Low dose chemotherapy involves smaller doses of medications that are given more often than the doses in traditional higher dose regimens. Learn about the advantages and effectiveness of each approach.

Chemotherapy is a category of medications that destroy cells by attacking them at different points in their life cycle.

The medications used for chemotherapy are very effective at targeting fast-growing cancer cells, but they can’t distinguish between cancer cells and noncancerous cells that are also fast-growing. This is why hair loss and skin changes are common side effects of chemotherapy.

When chemotherapy is given in large doses, many of your healthy cells feel the effects alongside cancer cells. Your healthy cells will mostly recover in time, but the cancer cells will not.

Because the side effects of traditional (high dose) chemotherapy can be difficult to cope with, researchers are investigating lower dose options to see whether they can find medication amounts that are still effective but cause fewer side effects.

This article explores types of low dose and high dose chemotherapy, when each type is used, and how well each works.

Low dose vs. high dose chemotherapies

Low dose (metronomic) chemotherapy is a condensed, lower dose form of chemotherapy that is given on a more frequent schedule than traditional regimens. Traditional chemotherapies are usually given at the highest possible dose that is safe.

The immediate and long-term side effects that can come with traditional dosing can scare some people away from these treatments. People who are older or more frail may become sicker or develop fatal complications from the chemotherapy.

Low dose regimens were developed to experiment with alternative dosing for more sensitive people. Giving smaller doses more often may reduce the toxic effects of these medications or at least make them more tolerable.

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Since low dose regimens have been developed, there has been some debate as to whether they are more effective than traditional chemotherapy for controlling or managing cancers.

A 2017 research review, which included six clinical trials, concluded that low dose chemotherapy regimens produced roughly the same benefit as traditional chemotherapy.

In one trial, several people dropped out of the study group that received traditional chemotherapy doses. At least two people in the trials died as a result of traditional chemotherapy treatment complications.

The review authors concluded that low dose regimens may be as effective as traditional dosing for people who might be more sensitive to these medications but that larger studies were needed.

Newer studies have also found that there are benefits to using more frequent, lower dose chemotherapy regimens, but results seem to vary by cancer type, stage, and the particular type of chemotherapy being used.

Types of cancer that low dose chemotherapy has been used for

Most studies so far have focused on the use of low dose chemotherapy in treating the following types of cancer:

But recent studies point out that most data on the use of these treatments for initial cancer management in comparison to traditional chemotherapy comes from studies in early phases. More information from trials in later phases would help provide more conclusive outcomes.

Many of these studies also look at low dose chemotherapy alongside other treatment regimens or as ongoing maintenance treatment alongside other therapies.

More research is needed to make sure people who use low dose therapy aren’t trading side effects for inadequate cancer treatment. Getting chemotherapy, at any dose, without the benefit of cancer treatment is the biggest downside and unanswered question when it comes to low dose chemotherapy.

Final score on low dose chemotherapy

Many studies are currently examining low dose chemotherapy options. On the surface, these regimens seem to be at least as effective as traditional chemotherapy in managing cancer while causing fewer side effects. However, large scale studies still need to be done to make an accurate comparison.

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Conventional chemotherapy uses the highest possible doses of medication, stopping just short of toxicity. Chemotherapy medications are good at killing cancer cells, but they can also destroy noncancerous cells.

Using the highest possible dose that the body can handle has traditionally been seen as the best strategy for fighting cancer. However, your tolerance for chemotherapy depends on your overall health and your specific type of cancer.

Roughly half of all cancers develop in people over 70 years old, and 30–50% of older adults with stage 3–5 solid tumors will experience chemotherapy toxicity at some point in their treatment.

There’s no good tool to predict who will develop toxicity, so doctors usually give people the option to try chemotherapy — and take the chance of developing toxicity — rather than see their cancer progress.

High dose chemotherapy has proven highly effective in treating or even curing many types of cancer, especially cancers that return after initial treatment. The downside is that these treatments often kill many healthy cells and destroy bone marrow, so people need additional treatments to manage toxicity and side effects.

Final score on high dose chemotherapy

Traditional and high doses of chemotherapy are very effective at treating most cancers or, at the very least, keeping them from progressing. However, many people who develop cancer are older or become frail from the disease and end up experiencing short- and long-term side effects from treatment.

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Using more frequent, lower dose regimens of chemotherapy is still a fairly new practice. Not everyone is willing to take a chance by using a lower (and possibly less potent) dose of medication when treating aggressive cancers that are usually treated with high dose chemotherapy.

Because of this, most of the information on the effectiveness of low dose therapies has been taken from studies that used low doses in frail adults, for limited cancer types, or alongside other treatments.

Larger studies are underway to try to answer this question on a larger scale, but early results suggest that, at least for some cancers, low dose chemotherapy regimens may be an option for treating cancer without the toxic effects of high doses.

More research is needed to accurately compare the results of treatment with high dose and low dose chemotherapy. Some studies suggest that low dose chemotherapy can be an option for many people, but research in this area is limited.

You can talk with your doctor about your specific cancer type and stage, as well as your overall health. The decision of which chemotherapy to use involves many factors, including the genetic profile of your cancer and what treatments your body can tolerate.