Spread of Tumours

Main Routes of Spread of tumours

• Direct spread

• Lymphatics

• Vascular spread

• Transcoelomic spread

• Perineural spread

Direct invasion

• Growth of cancers is accompanied by progressive infiltration, invasion and destruction by the surrounding tissue.

• In general they are poorly demarcate by surrounding normal tissue and well defined cleavage plane is lacking.

Mechanism of tumour cell invasion and metastasis

• Factors increasing cell mobility• Decreased adhererance of tumour cells• Increased growth factor secretion• Increased secretion of autocrine motility factor• Failure to synthesise basement membrane

• Factors for facilitation of movement through stroma• Secretion of collagenase, cathepsin B, gelatinase• Stimulation of stromal cells to secrete stromelysin & alternative

extracellular matrix

• Factors improving tumour cell survival and spread

Metastasis is mainly by• Lymphatic spread

• Haematogenous spread

• Transcoelomic spread

Lymphatic spread

• Carcinomas generally spreads via lymphatics first. But sarcomas can use this route too.

• The pattern of lymph node involvement follows the natural routes of drainage.

• Carcinoma of breast (upper outer quadrant) spread to axillary lymph nodes, the inner quadrant drain through the nodes along the internal mammary artery. Later supraclavicular and infraclavicular nodes may become involved.

Lymphatic spread

Skip metastasis• Local lymph nodes may be bypassed due

to venous lymphatic anastomosis or because the inflammation or radiation has obliterated the channels.

• Regional nodes act as a barrier to further spread of the tumour, at least for a time.

• The cells, after arrest within the node, may be destroyed.

• Drainage of tumour cell debris or tumour cell antigens, or both can induce reactive changes.

• The enlargement of the nodes may be due to – 1. Spread of the cancer cells– 2. Reactive hyperplasia

Vascular spread

Haematogenous spread s typical of sarcomas but is seen in carcinoma too.

• Tumour emboli

• Permeation

Via blood stream spread

• As tumour emboli– Osteosarcomas

metastatising to the lungs

– Gastrointestinal malignancies metastatising to the liver

Permeation• Cords of cells grow along the blood

vessels – Eg. In renal cell carcinoma the malignant cell

cords grow along the vessel walls, renal vein and IVC

Haematogenous spread

• Typical for sarcomas but also used by the carcinomas.

• Arteries: due to thicker walls are less readily penetrated. But is seen when a tumour pass through pulmonary capillary beds or pulmonary arterio-venous shunts or when pulmonary metastasis give rise to tumour emboli.

• Venous invasion follow venous flow draining the site of neoplasm. Eg. Liver and lung.( all portal drainage to the liver and all caval blood flows to the lungs)

• Cancers arising in close proximity to the vertebral column often embolise through the paravertebral plexus. Eg: thyroid and prostate carcinomas

Haematogenous spread contd…..

• Certain cancers have a propensity for venous invasion.

• Renal cell carcinoma invades branches of renal vein then renal vein and grow along the IVC in a snake like fashion some times reaching the right side of the heart.

• Hepatocellular carcinoma often penetrate the portal vein

• Such IV growth may not be accompanied by widespread dissemination.

Secondary carcinoma of

lung• These tan-white nodules

are characteristic for metastatic carcinoma. Metastases to the lungs are more common even than primary lung neoplasms simply because so many other primary tumours can metastasise to the lungs.

Secondary carcinoma of

lung

Secondary deposits in

lung

Metastatic tumour deposits in solid organs

• Liver, lung, brain, bone marrow

• Certain types of tumours have a characteristic patterns of spread. Eg. Prostatic ca is often spread to bone

• It is thought that the malignant cells and the target organ must express mutually compatible receptors and cell surface adhesion molecules which facilitate cellular anchorage and growth promotion

• Hepatic metastasis: portal circulation• Pulmonary metastasis: from systemic

circulation

Transcoelomic spread• Peritoneal cavity

• Pleural cavity

• Pericardial cavity

• Subarachnoid cavity

• Joint space

Transcoelomic spread contd…

• Krukenberg tumour• Gastric carcinoma with secondary deposits in the

ovary and pouch of Douglas• Colonic carcinoma with secondary deposits in the

ovary and pouch of Douglas

Transcoelomic spread• Tumour cells may remain confined to the

surface of the abdominal viscera without penetrating into the substance.

• Some times the mucous secreting tumours of the ovarian or appendiceal carcinoma fill the peritoneal cavity with gelatinous neoplastic mass referred to as pseudomyxoma peritonei.

• Adeno carcinoma Signet ring cell carcinoma

• Breast and lung tumours commonly involve pleural space and cause pleural effusion

• Ovarian and gastric tumours are responsible for peritoneal invovment and cause malignant ascitis.

• There is commonly an inflammatory response in the lining with the accumulation of protein rich fluid and inflammatory cells, proliferation of mesothelial cells and haemorhage

Transcoel--omic spread

• Diagnostic paracentesis of ascitic/ pleural fluid

Spread of lung carcinoma

• Local spread• Lymphatic spread• Transcoelomic

spread• Haematogenous

spread

Perineural spread• Spread along the

course of nerve bundles

• Common in prostate carcinoma and some basal cell carcinoma