DVT. It can be related to the deep vein thrombosis. Other options: tumor compression of nerve roots or penetration of pelvic muscles.
Sciatica, if any. This usually presents with abdominal pain, bloating, urinary symptoms, and weight gain. This would indicate advanced disease beyond the pelvis. Leg pain is not a classic symptom, but may occur due to the size the ovarian cancer grows to, and present as sciatica, a condition seen in pregnancy when the baby is at or near term, and presses on the sciatic nerve, causing pain in the back thigh.