Effects of pulsed electromagnetic fields on tumor cell viability: a meta-analysis of in vitro randomized controlled experiments

Abstract

Effects of pulsed electromagnetic fields on tumor cell viability: a meta-analysis of in vitro randomized controlled experiments Guangzhou An, Meilun Shen, Juan Guo, Xia Miao, Yuntao Jing, Keying Zhang, Ling Guo, Junling Xing. Effects of pulsed electromagnetic fields on tumor cell viability: a meta-analysis of in vitro randomized controlled experiments. Electromagn Biol Med. 2021 Jul 26;1-8. doi: 10.1080/15368378.2021.1958341. Abstract Malignant tumor treatment remains a big challenge till now, and expanding literature indicated that pulsed electromagnetic fields (PEMF) is promising in tumor treatment with the advantage of safety and being economical, but it is still controversial on whether PEMF could affect the tumor cell viability. Therefore, we conducted the meta-analysis to evaluate effects of PEMF on tumor cell viability. The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for studies published up to February 2021. Studies on the direct effects of PEMF on tumor cell viability, determined using colorimetric analysis, were included. Two authors extracted the data and completed the quality assessment. A meta-analysis was performed to calculate the absorbance values and 95% confidence intervals (CIs) using random-effects models. Seven studies, including 32 randomized controlled experiments, were analyzed. Compared with the control group, tumor cell viability in the PEMF exposure group was obviously lower (SMD, -0.67; 95% CI: -1.12 to -0.22). The subgroup meta-analysis results showed that PEMF significantly reduced epithelial cancer cell viability (SMD, -0.58; 95% CI: -0.92 to -0.23) but had no influence on stromal tumor cell viability (SMD, -0.93; 95% CI: -0.21 to 0.15). Our study demonstrated that PEMF could inhibit tumor cell proliferation to some extent, but the risk of bias and high heterogeneity (I2 > 75%) weakened the strength of the conclusions drawn from the analysis. pubmed.ncbi.nlm.nih.gov

AI evidence extraction

Main findings

Meta-analysis of 7 studies (32 randomized controlled in vitro experiments) found lower tumor cell viability in PEMF-exposed groups versus controls (SMD -0.67; 95% CI -1.12 to -0.22). Subgroup analysis reported reduced epithelial cancer cell viability (SMD -0.58; 95% CI -0.92 to -0.23) and no influence on stromal tumor cell viability (SMD -0.93; 95% CI -0.21 to 0.15). Authors noted high heterogeneity (I2 > 75%) and risk of bias.

Outcomes measured

• tumor cell viability (colorimetric absorbance)
• epithelial cancer cell viability
• stromal tumor cell viability

Limitations

• High heterogeneity (I2 > 75%)
• Risk of bias (as stated by authors)
• Limited number of included studies (7 studies)
• Findings differ by tumor cell type subgroup (epithelial vs stromal)

Suggested hubs

• in-vitro-studies (0.86)
  Meta-analysis of in vitro randomized controlled experiments on tumor cells exposed to PEMF.

{
    "study_type": "meta_analysis",
    "exposure": {
        "band": null,
        "source": "pulsed electromagnetic fields (PEMF)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Tumor cells (in vitro)",
    "sample_size": 32,
    "outcomes": [
        "tumor cell viability (colorimetric absorbance)",
        "epithelial cancer cell viability",
        "stromal tumor cell viability"
    ],
    "main_findings": "Meta-analysis of 7 studies (32 randomized controlled in vitro experiments) found lower tumor cell viability in PEMF-exposed groups versus controls (SMD -0.67; 95% CI -1.12 to -0.22). Subgroup analysis reported reduced epithelial cancer cell viability (SMD -0.58; 95% CI -0.92 to -0.23) and no influence on stromal tumor cell viability (SMD -0.93; 95% CI -0.21 to 0.15). Authors noted high heterogeneity (I2 > 75%) and risk of bias.",
    "effect_direction": "mixed",
    "limitations": [
        "High heterogeneity (I2 > 75%)",
        "Risk of bias (as stated by authors)",
        "Limited number of included studies (7 studies)",
        "Findings differ by tumor cell type subgroup (epithelial vs stromal)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "pulsed electromagnetic fields",
        "PEMF",
        "tumor",
        "cancer",
        "cell viability",
        "in vitro",
        "randomized controlled experiments",
        "meta-analysis",
        "heterogeneity"
    ],
    "suggested_hubs": [
        {
            "slug": "in-vitro-studies",
            "weight": 0.85999999999999998667732370449812151491641998291015625,
            "reason": "Meta-analysis of in vitro randomized controlled experiments on tumor cells exposed to PEMF."
        }
    ]
}

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