heart-lung machine to the process. The machine supplied oxygen and circulated the mixture of blood, drug and mineral solution (the perfusate) throughout the isolated limb. This method allowed an increase of 6 to 10 times the normal dosage of drug that could have been given locally to the cancer. The drug's toxic effects to the entire body were reduced and the rate of response was increased. The first report of a large number of patients treated with isolated limb perfusion at normal body temperature showed they had a survival rate 20 to 25 percent better than those treated in the conventional way.
A later development added heat to the perfusion system. Heat will kill tumor cells more often than normal ones at certain critical temperatures. The tumor-killing effect depends on the amount of heat used and the length of time it is applied. Using a heated perfusate improved the response rate in a 1967 study and heat has played a role in the procedure ever since.
What makes isolated limb perfusion particularly effective is that it delivers high-dose chemotherapy not only to the tumor but to the entire limb below the tourniquet, including potential sites of metastases. All that limits the dosage of the chemotherapy drug to be given is local tissue toxicity.
