In theory, clinicians who treat patients with advanced colorectal cancer can extend treatment indefinitely because of the low cumulative toxicity associated with therapy. However, researchers from the Medical Research Council Colorectal Cancer Group advise that it is safe to stop chemotherapy and then restart the treatment. In fact, doing so can enhance quality of life without compromising survival.
In a study of 354 patients with chemo-sensitive, advanced colorectal cancer, chemotherapy was safely stopped after 12 weeks and restarted if the disease progressed. The researchers found no clear evidence of a benefit with continuous chemotherapy.
Intermittent therapy, however, caused a reduction in toxicity; patients in the intermittent group received an average of 10 weeks less of trial chemotherapy than those receiving continuous therapy. There was no great difference in the use of second-line chemotherapy, which, the researchers say, can extend the patient’s treatment options. The introduction of second-line treatment can be delayed until the reused regimen fails.
Several guidelines for intermittent treatment have been suggested:
- The induction chemotherapy should last long enough and should be effective enough to ensure that the majority of patients’ responses take place during the induction period; however, a long induction treatment can lead to drug resistance, making rechalleng-ing less effective.
- Patients must respond well to reusing the same chemotherapy drugs.
- Some patients may respond better if there is a long gap between stopping and starting treatment.
- Diligent follow-up is essential to ensure that the treatment can be reintroduced at the first sign of progression and to provide reassurance and symptom control during the interval.
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