Sep 28

SS 25 - From Assessing Gaps to Treatment Delivery: Scaling Safe Radiotherapy in Resource-Limited Settings

232 - Radiotherapy Infrastructure and Excess Female Cancer Mortality in Low-Middle SDI Countries: Evidence from The IHME Global Burden of Disease (GBD) Project

05:10pm - 05:20pm ET

Room 109

Presenter(s)

Nikol Mladkova, MD, PhD, MPH - Westchester Medical Center, Valhalla, NY

N. Mladkova¹, and J. Suchy²; ¹Westchester Medical Center, New York Medical College, Valhalla, NY, ²Independent, New York, NY

Purpose/Objective(s):

Radiotherapy is a core treatment modality for several female malignancies, yet access to radiation infrastructure varies substantially worldwide. We examined whether national radiotherapy capacity is associated with smaller gaps between observed cancer mortality and the minimum mortality achievable at a given level of development.

Materials/Methods:

We conducted a cross-sectional ecological analysis of 132 countries using Global Burden of Disease (GBD) estimates. The primary outcome was absolute inefficiency, defined as the difference between a country’s observed age-standardized mortality (or DALY) rate and the minimum achievable rate at its level of Socio-demographic Index (SDI-based frontier).

We examined four cancers: breast (n=132), cervical (n=132), uterine (n=132), and ovarian (n=131).

The primary specification regressed absolute inefficiency on RT machine density without additional SDI adjustment. A pooled interaction model tested whether associations were stronger for cancers where RT is standard of care (breast, cervical) compared with ovarian cancer. Analyses were repeated in a low–middle SDI subsample (n=65; SDI 0.26–0.70) and using brachytherapy unit counts as the exposure.

Results:

In the full sample (n=132), higher radiotherapy density was associated with smaller frontier gaps for breast (ß = -65.0, p = 0.022) and cervical cancer (ß = -121.3, p < 0.001). No association was observed for ovarian cancer (ß = -3.1, p = 0.506). Uterine cancer showed a small positive association (ß = +7.6, p = 0.021).

The pooled interaction confirmed a significantly stronger effect for RT-standard cancers (ß_interaction = -95.4, p < 0.001), with no baseline density effect for ovarian cancer (p = 0.517).

In low–middle SDI countries, associations were amplified for breast (ß = -200.7, p = 0.004) and cervical cancer (ß = -153.1, p = 0.079), while uterine and ovarian cancers remained non-significant. The pooled interaction remained significant (ß = -173.9, p = 0.002).

In brachytherapy analyses (n=52 low–middle SDI countries with =1 unit), higher brachytherapy counts were associated with smaller frontier gaps for cervical (ß = -85.4, p = 0.003) and uterine cancer (ß = -8.4, p = 0.002), with no association for ovarian cancer (p = 0.401) and breast cancer (p = 0.055).

Conclusion:

Higher radiotherapy density is associated with decreased mortality gaps for breast and cervical cancer across all countries at a given development level. In low- and middle-income countries with brachytherapy units, greater RT infrastructure correlates with smaller gaps between observed and achievable cancer mortality for cancers where radiotherapy is standard of care (cervical, uterine), suggesting a treatment-specific rather than general-development pathway. These ecological findings support the hypothesis that radiotherapy access helps close the gap between actual and achievable cancer outcomes, particularly in resource-limited settings.