This page was reviewed under our medical and editorial policy by

Kevin King, MD, Radiation Oncologist, City of Hope | Downtown Chicago

This page was updated on December 27, 2023.

Chemoradiation is a type of treatment that may be recommended to cancer patients. This guide to chemoradiation therapy, also called chemoradiotherapy or CRT, may help patients and their families understand more about this treatment.

What is chemoradiation?

Chemoradiation is a type of cancer treatment in which both chemotherapy and radiation therapy are administered to a patient. Chemotherapy uses drugs to destroy cancer cells, and radiation therapy uses high-energy X-rays to destroy cancer cells.

These therapies may be combined to treat several types of locally advanced cancer tumors—where the cancer has not spread very far outside of the original site—including:

How is chemoradiation given?

Chemoradiation may be administered in different ways, depending on which type of cancer is being treated and the patient’s individual needs.

Sequential vs. concurrent chemoradiation

Chemoradiation may be administered sequentially or concurrently.

  • Sequential chemoradiation is when either chemotherapy or radiation is administered first, and the other follows after the last cycle.
  • Concurrent chemoradiation occurs when radiation therapy is administered during or very close to the chemotherapy treatment.

With sequential chemoradiation, the treatment time is longer. With concurrent chemoradiation, the treatment is more condensed, but there may be a higher risk of side effects. Many chemoradiation approaches with various timing intervals have been used across different patient groups and cancer types. Patients and their care teams should discuss the overall benefits and risks of each approach.

Adjuvant vs. neoadjuvant chemoradiation

CRT may also be administered as an adjuvant or neoadjuvant treatment option.

  • Neoadjuvant chemoradiation is a treatment given prior to surgery. It may assist in decreasing the size of a cancer tumor so that it may be more easily removed during surgery.
  • Adjuvant chemoradiation is administered after the surgery or main treatment to destroy any remaining cancer cells and help reduce the chance the cancer will return.
  • Chemoradiation can also be used as a definitive treatment approach for those patients who don’t require surgery.

A patient’s medical care team will discuss which type of chemoradiation will be used and how it will be administered.

Chemoradiation side effects

Any cancer treatment may cause side effects. Chemoradiation may cause a patient to experience both chemotherapy side effects and radiation therapy side effects, so this treatment may be more challenging for patients than receiving one treatment separately. However, every patient’s circumstances are unique. The overall health of the patient and how closely together the therapies are administered may factor into which side effects arise and their severity.

Side effects also vary based on the type of cancer, location(s) being treated and the type of medications given.

For example, side effects from CRT for anal cancer may include:

In comparison, patients undergoing CRT for lung cancer may experience:

  • Fatigue
  • Increased risk of infection
  • Shortness of breath
  • Cough
  • Sore throat
  • Hearing changes
  • Increased nosebleeds, bruising and bleeding gums
  • Loss of periods
  • Kidney damage
  • Loss of taste and/or swallowing challenges 
  • Hair loss
  • Numbness or tingling in extremities

Longer-term side effects may include:

  • Lung scarring
  • Chronic coughing and breathlessness
  • Narrowing of the food pipe

Before a course of treatment begins, care teams will advise patients on what to expect, including any additional side effects that may occur. If side effects do occur, a patient’s care team is always there to guide patients through the management of symptoms.

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Show references
  • American Society of Clinical Oncology (2022, May). What Is Chemotherapy? https://www.cancer.net/navigating-cancer-care/how-cancer-treated/chemotherapy/what-chemotherapy
  • American Society of Clinical Oncology (2022, May). What Is Radiation Therapy? https://www.cancer.net/navigating-cancer-care/how-cancer-treated/radiation-therapy/what-radiation-therapy
  • Rallis KS, Ho T, Yau L, Sideris M (2021). Chemoradiotherapy in cancer treatment: rationale and clinical applications. Anticancer Research, 41(1), 1–7. https://ar.iiarjournals.org/content/41/1/1
  • Torphy R, Ho F, Friedman C, et al. (2020). Concurrent versus sequential neoadjuvant chemoradiation therapy for esophageal and gastroesophageal junction adenocarcinoma. Journal of Clinical Oncology, 38(4), 395. https://ascopubs.org/doi/abs/10.1200/JCO.2020.38.4_suppl.395
  • Zheng S, Li L, Chen M, et al. (2022). Benefits of neoadjuvant therapy compared with adjuvant chemotherapy for the survival of patients with HER2-positive breast cancer: A retrospective cohort study at FUSCC. Breast, 63, 177–186. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9038764/
  • Xiao Wei MD, Hong Mei MD (2021). Concurrent vs sequential chemoradiotherapy for patients with advanced non–small-cell lung cancer: A meta-analysis of randomized controlled trials. Medicine. 100(11):p e21455. https://journals.lww.com/md-journal/fulltext/2021/03190/concurrent_vs_sequential_chemoradiotherapy_for.2.aspx
  • American Society of Clinical Oncology. Adjuvant Therapy. https://www.cancer.net/adjuvant-therapy
  • Cancer Research UK (2022, July 22). Chemoradiotherapy for Anal Cancer. https://www.cancerresearchuk.org/about-cancer/anal-cancer/treatment/chemoradiotherapy
  • Cancer Research UK (2023, February 16). Side effects of lung cancer chemoradiotherapy. https://www.cancerresearchuk.org/about-cancer/lung-cancer/treatment/chemoradiotherapy/side-effects