Does Endocrine Therapy for DCIS Patients Treated with Breast-Conserving Surgery Followed by Postoperative Radiation Therapy is Needed? A Brazilian Retrospective Cohort Study

PURPOSE/OBJECTIVE(S)

International previous clinical trials have demonstrated increased local control. Adjuvant endocrine therapy (ET) is a component of hormone receptor-positive breast ductal carcinoma in situ (DCIS) treatment. Previous trials have shown local control benefits. However, there are still questions regarding the reproducibility of those results in real-life scenarios and for different populations, especially in patients who received breast-conserving surgery followed by postoperative radiation therapy. Therefore, we retrospectively evaluated the impact of adjuvant ET for CDIS from a large State database in Brazil.

MATERIALS/METHODS

We retrospectively evaluated the Fundação Oncocentro de São Paulo (FOSP) database, which collects information on hospitals and oncology departments in the State of São Paulo, Brazil. The endpoints were local control (LC), disease-specific survival (DSS), and overall survival (OS). Moreover, we investigated the influence of medical practice (public health care system, insurance, private) and educational level (illiterate and incomplete middle school were grouped as low; complete middle school, high school, and undergraduate were grouped as medium/high).

RESULTS

Data from 2,192 patients who underwent breast-conserving surgery and postoperative radiotherapy and were treated between 2000 and 2020 were analyzed. The median follow-up time was 48.99 months (IQR 29.93 - 88.67). In the cohort, 53.33% (n = 1169) of patients received adjuvant ET, and 46.67% did not (n = 1023). Overall, patients not receiving adjuvant ET tend to be older (p = 0.021) and have a lower educational level (p < 0.001). Median OS and DSS were not reached. The 10-year OS and DSS for patients receiving adjuvant ET versus those not receiving it was 89.36% vs. 91.47% and 97.54% vs. 98.48%, respectively. The HR for OS for adjuvant ET vs. no ET was 0.96 (95% CI 0.63 - 1.4; p = 0.83). The HR for DSS for adjuvant ET vs. no ET was 0.79 (95% CI 0.29 - 2.12; p = 0.63). The only variable associated with survival was educational level. The 10-year OS was significantly higher for patients with medium/high educational levels (93.25% vs. 87.31%). The HR for death for medium/high versus low educational level was 0.51 (95% CI 0.32 - 0.83; p = 0.007). Recurrence rates were low in the cohort. Only 1.5% of patients had local recurrence, and 0.2% had a regional recurrence. There was no significant difference between recurrence rates for adjuvant ET (p = 0.19 and p = 0.78, respectively).

CONCLUSION

The benefits of adjuvant ET in DCIS patients found in international clinical trials could not be demonstrated in a Brazilian cohort. Educational level significantly impacted survival and ET usage, reflecting the influence of socioeconomic factors. Identifying these more vulnerable populations can allow for more precise interventions.

Brazilian Pediatric Patients with Gliomas: Treatment Characteristics and Survival Outcomes

PURPOSE/OBJECTIVE(S)

Despite being the second most frequent tumors in children, pediatric central nervous system (CNS) tumors are rare, and there are limited epidemiological data. The current study aimed to determine the survival rates of patients diagnosed with pediatric gliomas in Brazil, accounting for the influence of age, treatment modalities, and tumor site using population-based national database.

MATERIALS/METHODS

Patients diagnosed with pediatric gliomas of CNS from 1999-2020 were identified from The Fundação Oncocentro de São Paulo database. The Kaplan-Meier and the log-rank test were used for survival analysis.

RESULTS

A total of 1296 patients were included. The most common histologic tumor type were glioblastomas (38.27%; n = 496), pilocytic astrocytoma (32.87%; n = 426) and astrocytoma grade II (20.76%; n = 269) A total of 379 (29.24%) had brainstem tumor. The 1-year, 3-year 5-year OS for pilocytic astrocytoma were 93.72%, 89.98%, and 88.97%; for grade II 80,36%, 71,89%, 68,60%; for grade III 53,72%; 31,87%, 28,33%; and for glioblastoma 52,90%, 28,76%, 25,20%, respectively. Brainstem tumors had the worse OS compared to no brainstem tumors (p = 0.001). For high-grade glioma (grade III and IV) excluding brainstem tumors (n = 570), young patients had greater median OS (0 to 3 years: 22 months; 4 to 18 years: 13 months - p = 0.005). Regarding the treatment modalities, combined treatments were associated with higher median survival compared to less intensive therapy (surgery: 11 months; surgery and chemotherapy: 16 months; surgery, radiotherapy, and chemotherapy: 20 months; p = 0.005) CONCLUSION: In our cohort, low-grade gliomas had favorable prognoses and outcomes. Patients diagnosed with glioblastomas and brainstem gliomas had the worst OS. For high-grade gliomas, undergoing treatment de-intensification in the Brazilian pediatric population is associated with worse survival.

Timely Access to Oncological Treatment in Brazil: Analysis of the 60-Law Compliance in a State Database

PURPOSE/OBJECTIVE(S)

In oncology, time from diagnosis to treatment has already been shown to impact outcomes. In 2012, the Brazilian Government issued the 60-day Law, which stated that cancer treatment should start no longer than 60 days after histopathological diagnosis. However, there is scarce information on the effectiveness of the Law in improving timely access to treatment.

MATERIALS/METHODS

We retrospectively evaluate the Fundação Oncocentro de São Paulo (FOSP) database, which collects information on hospitals and oncology departments in the State of São Paulo, Brazil. The primary endpoint was time from diagnosis to first treatment (TDT), and we investigated the influence of medical practice (public health care system - SUS, insurance, private) and year of diagnosis (before and after 2012) on TDT. A sensitivity analysis was performed to evaluate information bias.

RESULTS

The database included 943,660 cancer patients diagnosed between 2000 and 2020. The median age was 62 years (range 0 - 113). The mean TDT was 65.95 days (SD 149.36), and the median time was 32 days (range 0 - 6891). Data was extremely skewed to the left, reflecting the fact that for 30.76% of patients (n = 290,262), the TDT was equal to 0 days. After excluding those patients, the mean TDT was 99.03 days (SD 173.85). Mean TDT was higher after the institution of the Law (63.1 versus 70.2 days, p < 0.001). On univariable analysis, there was a significant difference between mean times between medical practice (p < 0.001), and patients in the public health care system consistently showed longer intervals (82.1 days versus 58.3 and 39.3 for SUS, insurance, and private, respectively). This pattern remained in the sensitivity analysis. Overall, 59.9% of patients began treatment up to 60 days after diagnosis. However, 30.76% of these patients had TDT equal to zero. The proportion of patients with a TDT > 60 days was higher for SUS patients (39.52%). After the Law, the proportion of patients with a TDT > 60 days increased from 28.8% to 37.95%.

CONCLUSION

The approved and instituted 60-day Law did not improve timely access to treatment. Patients in the Public Healthcare System have experienced longer TDT, which could reflect barriers to access to care. The significant proportion of patients with a TDT of 0 days suggests information bias, which means that the actual scenario might be worse. There is an urgent need for public policies to ensure compliance with the Law.

A serum NMR metabolomic analysis of the Corynebacterium pseudotuberculosis infection in goats

Caseous lymphadenitis (CLA), an infectious disease caused by Corynebacterium pseudotuberculosis in small ruminants, is highly prevalent worldwide. Economic losses have already been associated with the disease, and little is known about the host-pathogen relationship associated with the disease. The present study aimed to perform a metabolomic study of the C. pseudotuberculosis infection in goats. Serum samples were collected from a herd of 173 goats. The animals were classified as controls (not infected), asymptomatic (seropositives but without detectable CLA clinical signs), and symptomatic (seropositive animals presenting CLA lesions), according to microbiological isolation and immunodiagnosis. The serum samples were analyzed using nuclear magnetic resonance (¹H-NMR), nuclear Overhauser effect spectroscopy (NOESY), and Carr-Purcell-Meiboom-Gill (CPMG) sequences. The NMR data were analyzed using chemometrics, and principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) were performed to discover specific biomarkers responsible for discrimination between the groups. A high dissemination of the infection by C. pseudotuberculosis was observed, being 74.57% asymptomatic and 11.56% symptomatic. In the evaluation of 62 serum samples by NMR, the techniques were satisfactory in the discrimination of the groups, being also complementary and mutually confirming, demonstrating possible biomarkers for the infection by the bacterium. Twenty metabolites of interest were identified by NOESY and 29 by CPMG, such as tryptophan, polyunsaturated fatty acids, formic acid, NAD⁺, and 3-hydroxybutyrate, opening promising possibilities for the use of these results in new therapeutic, immunodiagnosis, and immunoprophylactic tools, as well as for studies of the immune response against C. pseudotuberculosis. KEY POINTS: • Sixty-two samples from healthy, CLA asymptomatic, and symptomatic goats were screened • Twenty metabolites of interest were identified by NOESY and 29 by CPMG • ¹H-NMR NOESY and CPMG were complementary and mutually confirming.

Susceptibility of Malassezia pachydermatis Clinical Isolates to Allopathic Antifungals and Brazilian Red, Green, and Brown Propolis Extracts

Clinical mycoses treatment is associated with issues such as negative side effects, high cost, prolonged treatment, and resistant strain selection. Malassezia pachydermatis is the most frequently isolated yeast in cases of canine otitis and dermatitis. The number of fungal strains exhibiting primary resistance to several drugs in vitro is increasing. Propolis has a diverse chemical composition and well-known therapeutic properties against mycoses. An alternative method for producing propolis extracts using supercritical fluid has higher selectivity, yielding extracts with fewer pollutant residues. This study therefore aimed to evaluate the in vitro susceptibility profile of M. pachydermatis clinical isolates to precharacterized supercritical and ethanolic extracts. Three types of Brazilian propolis extracts (green, red, and brown) and commercial allopathic antifungals were used in this investigation. We used the microdilution broth technique to evaluate the susceptibility profile of the yeasts. The minimum inhibitory concentration (MIC) of the brown propolis ethanolic extract was ≥16 μg/mL for all isolates. The MICs of fluconazole, ketoconazole, itraconazole, and amphotericin B ranged from 8 to >64 μg/mL, 0.032–4 μg/mL, 0.0313–16 μg/mL, and 1–2 μg/mL, respectively. The MICs of ethanolic red propolis extracts were lower than those of supercritical red propolis extracts. However, the green propolis ethanolic extract had more pronounced fungicidal activity. Isolates with lower susceptibility to commercial fungicides were inhibited by red and green propolis extracts. These results indicate that propolis can potentially be used in in vivo experiments as a promising therapeutic agent against M. pachydermatis infections.

Systematic review of the outcome of cemented versus uncemented total hip arthroplasty following pelvic irradiation

PURPOSE

The objective of this study is to evaluate the outcomes of total hip arthroplasty (THA) in patients with radiation-related changes to the bone, and specifically whether there is a difference in outcomes between cemented and uncemented acetabular components.

METHODS

A database search was performed to identify available studies reporting adults undergoing THA who have previously had pelvic irradiation. Data were extracted and analysed with respect to the use of cemented versus uncemented acetabular components. Statistical analysis was performed using the Chi-square test for independence.

RESULTS

The all-cause revision rate was 24% in the cemented THA group (27/111), compared with 15% of uncemented THAs (22/143) (p = 0.073). Revision for acetabular aseptic loosening occurred in 16% of cases (18/111) in the cemented group and 10% (15/143) in the uncemented group (p = 0.178). Acetabular aseptic loosening was reported in 24% of cemented THAs (27/111) and 14% of uncemented THAs (20/143), which was statistically significant (p = 0.035). Not all of these went on to have revision THA. The Incidence of prosthetic joint infection was similar in both groups.

CONCLUSION

Overall outcomes appear to be better for uncemented THAs in post-radiotherapy patients, with a significantly lower rate of aseptic loosening and an appreciable (but not statistically significant) reduction in revision rate. The best outcomes seem to be associated with the use of acetabular reinforcement across both cemented and uncemented groups, but further work is needed to evaluate this.

Highly cross-linked polyethylene decreases the rate of revision of total hip arthroplasty compared with conventional polyethylene at 13 years' follow-up

AIMS

The purpose of this study was to compare the long-term results of primary total hip arthroplasty (THA) in young patients using either a conventional (CPE) or a highly cross-linked (HXLPE) polyethylene liner in terms of functional outcome, incidence of osteolysis, radiological wear and rate of revision.

METHODS

We included all patients between the ages of 45 and 65 years who, between January 2000 and December 2001, had undergone a primary THA for osteoarthritis at our hospital using a CPE or HXLPE acetabular liner and a 28 mm cobalt-chrome femoral head. From a total of 160 patients, 158 (177 hips) were available for review (CPE 89; XLPE 88). The mean age, body mass index (BMI) and follow-up in each group were: CPE: 56.8 years (46 to 65); 30.7 kg/m(2) (19 to 58); 13.2 years (2.1 to 14.7) and HXLPE: 55.6 years (45 to 65); BMI: 30 kg/m(2) (18 to 51); 13.1 years (5.7 to 14.4).

RESULTS

The mean Harris hip score (HHS) at final follow-up was 89.3 for the CPE group and 90.9 for the HXLPE group (p = 0.078). Osteolysis was present around 15 acetabular (17%) and 16 femoral (18%) components in the CPE hips compared with none (0%) in the HXLPE hips. The mean radiological linear wear of the CPE liners was 0.11 mm/year compared with 0.035 mm/year for the HXLPE liners (p = 0.006). The cumulative implant survival, with revision for polyethylene wear as the endpoint, was 86% (95% confidence interval 78 to 94) in the CPE group and 100% in the HXLPE group at 13 years (numbers at risk at 13 years - CPE: 65, XLPE: 61).

DISCUSSION

This study shows that HXLPE liners are associated with significantly less osteolysis and a lower rate of revision THA than CPE liners at long-term follow-up.

TAKE HOME MESSAGE

The findings of this study highlight the clinical benefits of using HXLPE liners in THA and support the routine use of the material in order to improve implant longevity and to decrease the number of patients needing revision for aseptic osteolysis.

A review of the surgical management of sacral chordoma

BACKGROUND

Sacral chordomas are rare low-to-intermediate grade malignant tumours, which arise from remnants of the embryonic notochord. This review explores prognostic factors in the management of sacral chordomas and provides guidance on the optimal treatment regimens based on the current literature.

PATIENTS AND METHODS

Electronic searches were performed using MEDLINE, Embase and the Cochrane library to identify studies on prognostic factors in the management of sacral chordomas published between January 1970 and December 2013. The literature search and review process identified 100 articles that were included in the review article. This included both surgical and non-surgical studies on the management of sacral chordomas.

RESULTS

Sacrectomy with wide resection margins forms the mainstay of treatment but is associated with high risk of disease recurrence and reduced long-term survival. Adequate resection margins may require sacrifice of adjacent nerve roots, musculature and ligaments leading to functional compromise and mechanical instability. Large tumour size (greater than 5-10 cm in diameter), dedifferentiation and greater cephalad tumour extension are associated with increased risk of disease recurrence and reduced survival. Chordomas are poorly responsive to conventional radiotherapy and chemotherapy.

CONCLUSION

Operative resection with wide resection margins offers the best long-term prognosis. Inadequate resection margins, large tumour size, dedifferentiation, and greater cephalad chordoma extension are associated with poor oncological outcomes. Routine long-term follow-up is essential to enable early detection and treatment of recurrent disease.

Abstract P5-14-10: Adjuvant intra-operative electron-beam therapy for early invasive breast carcinoma using non-dedicated linear accelerator: Toxicity, efficacy, and aesthetic satisfaction

INTRODUCTION: In May 2004 we started a prospective trial on adjuvant intraoperative electron-beam therapy (IORT) in early invasive breast cancer, but instead of a dedicated machine, we used a non-dedicated linear accelerator (NDLA).

OBJECTIVES: To analyze early and late complications, cosmetic satisfaction of patients, and recurrence rates.

METHODS: Patients with the following characteristics were included: invasive breast ductal carcinoma, local staging with mammogram, ultrasound and magnetic resonance imaging showing uni-central and uni-focal tumor, age≥40 years, T1N0. The procedure is done according to the following steps on table 1:

PROTOCOL STEPS1Surgery performed in an operative room close to linear accelerator suite2Wide local excision with frozen sections of surgical margins and sentinel lymph node biopsy3If positive margins, they are expanded until negativity. If sentinel node positive, or multicentric/multifocal tumor, IORT is aborted4With both margins and sentinel lymph node free, the parenchyma round the surgical cavity is detached from skin and pectoralis major muscle. A shield (lead/aluminum/silicone disc) is placed underneath the breast parenchyma to avoid foward radiation5The breast parenchyma is sutured above the shield surface6The parenchyma thickness is measured for selection of the suitable electron energy7A collimator (cilindrical radiation applicator) is chosen for entire coverage of parenchyma8The patient is transferred from operative room to linear accelerator room and the collimator is attached to the machine9A portal-film (6MV photon-beam) is taken to check the alignment between the shield and applicator10If portal-film shows unfavorable positioning, the shield is realigned and a new portal-film is taken. Upon satisfactory condition, a single dose of 21Gy is delivered at 90% isodosis11After IORT completion the surgical procedure is ended

RESULTS: Initially 194 patients were included, but due to intraoperative exclusion criteria (positive sentinel lymph nodes or margins), 159 were analyzed. The median age was 57.9 (40 to 85.4) years and the median follow-up was 56.6 (1 to 103.2) months. Seven patients recurred (4 local and 3 regional). The average estimates for overall and event-free survival were respectively 95.4 (CI 95% 93.1-97.6) months and 90.1 (CI 95% 85.8-94.5) months. The crude incidences for acute (up to one month after surgery) and late (after one month) toxicities were respectively 8.2% and 26.2%. Excellent, good, fair and bad cosmetic outcomes (Harvard/NSABP/RT OG scale) were observed in 70.9%, 14.2%, 3.7% and 3.0%, respectively. Collimator sizes were 4cm in 18.7%, 5cm in 80.6%, and 7cm in 0.7% of cases. The electron energy chosen for treatment was 6MeV in 7.4%, 9MeV in 52.2%, 12MeV in 35.8%, 15MeV in 3.7% and 18MeV in 0.7%. The alignment between the shield and the collimator was appropriate in 72.4% (27.6% of patients required repositioning). No infection cases were related to peri-hospitalar time.

CONCLUSIONS: IORT using NDLA has shown low toxicity profile, high favorable aesthetics outcomes, and good oncologic efficacy. The use of NDLA may be usefull in settings without dedicated equipment for breast IORT.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-10.

Custom rotating-hinge total knee replacement in patients with spina bifida and severe neuromuscular dysfunction

Spina bifida (SB) is a congenital disorder which may result in a number of musculoskeletal problems. Total knee replacement (TKR) in this patient group is technically demanding due to bone deformity, soft tissue contracture, muscle tone abnormality and ligament insufficiency. This is a retrospective review of three patients with SB and disabling knee arthritis who were managed with a custom rotating-hinge (RHK) total knee system. All patients reported an improvement in knee pain and stability at mean follow-up 47 months (43-53). Mean Oxford Knee score improved from 21 preoperatively to 32 at final follow-up. One patient required revision of tibial and patella components at 37 months for lateral patella instability and excessive wear. Custom RHK for patients with SB, severe neuromuscular dysfunction and bone deformity relieves pain, restores stability and improves early knee function; however there is a significant risk of extensor mechanism complications and functional outcome is worse than primary TKR in the general population.

Femoral diaphyseal endoprosthetic reconstruction after segmental resection of primary bone tumours

Segmental resection of malignant bone disease in the femoral diaphysis with subsequent limb reconstruction is a major undertaking. This is a retrospective review of 23 patients who had undergone limb salvage by endoprosthetic replacement of the femoral diaphysis for a primary bone tumour between 1989 and 2005. There were 16 males and seven females, with a mean age of 41.3 years (10 to 68). The mean overall follow-up was for 97 months (3 to 240), and 120 months (42 to 240) for the living patients. The cumulative patient survival was 77% (95% confidence interval 63% to 95%) at ten years. Survival of the implant, with failure of the endoprosthesis as an endpoint, was 85% at five years and 68% (95% confidence interval 42% to 92%) at ten years. The revision rate was 22% and the overall rate of re-operation was 26%. Complications included deep infection (4%), breakage of the prosthesis (8%), periprosthetic fracture (4%), aseptic loosening (4%), local recurrence (4%) and metastases (17%). The 16 patients who retained their diaphyseal endoprosthesis had a mean Musculoskeletal Tumour Society score of 87% (67% to 93%). They were all able to comfortably perform most activities of daily living. Femoral diaphyseal endoprosthetic replacement is a viable option for reconstruction following segmental resection of malignant bone disease. It allows immediate weight-bearing, is associated with a good long-term functional outcome, has an acceptable complication and revision rate and, most importantly, does not appear to compromise patient survival.

Total femoral endoprosthetic replacement following excision of bone tumours

We undertook a retrospective review of 33 patients who underwent total femoral endoprosthetic replacement as limb salvage following excision of a malignant bone tumour. In 22 patients this was performed as a primary procedure following total femoral resection for malignant disease. Revision to a total femoral replacement was required in 11 patients following failed segmental endoprosthetic or allograft reconstruction. There were 33 patients with primary malignant tumours, and three had metastatic lesions. The mean age of the patients was 31 years (5 to 68). The mean follow-up was 4.2 years (9 months to 16.4 years). At five years the survival of the implants was 100%, with removal as the endpoint and 56% where the endpoint was another surgical intervention. At five years the patient survival was 32%. Complications included dislocation of the hip in six patients (18%), local recurrence in three (9%), peri-prosthetic fracture in two and infection in one. One patient subsequently developed pulmonary metastases. There were no cases of aseptic loosening or amputation. Four patients required a change of bushings. The mean Musculoskeletal Tumour Society functional outcome score was 67%, the mean Harris Hip Score was 70, and the mean Oxford Knee Score was 34. Total femoral endoprosthetic replacement can provide good functional outcome without compromising patient survival, and in selected cases provides an effective alternative to amputation.

Endoprosthetic reconstruction of the distal tibia and ankle joint after resection of primary bone tumours

Endoprosthetic replacement of the distal tibia and ankle joint for a primary bone tumour is a rarely attempted and technically challenging procedure. We report the outcome of six patients treated between 1981 and 2007. There were four males and two females, with a mean age of 43.5 years (15 to 75), and a mean follow-up of 9.6 years (1 to 27). No patient developed a local recurrence or metastasis. Two of the six went on to have a below-knee amputation for persistent infection after a mean 16 months (1 to 31). The four patients who retained their endoprosthesis had a mean musculoskeletal tumour society score of 70% and a mean Toronto extremity salvage score of 71%. All were pain free and able to perform most activities of daily living in comfort. A custom-made endoprosthetic replacement of the distal tibia and ankle joint is a viable treatment option for carefully selected patients with a primary bone tumour. Patients should, however, be informed of the risk of infection and the potential need for amputation if this cannot be controlled.

Outcome of intralesional curettage for low-grade chondrosarcoma of long bones

BACKGROUND

Different treatment strategies for low-grade chondrosarcomas are reported in the literature with variable outcomes. The aim of this study was to assess the oncological and functional outcomes associated with intralesional curettage and cementation of the lesion as a treatment strategy.

PATIENTS AND METHODS

We performed a retrospective review of 39 consecutive patients with intramedullary low-grade chondrosarcoma of long bones treated by intralesional curettage and cementation at our institution between 1999 and 2005.

RESULTS

There were 10 males and 29 females with a mean age of 55.5 years (32-82), and a mean follow-up of 5.1 years (3-8.7). Local recurrence occurred in two patients (5%) within the first two years following index surgery. Both were treated by re-curettage and cementation of the resultant defects. A second local recurrence developed a year later in one of these two patients, for which a further curettage followed by local liquid nitrogen treatment was performed. Overall, there were no cases of post-operative complications or metastases. The patients were assessed using the Musculoskeletal Tumour Society scoring system (MSTS) to determine limb function. The average score achieved was 94% (79-100%).

CONCLUSION

Intralesional curettage is an effective treatment strategy for low-grade intramedullary chondrosarcoma of long bones, with excellent oncological and functional results. Careful case selection with stringent clinical and radiographic follow-up is recommended.

Very late local recurrence of Ewing's sarcoma--can you ever say 'cured'? A report of two cases and literature review

We report two rare cases of very late local recurrence of Ewing's sarcoma, occurring 16 years and 19 years after treatment of the primary tumour. In both cases, disease remission had been achieved. Both patients originally underwent non-surgical combined modality therapy following initial diagnosis and both were rendered disease-free. After a long latent phase, both started experiencing unexplained local symptoms. These were investigated at their local hospital but tumour recurrence was not initially considered as a cause of these symptoms. The two patients were eventually referred back to our institution after the diagnosis of recurrent Ewing's sarcoma was established. Both have successfully undergone complete excision of the recurrences and are receiving postoperative adjuvant therapy. These cases highlight the need to remain vigilant for local recurrence, however long after the initial diagnosis.

Invasion of epithelial mammalian cells by Paracoccidioides brasiliensis leads to cytoskeletal rearrangement and apoptosis of the host cell

Paracoccidioides brasiliensis (Pb) yeast cells can enter mammalian cells and probably manipulate the host cell environment to favor their own growth and survival. We studied the uptake of strain Pb 18 into A549 lung and Vero epithelial cells, with an emphasis on the repercussions in the cytoskeleton and the apoptosis of host cells. Cytoskeleton components of the host cells, such as actin and tubulin, were involved in the P. brasiliensis invasion process. Cytochalasin D and colchicine treatment substantially reduced invasion, indicating the functional participation of microfilaments (MFs) and microtubules (MTs) in this mechanism. Cytokeratin could also play a role in the P. brasiliensis interaction with the host. Gp43 was recognized by anti-actin and anti-cytokeratin antibodies, but not by anti-tubulin. The apoptosis induced by this fungus in infected epithelial cells was demonstrated by various techniques: TUNEL, DNA fragmentation and Bak and Bcl-2 immunocytochemical expression. DNA fragmentation was observed in infected cells but not in uninfected ones, by both TUNEL and gel electrophoresis methods. Moreover, Bcl-2 and Bak did not show any differences until 24 h after infection of cells, suggesting a competitive mechanism that allows persistence of infection. Overexpression of Bak was observed after 48 h, indicating the loss of competition between death and survival signals. In conclusion, the mechanisms of invasion of host cells, persistence within them, and the subsequent induction of apoptosis of such cells may explain the efficient dissemination of P. brasiliensis.

Pathogenesis II: fungal responses to host responses: interaction of host cells with fungi

Most of our knowledge concerning the virulence determinants of pathogenic fungi comes from the infected host, mainly from animal models and more recently from in vitro studies with cell cultures. The fungi usually present intra- and/or extracellular host-parasite interfaces, with the parasitism phenomenon dependent on complementary surface molecules. Among living organisms, this has been characterized as a cohabitation event, where the fungus is able to recognize specific host tissues acting as an attractant, creating stable conditions for its survival. Several fungi pathogenic for humans and animals have evolved special strategies to deliver elements to their cellular targets that may be relevant to their pathogenicity. Most of these pathogens express surface factors that mediate binding to host cells either directly or indirectly, in the latter case binding to host adhesion components such as extracellular matrix (ECM) proteins, which act as 'interlinking' molecules. The entry of the pathogen into the host cell is initiated by fungal adherence to the cell surface, which generates an uptake signal that may induce its cytoplasmic internalization. Once this is accomplished, some fungi are able to alter the host cytoskeletal architecture, as manifested by a rearrangement of microtubule and microfilament proteins, and this can also induce epithelial host cells to become apoptotic. It is possible that fungal pathogens induce modulation of different host cell pathways in order to evade host defences and to foster their own proliferation. For a number of pathogens, the ability to bind ECM glycoproteins, the capability of internalization and the induction of apoptosis are considered important factors in virulence. Furthermore, specific recognition between fungal parasites and their host cell targets may be mediated by the interaction of carbohydrate-binding proteins, e.g., lectins on the surface of one type of cell, probably a parasite, that combine with complementary sugars on the surface of host-cell. These interactions supply precise models to study putative adhesins and receptor-containing molecules in the context of the fungus-host interface. The recognition of the host molecules by fungi such as Aspergillus fumigatus, Paracoccidioides brasiliensis and Histoplasma capsulatum, and their molecular mechanisms of adhesion and invasion, are reviewed in this paper.

Adherence and intracellular parasitism of Paracoccidioides brasiliensis in Vero cells

Paracoccidioides brasiliensis is a dimorphic fungus known to produce invasive systemic disease in humans. The 43-kDa glycoprotein of P. brasiliensis is the major diagnostic antigen of paracoccidioidomycosis and may act as a virulence factor, since it is a receptor for laminin.Very little is known about early interactions between this fungus and the host cells, so we developed in vitro a model system employing cultured mammalian cells (Vero cells), in order to investigate the factors and virulence mechanisms of P.brasiliensis related to the adhesion and invasion process. We found that there is a permanent interaction after 30 min of contact between the fungus and the cells. The yeasts multiply in the cells for between 5 and 24 h. Different strains of P. brasiliensis were compared, and strain 18 (high virulence) was the most strongly adherent, followed by strain 113 (virulent), 265 (considered of low virulence) and 113M (mutant obtained by ultraviolet radiation, deficient in gp43). P. brasiliensis adhered to the epithelial cells by a narrow tube, while depressions were noticed in the cell surface, suggesting an active cavitation process. An inhibition assay was performed and it was verified that anti-gp43 serum and a pool of sera from individuals with paracoccidioidomycosis were able to inhibit the adhesion of P. brasiliensis to the Vero cells. Glycoprotein 43 (gp43) antiserum abolished 85% of the binding activity of P. brasiliensis. This fungus can also invade the Vero cells, and intraepithelial parasitism could be an escape mechanism in paracoccidioidomycosis.