The conventional approach to chemotherapy treatment for cancer is to give the patient a cocktail of different chemo drugs at the maximum tolerated dose (MTD). The idea of MTD treatment is to hit the cancer with the most toxic treatment the patient can stand in the hope that it causes the maximum damage to the disease. Normally a treatment consists of a number of cycles of chemo using a mix of drugs, with the idea that each drug will attack the tumour in a different way – reducing the chance of the tumour surviving the onslaught. And it’s an onslaught for the person receiving the treatment too – most chemotherapy drugs are toxic to a wide range of cells, not just cancer cells. Hence the hair loss, the nausea, the immune suppression, fatigue and the rest of the side effects that makes chemo so hard.
Of necessity a person needs recovery time after each cycle of chemotherapy. Blood counts need to recover, sickness needs to pass, people need to regain some strength. Unfortunately that’s recovery time that tumours can also use to recover. The highest rates of tumour kill tend to be at the least cycles, the later cycles tend to be less effective, particularly if resistance starts to kick in.
However, this isn't the only way of delivering treatment. An alternative approach to chemotherapy has been developing for some time. Low dose metronomic chemotherapy involves many of the same drugs as MTD chemo, but delivered at low doses, often in tablet form, but with no treatment breaks. The continuous dosing is possible because at these low doses the drugs work in very different ways to when they are delivered at MTD levels. The side effects are minimal as the drugs are no longer acting as potent toxins to massively kill cells.