ESTRO 2024 - Abstract Book

S250

Brachytherapy - Gynaecology

ESTRO 2024

IB

4

44.3

4

IIA

2

42.0

9

IIB

50

45.7

7

IIIA

2

41.0

4

IIIB

11

65.0

9

IIIC1

29

51.0

7

IIIC2

5

47.0

8

IVA

10

73.8

13

IVB

4

73.25

7

* diagnostic staging for 36 patients was not available at time of analysis

Table 2. The Spearman Rank correlation coefficients between the number of interstitial catheters inserted and the CTV HR volume, D 90 CTV HR and the D 2cc to the rectum, bladder and sigmoid.

A one-way ANOVA was conducted to compare the CTV HR volume at the time of brachytherapy against the initial diagnostic staging. The result did not demonstrate a significant difference in CTV HR volume amongst the different group stagings, p=0.07. The correlation coefficient between number of interstitial needles implanted during brachytherapy versus the CTV HR volume and dosimetric constraints (see Table 2) showed a very weak correlation against all variables; this was statistically significant for CTV HR volume, D 2cc rectum and bladder but not for D 90 CTV HR nor D 2cc sigmoid.

Conclusion:

Although not statistically significant there appears to be a trend towards a difference in CTV HR volume at time of brachytherapy across the diagnostic stage groups.

This dataset also demonstrates that the number of interstitial catheters does not correlate with the dose delivered and spared to the CTV HR and OARs respectively. Therefore to develop a better understanding of IC/IS optimisation in cervical brachytherapy further work will retrospectively plan the existing dataset aiming to optimally minimise the catheters utilised as well as evaluate the spatial relationship between interstitial catheters within the target volume and in relation to OARs.