Digital and surveillance epidemiology via internet search engine analysis has allowed for new insights into patients' and laypersons' health concerns and awareness. Google Trends in particular has become an increasingly well-published data resource as it automatically compiles all Google searches from 2004 to the present from internet users worldwide into an aggregated, passively-collected, and publicly viewable data site. Over the past few years, cancer awareness campaigns in the United States have greatly increased awareness of specific malignancies, such as breast and prostate. However, the hematologic malignancies have not had the same level of awareness, despite rising incidence rates for leukemia, lymphoma, and myeloma from 2004 to 2015. This study sought to examine patients' and laypersons' internet searches for terms related to the three major hematologic malignancies.
Google Trends (www.google.com/trends) was accessed to obtain the relative search engine traffic values for terms related to the three major blood cancers (leukemia, lymphoma, and myeloma) from January 2004 to December 2015. These values are defined as search volume indices (SVIs) and are directly obtainable from Google Trends. For comparison, SVIs for the term "cancer" were also collected during the same time frame. Using standard Boolean operators, searches for "cancer" were operationalized as CANCER + CANCERS + MALIGNANCY + MALIGNANCIES + MALIGNANT, searches for "leukemia" as LEUKEMIA + LEUKEMIAS, searches for "lymphoma" as LYMPHOMA + LYMPHOMAS + "NON HODGKIN" + NON HODGKIN + "HODGKIN DISEASE" + "HODGKIN'S DISEASE", and searches for "myeloma" as MYELOMA + MYELOMAS. Trends in the respective SVIs were analyzed with Mann-Kendall trend tests and Sen's slope estimators in R (V3.3.1), similar to previously published Google Trends analyses.
Individual inspection of each search term revealed the average SVI for "cancer" was 76.4, for "leukemia" was 68.0, for "lymphoma" was 75.5, and for "myeloma" was 30.4 during the time frame 2004 to 2015. Simultaneous inspection across search terms revealed the SVIs for "cancer" far outweighed searches for "leukemia," "lymphoma," and "myeloma" combined (mean SVIs 76 vs. 4, 4, and 1 respectively). Mann-Kendall trend tests showed a statistically significant decrease in searches for "leukemia" (S = -6460.0, p < 0.001) and "lymphoma" (S = -6338, p < 0.001) over time. "Myeloma" searches (S = -1321, p = 0.02) and "cancer" searches (S = -2389.0, p < 0.005) also showed a statistically significant decrease. Sen's slope estimators showed the greatest decline for "leukemia" (Q = -0.18, 95% CI: -0.19 to -0.17) and "lymphoma" (Q = -0.21, 95% CI: -0.22 to -0.20) and lowest decline for "cancer" (Q = -0.05, 95% CI: -0.06 to -0.04) and "myeloma" (Q = -0.01, 95% CI: -0.02 to 0.00).
Searches for "leukemia" and "lymphoma" have sharply declined over the time period 2004 to 2015 in the United States. Searches for "myeloma" have remained stably low over time with marginal decrease. Overall, internet searches for the hematologic malignancies represent a very small fraction of total searches for "cancer." These data suggest a declining awareness for the major hematologic malignancies despite their rising incidences in the United States. Patient awareness may be increased with greater efforts toward disease-specific advocacy campaigns and public health endeavors.
Khorana:Halozyme: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Leo: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Janssen Scientific Affairs, LLC: Consultancy, Honoraria, Research Funding.
Asterisk with author names denotes non-ASH members.