Gamma radiation sensitivity and risk of malignant and benign salivary gland tumors

A pilot case–control analysis

Authors

  • Rong Zheng M.D.,

    1. Department of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Li-E Wang M.D.,

    1. Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Melissa L. Bondy Ph.D.,

    1. Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Qingyi Wei M.D., Ph.D.,

    1. Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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  • Erich M. Sturgis M.D.

    Corresponding author
    1. Department of Head and Neck Surgery, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
    2. Department of Epidemiology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
    • Department of Head and Neck Surgery, Unit 441, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030-4009
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    • Fax: (713) 794-4662


Abstract

BACKGROUND

The salivary gland is a highly radiosensitive organ. Exposure to gamma radiation is a risk factor for both malignant (MSTs) and benign salivary gland tumors (BSTs), but the exact mechanisms remain unknown. The objectives of the current study were to determine whether gamma radiation–induced chromatid breaks increase the risk of MSTs and BSTs and whether there is any difference in risk between these two diseases.

METHODS

The authors performed a pilot case–control study of 57 patients with salivary gland diseases (45 patients with MSTs and 12 patients with BSTs) and 105 cancer-free controls. Peripheral blood lymphocytes from these participants were cultured and exposed to gamma radiation (1.5 grays). Five hours later, metaphase spread slides were evaluated. The chromatid breaks in 50 well-spread metaphase slides were counted to determine the average number of chromatid breaks per cell (b/c).

RESULTS

Multivariate logistic regression analyses revealed that gamma radiation–induced b/c values greater than the median of the controls were a significant risk factor for salivary gland tumors (adjusted odds ratio [OR], 17.25; 95% confidence interval [CI], 4.92–60.49). The risk remained significant for MSTs (adjusted OR, 40.45; 95% CI, 5.27–310.17) but was of borderline significance for BSTs (adjusted OR, 4.73; 95% CI, 0.94–23.87) when these tumors were analyzed separately.

CONCLUSIONS

In the current study, high levels of chromatid breaks in lymphocytes induced by gamma irradiation were associated with an independent risk for MSTs and were likely to increase the risk of BSTs. However, larger studies are needed to verify these findings. Cancer 2004. © 2003 American Cancer Society.

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