Prospective evaluation of argon gas probe delivery for cryotherapy of bone tumours

<p><b>INTRODUCTION</b>Cryosurgery for tumoural ablation traditionally involves instilling liquid nitrogen into a tumoural bed. The inability to control precise delivery can result in potentially disastrous consequences of skin necrosis and nitrogen gas embolism. In this study, we evaluated a probe-based closed cryosurgical system, which eliminates these risks.</p><p><b>MATERIALS AND METHODS</b>We performed a prospective evaluation of 36 cases of bone tumours treated with a probe-based cryosurgical system at the National University Hospital, Singapore. Cases consisted of patients with benign aggressive tumours (42%), primary malignant bone tumours (25%) and bone metastases (33%). In primary bone tumours, the aim of therapy was cure. In bone metastasis, the aim of therapy was palliation defined as the relief of symptoms for the patients' remaining lifetime.</p><p><b>RESULTS</b>In the primary bone tumour group, no recurrences were reported. In the metastases group, where the intention was palliation, there were 3 cases of radiological relapses (P = 0.02) and 2 clinical relapses. Kaplan-Meier evaluation showed a statistically significant tendency for radiological relapse in metastatic disease versus primary disease (P = 0.02). Median time for relapse free survival in the metastatic group was 17 months (P = 0.01). There were 4 deaths in the metastatic group due to progression of disease unrelated to the index region of cryosurgical treatment. There were no deaths in the primary bone tumor group. We had 2 complications from this therapy involving fractures through the cryoablated segments. One case healed spontaneously and the other was most expediently managed with a shoulder hemiarthoplasty. There were no skin burns or embolic complications.</p><p><b>CONCLUSION</b>Good clinical efficacy with probe delivered cryotherapy has been shown in this group of 32 patients with cure in all primary disease. Relapse occurred in only a small proportion of patients with bone metastasis.</p>

Demographic determinants of survival in osteosarcoma

<p><b>INTRODUCTION</b>Osteosarcoma treatment has experienced a renaissance in the last 3 decades with the institution of multimodality treatment involving multiagent chemotherapy and surgery. Yet globally, treatment success has stagnated at about 70% survival at 5 years in most single institution series. We performed survival analyses on 2 national databases in 2 countries and compared these with corresponding institution specific survival.</p><p><b>MATERIALS AND METHODS</b>All patients with the diagnostic code of non-metastatic intramedullary osteosarcoma in the long bones of the upper and lower limbs less than 30 years of age were selected from the Surveillance Epidemiology and End Result (SEER) database to ensure uniformity with respect to disease and treatment. We studied the factors: ethnicity, gender, age, grade, histology, size, site, surgery, compartmentalisation, number of primaries and venue of treatment for their contribution to survival. In addition, the data were stratified into 3 decades (seventies, eighties and nineties) to account for variations due to the evolution of treatment paradigms and imaging modalities.</p><p><b>RESULTS</b>Institution-specific survival was predictably better than national survival in the 4 databases. One thousand patients were selected from the SEER database. Oriental descent, state-specific treatment, female gender, treatment in the nineties, low-grade disease, intra-compartmental disease, small size, wide resections as opposed to forequarter or hindquarter amputations, and single primaries were good prognostic factors on univariate analysis as well as multivariate analysis (P <0.05). Survival was better in the more affluent states (P <0.05). Males were affected at an older age than females (P = 0.004). Blacks tended to have larger tumours although their overall survival was similar to whites. Orientals were more likely to be treated in the nineties with wide resections for smaller tumours and were located around states associated with good treatment. Orientals in Singapore and the United States had the same survival (P = 0.45). Survival in Orientals in Singapore was not significantly different from other races. The standard of healthcare for osteosarcoma varies greatly across the United States but is uniform in Singapore. Hence the observed differences in the United States were likely due to socioeconomic factors.</p><p><b>CONCLUSION</b>This analysis confirms the importance of a number of prognostic variables in osteosarcoma and suggests the possibility of an ethnic and economic bias for good survival.</p>

Tumour interstitial fluid pressure may regulate angiogenic factors in osteosarcoma

<p><b>PURPOSE</b>We have previously shown that osteosarcomas have states of increased interstitial fluid pressure (IFP) which correlate with increased proliferation and chemosensitivity. In this study, we hypothesized that constitutively raised IFP in osteosarcomas regulates angiogenesis.</p><p><b>MATERIALS AND METHODS</b>Sixteen patients with the clinical diagnosis of osteosarcomas underwent blood fl ow and IFP readings by the wick-in-needle method at the time and location of open biopsy. Vascularity was determined by capillary density in the biopsy specimens. We performed digital image analysis of immunohistochemical staining for CD31, VEGF-A, VEGF-C and TPA on paraffin-embedded tissue blocks of the biopsy samples. Clinical results were validated in a pressurised cell culture system.</p><p><b>RESULTS</b>IFPs in the tumours (mean 33.5 +/- SD 17.2 mmHg) were significantly higher (P = 0.00001) than that in normal tissue (2.9 +/- 5.7 mmHg). Pressure readings were significantly higher in low vascularity tumours compared to high vascularity tumours (P <0.001). In the osteosarcoma cell lines, growth in a pressurised environment was associated with VEGF-A downregulation, VEGF-C upregulation and TPA upregulation. The reverse was seen in the OB cell lines. Growth in the HUVEC cell line was not significantly inhibited in a pressurised environment. Immunohistochemical assessment for VEGF-A (P = 0.01), VEGF-C (P = 0.008) and TPA (P = 0.0001) translation were consistent with the findings on PCR.</p><p><b>CONCLUSION</b>Our data suggest that some molecules in angiogenesis are regulated by changes in IFP.</p>