ESTRO 2024 - Abstract Book

S4197

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2024

needed according to institutional standard of care. Total workflow time for each fx was measured from the time the patient entered the treatment room to the time when the patient exited the treatment room. Feasibility was defined as the delivery of the first fx within the first on-table attempt for at least 70% of patients. For patients who could not complete the first fx on-table attempt, their MRI images were used for offline planning, and they were treated with IGRT at a later date. Local control and acute (within 90 days) toxicity were measured from the date of first fx. Toxicity was graded according to the Common Terminology Criteria for Adverse Events version 5.0.

Results:

Ten patients with oligometastatic disease of the spine were treated on this study. Patient characteristics are demonstrated in Table 1. 60% (6/10) of patients were treated to 35 Gy/5 fx and 40% (4/10) of patients were treated to 24 Gy/2 fx. Median time from consult to first fx was 20 days (7-37). 80% (8/10) of first fx were delivered on the 1st on table attempt. The two patients who did not complete their first fx on-table attempt were unable to tolerate the attempt due to intractable pain. The average total workflow time for the first fx was 135 minutes (min) (78-169), average total workflow time for non-1st fx was 65 min (45-96), and average total workflow time for all fx was 88 min (66-111). All patients received all of their scheduled fx except one patient who was admitted for intractable pain and urinary retention after their third fx and did not receive the final two fx of their five fx regimen. At a median follow up of 17 months (0-66), 20% (2/10) of patients had experienced a local failure and there were no grade 3 or greater acute toxicities.

Primary disease

Location of disease

Patient # Age

Histology

KPS

ISRC CTV Dose

Fx

1

80

Lung

Adenocarcinoma

80

L1

1,2,3,6

35

5

2

39

Kidney

Sarcomatoid/rhabdoid 100

T2

1,2,6

35

5

Poorly differentiated carcinoma

3

63

Thymus

100

C5

1,2,3,5,6

35

5

4

72

Skin

Melanoma

100

T12

1,2,6

35

5

5

74

Lung

Squamous cell

80

L5

1,2,3,5,6

35

5

6

50

Breast

Invasive ductal

100

L1

1,2,6

35

5

Oral cavity

7

63

Squamous cell

90

T2

1,2,3,4

24

2

8

52

Lung

Biphasic blastoma

80

T12

1,4,5,6

24

2

9

67

Lung

Small cell

90

T10

1,2,3,5,6

24

2

Biliary tree

10

26

Cholangiocarcinoma

60

L1, L3

1

24

2

Table 1.