Patient description: The patient is a 37-year-old woman who came to the clinic for a routine Pap smear. The test revealed stage 1B of cervical cancer. The patient tested positive for HPV 16. She has three sexual partners and four children. She underwent tubal ligation. She smokes 30 packs/year and drinks alcohol frequently. She is otherwise healthy. She was offered a radical hysterectomy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Cervical Carcinoma Endometrioid Adenocarcinoma Malignant Female Reproductive System Neoplasm Recurrent Cervical Carcinoma Stage I Uterine Corpus Cancer AJCC v7 Stage I Vaginal Cancer AJCC v6 and v7 Stage IA Uterine Corpus Cancer AJCC v7 Stage IB Cervical Cancer AJCC v6 and v7 Stage IB Uterine Corpus Cancer AJCC v7 Stage IB2 Cervical Cancer AJCC v6 and v7 Stage II Cervical Cancer AJCC v7 Stage II Uterine Corpus Cancer AJCC v7 Stage II Vaginal Cancer AJCC v6 and v7 Stage IIA Cervical Cancer AJCC v7 Stage IIB Cervical Cancer AJCC v6 and v7 Stage III Cervical Cancer AJCC v6 and v7 Stage III Uterine Corpus Cancer AJCC v7 Stage III Vaginal Cancer AJCC v6 and v7 Stage IIIA Cervical Cancer AJCC v6 and v7 Stage IIIA Uterine Corpus Cancer AJCC v7 Stage IIIB Cervical Cancer AJCC v6 and v7 Stage IIIB Uterine Corpus Cancer AJCC v7 Stage IIIC Uterine Corpus Cancer AJCC v7 Vaginal Carcinoma Patients must have one of the following biopsy proven gynecological cancer and a decision to treat with radiotherapy and concurrent cisplatin chemotherapy (RT-CT) Newly diagnosed epithelial carcinoma of the cervix, cT1B-3B, N0/1, M0/1 Patient may have small volume metastatic disease in para-aortic or supraclavicular lymph nodes or at other metastatic sites as long as, in the best judgment of the treatment team, a radical course of pelvic radiotherapy is warranted to assure local disease control Newly diagnosed epithelial carcinoma of the upper 1/3 vagina, T1-3, N0/1, M0/1 Patient may have small volume metastatic disease in para-aortic or supraclavicular lymph nodes or at other metastatic sites as long as, in the best judgment of the treatment team, a radical course of pelvic radiotherapy is warranted to assure local disease control Newly diagnosed endometrioid adenocarcinoma of the uterus, cT1-3, N0/1, M0 unsuitable for primary surgery because of the extent of local disease; these patients are eligible if a prior decision has been made to treat radically with neoadjuvant chemoradiation followed by surgery or further radiotherapy (including brachytherapy) depending on response Central pelvis or sidewall recurrence of epithelial carcinoma of the cervix of endometrioid adenocarcinoma of the uterus after previous surgery without previous pelvic radiotherapy Patients must be planned to receive whole pelvic radiotherapy to a total dose of 45 Gy or greater Patients must be able to receive weekly cisplatin Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 (Karnofsky >= 60%)  Patients who have received any radiotherapy or chemotherapy for their current gynecological cancer Patients who received prior pelvic radiotherapy for any indication Patients who have a mean resting correct corrected QT (QTc) interval using the Fridericia formula (QTcF) > 470 msec (as calculated per institutional standards) obtained from 3 electrocardiograms (ECGs) 2-5 minutes apart at study entry, or congenital long QT syndrome; AZD1775 should not be given to patients who have a history of Torsades de pointes unless all risk factors contributed to Torsades have been corrected; AZD1775 has not been studied in patients with ventricular arrhythmias or recent myocardial infarction Patients requiring para-aortic radiotherapy Patients who are receiving any other investigational agents or anticancer therapy concurrently or within 4 weeks (i.e. 28 days) History of allergic reactions attributed to compounds of similar chemical or biologic composition to AZD1775 or cisplatin Uncontrolled intercurrent illness including, but not limited to, myocardial infarction within 6 months, congestive heart failure, symptomatic congestive heart failure, unstable angina pectoris, active cardiomyopathy, unstable ventricular arrhythmia, uncontrolled hypertension, uncontrolled psychotic disorders, serious infections, active peptic ulcer disease, active liver disease or cerebrovascular disease with previous stroke, or psychiatric illness/social situations that would limit compliance with study requirements Pregnant women are excluded from this study because AZD1775 and chemoradiation are agents with the potential for teratogenic or abortifacient effects; because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with AZD1775 and cisplatin, breastfeeding must be discontinued if the mother is treated with AZD1775 and cisplatin; these potential risks may also apply to other agents used in this study Patients with another uncontrolled malignancy; patients with a previous malignancy, treated curatively and without evidence of disease relapse are eligible Human immunodeficiency virus (HIV)-positive patients on combination antiretroviral therapy are ineligible because of the potential for pharmacokinetic interactions with AZD1775; in addition, these patients are at increased risk of lethal infections when treated with marrow-suppressive therapy; appropriate studies will be undertaken in patients receiving combination antiretroviral therapy when indicated