Selenium

TOTAL REFERENCES RETRIEVED: 1,027

• FINAL NUMBER STUDIES INCLUDED = 16
• TOTAL PATIENTS INCLUDED IN REVIEW = 1,120 
• SAMPLE RANGE ACROSS STUDIES: 6–48 patients
• KEY SAMPLE CHARACTERISTICS: Mean age was 49 years; various tumor types; cancer therapies consisted of chemotherapy, radiotherapy, chemoradiotherapy, and hematopoietic stem cell transplantation

PHASE OF CARE: Multiple phases of care

Outcome mineral derivatives included zinc (n = 549, seven studies), calcium phosphate (n = 227, three studies), povidone-iodine (n = 228, two studies), and selenium (n = 116, two studies). The severity of OM was measured across variable OM grading systems. In 13 studies, individuals in treatment groups (n = 958) experienced peak OM less than controls (g = −0.47,95% CI −0.7 to −0.2, p = 0.0006). In five studies, time to OM onset was significantly delayed in treatment versus controls (g = −0.51, 95% CI−0.8 to −0.2, p = 0.0002), but the mean duration of OM, pain incidence, and analgesic use was not significantly different. 

The general positive effect trend suggested that individuals taking mineral derivatives during cancer therapies were less likely to experience peak OM. However, the significant bias and heterogeneity in this analysis indicated the need for additional methods because of diverse protocols and novel recordings (serum mineral levels and cell signals) in estimating a uniform true effect. The decision analysis favored selenium.

This review was limited in recommending a definitive mineral derivative to alleviate OM. Limitations included high heterogeneity implicated by variable conditions (i.e., different protocols, diverse cancer therapies). In addition, a placebo effect may have undermined nonblinded studies at a high risk of bias.

Future trials should consider serum levels and computer simulations when designing mineral tolerance thresholds to weigh benefits and harms.
 

To evaluate the efficacy of selenium intake for prevention of oral mucositis (OM) in patients with hematologic malignancies who are candidates for allogeneic hematopoietic stem cell transplantation (HSCT) after receiving high-dose chemotherapy (HDC)

Patients randomly were assigned to the selenium or control group in a blocked, randomization schedule. They were given either a selenium tablet (200 mcg) or placebo tablet twice daily, from the starting day of HDC to 14 days after transplantation. Chemotherapy was the same for all patients. All patients received a similar regimen for prevention of mucositis, including nystatin, sucralfate, and mouthwashes with chlorhexidine, plus 10 cc diluted povidone-iodine every three hours. Narcotic analgesics rarely were used to alleviate OM.

• N = 77 patients participated, 74 patients completed, and 3 patients discontinued
• MEAN AGE = 33.3 years
• MEDIAN AGE: 32 years
• RANGE: 18–55 years
• MALES: 56%, FEMALES: 44%
• KEY DISEASE CHARACTERISTICS: Acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL)
• OTHER KEY SAMPLE CHARACTERISTICS: Disease status before transplant was evenly matched in the study and control group.

• SITE: Hematology-Oncology and Stem Cell Transplantation Research Center    
• SETTING TYPE: Shariati Hospital  
• LOCATION: Tehran, Iran

• PHASE OF CARE: Treatment
• APPLICATIONS: Adult patients with AML or ALL undergoing allogeneic HSCT

• Double-blind, randomized, controlled study

• Five-grade World Health Organization (WHO) toxicity scale for OM
  • Assessment was carried out by one author under the supervision of the attending physician; both were blinded to patients’ allocation.
  • Assessed on a daily basis (except for weekends and holidays)
  • Assessed from day one of HDC until 21 days after transplantation, or until OM was resolved

The cumulative incidence of OM (WHO scale grades of 1–4) in the selenium group and control group was not significantly different. The incidence of severe OM (grades 3 and 4) was significantly lower in the selenium group (10.8% versus 35.1%, P = 0.013). Two patients in the control group experienced WHO OM grade 4, and none of the patients in the selenium group experienced grade 4. Mean duration of OM was not different between the two groups. Mean duration of OM from the beginning of grade 2, moving up to grade 4, and then returning to grade 2 was significantly lower in the selenium group. No difference was seen in the start day of OM between the two groups.

Selenium supplementation during HDC may prevent severe OM in patients undergoing allogeneic HSCT. Further testing is needed before selenium can be recommended. Further testing is needed to establish optimal dose, time to initiate, and duration of treatment with selenium.

• Small sample: < 100
• Single institution
• No mention of how the outcome assessor was trained to do the assessments
• Authors contradicted themselves when they stated no patients in the selenium group experienced grade 4 OM, yet also stated in the results that mean duration from beginning of grade 2, moving up to grade 4, and returning to grade 2 was significantly lower in the selenium group.

Nurses need to be informed about possible effective methods for reducing and eliminating OM to guide their patients.