Cancer remains a leading cause of morbidity and mortality in Latin America, including Mexico, where late-stage diagnosis limits treatment efficacy. While awareness months (AM) aim to promote early detection, their impact on public engagement in this region remains poorly characterised. The current study assesses the impact of these campaigns on public interest in cancer and screening in Mexico using Google Trends, with regional comparisons. A retrospective infodemiologic time-series analysis was conducted using monthly Google Trends data from Mexico, contextualised with data from other major Latin American countries. Relative search volume indices were used to evaluate public interest in breast (BC), prostate (PC), cervical (CC) and colorectal cancer (CRC) and their respective screening methods from 1 May 2005 to 1 May 2025. Interrupted time-series models with generalised least squares and autoregressive adjustments were applied to estimate immediate and short-term lagged changes in public interest during cancer AM while accounting for underlying temporal trends. In Mexico, BC AM generated the strongest increase in public interest (β = 29.09, p < 0.001), the highest among all countries. PC showed modest increases during its AM (β = 14.7, p < 0.001), although baseline interest declined over time. Effects for CRC and CC were minimal or negative (β = −0.31 and β = −1.31, respectively). Screening-related searches increased substantially for BC (β = 14.9, p < 0.001) and modestly for PC (β = 11.7, p < 0.001), with negligible changes for colorectal and cervical screening. Lagged analyses confirmed delayed effects. Cancer awareness campaigns in Mexico produce uneven online engagement. BC generates the strongest public interest, while the other campaigns may require enhanced communication strategies to improve effectiveness.