ESTRO 2024 - Abstract Book

S1091

Clinical - Gynaecology

ESTRO 2024

2576

Digital Poster

Pelvic insufficiency fractures after EBRT for gynecological cancers: a single-institution experience

Patrizia Ferrazza 1 , Elena Magri 1 , Dea Veshaj 1 , Anna Delana 2 , Laura Bandera 1 , Giuseppina De Marco 3 , Jessica Imbrescia 3 , Giulia Miranda 3 , Maria Victoria Gutierrez 4 , Frank Lohr 3,5 , Valentina Vanoni 1 1 APSS Ospedale Santa Chiara, UO Radiotherapy, Trento, Italy. 2 APSS Ospedale Santa Chiara, UO Medical Physics, Trento, Italy. 3 AOU Policlinico Modena, UO Radiotherapy, Modena, Italy. 4 AOU Policlinico Modena, UO Medical Physics, Modena, Italy. 5 University of Modena, Department of Medical and Surgical Sciences, Modena, Italy

Purpose/Objective:

To evaluate the incidence and risk factors for pelvic insufficiency fracture (PIF) in patients treated with definitive radiotherapy (DRT) or post-operative radiotherapy (PORT) for locally advanced cervical cancer or endometrial cancer.

Material/Methods:

Between Jenuary 2016 and December 2022, 158 patients (pts) with cervical cancer (96 pts) or endometrial cancer (62 pts) underwent definitive or post-operative external beam radiotherapy. The median age was 56 years (range, 30-83 years). Our analysis includes all International Federation of Gynecologic Oncology and Obstetrics (FIGO) stages (I-IVB). 92 pts underwent definitive treatment, 66 post-operative treatment.

The following clinical characteristics were extracted from pts medical charts: age at diagnosis, BMI, menopausal status, use of chemotherapy and history of pre-existing osteoporosis

All treatments were planned with VMAT technique. The pelvis received a dose of 45-50.4 Gy in 1.8-2 Gy/fx. Squential or Concomitant boost of 8.96-20 Gy (2.12-2.Gy/fx) was given in patients with nodal involvment (44 pts). In 142 pts high dose rate brachytherapy was performed: in 90 pts for cervical cancer (30 Gy/5fx or 28 Gy/4fx), and in 52 pts for endometrial cancer (10 Gy/2fx or 15 Gy/3fx).

76% of pts received concurrent chemotherapy and only 2 pts received neoadjuvant chemotherapy.

Follow-up with magnetic resonance or CT scan was performed routinely every 4-6 months. PIF was defined as a low density line or a fracture line with or without sclerotic changes in the pelvic bones on CT images or a hypointense line surrounded by bone marrow edema in any of the pelvic bones on T2 or post-contrast T1 weighted fat-suppressed MRI sequences

Results:

Median follow-up was 36 months (range 6-80 months). Thirty six pts (22.78%) developed PIF, and 3 of them developed multiple fractures. 28 pts developed PIF after DRT and 8 pts after PORT. The median time to fracture was 6 months (range, 2-24 months). The most commonly involved fracture site was the sacrum (21 pts), lumbar vertebrae (2 pts), pubis (3pts) and sacroiliac joint (9 pts). Only 1 patient presented with acetabulum fractures and no iliac bone or femoral head/neck fractures were observed. Eleven women were simptomatic for lower back pain or pelvic pain.