Our proposal delves into the complex web of spillover effects from colorectal, breast, and cervical cancer screenings. Spillover effects are a new research focus in public health, defined as unintended and unaccounted additional effects stemming from health policy decisions. We aim to illuminate both the hidden benefits—like improved healthcare capacity, reduced adverse health outcomes, and socioeconomic stability—and the overlooked drawbacks, such as resource strains, increasing the health inequality gap, and increased carbon footprint. By comprehensively analysing and quantifying these effects, we seek to pave the way for more equitable and sustainable healthcare practices in Brussels. Our research proposal will not only introduce the concept of spillover analysis to the field of cancer policy research, but also actively shared and promoted by non-academic stakeholders, policy makers, and clinicians.