original and conformal plans (1.27, 2.34, and 1.76, respectively, p = 0.0001). CONCLUSION: In a retrospective review, preoperative IMRT substantially lowered the dose to the future surgical skin flaps, sparing a greater percentage of this structure's volume without compromising target (tumor) coverage.

Adult↗

PubMed2006

A magnetic resonance imaging study of prostate deformation relative to implanted gold fiducial markers.

PURPOSE: To describe prostate deformation during radiotherapy and determine the margins required to account for prostate deformation after setup to intraprostatic fiducial markers (FM). METHODS AND MATERIALS: Twenty-five patients with T1c-T2c prostate cancer had three gold FMs implanted. The patients presented with a full bladder and empty rectum for two axial magnetic resonance imaging (MRI) scans using a gradient recalled echo (GRE) sequence capable of imaging the FMs. The MRIs were done at the time of radiotherapy (RT) planning and a randomly assigned fraction. A single observer contoured the prostate surfaces. They were entered into a finite element model and aligned using the centroid of the three FMs. RESULTS: During RT, the prostate volume decreased by 0.5%/fraction (p = 0.03) and the FMs in-migrated by 0.05 mm/fraction (p < 0.05). Prostate deformation was unrelated to differential bladder and bowel filling, but was related to a transurethral resection of the prostate (TURP) (p = 0.003). The standard deviation for systematic uncertainty of prostate surface contouring was 0.8 mm and for FM centroid localization was 0.4 mm. The standard deviation of random interfraction prostate deformation was 1.5 mm and for FM centroid variability was 1.1 mm. These uncertainties from prostate deformation can be incorporated into a margin recipe to determine the total margins required for RT. CONCLUSIONS: During RT, the prostate exhibited: volume decrease, deformation, and in-migration of FMs. Patients with TURPs were prone to prostate deformation.

Aged↗

PubMed2006

Bone invasion in extremity soft-tissue sarcoma: impact on disease outcomes.

BACKGROUND: The purpose of the current study was to evaluate histologic bone invasion as a predictor of oncologic outcome in extremity soft-tissue sarcoma (STS) patients presenting to a specialty sarcoma center between 1986 and 2001. METHODS: All patients who underwent surgery for extremity STS were identified from the prospective database at the study institution. Patient demographic features were compared using chi-square analyses or independent-sample Student t-tests. The disease outcomes were compared for those with and without bone invasion using Kaplan-Meier survival analysis and Cox modeling. RESULTS: In a review of 874 patients with STS of the extremity, 48 patients (5.5%) had evidence of bone invasion. Patients with bone invasion presented with larger tumors that were more frequently deep in the extremity and more often had metastases at presentation. Patients with bone invasion had lower metastasis-free survival but bone invasion was not found to be an independent prognostic factor (P = .274) on Cox modeling. Bone invasion was found to be prognostic of overall survival on multivariate analysis (P < .0001). CONCLUSIONS: In a small percentage of patients with STS, bone resection may be required to obtain an adequate surgical margin, thereby limiting the risk of local tumor recurrence. Histologic bone invasion portends a poorer prognosis in terms of overall survival.

Adult↗

PubMed2006

Long-term results of two prospective trials of preoperative external beam radiotherapy for localized intermediate- or high-grade retroperitoneal soft tissue sarcoma.

BACKGROUND: The reported data on surgery plus radiotherapy for retroperitoneal soft tissue sarcomas (RPS) have been mostly from retrospective studies. We evaluated the long-term outcome of patients with operable RPS who were treated with protocol-based preoperative radiotherapy followed by complete surgical resection. METHODS: Data from two prospective trials that included preoperative radiotherapy and surgery for patients with radiographically resectable RPS were combined to define long-term relapse rates and survival. RESULTS: Seventy-two patients with intermediate- or high-grade RPS were treated with preoperative radiotherapy (median dose, 45 Gy; range, 18.0-50.4 Gy). Fifty-four patients (75%) had primary RPS, whereas 18 (25%) had recurrent disease. The median tumor size was 15.5 cm. Sixty-four patients completed the planned preoperative radiotherapy; 57 (89%) underwent laparotomy with curative intent, and 54 (95%) had a macroscopically complete (R0 or R1) resection. With a median follow-up of 40.3 months, 28 patients (52%) who received preoperative radiotherapy and underwent a macroscopically complete resection had recurrences. For the 54 patients who underwent R0 or R1 resection after preoperative radiotherapy, the 5-year local recurrence-free, disease-free, and overall survival rates were 60%, 46%, and 61%, respectively. The median overall survival has not been reached (>60 months). CONCLUSIONS: Patients with intermediate- or high-grade RPS treated with preoperative radiotherapy plus complete resection had a median survival >60 months. This compares favorably to historical data for similar patients treated with surgery alone.

Adult↗

PubMed2005

The surgical and functional outcome of limb-salvage surgery with vascular reconstruction for soft tissue sarcoma of the extremity.

BACKGROUND: This study compared the surgical, oncological, and functional outcomes of patients undergoing limb-salvage surgery for extremity soft tissue sarcoma with vascular resection and reconstruction with the outcomes of those undergoing limb-salvage without vascular reconstruction. METHODS: Nineteen patients were identified from a prospective soft-tissue sarcoma database who underwent vascular resection and reconstruction as part of their limb-salvage surgery and who were followed up for at least 1 year or until death. Each of these 19 patients was case-matched to 2 additional patients on the basis of tumor location, size, and depth; patient age; and timing of radiation. To compare functional outcome, a subset of patients was case-matched with additional criteria including wound-complication status, motor nerve sacrifice, similar preoperative function as determined by the Toronto Extremity Salvage Score, and no metastases at diagnosis or the 1-year follow-up. RESULTS: Patients in the vascular reconstruction group were more likely to require a muscle transfer (53% vs. 18%; P = .008), experience a wound complication (68% vs. 32%; P = .03), experience deep venous thrombosis (26% vs. 0; P = .003), experience significant limb edema (87% vs. 20%; P = .001), and ultimately require an amputation (16% vs. 3%; P = .07). Patients who underwent vascular reconstruction had only slightly lower Toronto Extremity Salvage Score scores 1 year after surgery (78.5 vs. 84.2; P = .35). There were no significant differences in local or systemic tumor relapse between the two groups. CONCLUSIONS: Vascular reconstruction is a feasible option in limb-salvage surgery for soft tissue sarcoma but is associated with an increased risk for postoperative complications, including amputation. Although function is not significantly worse after vascular reconstruction, the results are less predictable.

Adult↗

PubMed2005

Epineural dissection is a safe technique that facilitates limb salvage surgery.

UNLABELLED: Epineural dissection has been used in our center for the past 19 years as a means of preserving the sciatic nerve when it is closely applied to a soft tissue sarcoma. Our aim in doing this study was to establish if this technique resulted in increased local or systemic recurrence of the tumor. In addition, we assessed functional outcomes. Forty-three patients had an epineural dissection done during primary resection of a malignant thigh tumor. These patients were compared with 44 patients with tumors that were of similar size and grade but distant from the nerve. We also analyzed seven patients who required nerve resection. There was no difference in local or systemic recurrence rates or functional outcomes when epineural dissection was done. Those with nerve resection had worse Musculoskeletal Tumor Society scores but equivalent Toronto Extremity Salvage Scores to those with an epineural dissection. We conclude that epineural dissection (when combined with radiotherapy in a planned multidisciplinary approach to limb salvage) is both a safe and effective procedure to preserve the sciatic nerve and that nerve resection should be limited to situations where the nerve is completely encased in tumor. LEVEL OF EVIDENCE: Prognostic study, Level II-2 (retrospective cohort study). See the Guidelines for Authors for a complete description of levels of evidence.

Cohort Studies↗

PubMed2004

The indications for and the prognostic significance of amputation as the primary surgical procedure for localized soft tissue sarcoma of the extremity.

BACKGROUND: The indications for primary amputation of a localized soft tissue sarcoma (STS) of the extremity are not well defined in the literature. However, it has been suggested that patients who require an amputation to treat an STS are at increased risk for developing metastases. We categorized the main indications for primary amputation in our patient population and compared their oncological outcome with the outcome of patients who underwent limb-sparing surgery. METHODS: 413 consecutive patients treated surgically at a single center for primary, nonmetastatic, deep, intermediate-, or high-grade STS of the extremity were reviewed. Indications for primary amputation were identified. Demographics and outcomes were compared between the amputation and limb-salvage groups. Multivariate Cox model analysis was used to identify independent risk factors for systemic relapse. RESULTS: Twenty-five (6%) of 413 patients with STS underwent primary amputation: they were older (P = .05), had larger tumors (P = .001), and had a significantly greater risk of developing metastatic disease than patients who underwent limb-sparing procedures (P = .008). However, multivariate analysis demonstrated that the only independent predictors of systemic relapse were tumor size (P = .0001) and tumor grade (P = .0001). Primary amputation was not an independent risk factor for metastatic disease. CONCLUSIONS: The decision to perform a primary amputation for an STS of the extremity is based on the location and local extent of the tumor, and the expected function of the extremity after tumor resection. The higher risk of metastases for patients who require primary amputation is accounted for by independent risk factors associated with their tumors--predominantly large tumor size.

Adolescent↗

PubMed2004

Radiation response: an additional unique signature of myxoid liposarcoma.

PURPOSE: Historically, myxoid liposarcoma (MLS) has been reported to show a marked clinical response to radiotherapy (RT), but objective data to support that contention have been lacking. We performed a retrospective analysis of the response of a group of MLS tumors to preoperative RT using tumor dimensions calculated from pretreatment imaging and the subsequent surgical specimen obtained approximately 1 month after RT. METHODS AND MATERIALS: Data were abstracted from the Princess Margaret Hospital prospective database on a series of patients with MLS who had undergone preoperative RT between 1991 and 1999. A group of malignant fibrous histiocytoma (MFH) patients treated on the same protocol served as controls. Pretreatment and posttreatment three-dimensional measurements were obtained; comparison tumor volume measurements were estimated using the ellipsoid formula, and the analysis was also repeated using the maximal tumor dimension. Identical measurement procedures were used for the MLS (experimental) and MFH (control) cases. RESULTS: A total of 16 MLS tumor specimens were available for analysis, and 16 MFH cases were randomly chosen for comparison. The mean pretreatment and posttreatment volume of the MLS tumors was 415 and 199 cm(3), respectively (P = <0.0001). The mean pretreatment and posttreatment volume of the MFH tumors was 264 and 273 cm(3), respectively (p = 0.804). The proportional reduction in the median tumor volume was 59% and -7% for MLS and MFH tumors, respectively. Both the absolute and the proportional reduction in volume for MLS tumors vs. MFH tumors was statistically significant (p = 0.006 and p = 0.002, respectively). CONCLUSION: These results provide the first objective data to support the idea that MLS tumors show a statistically significant reduction in size when treated with RT and that this response is greater than that of MFH tumors given the same RT. These results may be relevant to the management of MLS with combined RT and surgery in difficult anatomic situations in which adequate surgical excision is not feasible. They also confirm another unique characteristic of this unusual subtype of soft tissue sarcoma.

Adult↗

PubMed2004

On-line aSi portal imaging of implanted fiducial markers for the reduction of interfraction error during conformal radiotherapy of prostate carcinoma.

PURPOSE: An on-line system to ensure accuracy of daily setup and therapy of the prostate has been implemented with no equipment modification required. We report results and accuracy of patient setup using this system. METHODS AND MATERIALS: Radiopaque fiducial markers were implanted into the prostate before radiation therapy. Lateral digitally reconstructed radiographs (DRRs) were obtained from planning CT data. Before each treatment fraction, a lateral amorphous silicon (aSi) portal image was acquired and the position of the fiducial markers was compared to the DRRs using chamfer matching. Couch translation only was used to account for marker position displacements, followed by a second lateral portal image to verify isocenter position. Residual displacement data for the aSi and previous portal film systems were compared. RESULTS: This analysis includes a total of 239 portal images during treatment in 17 patients. Initial prostate center of mass (COM) displacements in the superior, inferior, anterior, and posterior directions were a maximum of 7 mm, 9 mm, 10 mm and 11 mm respectively. After identification and correction, prostate COM displacements were <3 mm in all directions. The therapists found it simple to match markers 88% of the time using this system. Treatment delivery times were in the order of 9 min for patients requiring isocenter adjustment and 6 min for those who did not. CONCLUSIONS: This system is technically possible to implement and use as part of an on-line correction protocol and does not require a longer than standard daily appointment time at our center with the current action limit of 3 mm. The system is commercially available and is more efficient and user-friendly than portal film analysis. It provides the opportunity to identify and accommodate interfraction organ motion and may also permit the use of smaller margins during conformal prostate radiotherapy. Further integration of the system such as remote table control would improve efficiency.

Humans↗

PubMed2004

Carbonic anhydrase IX as a marker for poor prognosis in soft tissue sarcoma.

PURPOSE: Hypoxia is associated with malignant progression and poor outcome in several human tumors, including soft tissue sarcoma. Recent studies have suggested that carbonic anhydrase (CA) IX is an intrinsic marker of hypoxia, and that CA IX correlates with poor prognosis in several types of carcinoma. The aim of this study was to quantify the extent of CA IX expression and to investigate whether CA IX is a marker for poor prognosis in soft tissue sarcoma patients at high risk of developing metastasis. EXPERIMENTAL DESIGN: Archival paraffin-embedded blocks were retrieved from 47 patients with deep, large, high-grade soft tissue sarcoma. Sections from two separate and representative tumor areas were immunostained for CA IX, and the CA IX-positive area fraction was quantified by image analysis, excluding areas of normal stroma and necrosis that were identified from serial H&E-stained sections. Patients were then subject to survival analysis. RESULTS: CA IX-positive area fractions of viable tumor tissue varied significantly between tumors (range, 0-0.23; median, 0.004), with positive membranous CA IX staining in 66% (31 of 47) of the tumors. Patients with CA IX-positive tumors had a significantly lower disease-specific and overall survival than patients with CA IX-negative tumors (P = 0.033 and P = 0.044, respectively). CONCLUSIONS: These data suggest that CA IX, a potential intrinsic marker of hypoxia, predicts for poor prognosis in patients with deep, large, high-grade soft tissue sarcoma. Larger studies are required to determine whether CA IX has independent prognostic value in this group of tumors.

Adult↗

PubMed2004

Stage II testicular seminoma: patterns of recurrence and outcome of treatment.

OBJECTIVES: To review treatment outcome and patterns of failure for patients with stage II testicular seminoma and to identify prognostic factors for relapse. METHODS: From 1981 to 1999, 126 men with stage II seminoma were treated at Princess Margaret Hospital. Of these, 95 were treated with radiotherapy (RT) and 31 with chemotherapy (ChT). Patient and tumour characteristics were analyzed for prognostic significance for subsequent relapse. RESULTS: At median follow-up of 8.5 years, the 5- and 10-year overall survival were both 93%, the 5- and 10-year cause-specific survival were both 94% and the 5- and 10-year relapse-free rates were both 85%. Patients with stage IIA and IIB disease treated with RT and stage IIB treated with chemotherapy had 5-year relapse-free rates of 91.7%, 89.7% and 83.3%, respectively. Seventeen percent of patients treated with radiotherapy and 6% of those treated with chemotherapy have relapsed. Of the RT patients the commonest sites of relapse were left supraclavicular fossa, lung/mediastinum, bone, para-aortics and liver; nine patients had a solitary site of relapse. Two patients treated with chemotherapy had recurrence in the para-aortic and iliac nodes. For RT patients, larger primary tumour size was associated with a reduction in relapse rate. Age, rete testis invasion and lymphovascular invasion were found not to be of prognostic significance. CONCLUSIONS: In stage IIA/B seminoma, radiotherapy continues to provide excellent results, as the majority of patients will be cured with this treatment alone. Chemotherapy is the treatment of choice for stage IIC seminoma.

Adult↗

PubMed2004

Lymph node metastasis in soft tissue sarcoma in an extremity.

For patients with soft tissue sarcoma in an extremity, the outcome is thought to be poor if lymph node metastasis develops. The purpose of this study was to examine the impact of lymphatic involvement from soft tissue sarcoma on patient survival. Thirty-nine (3.7%) of 1066 patients who had surgery for soft tissue sarcoma in an extremity had lymph node metastases develop. Three (20%) of 15 patients with epithelioid sarcoma, four (19%) of 21 patients with rhabdomyosarcoma, two (11.1%) of 18 patients with clear cell sarcoma, and two (11.1%) of 18 patients with angiosarcoma had lymphatic involvement. Thirty patients who had resection of involved lymph nodes had an estimated 5-year survival of 57%, whereas nine patients treated without surgery all died within 30 months. An estimated 4-year survival of 71% for patients with isolated lymph node metastases was significantly better than 21% for patients with synchronous systemic and lymph node involvement. There was no difference in outcome for patients with isolated lymphatic involvement compared with patients with American Joint Committee on Cancer Stage III extremity sarcomas. These results suggest that long-term survival is possible after surgical resection of lymphatic metastases from soft tissue sarcoma. The American Joint Committee on Cancer should consider separating isolated nodal metastases from systemic involvement in patients with Stage IV sarcoma.

Adolescent↗

PubMed2003

Appropriate radiation volume for stage IIA/B testicular seminoma.

PURPOSE: Prophylactic left supraclavicular fossa irradiation has been suggested to reduce relapse rates in patients treated for Stage IIA/B testicular seminoma. To address this issue, we reviewed patterns of failure and treatment outcome in patients treated with radiation therapy at our institution. METHODS AND MATERIALS: Between 1981 and 1999, 79 men with Stage II seminoma (IIA, 49; IIB, 30) were treated with radiation therapy (RT) to the para-aortic and ipsilateral (+/- contralateral) pelvic lymph nodes (dose: 25-35 Gy). RESULTS: With a median follow-up of 8.5 years, the 5-year relapse-free rate was 91% (standard error: 3%), and 2 patients have died of seminoma, giving a 5-year cause-specific survival of 97%. A total of 7 patients have relapsed with 2 isolated to the left supraclavicular fossa. Five of 7 patients have been successfully salvaged. CONCLUSIONS: Prophylactic left supraclavicular fossa irradiation might have prevented relapse in 2 of 79 patients in Stage IIA/B seminoma. However, 97% of patients would have received unnecessary left neck RT, so we continue to recommend, as standard treatment, infradiaphragmatic RT only.

Adult↗

PubMed2003

The influence of anatomic location on outcome in patients with soft tissue sarcoma of the extremity.

BACKGROUND: The anatomic location of an extremity soft tissue sarcoma may influence the patient's presentation, management, and local and systemic recurrence rates. The objective of this study was to compare the presentation, management, and outcome of patients with soft tissue sarcomas of the upper extremity and the lower extremity. METHODS: Prospectively collected data from patients who underwent limb-sparing surgery for extremity soft tissue sarcoma between January, 1986 and April, 1997 were analyzed. Local recurrence free rates and metastasis free rates were calculated using the method of Kaplan and Meier. Univariate and multivariate analyses of potential predictive factors were evaluated with the log-rank test and the Cox proportional hazards model. RESULTS: Of 480 eligible patients, 48 patients (10.0%) had a local recurrence, and 131 patients (27.3%) developed distant metastasis. The median follow-up of survivors was 4.8 years (range, 0.1-12.9 years). Patients with upper extremity tumors had smaller lesions (6.0 cm vs. 9.3 cm; P < 0.001), more often underwent unplanned excision before referral (89 patients [64.0%] vs. 160 patients [46.9%]; P < 0.001), and less often received radiotherapy (98 patients [70.5%] vs. 289 patients [84.8%]; P < 0.001). The 5-year local recurrence free rate was 82% for patients with sarcomas of the upper extremity and 93% for patients with sarcomas of the lower extremity (P = 0.002). The 5-year metastasis free rate was 82% for patients with sarcomas of the upper extremity and 69% for patients with sarcomas of the lower extremity (P = 0.013). CONCLUSIONS: Local recurrence was more frequent in patients who had sarcomas of the upper extremity compared with patients who had sarcomas of the lower extremity. Factors that contributed to this difference included histologic type, the use of radiotherapy, and local anatomy. Metastasis was more frequent among patients with sarcomas of the lower extremity, because those tumors tended to be large and deeper compared with upper extremity tumors.

Adolescent↗

PubMed2002

Initial results of a trial of preoperative external-beam radiation therapy and postoperative brachytherapy for retroperitoneal sarcoma.

BACKGROUND: Surgical resection alone does not cure the majority of patients with retroperitoneal sarcoma (RPS). We evaluated the effects of preoperative external-beam radiotherapy (XRT) and postoperative brachytherapy (BT) combined with complete surgical resection. METHODS: Fifty-five patients with primary or locally recurrent RPS judged to be resectable were entered onto a trial of combined therapy and observed prospectively. Forty-six patients underwent complete gross resection with curative intent. Of these, 41 patients completed preoperative XRT and 23 patients received BT. Outcome measures were treatment toxicity, overall survival, and disease-free survival (DFS). RESULTS: Preoperative XRT was very well tolerated and was associated with Radiation Therapy Oncology Group acute toxicity scores of < or = 2 in all patients. Acute postoperative and BT-related toxicity resulted in modified RTOG scores of > or = 3 in 39.1% (18 of 46) of patients. Late toxicity was associated with death in 4.3% (2 of 46) and with life-threatening illness in 2.2% (1 of 46) of patients, all of whom had been treated with BT to the upper abdomen. The 2-year overall survival and DFS for resected RPS were 88% and 80%, respectively. Significantly better 2-year DFS was achieved in patients with primary RPS and in those with low-grade tumors (93% and 95%, respectively). CONCLUSIONS: The initial results of combined therapy are promising. Although preoperative XRT was very well tolerated, BT to the upper abdomen was associated with substantial toxicity. Our current protocol includes selective application of BT to the lower abdomen only.

Adult↗