Tumour interstitial fluid pressure may regulate angiogenic factors in osteosarcoma.

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: Our data suggest that some molecules in angiogenesis are regulated by changes in IFP.

Tumor interstitial fluid pressure may regulate angiogenic factors in osteosarcoma.

We have previously shown that osteosarcomas (OS) 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 OS regulates angiogenesis. Sixteen patients with the clinical diagnosis of OS underwent blood flow 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 pressurized cell culture system. Interstitial fluid pressures in the tumors (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 tumors compared to high vascularity tumors (p < 0.001). In the OS cell lines, growth in a pressurized environment was associated with VEGF-A downregulation, VEGF-C upregulation, and TPA upregulation. The reverse was seen in the OB cell line. Growth in the HUVEC cell line was not significantly inhibited in a pressurized 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. Our data suggests that some molecules in angiogenesis are regulated by changes in IFP.

Sacral resection for recurrent rectal cancer: analysis of morbidity and treatment results.

PURPOSE: Composite sacropelvic resection for locally advanced recurrent rectal cancer is a high-risk procedure that benefits select patients. We reviewed our recent institutional experience to evaluate case selection, morbidity, and outcomes. METHODS: Between 1987 and 2004, 29 patients underwent composite resection for recurrent locoregional rectal cancer (17 females; median age, 60 years). Clinicopathologic indicators were evaluated as indicators of survival by log-rank test and Cox proportional hazards model. RESULTS: Of 29 total patients, 27 (93 percent) received radiotherapy with their previous surgery (n = 10; 34 percent) or before sacrectomy (n = 17; 59 percent), and 12 (41 percent) received intraoperative therapy. Sacral resections were performed at S2/S3 (55 percent) or S4/S5 (45 percent) using anterior (41 percent) or combined anterior-posterior approach (59 percent), with adherence to (62 percent) or cortical invasion in (38 percent) the sacrum. A majority of those who had undergone previous abdominoperineal resection had total exenteration (9/13), whereas most patients who had undergone a previous sphincter-preserving procedure had abdominoperineal resection (12/16) and none had exenteration. Pedicle flaps (omental, 11; abdominal rectus, 7) often were used. A median of five (range, 1-33) units of blood was given intraoperatively. Transfusions were associated with previous abdominoperineal resection (P < 0.03), correlating strongly with postoperative morbidity (P < 0.02). There were 33 complications in 17 (59 percent) patients, most commonly perineal wound breakdown (9 (31 percent)) and pelvic abscess (5 (17 percent)). Median hospital stay was 18 (range, 7-56) days, significantly longer in patients with previous abdominoperineal resection (P < 0.02) or postoperative morbidity (P < 0.03). The only postoperative death was from pelvic sepsis. Resection was complete (R0) in 18 patients (62 percent), with microscopically positive margins (R1) in 10 (34 percent) and grossly positive margins (R2) in 1 (3 percent). Two-year and five-year recurrence rates were 47 and 85 percent, respectively; disease-specific survival was 63 and 20 percent, respectively. Less transfusion (P = 0.03), R0 resection (P = 0.005), lack of anterior organ involvement (P = 0.02), and absence of cortical bone invasion (P < 0.001) were associated with better survival on univariate analysis; original colorectal cancer stage was not. CONCLUSIONS: Sacrectomy for rectal cancer is a high-risk procedure that can achieve clear resection margins with low mortality in select patients. This procedure has a low cure rate but may provide local disease control with acceptable morbidity.

Elevated physiologic tumor pressure promotes proliferation and chemosensitivity in human osteosarcoma.

PURPOSE: This study investigates the effect of constitutively raised interstitial fluid pressure on osteosarcoma physiology and chemosensitivity. EXPERIMENTAL DESIGN: We did pressure and blood flow assessments at the time of open biopsy in patients with the diagnosis of high-grade osteosarcoma and correlated this to survival and chemotherapy-associated tumor necrosis. Osteosarcoma cell lines were then evaluated for proliferative and therapeutic indices in a replicated high-pressure environment. RESULTS: Sixteen osteosarcomas in vivo were assessed and exhibited elevated interstitial fluid pressures (mean 35.2 +/- SD, 18.6 mmHg). This was not associated with significantly impeded blood flow as measured by a Doppler probe at a single site (P < 0.12). Nonetheless, greater chemotherapy-associated necrosis and associated longer survival were seen in tumors with higher interstitial fluid pressures (P < 0.05). In vitro, cells undergo significant physiologic changes under pressure. Osteosarcoma cell lines grown in a novel hydrostatically pressurized system had variable cell line-specific growth proportional to the level of pressure. They were more proliferative as indicated by cell cycle analysis with more cells in S phase after 48 hours of pressurization (P < 0.01). There was a significant elevation in the cell cycle-related transcription factors E2F-1 (P < 0.03) and E2F-4 (P < 0.002). These changes were associated with increased chemosensitivity. Cells tested under pressure showed an increased sensitivity to cisplatin (P < 0.00006) and doxorubicin (P < 0.03) reminiscent of the increased chemotherapy-associated necrosis seen in tumors with higher interstitial fluid pressure in the clinical study. CONCLUSIONS: The results of this study suggest that cells in the in vivo pressurized environment are at a higher state of regenerative activity than is demonstrable in conventional cell culture systems. Variations in tumor interstitial fluid pressure have the potential to alter chemotherapeutic effects.