Treating circulating cell clusters

A system for removing cancer-associated cell clusters from blood circulation of a subject, the system comprising:

• a filter module comprising:
• (a) an input port;
• (b) an output port;
• and
• (c) a membrane having pores configured to allow at least a portion of a subject's blood to pass through the pores from a first side to a second side of the membrane;
• (d) a first chamber in fluid communication with the input port and located at the first side of the membrane;
• (e) a second chamber in fluid communication with the output port and located at the second side of the membrane;
• wherein the pores in the membrane have a minimum size not less than about 20 microns, configured to allow individual cancer-associated cells to pass through the pores from the first side to the second side of the membrane;
• wherein the input port is configured to allow the subject's blood to flow into the first chamber to contact the membrane;
• wherein the filter module is configured to retain circulating cancer-associated cell clusters on the first side of the membrane, each cluster comprising three or more cells;
• and
• wherein the filter module is configured to allow individual circulating cancer cells in the subject's blood to pass from the first chamber through the pores to the second side of the membrane and into the second chamber;
• and
• wherein the filter module is configured to return blood and the individual circulating cancer cells from the second chamber to the subject's blood circulation via the output port.