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Getting chemotherapy, radiation, or other cancer treatment

Also called: Cancer treatment side effects

People getting chemotherapy, radiation, or other cancer treatment can have side effects. A fever during chemotherapy can be dangerous because the immune system is weaker. Call your cancer team right away with a fever of 100.4°F or higher.

Common causesChemotherapy, radiation, immunotherapy
Usually serious?Can be
Get checked ifFever, bleeding, or severe symptoms
If you think it's an emergency, call 911.Thinking about suicide? Call or text 988.

Overview

Side effects include tiredness, nausea, mouth sores, and low blood counts.

Immunotherapy can cause inflammation in many organs.

When to get medical care

Call 911Trouble breathing, chest pain, or fainting.
Get care todayFever of 100.4°F or higher. Bleeding. Vomiting or diarrhea you can't control.
See a doctor soonNew symptoms during treatment.

Causes

Related to cancer treatment.

OwieClear has pages on 2 conditions that can cause getting chemotherapy, radiation, or other cancer treatment. Each shows how soon to get care.

Common causes

What you can do at home

  • Take your temperature if you feel unwell.
  • Keep your cancer team's number handy.

Medicines

Your cancer team will treat side effects.

At the doctor

Your cancer team will check.

Questions you may be asked

  • Symptoms
  • Treatment schedule

The exam

A physical exam.

Tests

  • Blood counts

Prevention

Lower infection risk.

  • Wash hands
  • Avoid sick contacts

Check your symptoms

Most symptoms have more than one possible cause. The symptom checker looks at all of your symptoms together, plus your age, and shows how soon to get care.

Start the symptom checker

Sources

Last updated 2026-11-13.