Colorectal cancer care beyond earth: is treatment in microgravity feasible?

To the Editor,As humanity re-enters the era of lunar exploration, exemplified by initiatives such as Artemis Program, the medical challenges of long-duration space missions are gaining increasing attention. Among these, the feasibility of managing complex diseases such as colorectal cancer (CRC) in microgravity environments remains largely unexplored.Colorectal cancer is among the most prevalent malignancies worldwide, ranking third in incidence and second in cancer-related mortality globally, with approximately 1.9 million new cases and 900,000 deaths reported annually1. Its high burden is not limited to older populations; rising incidence in adults under 50 has been increasingly documented over recent decades, raising concerns about its relevance across diverse demographic groups, including those who may participate in future crewed space missions2. Given that long-duration spaceflight candidates undergo rigorous medical screening, the current probability of an active CRC diagnosis during a mission is low; however, the risk cannot be entirely excluded, particularly as mission durations extend and crew demographics evolve. Moreover, the immunosuppressive and pro-inflammatory effects of the space environment may accelerate disease progression or unmask subclinical pathology. Beyond the epidemiological rationale, the microgravity environment introduces a fundamentally altered pharmacological landscape that has direct implications for CRC treatment. Chemotherapeutic agents currently used in CRC management including fluoropyrimidines, oxaliplatin, and targeted biologics rely on predictable absorption, distribution, metabolism, and elimination profiles that are calibrated for a 1-g environment. In microgravity, fluid shifts, altered gastrointestinal motility, changes in hepatic blood flow, and modified protein-binding dynamics may substantially perturb drug pharmacokinetics and pharmacodynamics, potentially compromising therapeutic efficacy or heightening toxicity risk3,4. Concurrently, emerging evidence suggests that microgravity itself may exert intrinsic anti-tumor effects by promoting cancer cell apoptosis, disrupting cytoskeletal architecture, and impairing metastatic migration observations that have begun to reframe microgravity not merely as a hostile environment for treatment delivery, but as a potential novel therapeutic modality in its own right4,5,6. The convergence of these dimensions the growing global burden of CRC, the evolving demographics of space exploration, the pharmacological challenges of drug delivery in weightlessness, and the nascent therapeutic promise of the microgravity environment collectively establishes a compelling scientific imperative to investigate whether CRC diagnosis, surgical management, and systemic treatment can be meaningfully adapted to the unique constraints of space, before such scenarios become an operational reality.