Biomedical subjects

Robert S Bell

Publications and source records attributed to Robert S Bell.

At least 19 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

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

Evaluating function and health related quality of life in patients treated for extremity soft tissue sarcoma.

OBJECTIVE: To evaluate how functional disability impacts on health related quality of life (HRQOL) of patients with extremity soft tissue sarcoma (STS) at 1 year post-surgery. DESIGN AND SETTING: Survey of extremity STS patients pre-surgery and one-year post-treatment. PARTICIPANTS: 100 participants who were treated for extremity STS between 2001 and 2003 at four Canadian hospitals. Patients were over 16 years, non-metastatic at diagnosis, and had limb salvage surgery. OUTCOME MEASURES: Musculoskeletal Tumor Society Rating Scale (MSTS), a measure of impairment; Toronto Extremity Salvage Score (TESS), a measure of activity limitations; Reintegration to Normal Living Index (RNL), a measure of participation restrictions; and EQ-VAS, a measure of HRQOL. RESULTS: After adjusting for demographic and clinical variables, impairment explained 54%, activity limitations explained 48%, and participation restrictions explained 61% of the variation in HRQOL. After adjustment, when all three functional measures were included in the model, only participation restrictions had a significant impact on HRQOL explaining 63% of the variation. CONCLUSION: Impairment and activity limitations affect the daily activities a patient can perform, but it is the restriction in participation of life roles and situations that has the greatest effect on patient's HRQOL.

Activities of Daily Living↗

PubMed2006

hCDC4 variation in osteosarcoma.

The hCDC4 gene (also known as Fbw7 or Archipelago) encodes an F-box protein that is responsible for targeting cyclin E for Skp1-cullin-F box protein (SCF) ubiquitination and proteosomal degradation. Disruption of this pathway has been associated with chromosomal instability and aneuploidy in several cancer cell lines and primary tumors. This study aimed to examine whether hCDC4 mutations contribute to aneuploidy in osteosarcoma. We analyzed 147 primary high-grade osteosarcoma specimens and 6 osteosarcoma cell lines. The protein truncation test (PTT) and single-strand conformation polymorphism (SSCP) analysis with subsequent sequencing were performed to detect alterations of the hCDC4 gene. All specimens exhibited the same PTT pattern of normal bands with less intense common bands. Two shifts were detected by SSCP, and subsequent DNA analysis identified one in-frame three-base GAG (424-426) deletion and one silent nucleotide substitution (C1261T). We conclude that somatic hCDC4 mutations are infrequent in osteosarcoma, and are unlikely to play an important role in aneuploidy of this tumor.

Aneuploidy↗

PubMed2006

Aseptic loosening is uncommon with uncemented proximal tibia tumor prostheses.

UNLABELLED: Aseptic loosening is a frequent cause of failure of cemented proximal tibia tumor endoprostheses. Uncemented prostheses may lessen this risk. We identified complications including aseptic loosening that affected prosthetic survival, limb survival and functional outcome for 44 consecutive patients after sarcoma resection from the proximal tibia and uncemented endoprosthetic reconstruction. At a mean final followup of 60 months (range, 9-152 months), there were no cases of aseptic loosening. Twelve (27%) patients suffered 14 complications leading to prosthetic failure due to infection (n = 7), stem fracture (n = 2), rotational instability (n = 1), vascular compromise (n = 2) and local tumor relapse (n = 2). However, limb salvage was successful in 37 of 44 (84%) patients. Functional assessment for 35 patients revealed a mean Toronto Extremity Salvage Score of 77/100 (range, 33-98) and Musculoskeletal Tumor Society 1987 and 1993 scores of 25/35 (range, 13-31) and 75/100 (range, 33-97), respectively. Mean knee joint flexion was 91 degrees (range, 0-110 degrees ) and knee extension lag was 6 degrees (range, 0-30 degrees ). Three patients with knee extensor complications had inferior functional outcomes. Aseptic loosening is uncommon with uncemented proximal tibia reconstruction, but decreasing other complications at this location remains challenging. LEVEL OF EVIDENCE: Therapeutic study, level IV-1 (case series).

Adolescent↗

PubMed2005

Wound healing morbidity in STS patients treated with preoperative radiotherapy in relation to in vitro skin fibroblast radiosensitivity, proliferative capacity and TGF-beta activity.

BACKGROUND AND PURPOSE: In a recent study, we demonstrated that the ability of dermal fibroblasts, obtained from soft tissue sarcoma (STS) patients, to undergo initial division in vitro following radiation exposure correlated with the development of wound healing morbidity in the patients following their treatment with preoperative radiotherapy. Transforming growth factor beta (TGF-beta) is thought to play an important role in fibroblast proliferation and radiosensitivity both of which may impact on wound healing. Thus, in this study we examined the interrelationship between TGF-beta activity, radiosensitivity and proliferation of cultured fibroblasts and the wound healing response of STS patients after preoperative radiotherapy to provide a validation cohort for our previous study and to investigate mechanisms. PATIENTS AND METHODS: Skin fibroblasts were established from skin biopsies of 46 STS patients. The treatment group consisted of 28 patients who received preoperative radiotherapy. Eighteen patients constituted a control group who were either irradiated postoperatively or did not receive radiation treatment. Fibroblast cultures were subjected to the colony forming and cytokinesis-blocked binucleation assays (low dose rate: approximately 0.02 Gy/min) and TGF-beta assays (high dose-rate: approximately 1.06 Gy/min) following gamma-irradiation. Fibroblast radiosensitivity and initial proliferative ability were represented by the surviving fraction at 2.4 Gy (SF(2.4)) and binucleation index (BNI), respectively. Active and total TGF-beta levels in fibroblast cultures were determined using a biological assay. Wound healing complication (WHC), defined as the requirement for further surgery or prolonged deep wound packing, was the clinical endpoint examined. RESULTS: Of the 28 patients treated with preoperative radiotherapy, 8 (29%) had wound healing difficulties. Fibroblasts from patients who developed WHC showed a trend to retain a significantly higher initial proliferative ability after irradiation compared with those from individuals in the treatment group with normal wound healing, consistent with the results of our previous study. No link was observed between fibroblast radiosensitivity and WHC. Neither active nor total TGF-beta levels in cultures were significantly affected by irradiation. Fibroblast proliferation in unirradiated and irradiated cultures, as well as radiosensitivity, was not influenced by TGF-beta content. TGF-beta expression in fibroblast cultures did not reflect wound healing morbidity. CONCLUSIONS: These data are consistent with our previous study and combined the results suggest that in vitro fibroblast proliferation after irradiation may be a useful predictor of wound healing morbidity in STS patients treated with preoperative radiotherapy. TGF-beta levels in culture do not predict WHC, suggesting that the role of TGF-beta in wound healing is likely controlled by other in vivo factors.

Adolescent↗

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

Histologic assessment of peritumoral edema in soft tissue sarcoma.

PURPOSE: To evaluate whether satellite tumor cells can be identified histologically in the tissues surrounding a soft tissue sarcoma and whether their presence correlates with increased T(2)-weighted signal intensity on MRI. METHODS AND MATERIALS: Fifteen patients with a high-grade extremity or truncal soft tissue sarcoma underwent preoperative MRI. The extent of high T(2)-weighted signal changes in the tissues surrounding tumor, thought to represent peritumoral edema/reactive changes, was determined. Twelve patients received i.v. gadolinium, and contrast enhancement was determined. All patients underwent surgical resection in the absence of preoperative chemotherapy or radiotherapy. The presence of tumor cells in the surrounding tissues was determined histologically in representative paraffin-embedded sections and correlated with the MRI findings. RESULTS: The extent of peritumoral T(2)-weighted MRI signal changes ranged from 0 to 7.1 cm (mean, 2.5 cm); contrast enhancement ranged from 0 to 5.3 cm (mean, 1.1 cm). Sarcoma cells were identified histologically in the tissues beyond the tumor in 10 of 15 cases. In 6 cases, tumor cells were located within 1 cm of the tumor margin, and in 4 cases, malignant cells were found at a distance >1 cm and up to a maximum of 4 cm. The location of tumor cells beyond the margin did not correlate with tumor size nor did it correlate with the location or extent of peritumoral changes. CONCLUSION: The ability to identify tumor cells beyond the margin of a soft tissue sarcoma has important implications in planning appropriate targets for treatment. This could influence the use of new radiotherapy technologies such as intensity-modulated radiotherapy that aim to minimize treatment volumes through conformal planning.

Adult↗

PubMed2005

TP53 mutations and outcome in osteosarcoma: a prospective, multicenter study.

PURPOSE: Mutations of the TP53 gene have been associated with resistance to chemotherapy as well as poor prognosis in many different malignancies. This is the first prospective study of the prognostic value of somatic TP53 mutations in patients with newly diagnosed extremity osteosarcoma. PATIENTS AND METHODS: One hundred ninety-six patients with high-grade, nonmetastatic osteosarcoma of the extremities were enrolled from seven tertiary care institutions and observed prospectively for tumor recurrence (median follow-up duration, 44 months). All patients received neoadjuvant or adjuvant chemotherapy and surgery. Tumors were analyzed for the presence of TP53 mutations by polymerase chain reaction single-strand conformation polymorphism analysis and direct DNA sequencing. The association of the status of the TP53 gene with the risk of systemic recurrence was examined using survival analyses with traditional and histologic markers as prognostic factors. RESULTS: Patient age was the only factor that varied with TP53 gene status (P = .05). No relationship was identified between TP53 status and systemic relapse (relative risk, 1.24; P = .41). Analyses based on missense or nonsense mutations gave similar results (P > .10). In multivariate analysis, large (> 9 cm) tumor size (relative risk, 1.9; P = .006) and poor histologic response (< or = 90% necrosis) to chemotherapy (relative risk, 2.14; P = .02) were the only significant independent predictors of systemic outcome. CONCLUSION: We found no evidence that TP53 mutations predict for development of metastases in patients with high-grade osteosarcoma. Identification of other genes that influence chemotherapy response and clinical outcome in osteosarcoma is needed to facilitate further improvements in patient outcomes.

Adolescent↗

PubMed2005

Periprosthetic bone remodeling around a prosthesis for distal femoral tumors: longitudinal follow-up.

Serial measurements using dual-energy x-ray absorptiometry (DEXA) were undertaken to evaluate progressive periprosthetic bone loss in patients treated for primary bone tumors of the distal femur using an uncemented tumor prosthesis. Twelve patients underwent sequential DEXA analysis on average 26.5 and 90.9 months postsurgery. Changes in bone mineral density were measured in regions of interest (ROIs) around the prosthesis stem. The test-retest reliability coefficient (r) ranged from 0.92 to 0.99 for all ROI. In the most distal ROI (ROI1), 10 of 11 patients with 2 measurements showed no change or a small increase in absolute bone mineral density. The results in other ROIs were similar. This longitudinal DEXA data suggest that progressive bone resorption is not problematic with an uncemented distal femur endoprosthesis at intermediate follow-up. Key words: DEXA, stress shielding, uncemented endoprothesis, tumor, bone loss.

Absorptiometry, Photon↗

PubMed2005

Outcome after pelvic sarcoma resection reconstructed with saddle prosthesis.

UNLABELLED: We retrospectively reviewed 27 patients who had saddle prosthetic reconstruction for pelvic sarcoma from 1991 to 2001 with a mean followup of 45 months. Functional outcome was assessed with Musculoskeletal Tumor Society Scores of 1987 and 1993 and the Toronto Extremity Salvage score. Survival, recurrences, and complications were recorded. Seven (26%) patients had Type II (periacetabular) pelvic resection and 20 had Types II and III (periacetabular and pubis) pelvic resection. Eleven patients had chemotherapy treatment. None received radiation therapy. At final followup 14 patients were free of disease, 11 patients died, and two patients were alive with disease. The survival rate was 60%. Twenty-two percent had local recurrence, and 22% had metastasis. The mean Musculoskeletal Tumor Society Score 93 score in 17 patients was 50.8% +/- 21.7%, the mean Musculoskeletal Tumor Society Score 87 score was 15.3 +/- 6.1, and the mean Toronto Extremity Salvage score was 64.4% +/- 17.2%. Infection occurred in 10 patients; six were deep infections. There were five nerve palsies. Heterotopic ossification occurred in 10 patients, fracture occurred in six patients, and dislocation occurred in six patients. Limb shortening was progressive until it stabilized at 12 months, and ultimately ranged between 1 and 6 cm. Five patients were retired, five had full-time employment, and six were disabled. Reconstruction with the saddle prosthesis after resection for pelvic sarcoma is associated with substantial morbidity. However, the functional results seem to confer an advantage when compared with the considerable disability incurred after hemipelvectomy. LEVEL OF EVIDENCE: Therapeutic study, Level IV-1 (case series without control group). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗

PubMed2005

Iliosacral resection for primary bone tumors: is pelvic reconstruction necessary?

UNLABELLED: Iliosacral resection for primary bone tumors creates a large unstable pelvic ring defect, the treatment of which remains controversial. We did this study to determine if skeletal reconstruction of such defects is necessary. Sixteen patients whose data were collected prospectively had iliosacral resection with a minimum followup of 12 months. The surgical and functional results of patients who had skeletal reconstruction (n = 4) were compared with the results of patients who did not have iliosacral repair (n = 12) using a case-control design. Function was evaluated by assessing impairment using the Musculoskeletal Tumor Society 1987 and 1993 rating scales, and disability was measured using the Toronto Extremity Salvage Score. Although all four iliosacral arthrodeses initially healed, one allograft used for reconstruction fractured and another was removed because of progressive lumbosacral spinal instability. Patients treated without pelvic reconstruction had fewer operative complications. Although the Toronto Extremity Salvage Score and the Musculoskeletal Tumor Society 1987 and 1993 scores were similar for both patient groups, those patients who were treated without reconstruction were less likely to require the use of an ambulatory assistive device, less likely to require narcotics or have chronic pain, and more likely to return to work. These results suggest that reconstruction of the skeletal defect to restore pelvic stability after iliosacral resection is not mandatory. LEVEL OF EVIDENCE: Therapeutic study, Level III-1 (case-control study). See the Guidelines for Authors for a complete description of levels of evidence.

Adolescent↗

PubMed2005

Outcome in two groups of patients with allograft-prosthetic reconstruction of pelvic tumor defects.

UNLABELLED: To predict the outcomes obtained with allograft-implant composite reconstruction of pelvic defects after bone tumor resection better, a retrospective review of a prospectively collected database was done and two groups of patients were identified. These groups were compared with respect to oncologic and functional outcomes in this investigation. Group 1 included 21 patients with allograft total hip replacement reconstruction for pelvic bone tumors that required Type I and II or Type I, II, and III pelvic resections. Group 2 included five patients who required an acetabular allograft in combination with proximal femoral replacement for reconstruction of Type II pelvic resections done to treat proximal femoral bone sarcomas that invaded or surrounded the hip joint. Functional assessment was measured with three instruments (Toronto Extremity Salvage Score, Musculoskeletal Tumor Society 1987, and the Musculoskeletal Tumor Society 1993 scores). In Group 1, nine of 19 evaluable patients (two patients died in the immediate postoperative period) either retained the allograft until their death or were still alive at last followup with their allograft in place. An additional patient had revision surgery to an allograft-saddle composite that remains intact. The functional results in Group 1 were influenced heavily by the occurrence of deep infection. Nine of 19 evaluable patients developed infection, with seven patients requiring either removal of the graft (three patients) or hindquarter amputation (four patients). Two patients retained their infected allografts with long-term antibiotic suppression. In 10 Group 1 patients who did not develop infection, reasonable functional results were obtained. Group 2 patients had no infections and better functional results. LEVEL OF EVIDENCE: Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Adolescent↗

PubMed2005

Uncemented tumor endoprostheses at the knee: root causes of failure.

UNLABELLED: Although cemented tumor endoprostheses are the most commonly used method for reconstruction of the distal femur or proximal tibia after resection of primary bone tumors, aseptic loosening remains a common complication. Uncemented tumor prostheses may minimize this problem. We investigated the root causes of prosthetic failure for 99 patients with a fixed-hinge, bone-ingrowth Kotz Modular Femur and Tibia Resection System endoprosthesis and compared complications that led to implant failure with results in the literature. Of the 74 distal femoral implants and 25 proximal tibial implants, 25 patients had complications that resulted in prosthetic failure (removal of the prosthesis) at a median of 24.1 (range, 0.8-72.6) months. Failure was caused by prosthesis (n = 18) or oncologic-related (n = 7) complications. However, limb-salvage was possible for 87 of 99 patients. Smaller stem size in the distal femur and longer bone resection length in the proximal tibia were significantly associated with increased risk of prosthetic failure by multivariate analysis. The risk of stem fracture (6 of 99 patients) and infection (10 of 99 patients) was higher than other reports, but aseptic loosening (2 of 99 patients) was uncommon. These results suggest that although the bone-ingrowth surface of this prosthesis leads to a very low aseptic loosening rate, the higher risk of stem fracture and infection must be addressed in future implant designs. LEVEL OF EVIDENCE: Therapeutic study, level IV-1 (case series).

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↗

PubMed2005

Fractures following radiotherapy and limb-salvage surgery for lower extremity soft-tissue sarcomas. A comparison of high-dose and low-dose radiotherapy.

BACKGROUND: The purpose of the present retrospective study was to determine the correlation between radiation therapy and the risk of postradiation fracture following combined therapy for the treatment of soft-tissue sarcomas of the lower extremity. METHODS: Three hundred and sixty-four patients with lower extremity sarcomas that had been treated with combined external beam radiation therapy and limb-salvage surgery were evaluated on the basis of a combined chart and data-base review. For the purposes of analysis, high-dose radiation was defined as 60 or 66 Gy and low-dose radiation was defined as 50 Gy. The timing of irradiation was defined as preoperative, postoperative, or preoperative followed by a postoperative boost. Univariate and multivariate analyses were used to determine which factors were associated with fracture risk. RESULTS: Twenty-seven fractures occurred in twenty-three patients. Twenty-four fractures occurred in twenty patients who had been managed with high-dose radiation. Seventeen of these patients had received postoperative radiation (with fifteen patients receiving 66 Gy and two receiving 60 Gy), and three had received preoperative radiation with a postoperative boost (total dose, 66 Gy). Three fractures occurred in three patients who had received preoperative, low-dose radiation (50 Gy). Of the twenty-three patients who sustained a pathologic fracture, eighteen were female and five were male. The crude median time to fracture was forty-three months. Most fractures occurred in the femoral shaft (thirteen) or the femoral neck (eight). High-dose radiation was associated with a greater risk of fracture when compared with low-dose radiation (p = 0.007). CONCLUSIONS: Women more than fifty-five years of age who are managed with removal of a thigh sarcoma combined with radiation therapy have a higher risk of pathologic fracture. The frequency of pathologic fractures associated with higher doses (60 or 66 Gy) of radiation is significantly higher than that associated with lower doses (50 Gy).

Adolescent↗

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↗