could we consider the Pancreas as an organ at risk during gastric cancer radiotherapy?
Ghaiet El Fida Noubbigh,
Tunisia
PO-1893
Abstract
could we consider the Pancreas as an organ at risk during gastric cancer radiotherapy?
Authors: Ghaiet El Fida Noubbigh1, Mariem Frikha2, Soufiane EL Alami2, Safia Yahyaoui2, Samia Zaraa2, Amani Yousfi2, Alia Mousli2, Rim Abidi2, Inthidhar Saidani2, Marwen Mahdhouani3, Khalil Mahjoubi2, Chiraz Nasr2
1institut salah azaeiz, Radiotherapy, Tunis, Tunisia; 2institut salah azaeiz, Radiotherapy , Tunis, Tunisia; 3 institut salah azaeiz, Radiotherapy , Tunis, Tunisia
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Purpose or Objective
The toxicity of the post-operative
radiotherapy of gastric cancer remains one of the major concerns in practice
because of the organ proximity and their great mobility in the abdominal cavity.
As the pancreas has both an exocrine and
endocrine function, these capacities could be loosed after abdominal
irradiation with a significant risk of malabsorption syndrome, diabetes or
pancreatitis. However, the pancreas is not yet considered as an organ at risk
and there are few reports in the literature that published the relationship dose-effect
to establish dose constraints for planning. The purpose of our study is to analysis
the absorbed dose by pancreas during gastric cancer radiotherapy.
Material and Methods
This is a
retrospective study analyzing the dosimetric plans of all patients
treated with postoperative radiotherapy for gastric cancer between 2015 and
2020 at the Salah Azaeiz Institute according to the MacDonald protocol. The
dose was 45Gy for R0 and 50.4 Gy for R1. The treatment plan was performed with 3D
conformal technique with two opposite anterior-posterior beams and two lateral
beams. The pancreas was delineated according to RTOG recommendations.
We recorded
the pancreas Volume, mean dose
(Dmean), the maximum dose (Dmax), the minimum
dose (Dmin) from the dose-volume histogram. The data analysis was done by SPSS version 20.
Results
Thirty patients were
included. Ninety three percent of the patients undergone 45 Gy in 25 fractions.
The median of
pancreatic volume was 31 cm 3[15-63].
The median of Dmoy,
Dmax, Dmin were respectively 44.95 Gy
[36-51.28], 47Gy [42-53.8], 43Gy [2.6-49.87]
The 3rd quartile (Q3)
of Dmoy, Dmax, Dmin were respectively
45.65Gy , 47.9Gy and 44 Gy
The following table summarizes the results of the dosimectric data for the panacreatic analysis:
| volume(cm3) | Dmoy(Gy) | Dmax(Gy) | Dmin(Gy) |
| Mean | 31 | 44.95 | 47 | 43 |
| Minimuim | 15 | 36 | 42 | 2.6 |
| Maximuim | 63 | 51.28 | 53.8 | 49.87 |
| Q3 | 41 | 45.62 | 47.9 | 44 |
Conclusion
According to some
studies, the pancreas could be considered as the
salivary gland of the gastrointestinal tract. Doses to the pancreas in
abdominal irradiations have been reported to be more than 30 Gy, which agreed
with our study. However, according to a recent study published in 2018, the
average doses to the pancreas should not exceed 20-25 Gy for preservation of
its exocrine function and 25 Gy in the tail for preservation of its endocrine
function. However, these results should be confirmed by larger series. Until
then, why not propose systematic delineation of the pancreas during abdominal
irradiation?