Haematogenous spread

Haematogenous spread

5 At a tumour size of 1–2 /uni00A0 mm (10 cells) neoangiogenesis occurs. The onset of angiogenesis ushers in rapid growth, invasion and metastatic potential. Haematogenous metastasis occurs to the skeletal system (in order of frequency: lumbar vertebrae, neck of femur, thoracic vertebrae, rib and skull). The bony metastasis is generally osteolytic, although osteosclerotic and mixed types may be seen. Haematogenous metastasis may ) and also occur to the liver, lungs and brain and, occasionally , the adrenal glands and ovaries. In limbs these deposits occur above the elbow and above the knee (haematopoietic vascular bone marrow is confined to the axial skeleton and in limbs above the elbows and the knees). Extensive bone marrow replacement by tumour cells may result in release of immature blast cells in the peripheral blood, giving rise to ‘leukoerythroblastic anaemia’. Peripheral blood samples for circulating cell-free tumour deoxyribonucleic acid (cf-DNA) and circulating tumour cells are being studied as potential prognostic markers to predict disease recurrence.