Tumours of the salivary glands are rare accounting for between 2-5% of all head and neck tumours. Mobile phones are low-powered radiofrequency transmitters, operating at frequencies between 450 and 2700 MHz with peak powers in the range of 0.1 to 2 watts. The International Agency for Research on Cancer (IARC) included radiofrequency electromagnetic fields as possibly carcinogenic to humans, pertaining to the group 2B in 2012. Some studies have examined the association between cell phone use and the development of tumours in the parotid glands but results are conflicting.

The aim of this review was to assess whether individuals who use cell phone have increased odds of developing parotid gland tumours.

Methods

Searches were conducted in the PubMed/MEDLINE, Embase, and SciELO databases with no restrictions on language, publication date, and place of publication.  Two reviewers independently selected studies and assessed study quality using the Newcastle–Ottawa Scale (NOS).  Authors were contacted for missing data. Fixed and random effects meta-analysis were conducted

Results

• 3 case-control studies involving a total of 4766 patients (768 cases, 3998 controls) were included.
• Studies were conducted in, China, Israel and Denmark and Sweden.
• Meta-analysis of the 3 studies suggest an increase in the odds of parotid tumours with cell phone use with fixed effect model.
  • Fixed effects odds ratio = 1.28 (95%CI; 1.09–1.5) P = 0.0025.
  • Random effects odds ratio = 1.27 (95%CI: 0.99–1.63) P = 0.0564.

Conclusions

The authors concluded

Taken together, our results provide evidence of association between cell phone use and parotid tumour although their association presents mild effect.

Comments

This review included 3 case control studies but no clear details of the inclusion and exclusion criteria for the review were provided. There was also no review protocol registered so these could not be checked.  The text suggests that the 3 included studies included 5087 patients in total although in the table listing the numbers of patients in the cases and controls there are only 4766 patients.  While the fixed effects model suggests that there was a statistically significant increase in the odds of parotid tumours with cell phone use the random effects model was not statistically significant. Given the small number of studies available for the review the conclusion that the findings provide evidence of an association between cell phone use and parotid tumour should be viewed with caution.

Links

Primary paper

de Siqueira EC, de Souza FT, Gomez RS, Gomes CC, de Souza RP. Does cell phone use increase the chances of parotid gland tumour development? A systematic review and meta-analysis. J Oral Pathol Med. 2016 Dec 9. doi: 10.1111/jop.12531. [Epub ahead of print] Review. PubMed PMID: 27935126.

Other references

IARC monographs on the evaluation of carcinogenic risks to humans