Tailored dosage of chemotherapy effective in treating breast cancer

By tailoring the dosage of chemotherapy to each individual patient, the treatment of breast cancer could be improved considerably. This is shown in a dissertation by Uppsala researcher Henrik Lindman at Uppsala University in Sweden. The method has proven to yield excellent results in clinical tests.

The dissertation reports that an alternative way of tailoring the dosage of chemotherapy has been studied and found to work. If the advantages of this method compared to standard treatment can be verified in the follow-up study that has just been completed on more than 1,500 patients in Sweden and Denmark, we may be facing a more extensive change in the treatment of cancer, one that reaches far beyond the sphere of breast cancer. One clear advantage of the method, apart from fewer side-effects and less risk of under-dosage, is that it should provide a way of determining the value of new chemotherapies, since it is probable that tailored dosages will prevent improper dosage regimens to a greater extent than previously.

In treating cancer, the dosage of chemotherapy is normally determined on the basis of the body surface area of the patient, which factors in height and weight. This method has proven to be insufficient when it comes to differences among patients in the amount of chemotherapy in the blood. Some patients receive overdoses with severe side-effects as a result, while others receive under-dosed regimens that risk leaving the tumor insufficiently treated.

Henrik Lindman has studied a method of tailoring just the right dosage for each patient. This is done by measuring the decline in, above all, white corpuscles after each treatment and thereafter adjusting the following treatment. The method proved successful in the three different pioneering trials on women with breast cancer. The differences in tolerated chemotherapy were up to a factor of three across different patients, which, among other things, may be dependent on genetic differences in sensitivity. In a Nordic collaborative project, 525 women with breast cancer at high risk of recurrence were selected for treatment. Half of the patients received 9 doses of tailored treatment while the other half received high-dosage regimens with bone-marrow transplants after three standard dosages of chemotherapy. Patients receiving tailored treatment experienced a lower rate of recurrence of breast cancer (28% compared with 37% after 3 years).

The other two studies involved, respectively, 26 and 44 patients with metastasized breast cancer. Here, too, the effect of treatment was good in comparison with previous experience (81% and 63%, respectively, saw a dramatic reduction in their tumors). Women who could withstand the highest dosages did not experience more general side-effects than those who were given lower dosages.