Solid Tumors

Patients must have histologically-proven adenocarcinoma of the rectum with no distant metastases. Patients must have received a minimum radiation dose of 40Gy and not more than 54 Gy.

If patients did not participate in NSABP R-04, they must have received one of the treatments listed:
XRT + continuous infusion 5-FU
XRT + 5-FU +/- LV
XRT + capecitabine
XRT + 5-FU + Oxaliplatin
XRT + Capecitabine + Oxaliplatin

VTE Treatment Group: Eligible subjects must be age 18 years or older, diagnosed with active cancer and have a documented first venous thromboembolic event. Subjects must be currently receiving any treatment for cancer. In addition, subjects must have a documented first venous thromboembolic event (VTE). Subjects must not be in need of long-term anticoagulant therapy or be undergoing high dose chemotherapy for peripheral blood stem cell or bone marrow transplantation, induction chemotherapy for acute leukemia or has other conditions associated with persistent thrombocytopenia of less than 100x109/L for a duration of at least four consecutive weeks.

Control Group Patients: Eligible control patients will be matched patients aged 18 years or older and diagnosed with active cancer meeting the same criteria as above but without thrombosis

All eligible subjects with VTE will receive tinzaparin 175 U/kg/day for at least 6 months with another 6 months at the investigator's discretion (up to one year study treatment). Plasma markers of hemostasis, fibrolysis, and angiogenesis will be measured at baseline and at 7 days, 1 month, and 6 months after start of tinzaparin treatment (if subject agrees).

Patients with cancer but without blood clots (control group) will also be enrolled in this study but will not receive study drug. For these patients, information regarding overall heath and response to their cancer treatment will be monitored. Plasma markers of hemostasis, fibrinolysis, and angiogenesis will be measured at baseline and at 7 days, 1 month, and 6 months (if subject agrees)