Target audiences for this presentation are general and sub-specialty radiologists, radiology fellows/residents, MR technologists, and imaging scientists who would like to refresh and sharpen their diagnostic imaging skills of using MR imaging to evaluate patients with various types of malignant diseases of the uterus.

Endometrial Cancer:

Endometrial cancer is the most common malignancy of the female genital tract and the fourth most common cancer among women in developed countries [Global Cancer Facts & Figures 3rd Edition. Atlanta: American Cancer Society; 2015] (1). The main risk factor for endometrial cancer is endogenous and exogenous estrogen exposure. The incidence of endometrial cancer in developed countries is on the rise because of an aging population, epidemic of obesity, and growing prevalence of diabetes mellitus, all associated with increased estrogenic exposure (2).

Abnormal uterine bleeding is the most common presenting symptom of endometrial cancer. It is observed in up to 90% of patients (usually after menopause) and is evaluated further with pelvic ultrasonography (US) and endometrial biopsy. In postmenopausal women, endometrial thickness cutoff of 5 mm on pelvic US produced the sensitivity of 90% and specificity of 54% for endometrial cancer compared with 98% and 35%, respectively, when the cutoff of 3 mm was used (3).

Presence of regional lymph node metastasis is the most important prognostic factor for patients with endometrial cancer (4-6). The likelihood of nodal metastasis is determined by tumor grade and histologic subtype, depth of myometrial invasion, cervical stromal invasion, and lymphovascular space involvement (7-9). While tumor grade and histologic subtype are available from the initial biopsy specimens, endometrial biopsy and final surgical pathology specimens are discordant in up to 30% because only a small fraction of tumor is sampled during the biopsy (10). Lymphovascular space invasion is the best predictor of lymph node status, but this information is not available until after the surgery (11).

The role of preoperative evaluation is to risk-stratify the patients in order to establish the risk of recurrence and to inform the surgical management. MR imaging is the most accurate imaging modality for preoperative staging of patients with endometrial cancer and it has high interobserver agreement (12). MR imaging can provide the surgeon with the information about the local extent of disease including the depth of myometrial invasion, cervical stromal invasion, extra-uterine extension, and lymph node status (12). In young patients with endometrial cancer who desire to preserve their fertility, MRI is useful to establish the absence of myometrial invasion. Absence of myometrial invasion is one of the several eligibility criteria that should be met prior to the initiation of conservative management for endometrial cancer (13).

Suggested MRI Protocol:

· Large field-of-view axial T1W and T2WI to include para-aortic regions

· Small field-of-view high resolution sagittal T2WI

· Small field-of-view high resolution axial oblique T2WI perpendicular to the uterine corpus

· Sagittal and axial oblique DWI to match T2WI

· Sagittal and axial oblique dynamic contrast-enhanced images pre and post contrast administration

Pertinent Imaging Findings to Include In the Radiology Report:

· Tumor size

· Depth of myometrial invasion (any myometrial invasion if the patient is being considered for fertility preserving treatment)

· Cervical stromal invasion

· Uterine serosal, vaginal, and adnexal involvement

· Involvement of the bladder and rectum

· Pelvic and para-aortic lymph node status

· Distant metastasis

Cervical Cancer:

Cervical cancer is the fourth most common cancer and the fourth leading cause of death among women worldwide [Global Cancer Facts & Figures 3rd Edition. Atlanta: American Cancer Society; 2015]. The highest incidence rates of cervical cancer are in Central and South America and sub-Saharan Africa. Cervical cancer is the first malignancy where direct relation between a viral infection and cancer was proposed (14). It is thought that a woman must be infected with HPV before she develops cervical cancer and two-thirds of all cervical cancers are caused by HPV 16 and 18 (15, 16).

In developed countries, most cervical cancers are diagnosed in asymptomatic patients at the time of routine screening with a Pap smear. Symptomatic patients usually present with abnormal vaginal bleeding and occasional vaginal discomfort or malodorous discharge.

Cervical cancer arises from the squamocolumnar junction which migrates over the years form the ectocervix in young women into the endocervical canal in older women. Therefore, exophytic tumors are typical for young women while endophytic tumors are more characteristic for older women.

Squamous cell carcinoma and adenocarcinoma are the two most common histologic subtypes of cervical cancer accounting for 69% and 25% of cases, respectively [Ries LAG, Melbert D, Krapcho M, et al. SEER Cancer Statistics Review, 1975-2004. National Cancer Institute; Bethesda, MD 2007]. The incidence of adenocarcinoma is on a rise in the more developed countries because adenocarcinoma in situ (the precursor lesion) is detected less efficiently by Pap-smear screening compared to preinvasive squamous lesions (squamous dysplasia and cervical intraepithelial neoplasia, CIN).

Cervical cancer is most commonly staged based on the International Federation of Gynecology and Obstetrics (FIGO) system, last revised in 2009 (17). The FIGO staging of cervical cancer is clinical and does not rely on either surgical or pathologic findings. This allows uniformity of staging for all patients worldwide, which is of particular importance because cervical cancer is most prevalent in countries where surgical and diagnostic resources are limited. The FIGO staging committee has acknowledged the limitations of clinical staging and, where available, has incorporated cross-sectional imaging into the initial assessment and treatment planning of patients with cervical cancer (17).

MR imaging is central to risk-stratify patients with cervical cancer and to inform treatment decisions. MR imaging can evaluate such important prognostic factors as tumor size, parametrial invasion, pelvic sidewall involvement, and lymph node metastasis. MRI can help to distinguish early stage disease (up to 4cm), which is treated surgically, from early stage bulky disease (greater than 4cm) and locally advanced disease, which are treated with definitive combined chemotherapy and radiation (12, 18).

MRI is also critical to assess the eligibility for fertility sparing procedures in patients with early-stage cervical cancer who desire fertility preservation. MRI can determine maximal tumor size, tumor-to-internal cervical os distance, depth of cervical stromal invasion, presence of parametrial invasion, and lymph node status (19).

Suggested MRI Protocol:

· Large field-of-view axial T1W and T2WI to include para-aortic regions

· Small field-of-view high resolution sagittal T2WI

· Small field-of-view high resolution axial oblique T2WI perpendicular to the cervix

· Sagittal and axial oblique DWI to match T2WI

· Sagittal and axial oblique dynamic contrast-enhanced images pre and post intravenous contrast administration

Pertinent Imaging Findings to Include In the Radiology Report:

· Tumor size

· If considered for fertility preservation, tumor-to-internal cervical os distance

· Tumor extension into the uterus and vagina

· Parametrial extension

· Presence of hydronephrosis or pelvic sidewall involvement

· Involvement of the bladder or rectum

· Pelvic and para-aortic lymph node status

· Distant metastasis