Oncology drug shortages and disruptions to cancer treatment delivery in Mexico: A national oncologist survey.

1599 Background: Oncology drug shortages increasingly disrupt cancer care delivery worldwide, yet quantitative data describing their impact on treatment decisions in middle-income countries are limited. This study evaluates how drug and supply shortages affected cancer treatment delivery in Mexico during 2024–2025. Methods: Between September and December 2025, we conducted a national, cross-sectional, anonymous online survey of practicing oncologists in Mexico. The survey, promoted by the Mexican Society of Oncology (SMEO), consisted of structured multiple-choice questions assessing whether oncology drug or supply shortages required treatment modifications during routine clinical practice within the preceding 12 months. Respondents could select multiple types of treatment adaptations. Descriptive statistics were used to summarize responses. Results: A total of 196 oncologists and hematologists completed the survey. Overall, 191 respondents (97.4%) reported performing at least one therapeutic modification due to drug or supply shortages. The most frequently reported modifications were changes in treatment regimen (79.6%), omission of one or more planned treatment cycles (71.9%), and delayed or non-timely administration (62.8%). Additional adaptations included substitution with alternative drugs within the same pharmacologic class (57.7%), non–clinically indicated dose reductions (37.8%), and use of non–guideline-approved regimens (25.5%). Referral of patients to other institutions because of treatment unavailability wasreported by 12.8% of respondents. Only 2.6% reported no treatment modifications. Conclusions: In this national survey of oncologists and hematologists, drug and supply shortages in Mexico were highly prevalent and associated with frequent, clinically meaningful disruptions to cancer treatment delivery, including regimen changes, treatment omissions, and delays. These findings highlight a substantial challenge for cancer care delivery in a middle-income setting and underscore the need for health-system strategies aimed at preserving treatment continuity. Shortage-related therapeutic modifications reported by oncologists (n = 196). Therapeutic modification due to shortage n (%) Any modification performed 191 (97.4) Change of treatment regimen 156 (79.6) Omission of ≥ 1 planned treatment cycle 141 (71.9) Delayed / non-timely administration 123 (62.8) Drug substitution within same class 113 (57.7) Non-indicated dose reduction 74 (37.8) Non–guideline-approved regimen 50 (25.5) Referral to another institution 25 (12.8) No modifications performed 5 (2.6)