A Novel Imaging Modality to Evaluate Radiation-Induced Uterine Injury

The goal of this pilot study is to assess the ability of a new imaging modality, shear-wave-elastography (SWE) and magnetic resonance imaging (MRI) to identify radiation-induced uterine injury (RIUI). The investigator will recruit female patients treated for colorectal or anal cancer at 15 to 39 years with ≥ 50 Gy pelvic radiation (PRT) at least 12 months prior to study initiation.

The investigator will recruit female patients treated for colorectal or anal cancer at 15 to 39 years with ≥ 50 Gy pelvic radiation (PRT) at least 12 months prior to study initiation.12 months is selected to increase the occurrence of uterine fibrosis. The investigator will perform transabdominal standard B-mode and Doppler US, SWE and pelvic MRI and characterize uterine parameters. The B-mode and Doppler US will be referred to collectively as US. This will provide essential information to design an intervention trial of a novel therapeutic approach to the treatment of radiation-induced uterine damage. The overall objective of the study will be achieved through the following specific aims:

Aim 1: Assess the feasibility of SWE and pelvic MRI to identify and characterize uterine fibrosis. Hypothesis: A grid map sampling of the uterus will indicate feasibility of SWE and pelvic MRI to detect and characterize uterine fibrosis.

Approach: SWE and MRI will be performed at time of study recruitment. US procedures will be transabdominal. When possible, and with participant consent, transvaginal US will also be performed. MRI images will also be sampled from existing pretreatment studies performed as standard of care.

Perform SWE and MRI sampling of the uterus from fundus to lower uterine segment at two locations each from the upper, mid, and lower thirds of the uterus (six grid sample locations).

Obtain five measurements at each location to evaluate for the presence and degree of fibrosis:

1. Assess the relationship between SWE measurements in kiloPascals (kPa) and each MRI parameter among cases at the post-treatment timepoint.
2. Assess the relationship between SWE measurements and each MRI parameter in kPa among controls at one random timepoint.
3. Evaluate differences in kPa between cases and controls according to SWE at the post-treatment timepoint. The imaging study will be considered feasible if at least 85% (e.g., ≥15/17) of all enrolled cases achieve the diagnosability criteria by SWE, defined as having the interquartile range to median ratio (IQR/M) of the measurements (kPa) \<=30% at any of the six locations.

Aim 2: Characterize uterine parameters after PRT. Hypothesis: Patients treated with PRT for colorectal/anal cancer will have decreased uterine volume and increased arterial resistive indices (blood flow) on US.

Approach:

2a. Perform US and estimate uterine volumes and arterial resistance. Use descriptive statistics to compare values to controls in the same age group.

2b. Perform MRI and describe changes in each parameter among cases between the pre- and post-treatment timepoints. Assess changes in: size of the uterus from baseline, junctional zone anatomy, endometrial thickness, cervical length, myometrial thickness, T2 signal of the myometrium (normalized for skeletal muscle signal acting as an internal control), and enhancement features.

Eligibility Criteria:
Inclusion Criteria:

1. Female
2. 15 ≤ age of treatment \< 40 years
3. Treated with PRT at UCH
4. Received ≥ 50 Gy PRT

Exclusion Criteria:

1. Patients who underwent hysterectomy for treatment of a primary gynecologic malignancy
2. Patients that are currently pregnant