Sep 28

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

235 - Early Institutional Experience with Online Adaptive Radiotherapy in Latin America: Workflow Time Analysis

05:40pm - 05:50pm ET

Room 109

Presenter(s)

M. Dolores De La Mata Moya, MD, PhD, MPH - Centro Medico ABC, Mexico City, CIUDAD DE MEXICO

M. D. De La Mata Moya¹, G. Cuamani¹, M. Hernandez-Bojorquez², R. C. Ronquillo Gomez³, D. N. Briceno Guel³, A. S. Ramirez Estudillo⁴, A. A. Martinez Gomez³, I. Martinez Oliver³, L. K. Sanchez Colin³, J. R. Miranda Garcia³, J. E. Morales Nolasco³, I. O. Ayala Iturbe³, K. M. Ojeda Soto³, and R. Sanchez Castro³; ¹Centro Medico ABC, Mexico City, Mexico, ²Centro Médico ABC, Mexico City, DF, Mexico, ³Centro Medico ABC, Mexico CIty, Mexico, ⁴Centro Medico ABC, Mexico City, DF, Mexico

Purpose/Objective(s):

Report the initial institutional experience with online adaptive radiotherapy (ART), focusing on detailed workflow time metrics. This represents the first clinical integration of online ART in Latin America.

Materials/Methods:

Between July/2025-January/2026, a total of 22 patients (p.) treated with online ART (298 delivered fractions): Stereotactic Body Radiation Therapy (SBRT) and conventional or moderate hypofractionated (Conv/Hypo) treatments were included.

Workflow time metrics were prospectively collected. For all fractions: patient set-up time, beam delivery time, and door-to-door time, were recorded. A subset of eight patients (97 fractions) was comprehensively analyzed to extract adaptive workflow components, including autocontouring of organs at risk (OARs), influencers, and targets (review and editing); real-time dose calculation; and secondary verification. Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) techniques were included. Summary measures were calculated using the mean per patient for statistical analysis.

Results:

Patient distribution was as follows: 16 p. (72.7%) were male and 6p. (27.3%) were female. Nine patients received SBRT, while 13p. underwent Conv/Hyp. Among Conv/Hyp treatments, the most frequently treated primary tumors were prostate, gynecologic, and head and neck cancers. In the SBRT cohort, the most common treatment sites were liver, nodal disease, and prostate. Treatment time analysis is detailed in Table 1.

Mean door-to-door treatment times were 21.3 minutes (min.) for IMRT and 23.1 min. for VMAT in the Conv/Hyp group, and 34.3 minutes for IMRT and 39.7 minutes for VMAT in the SBRT group. The use of adaptive tools increased treatment time by approximately 11 minutes in the Conv/Hyp cohort and 18 min for SBRT group.

Conclusion:

Online ART workflow duration varies according to fractionation, treatment technique, operator expertise, tumor site, and patient-specific factors. The treatment times observed during this initial eight-month experience are consistent with ranges reported by international centers. These findings support the feasibility and clinical integration of online ART in a Latin American.

Abstract 235 - Table 1

Set-up time

Segmentation

Dose calculation

Verification

Beam delivery

Door to door

Mean

Median

Mean

Median

Mean

Median

Mean

Median

Mean

Median

Mean

Median

Conv/Hypo

IMRT

6 (+-2,7)

4,7

5 (+-1,7)

4,5

4,6 (+-0,4)

4,4

2,2 (+-0,4)

2,35

3,3 (+-1)

3,03

21,9 (+-3,3)

21,3

VMAT

3,6 (+-2)

3,08

4,4 (+-2,1)

3,4

7,2 (+-2,3)

6,4

1,8 (+-0,5)

1,62

3,3 (+-3,3)

2,7

22,6 (+-1,2)

23,1

SBRT

IMRT

12,8 (+-4,9)

11,39

11,9 (+- 2,3)

11.8

7,3 (+-1,5)

7,0

4,9 (+-1,9)

4,2

36,6 (+-7,6)

34,34

VMAT

13,1 (+-1)

13,2

9,0 (+- 1,2)

9,0

8,5 +- (0.42)

8,5

2,7 (+-0,5)

2,8

38,4 (+-6,2)

39,7