This graph depicts the SVI for the term skin cancer over time from 2010 to 2014. Peaks in search volume are seen during the summer months.
Bloom R, Amber KT, Hu S, Kirsner R. Google Search Trends and Skin CancerEvaluating the US Population’s Interest in Skin Cancer and Its Association With Melanoma Outcomes. JAMA Dermatol. 2015;151(8):903-905. doi:10.1001/jamadermatol.2015.1216
Whether there is an association between population inquisitiveness in skin cancer and melanoma incidence, mortality, and the mortality to incidence ratio is unknown. Google Trends quantifies interest in topics at the population level by analyzing all search queries for a specific term, thus serving as an increasingly useful research tool.1 Search volume indexes (SVIs) are normalized values based on total searches during a specified period per selected region. We decided to use this innovative tool to evaluate whether population inquisitiveness on melanoma and skin cancer was correlated with a lower incidence, mortality, and mortality to incidence ratio.
We attained search data using Google Trends,2 extracting data from each state from January 1, 2010, to January 1, 2014, for the search terms skin cancer to represent a lay term and melanoma. Independent review board approval and patient informed consent were not required. The overall SVIs were plotted over time to identify periods with greater interest in skin cancer.
We used Pearson correlations to evaluate the association of skin cancer and melanoma SVI data from 2010 with melanoma incidence, mortality, and mortality to incidence ratios. Incidence and mortality values were taken from the 2011 US Cancer Statistics.3 We used data for melanoma because nonmelanoma skin cancer data are not routinely reported. Data were managed using SPSS statistical software, version 20 (SPSS Inc), with significance set as P < .05.
Searches increased during each summer yearly but have remained stable for 5 years (2010-2014) (Figure). Searches for melanoma mirrored the search volume for skin cancer. There is a significant correlation between skin cancer SVI for all states and melanoma mortality (R = 0.345, P = .01); however, no significant correlation was found between SVI and melanoma incidence (R = 0.061, P = .67). At the level of individual states, the 2010 SVI data for the terms skin cancer and melanoma did not significantly correlate with melanoma incidence and mortality. Moreover, no significant correlation was found between SVI and the melanoma mortality to incidence ratio (R = 0.225, P = .13). Of note, this analysis was not performed for Alaska, the District of Columbia, Nevada, or Vermont because neither mortality nor incidence was reported. States with the top 10 SVIs for skin cancer and melanoma are listed in the Table.
Our study found an increase in the general populations’ interest in learning about skin cancer during the summer months. The level of interest for skin cancer and melanoma by state did not correlate with the melanoma mortality to incidence ratio, suggesting that increased search volumes may not be associated with early detection. The positive correlation between skin cancer SVI and increased melanoma mortality may be explained by increased searches from those directly or indirectly affected by advanced melanoma.
Several limitations exist in using Google Trends analysis as an indicator of general population interests in skin cancer. Google Trends analysis is restricted to only the segment of the population with access to the Internet. As of March 2014, this was estimated to be 87% of the US population.4 As a whole, Google search represents 64.5% of all US desktop search engine queries.5 Our study is additionally limited by the use of only melanoma data because nonmelanoma skin cancer data are not routinely reported in the United States. Regardless, analysis using melanoma data is still relevant because it provides an important benchmark for prevention and outcome.
A better understanding of the US population’s interest and means of accessing information regarding skin cancer is essential to improving educational and preventive initiatives. The use of the Google Trends application provides a novel means for determining this interest. Because the US population seeks information regarding skin cancer at a greater level during the summer months, this might be the most efficient time for educational and public health initiatives.
Accepted for Publication: March 30, 2015.
Corresponding Author: Kyle T. Amber, MD, 10660 SW 75th Ave, Miami, FL 33156 (KAmber@med.miami.edu).
Published Online: June 10, 2015. doi:10.1001/jamadermatol.2015.1216.
Author Contributions: Drs Amber and Kirsner had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Bloom, Amber.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Bloom, Amber.
Critical revision of the manuscript for important intellectual content: Amber, Hu, Kirsner.
Statistical analysis: Amber.
Administrative, technical, or material support: Bloom.
Study supervision: Amber, Hu, Kirsner.
Conflict of Interest Disclosures: None reported.