Characterization of the Intestinal and Vaginal Microbiota in Long-term Survivors of Gynecological Cancer

The human epithelial surface is colonized by a community of microorganisms, the microbiota, which disruption (dysbiosis) can impact a variety of functions, leading to inflammation, altered immunity and numerous diseases, including cancer. Pelvic cancers are among the most frequently diagnosed cancers worldwide, and pelvic radiotherapy is often an essential part of multimodal therapeutic approaches but can lead to a wide range of complications for which there is currently no treatment.

The gut microbiota is altered by radiotherapy, and a relationship between gut microbiota composition, health status, and pelvic radiotherapy has been suggested. In recent years, there has been growing evidence that radiotherapy also alters the vaginal microbiota.

The study proposes the characterization of the intestinal and vaginal microbiota in long-term radiated cervical and endometrial cancer survivors to study its association with long-term radiotherapy side effects. For this purpose, a descriptive cross-sectional study will be carried out in patients affected by cervical or endometrial cancer, in early stages, with good vital prognosis who have received radiotherapy, using healthy postmenopausal women as a control group.

If the microbiota is indeed associated with the side effects of radiotherapy, this would open the possibility of identifying predictive markers, using machine learning analysis of the patients' quality of life, and would help in the search for future therapies based on the restoration of the vaginal and intestinal microbiota. Through network analysis, it would be possible to find out which factors related to patients' diet and lifestyle could be related to dysbiosis and radiotherapy-induced adverse outcomes and poor quality of life.

Inclusion criteria

• primary diagnosis of cervical cancer or endometrial cancer.
• who have received external radiotherapy (with or without brachytherapy, with or without concomitant chemotherapy) more than 24 months ago.
• with clinical control in the last year that evidences that they are free of disease.
• who understand Spanish and have sufficient reading level to understand the questions of the quality of life questionnaires.
• sign and date the informed consent.

Exclusion criteria

• Recurrent or metastatic disease.
• Treatment with antibiotics or corticosteroids (3 months prior to taking the sample).
• Extreme diets (vegetarian, vegan).
• Pregnancy or lactation.
• Documented gastrointestinal diseases (gastric or duodenal ulcers, irritable colon, ulcerative colitis, Crohn's disease).
• Alcoholism (Defined as risk consumption (20-40 gr/day in women; which would be equivalent to 2-4 gr/day)
• Oral or vaginal hormone replacement therapy.
• Spermicidal products in the last 48 hours.
• Sexual intercourse in the last 48 hours.
• Immunocompromised patients.

Control patients: healthy postmenopausal women with last menstrual period more than 12 months ago in those over 40 years of age.

Exclusion criteria

(controls):

• Previous diagnosis of gynecologic or breast cancer.
• Current postmenopausal genital bleeding.
• Current vulvovaginal leucorrhea.