Adult cancer patients who have a selenium deficiency can benefit from selenium supplementation during their radiotherapy and/or chemotherapy. This is the conclusion from a 2024 systematic review. The researchers examined the pooled data from 12 clinical studies enrolling 2,483 patients. The reviewed studies investigated the use of selenium substitution therapy in adult cancer patients undergoing cancer treatment [Krannich 2024].
The researchers defined selenium deficiency as serum or plasma selenium concentrations below 80 mcg/L or as whole blood selenium concentrations below 100 mcg/L. Furthermore, they regarded serum or plasma selenium levels over 130 mcg/L as replete status [Krannich 2024].
The available research shows that an insufficient intake of selenium correlates with an increased risk of cancer and impaired immune response [Krannich 2024; Alexander & Olsen 2023]. Accordingly, supplementation to maintain normal selenium levels in the blood may prevent selenium deficiency during cancer treatment [Krannich 2024].
Unfortunately, the available research studies of the effect of selenium supplementation in cancer treatment are quite diverse and thus not suitable for comparison and generalization. The available selenium and cancer studies vary considerably [Krannich 2024]:
- in the form and dosage of the selenium preparation administered
- in the length of the selenium administration
- in the indications of the study participants
- in the endpoints measured in the studies
Types of Cancers Studied
The review of selenium as a complementary treatment in cancer patients covered several types of cancer [Krannich 2024]:
- acute myeloid or acute lymphocytic leukemia
- breast cancer
- cervical and endometrial cancer
- head and neck cancer
- non-Hodgkin lymphoma
- prostate cancer and non-invasive urothelial carcinoma
- stage I non-small lung cancer
- thyroid cancer
Due to the heterogeneous study results and the methodological limitations of the included studies, the review authors could not make a clear statement regarding the effectiveness of selenium supplementation in cancer treatment except in the case of radiotherapy patients [Krannich 2024].
Common Study Outcomes Investigated
As indicated above, adult cancer patients who were undergoing radiotherapy and who had low levels of selenium at baseline had significantly reduced radiotherapy toxicities. On the other hand, radiotherapy patients who had sufficient concentrations of selenium at baseline did not benefit notably from the selenium supplementation [Krannich 2024].
Beyond this, the researchers found no statistically significant association between the blood levels of selenium and the following study outcomes [Krannich 2024]:
- overall survival
- progression free interval period
- prostate-specific antigen test
- quality of life
- recurrence free interval period
Given the heterogeneous composition of the reviewed studies, the researchers could not make a clear statement about the efficacy of selenium supplementation in cancer treatment other than in patients receiving radiotherapy. The review authors recommend that future studies of selenium supplementation and cancer treatment make selenium deficiency an inclusion criterion. In future studies, the researchers should measure and analyze selenium levels during the course of the intervention [Krannich 2024].
Conclusion: Selenium Status and Cancer Treatment
The authors highlighted the following discoveries in their evaluation of the effectiveness of selenium as a complementary treatment in cancer patients [Krannich 2024]:
- Selenium supplementation relieves radiotherapy-associated difficulty in swallowing.
- Selenium supplementation reduces chemotherapy-induced diarrhea.
- Selenium supplementation reduces the severity of oral mucositis in leukemia patients.
- Selenium supplementation mitigates myelosuppression in cervical cancer treatment.
- Selenium supplementation had no significant effect on the progression of prostate cancer.
- Selenium supplementation did not seem to reduce the impact of conventional cancer therapies.
- Selenium supplementation did not seem to have a negative effect on disease-free survival or on overall survival of cancer patients [Krannich 2024].
Sources
Alexander J, Olsen AK. Selenium – a scoping review for Nordic Nutrition Recommendations 2023. Food Nutr Res. 2023 Dec 28;67.
EFSA Panel on Nutrition, Novel Foods and Food Allergens. Scientific opinion on the tolerable upper intake level for selenium. EFSA J. 2023 Jan 20;21(1):e07704.
Krannich F, Mücke R, Büntzel J, Schomburg L, Micke O, Hübner J, Dörfler J. A systematic review of Selenium as a complementary treatment in cancer patients. Complement Ther Med. 2024 Nov;86:103095.
The information presented in this review article is not intended as medical advice. It should not be used as such.