HIGH DOSE RATE BRACHYTHERAPY IN THE TREATMENT OF OPERATED ENDOMETRIAL CANCERS: ABOUT 60 CASES

Introduction:Endometrial cancer is the third gyneco-mammary cancer in the radiotherapy-brachytherapy department of the RABAT national oncology institute.Brachytherapy has an important place in the therapeutic strategy.

The objective of the study:Is to analyze the coverage of target volumes as well as the dose to organs at risk with three-dimensional dosimetric planning and toxicity assessment.

Material and methods:This is a retrospective study of 60 cases of operated endometrial cancers treated by high dose rate brachytherapy without external radiotherapy or chemotherapy collected in the radiotherapy department of the National Institute of Oncology RABAT between January 2018 and December 2020. A dosimetric scan without injection was performed at the first session and was used to delineate the clinical anatomic target volume (CTV). We evaluated the D100 of the clinical target volume and the D2 cm3 of the bladder, rectum and small intestine. We also analyzed acute genitourinary and gastrointestinal toxicity.

Results:The average age of the patients was 49 years. Endometrioid carcinoma accounted for 98.5%, with one case of mucinous carcinoma. All patients underwent surgery.The brachytherapy protocol used was 3 × 7 Gy (75%) or 4 × 5.5 Gy (17%) in weekly sessions A single patient received a reduced total dose of 19.8 Gy in 3 fractions of 5.5 Gy due to a high rectal dose.The average target volume coverage (D100) was 96.50%.The average D2 cm3 per session received by the bladder, rectum and small intestine were 4.06 Gy, 4.9 Gy and 2.8 Gy, respectively.Regarding genitourinary toxicity, we noted two grade 1 cystitis, one grade 2, two grade 1 mucositis and one grade 2.For gastrointestinal toxicity, no cases of grade greater than 1 were noted.No grade 3 or 4 toxicities were recorded.

Conclusion:High dose rate brachytherapy has an important place in the therapeutic strategy for endometrial cancer.The very low toxicity recalls the good tolerance of this treatment whichapplies to the entire population.