Satisfaction, Continuity, and Bleeding Patterns in Patients With Breast Cancer Using Copper and Silver Intrauterine Device (IUD) Compared to Copper IUD: a Randomized Clinical Trial

A randomized (1:1) controlled clinical trial is proposed. Women aged 18 to 45 years, diagnosed with breast carcinoma through histopathological study will be included. The study will be conducted at the Family Planning Outpatient Clinic of the Division of Gynecology, Hospital das Clínicas, Faculty of Medicine, University of São Paulo (HC-FMUSP). The primary source of recruitment of patients will be the Mastology Outpatient Clinic of the São Paulo Cancer Institute "Octavio Frias de Oliveira" (ICESP). After selecting the patients and signing the informed consent form (ICF), research participants will receive specific reproductive counseling, with guidance on all contraceptive methods available and appropriate for their health condition.

To minimize selection bias, subjects will be randomized to one of two groups: 1) Copper IUD (TCu380A); or 2) Copper and silver IUD (TCu380Ag), in a proportion 1:1. The randomization sequence was generated using the website http://www.randomization.com. Information on which treatment each woman will be assigned will be kept in a sealed, opaque envelope identified with a number. The envelope will only be opened after the participant has signed the ICF. Once the allocation is made, it cannot be changed. Only the professional who inserts the device knows the type of IUD. Patients will not know which type of IUD they will use to minimize performance bias, i.e., they will be blinded to the nature of the inserted device. Blinding will not be revealed until the end of the study.

Patients will be evaluated 3, 6 and 12 months after IUD insertion. This follow-up will be carried out at the Family Planning Clinic of the Gynecology Division at HC-FMUSP. After informed consent, patients will be asked about their current age, occupation, scholarship, ethnicity/race, date of cancer diagnosis, age at menarche and first sexual intercourse, number of lifetime partners, sexual orientation, number of pregnancies, deliveries and abortions, duration of breastfeeding, age of first and last birth, date of last menstruation, lifetime use of hormonal and emergency contraception, condom use, pregnancy desire after cancer treatment, comorbidities, type of surgery (conservative or mastectomy), current use of SERMS (selective estrogen receptor modulators; tamoxifen or raloxifene), aromatase inhibitors and anticoagulants, smoking (quantity and duration), alcoholism (frequency and dose), physical activity (type, time and duration), family history of malignant neoplasms. Tumor staging (TNM) and the immunohistochemical panel will also be recorded. In addition, the menstrual bleeding pattern will be questioned (through the recall of the last three months), including the interval between cycles, number of days of menstruation and number of pads or tampons used and the occurrence of menstrual cramps and the use of analgesics during the menstrual period. At inclusion, weight (kg), height (cm), blood pressure (mmHg), waist circumference (cm) and hip (cm) will be measured. At the time of the gynecological examination, Pap smear and endocervical swab for Chlamydia trachomatis (PCR) will be collected. Blood samples will be collected for the following laboratory tests: blood count and serum levels of FSH, estradiol, iron, ferritin, transferrin, and total iron binding capacity. Dependent variables will be considered: continuation rates, satisfaction, quality of life, pregnancy, rates, and reasons for discontinuation, with an emphasis on abnormal uterine bleeding. The independent variable will be the IUD type. The control variables will be the aforementioned clinical and sociodemographic parameters.

After being included in the study, the IUD will be inserted by a trained professional, if there is assurance that the patient is not pregnant. Hysterometry (in centimeters) will be measured and recorded before insertion of the IUD. After insertion, the pain attributed to the procedure will be questioned, in a global way, through a visual analogue pain scale. For greater uniformity, all IUDs will be inserted on an outpatient basis, without local anesthesia and/or sedation.

After 30 to 90 days of insertion, patients will undergo a physical examination (visualization of the IUD thread) and transvaginal ultrasound to verify if the IUD is in situ.