Biomedical subjects

Peter C Ferguson

Publications and source records attributed to Peter C Ferguson.

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

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

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↗

PubMed2006

Prognosis of radiation-induced bone sarcoma is similar to primary osteosarcoma.

UNLABELLED: Radiation-induced sarcoma of bone (RISB) is thought to be associated with a poor prognosis. The purpose of this study was to determine disease-free and overall survival of patients treated for RISB, and whether there is a role for limb sparing surgery. Twenty-four patients had a mean latency of 16 years between radiation for their index cancer and RISB diagnosis. The most common tumor was osteosarcoma (n = 17). Ten patients with localized disease treated aggressively with chemotherapy and surgical resection had estimated 5-year disease-free and overall survival rates of 58% and 69% respectively. Patients treated by surgery alone or those with metastases at diagnosis had inferior outcomes. Patients who received a complete course of chemotherapy demonstrated better histologic tumor response and improved survival. There was no difference in survival between the limb sparing surgery (n = 12) or amputation (n = 8) groups. However, limb salvage patients had slightly higher rates of local tumor relapse and post-operative complications. Functional outcome following limb sparing surgery for 10 patients with RISB was similar to a matched cohort treated for primary osteosarcoma. An aggressive treatment approach for patients with RISB may provide similar rates of local recurrence and metastasis and functional outcomes compared to patients with primary osteosarcoma. LEVEL OF EVIDENCE: Therapeutic study, level IV-1.

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

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

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

Surgical considerations for management of distal extremity soft tissue sarcomas.

PURPOSE OF REVIEW: This review focuses on the surgical management of soft tissue sarcomas of the hands and the feet. With recent advances in limb salvage surgery and radiotherapy delivery, local control of soft tissue sarcoma in the extremity has become optimized, and the associated functional results of this treatment have taken on extreme importance. Techniques to limit the amount of normal tissue resected and to reconstruct the resulting defects are critical to the final functional result. RECENT FINDINGS: Several features of soft tissue sarcoma unique to the hand and foot have been reported. Certain histologic subtypes of soft tissue sarcoma have been noted to arise preferentially in the hand and the foot, such as epithelioid sarcoma, clear cell sarcoma, and synovial sarcoma. Patients with hand and foot sarcomas have been described as having improved overall survival, but this is likely a result of the smaller size of tumors arising in these locations. Reconstruction of bone defects using various techniques, vascular reconstruction, tendon transfers, and soft tissue reconstruction using regional flaps in the hand and free flaps in the foot have resulted in good functional outcomes. Amputation and early prosthetic fitting still have a role in management of some soft tissue sarcomas, most frequently in the foot. SUMMARY: Limb salvage remains the standard of care for extremity soft tissue sarcomas. Given the fact that patients have good oncologic and functional outcomes with limb salvage in tumors in the hand and foot, surgical oncologists should have this goal for each patient.

Extremities↗

PubMed2004

Primary multidisciplinary management of extremity soft tissue sarcomas.

Soft tissue sarcomas (STS) are a rare and heterogeneous group of malignancies that most commonly present as large painless masses deep in the muscular compartments of the extremities. Investigation and treatment of these patients must be undertaken at a tertiary referral unit. Staging studies must include a high-quality magnetic resonance imaging (MRI) scan of the local site and a computed tomography (CT) scan of the chest to investigate for possible metastatic disease. Review of biopsy material must be undertaken by an experienced musculoskeletal pathologist. Currently, histologic diagnosis and grade are assigned to the tumor, but in tumors such as synovial sarcoma and Ewing's family of tumors, molecular evaluation is becoming crucial for diagnostic, prognostic, and therapeutic reasons. Surgical resection of sarcomas with negative surgical margins remains the mainstay of treatment. Surgical treatment alone is indicated for small superficial masses that are not adjacent to bone or neurovascular structures. However, in large deep masses where surgical margins are likely to be close in order to preserve important neurovascular structures and bone, combined treatment using surgical resection and radiation results in acceptable local control rates and reasonable patient function. It is incumbent on the management team to decide on timing of radiotherapy as a practice. This decision is based on several factors but potential complications must be taken into account. In this regard the long-term effects on normal tissues must be considered. Functional outcome has become an essential consideration when recommending treatment. If promising techniques become available to reduce the incidence of wound complications or to decrease the dose of radiation to normal tissue, preoperative radiation should be considered in light of its lower incidence of long-term effects that result in reduction in patient function.

Drug Therapy↗

PubMed2004

Change in histological grade in locally recurrent soft tissue sarcomas.

Histological examination of locally recurrent soft tissue sarcomas usually reveals an appearance similar to that of the original tumour. Occasionally, however, recurrent sarcomas appear more or less malignant histologically than the initial lesion. The goals of this paper were to identify the frequency with which this phenomenon occurs, factors that predict for a change in grade and to determine if this change is associated with a different prognosis from other patients with local recurrence. From a large sarcoma database, 124 patients with local recurrence were identified. These patients were distributed into groups who had no change in histological grade, increased histological grade or decreased histological grade on local recurrence. Increased grade occurred approximately 20% of the time, whereas decreased grade occurred in 7% of cases. A histological diagnosis of myxofibrosarcoma was predictive of an increase in histological grade on local recurrence. An increase in histological grade with local recurrence was not associated with a poorer survival.

Adult↗

PubMed2004

Possible metastasis of osteosarcoma to a remote biopsy site: a case report.

In a patient who presented with an osteosarcoma of the proximal humerus, systemic staging revealed a lesion in the contralateral humerus, which was shown to be an enchondroma after open biopsy. The patient had a local recurrence develop, which necessitated forequarter amputation. Shortly thereafter, the patient had pain develop at the contralateral biopsy site, and examinations and repeat biopsy revealed metastatic osteosarcoma. We think it is likely that surgical trauma contributed to the development of this unusual metastasis. In this clinical situation, consideration should be given to doing the biopsy and definitive resection on separate occasions.

Adult↗

PubMed2004

Functional outcome of endoprosthetic proximal femoral replacement.

Endoprosthetic proximal femur replacement is a well-accepted method for treatment of primary bone tumors; however the functional results of treatment are not well documented. To evaluate functional outcomes, we recorded the Toronto Extremity Salvage Score and Musculoskeletal Tumor Society 1987 and 1993 scores in 29 patients, and also recorded Musculoskeletal Tumor Society scores alone in four more patients treated with endoprosthetic proximal femur replacement. The mean followup was 3 years. Twelve patients had a total hip endoprosthetic proximal femur replacement, and 21 had a bipolar hip endoprosthetic proximal femur replacement. In nine patients, the greater trochanter was attached to the femoral prosthesis. Sixteen patients had an abductor soft tissue repair, and in eight patients, no abductor repair was possible. The mean Musculoskeletal Tumor Society 1987 score was 23.2 +/- 4.1 points of 35 points. The mean Musculoskeletal Tumor Society 1993 score was 67.7 +/- 12.0%. The Toronto Extremity Salvage Score mean was 76.2 +/- 16.2 points of 100 points. Functional scores did not differ significantly between abductor repair types. There was a trend toward less disability in patients with abductor soft tissue repair compared with patients with no abductor repair. Functional results were similar in patients receiving bipolar and total hip replacements.

Arthroplasty, Replacement, Hip↗

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↗

PubMed2004

Management of soft tissue sarcomas of the extremities.

Soft tissue sarcomas are a diverse and rare group of neoplasms often found in the extremities. Treatment is best carried out in regional cancer centers by a multidisciplinary group with a common interest in these disorders. Treatment is usually surgical, with radiation used in select cases to try to reduce the risk of local recurrence. The role of chemotherapy is controversial, but it may be useful in patients at highest risk of developing metastatic disease. The development of newer forms of targeted systemic therapy and techniques to reduce the morbidity from local treatment to the extremity are areas of intense research interest.

Combined Modality Therapy↗

PubMed2003

Acetabular metastases: planning for reconstruction and review of results.

The treatment of acetabular bone metastases presents numerous clinical challenges including the necessity for careful patient selection for surgery, determination of the extent of bone destruction, and providing the patient with stable surgical reconstruction of the pelvis. There are relatively few patient series reported in the literature to inform treatment planning, surgical reconstruction techniques, and patient outcomes. We describe a rationale for assessment of patients with acetabular metastases and options for reconstruction. The three general principles for surgical treatment of metastatic bone disease (tumor removal, filling of the resultant bone defect, and bypass of the defect) are defined for acetabular metastases. The results of surgical treatment are described with reference to recent articles in the literature. The reconstruction of acetabular metastatic disease is a major surgical procedure with a significant risk of complications. The surgeon must be certain that the patient's longevity and potential improvement in quality of life justify the risk of the operation.

Acetabulum↗