The effect of the setting of a positive surgical margin in soft tissue sarcoma

BACKGROUND

The objectives of this study were to evaluate the risk of local recurrence and survival after soft tissue sarcoma (STS) resection with positive margins and to evaluate the safety of sparing adjacent critical structures.

METHODS

One hundred sixty-nine patients with localized STS who had positive resection margins were identified from a prospective database. Patients who had positive margins were stratified into 3 groups, each representing a specific clinical scenario: critical structure positive margin (eg major nerve, vessel, or bone), tumor bed resection positive margin, and unexpected positive margin. The rates of local recurrence-free survival (LRFS) and cause-specific survival (CSS) were calculated and compared with relevant control patients who had negative margins after STS resection.

RESULTS

After planned close dissection to preserve critical structures, the 5-year LRFS and CSS rates both depended on the quality of the surgical margins (97% and 80.3%, respectively, for those with negative margins vs 85.4% and 59.4%, respectively, for those with positive margins; P = .015 and P = .05, respectively). Negative margins achieved through resection of critical structures because of tumor invasion or encasement only slightly improved the 5-year rates of LRFS (91.2%) and CSS (63.6%; P = .8 and P = .9, respectively). The lowest 5-year LRFS and CSS rates were 63.4% and 59.2%, respectively, after an unexpected positive margin during primary surgery.

CONCLUSIONS

After patients undergo resection of STS with positive margins, oncologic outcomes can be predicted based on the clinical context. Sparing adjacent critical structures in this setting is safe and contributes to improved functional outcomes.

Chemotherapy influences the pseudocapsule composition in soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas are a heterogeneous group of malignant tumors. Standard treatment for soft tissue sarcoma of the extremity is surgical excision and adjuvant therapy; however, the role of neoadjuvant chemotherapy is controversial.

QUESTIONS/PURPOSES

We sought to (1) define the histologic characteristics of the pseudocapsule in soft tissue sarcomas; (2) compare the appearance of this structure in chemotherapy-treated versus untreated soft tissue sarcomas; and (3) evaluate the effect of chemotherapy on the presence and viability of tumor cells at the host-sarcoma interface.

METHODS

Twenty-eight patients with biopsy-proven, deep, high-grade extremity soft tissue sarcomas greater than 5 cm (AJCC stage III) treated with chemotherapy and surgical excision were compared histologically with 47 matched control subjects treated with surgery alone.

RESULTS

A pseudocapsule was identifiable in the majority of tumors and consisted of two identifiable layers, each with specific histological characteristics suggesting the biologic processes occurring in these layers are different. The pseudocapsule was more frequently observed in the group treated with chemotherapy and it was more frequently continuous, thicker, and better developed in this group. Chemotherapy decreased the number of tumors with malignant cells identified within and beyond the pseudocapsule.

CONCLUSIONS

Neoadjuvant chemotherapy contributed to the development of a pseudocapsule and decreased the number of tumors with malignant cells identified within and beyond the pseudocapsule.

CLINICAL RELEVANCE

These findings may provide a histological explanation for the clinical effect of chemotherapy in soft tissue sarcoma.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Early follow-up of a custom non-fluted diaphyseal press-fit tumour prosthesis

PURPOSE

The objective of this study was to evaluate the early results of a custom non-fluted diaphyseal press-fit stem for use with the global modular replacement system (GMRS) tumour prosthesis and the early complications associated with this implant.

METHODS

A total of 53 patients (54 implants) were identified from a prospective database where a custom non-fluted diaphyseal press-fit stem was used as part of the reconstruction of the limb. All patients had a minimum of 22 months of follow-up.

RESULTS

The rates of stem revision for any reason were calculated. The median follow-up was 36 months (range 22-85 months). Aseptic loosening was not observed in any patient.

CONCLUSIONS

At early term follow-up, an uncemented non-fluted stem used with the GMRS tumour endoprosthesis provides a stable bone-prosthesis interface with no evidence of aseptic loosening.

Valgus slipped capital femoral epiphysis

Slipped capital femoral epiphysis (SCFE) is a posteromedial displacement of the epiphysis on the metaphysis. Superolateral displacement of the epiphysis, the valgus SCFE, was first described by Müller, although some authors question its existence. We report 4 additional cases and review the literature regarding valgus SCFE. A retrospective review was performed; the child's sex, race, age, weight and height, symptom duration, type of SCFE (stable/unstable), and slip severity were recorded. There were 105 children (67 boys and 38 girls) with 141 idiopathic SCFEs. Four children were noted to have 7 stable valgus SCFEs. Statistically significant differences between the valgus and varus SCFEs were noted for symptom duration and body mass index, and valgus SCFEs tended to be less severe. When combining the data from the literature and the author's institution, there were 22 children with 30 valgus SCFEs at average age of 12.4 +/- 1.8 years; weight, 69.3 +/- 20.6 kg; height, 155.3 +/- 12.4 cm; and body mass index, 27.l +/- 7.1 kg/cm. The demographics of children with valgus SCFE are similar to children with routine SCFE except for sex: 76% of valgus SCFEs occurred in girls. Awareness of valgus SCFEs is necessary for both diagnosis and treatment. In a "valgus" SCFE, Klein line will always be normal, emphasizing the need for lateral radiographs when evaluating all children for SCFE. Single central screw fixation must be approached with caution because the more medial screw entry point places the screw path in immediate proximity to the femoral neurovascular bundle.

Epidemiology and mechanisms of femur fractures in children

The most common pediatric orthopaedic injury requiring hospitalization is a femur fracture. This study aimed to identify the epidemiology and mechanisms of injury so that these injuries might be reduced through specifically targeted safety measures. Data for this study were culled from the 2000 Kids' Inpatient Database representing over 2.5 million pediatric hospital discharges. Of the nearly 10,000 femur fractures, 1076 (11%) occurred in children younger than 2 years; 2119 (21%) in children aged 2 to 5 years; 3237 (33%) in children aged 6 to 12 years; and 3528 (35%) in adolescents aged 13 to 18 years. The most (71%) occurred in male patients. Falls and motor vehicle collisions accounted for two thirds of those injuries, with the incidence of falls greater in the younger children and motor vehicle collisions more prevalent in older children. Fifteen percent of femoral fractures in children younger than 2 years were because of child abuse. Length of hospital stay, number of diagnoses and procedures, and hospital charges were greatest in the adolescent age group, likely because of high-energy trauma with resultant polytrauma. Hospital charges were more than 222 million dollars with the average charge over 2.5 times that in adolescents compared with infants/toddlers. Pediatric orthopaedists must continue to press for increased safety for our children, particularly adolescent motor vehicle safety. Abuse should be considered when a child younger than 2 years presents with a femoral fracture.

Cutting edge: induction of the antigen-processing enzyme IFN-gamma-inducible lysosomal thiol reductase in melanoma cells Is STAT1-dependent but CIITA-independent

Presentation and CD4(+) T cell responses to Ag in the context of MHC class II molecules require processing of native proteins into short peptide fragments. Within this pathway, IFN-gamma-inducible lysosomal thiol reductase (GILT) functions to catalyze thiol bond reduction, thus unfolding native protein Ag and facilitating further processing via cellular proteases. In contrast with professional APCs such as B cells, class II-positive human melanomas expressed relatively little to no GILT protein or mRNA. Tumor cell GILT expression was partially restored with IFN-gamma treatment but unlike other genes required for class II Ag presentation, GILT was not regulated by CIITA. Rather, studies revealed STAT1 plays a direct role in IFN-gamma-inducible GILT expression. These results define a molecular mechanism for the uncoupled regulation of MHC class II genes and the processing enzyme GILT in human melanomas.

Inhibition of glycolipid shedding rescues recognition of a CD1+ T cell lymphoma by natural killer T (NKT) cells

Neoplastic transformation of cells is accompanied by an aberration of cell surface glycolipid composition. These tumor-associated, altered glycosphingolipids are often shed into the tumor cell microenvironment and mediate immunosuppressive activity. The nature and form of glycolipids shed by a variety of tumor cell lines and the mechanism(s) of shedding have been well characterized. The murine T cell lymphoma line, L5178Y-R, is known to shed a tumor-associated glycolipid, gangliotriaosylceramide, into the culture medium. We analyzed the effect of glycolipids from L5178Y-R on antigen presentation by murine CD1d1 molecules. CD1d1 molecules present glycolipid antigens to a specialized class of T cells called natural killer T (NKT) cells that mainly express a T cell receptor alpha chain (Valpha14Jalpha281) associated with Vbeta chains of limited diversity. In the current report, we found that L5178Y-R cells express CD1 on their cell surface yet are unable to stimulate CD1d1-specific NKT cells. We hypothesized that the glycolipid(s) shed by L5178Y-R inhibited antigen presentation by CD1d1. Pretreatment of CD1d1(+) cells with conditioned medium from L5178Y-R inhibited CD1-specific stimulation of canonical (Valpha14(+)) but not noncanonical (Valpha5(+)) NKT cells. Exogenous addition of lipids extracted from L5178Y-R cells as well as purified gangliotriaosylceramide mimicked this effect. Inhibition of glycolipid shedding in L5178Y-R cells with d-1-phenyl-2-hexadecanoylamino-3-morpholino-1-propanol resulted in the rescue of CD1d1 recognition by canonical (but not noncanonical) NKT cells. These results suggest that one means by which certain tumor cells can evade the host's innate antitumor immune response is by shedding glycolipids that inhibit CD1-mediated antigen presentation to NKT cells.

Oral tolerance induction by type V collagen downregulates lung allograft rejection

Immunization with specific proteins or peptides has been used to induce immunologic tolerance to allografts other than the lung. Recently, we have reported that the immune response to lung alloantigen also involves an immune response to type V collagen [col(V)]. The purpose of the current study was to determine if oral administration of col(V) to lung allograft recipients before transplantation downregulates acute rejection episodes. The data show that, compared with controls, col(V)-fed recipients had fewer polymorphonuclear cells and lymphocytes in allograft bronchoalveolar lavage fluid, and reduced rejection pathology. Data showing that col(V)- fed allograft recipients had diminished delayed-type hypersensitivity (DTH) responses to donor alloantigens suggest that feeding col(V) prevented allograft rejection by inducing tolerance to donor antigens. Systemic production of transforming growth factor (TGF)-beta, interleukin (IL)-4, or IL-10 has been reported to be a mechanism for oral tolerance-induced suppression of immune responses. Feeding col(V) induced upregulated production of TGF-beta, but not IL-4 or IL-10 in serum. Neutralizing TGF-beta recovered the DTH response to donor antigen in tolerant allograft recipients. Collectively, these data show that oral administration of col(V) is a novel approach to induce immunologic tolerance to lung allografts, and that TGF-beta contributed to suppression of the rejection response.