Do side effects indicate that a cancer drug is working?

Treatment and doctors

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Chemotherapy often has the impression that the treatment is worse than the disease.

The approach earned this reputation decades ago, but today it does not represent the reality of mesothelioma treatment for most patients.

Cancer drugs cause unpleasant and sometimes dangerous side effects. However, the expectation of serious side effects can sometimes make patients feel anxious, confused and even frustrated when it turns out that their treatment regimen is not that bad.

In cancer treatment, the idea of ​​”no pain, no gain” is a myth. A positive response to treatment depends in large part on minimizing and managing side effects. Prescription drugs can control some side effects, and the new generation of cancer drugs cause fewer side effects to begin with.

Side effects do not indicate the effectiveness of the treatment

dr. Raja Mudad, Medical Director of the Chemotherapy Treatment Unit of the Sylvester expanded cancer center in Miami, has experience treating mesothelioma with chemotherapy and immunotherapy.

“Most patients have heard about side effects from reading on the Internet or through other patients,” Mudad told

When patients do this type of informal research, they can expect side effects such as complete hair loss, crippling nausea, and debilitating fatigue during treatment.

“Most patients are usually apprehensive about taking chemotherapy because of this misconception,” Mudad said.

Some patients even assume that if they don’t experience any side effects, the treatment isn’t working. Mudad debunked this myth.

“There is absolutely no relationship between effectiveness and side effects,” he said. “A patient can respond without side effects or not respond and have side effects. To measure the effectiveness of a cancer drug, we usually perform scans after two to four treatments to assess shrinkage in the tumor.”

Difference Between Symptoms, Side Effects and Response

Cancer and chemotherapy can both cause fatigue, digestive problems, and low blood cell counts, so it’s easy to confuse mesothelioma symptoms and side effects of drugs.

To better understand what a patient may experience during cancer treatment, it is important to know the difference between symptoms, side effects, and response:

  • Symptoms are side effects caused by tumors pressing against or invading organs and tissues in the body. As cancer develops, it can also cause painful fluid retention, as well as weight loss and fatigue when cancer cells use up the body’s energy supply.
  • Effects are side effects caused when drugs damage healthy cells in addition to cancer cells. Chemotherapy drugs usually affect all rapidly reproducing cells in the body, especially cells in the stomach, intestines, bloodstream, and hair follicles.
  • Answer is how doctors describe the effect of a drug on cancer. A “complete response” means the cancer has gone, while a “partial response” means the tumors have shrunk. “Stable disease” means no effect, and “disease progression” means tumors are still growing despite treatment.

Doctors can help patients manage side effects

A positive response does not depend on a patient having serious side effects. In fact, side effects are exactly what limits the effectiveness of cancer treatments in many cases.

For example, nausea and vomiting are two of the most common side effects of: chemotherapy. In addition to reducing quality of life, these side effects can prevent patients from getting the nutrition their bodies need to heal.

“Today we have better drugs to prevent side effects, and most patients don’t experience many side effects from chemotherapy,” explains Mudad.

To help patients manage nausea, doctors often prescribe a medication such as palonesetron (Aloxi), aprepitant (Emend), or ondansetron (Zofran).

Treatments for emerging cancer are less toxic

Chemotherapy can also cause rare, life-threatening side effects, depending on a patient’s blood chemistry and overall health.

Even if a treatment is proven to kill cancer cells, if it poses an unacceptably high risk to an individual patient, doctors may need to reduce the dosage so much that the treatment is no longer effective.

For this reason, researchers are constantly looking for ways to reduce the toxicity of cancer treatments. Doctors can administer less toxic drugs in higher doses, increasing the likelihood of a partial or complete response.

Mudad reported positive developments in the treatment of mesothelioma.

“The availability of newer drugs like Avastin and immunotherapy treatments has added new options for patients, and these drugs are much less toxic than chemotherapy.”

Avastin is a brand name for bevacizumab, used by the National Comprehensive Cancer Network (NCCN) added to the recommended treatment regimen for mesothelioma in 2016.

Researchers continue to study immunotherapy drugs such as pembrolizumab (Keytruda), nivolumab (Opdivo), and ipilimumab (Yervoy) in clinical trials of mesothelioma.

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