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Our highly trained specialists are available 24/7 via phone and on weekdays can assist through online chat. We connect patients, caregivers, and family members with essential services and resources at every step of their cancer journey. Ask us how you can get involved and support the fight against cancer. Some of the topics we can assist with include:
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Radiation therapy can be used to treat CUP. However, the goal of radiation therapy may change based on your situation.
For some cancers that have not spread too far from where they started, it can be used alone or with other treatments such as surgery with the goal of trying to cure the cancer. When cancer has spread extensively, radiation can be used to relieve symptoms such as pain, bleeding, trouble swallowing, intestinal blockage, compression of blood vessels or nerves by tumors, and problems caused by metastases to bones.
Radiation therapy uses high-energy rays (or particles) to kill cancer cells or slow their rate of growth.
Internal radiation therapy lets your doctor give a dose of radiation to a smaller area and in a shorter time than is possible with external radiation treatment.
Sometimes, both internal and external beam radiation therapies are used together.
Depending on where the radiation is aimed or placed and what dose is given, side effects may include the following:
Radiation therapy to the head and neck area often causes damage to the throat and salivary glands, which can result in:
Over the long term it can also lead to cavities in the teeth and thyroid problems (from damage to the thyroid gland). This might mean that you will need pills to replace thyroid hormone.
Most of these side effects go away after treatment ends, but some are long-term and may never go away completely.
If chemotherapy is given along with radiation, the side effects are often more severe.
There are ways to relieve many of these side effects, so it’s important to tell your cancer care team about any changes you notice.
To learn more about how radiation is used to treat cancer, see Radiation Therapy.
To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
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National Cancer Institute. Physician Data Query (PDQ). Cancer of Unknown Primary Treatment. 05/6/2024. Accessed at: https://www.cancer.gov/types/unknown-primary/hp/unknown-primary-treatment-pdq on May 20, 2024.
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Occult Primary. v.2.2024. Accessed at https://www.nccn.org on May 20, 2024.
Tomuleasa C, Zaharie F, Muresan MS, et al. How to diagnose and treat a cancer of unknown primary site. J Gastrointestin Liver Dis. 2017 Mar;26(1):69-79. doi: 10.15403/jgld.2014.1121.261.haz.
Varadhachary GR, Lenzi R, Raber MN, Abbruzzese JL. Carcinoma of Unknown Primary In: Neiderhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. 础产别濒辞蹿蹿’蝉 Clinical Oncology. 5th ed. Philadelphia, PA. Elsevier: 2014:1792-1803.
Last Revised: May 27, 2024
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