Análisis del volumen tumoral en resonancia magnética prequirúrgica como factor pronóstico independiente en el cáncer de endometrio

Abstract

Introduction: Endometrial cancer (EC) is the most frequent gynecological malignancy in developed countries, and is, after breast cancer, the second most frequent neoplasm in Spain in the female population. The incidence of EC has been increasing in recent decades, according to the Globocan report, due to risk factors such as population aging and obesity. About 40% of cases are diagnosed after the age of 65 and patients frequently present comorbidities such as obesity, diabetes, and hypertension, which increases the complexity of managing this disease. EC presents a high cure rate when it occurs in its initial stages, with an overall survival at 5 years of 80-85%. The good prognosis of this disease is mainly due to early diagnosis and optimal therapeutic management. The complementary tests are aimed at carrying out a study of the extension of the disease and will help to assess whether the patient is a candidate for surgery and adjust its radical nature. Surgical treatment is the most common treatment and the form of staging. The age of the patients and their associated comorbidity may condition the type of intervention. Pre-surgical assessment may allow limiting the extent of surgery based on the probabilities of lymph node involvement and the risk of recurrence. Magnetic Resonance Imaging (MRI) is the method of choice for local preoperative evaluation. MRI allows the introduction of other parameters that optimize the pre-surgical study, such as tumor volume. Imaging tumor volume has previously been used as a prognostic factor in other cancers, such as lung cancer, oral, pharyngeal, and esophageal carcinoma, and breast cancer. Due to the high incidence of endometrial cancer in our population, it is necessary to find other markers that are useful in planning treatment and subsequently in predicting the risk of disease recurrence. Aim: This thesis aims to evaluate the prognostic role of tumor volume calculated by MRI in CE. Hypothesis: Tumor volume, calculated presurgically using MRI, is an independent and potentially relevant prognostic factor in endometrial cancer. Methodology: Retrospective analytical observational cohort study conducted in patients with EC diagnosed and managed in the Gynecological Oncology Unit of the Juan Ramón Jiménez Hospital between January 2016 and December 2021. In the first phase, a systematic review of everything published to date on image tumor volume and its implication in EC was carried out. And in a second phase, the entire EC population was analyzed, the preoperative MRI was evaluated, including the calculation of the tumor volume in said population by measuring the three maximum diameters of the tumor according to the Ellipse formula and by means of an automatic method with a manual ROI in different sections, finally, analyzing the relationship between volume, prognostic factors and survival. Results: 194 patients with EC were identified. A total of 127 patients with endometrioid-type EC were studied by preoperative MRI. Tumor volume was significantly higher in patients with deep myometrial invasion, cervical stromal involvement, and serosa involvement. A directly proportional relationship was found between tumor volume and lymph node metastases, high histological grade, lymphovascular space involvement (LVSI), advanced International Federation of Gynecology and Obstetrics (FIGO) stage. (p<0.001) The statistical analysis showed as independent risk factors for lymph node metastases; high histological grade (p: 0.001), tumor volume >25cm3 (p<0.001), LVSI involvement, and elevated preoperative Ca 125 (p<0.001). Patients in the absence of these risk factors did not present lymph node involvement, regardless of the depth of myometrial invasion. Personalized ROC curves showed that tumor volume >10 cm3 predicts deep myometrial invasion and volume >25 cm3 predicts lymph node metastasis. A volume index >17 cm3 was associated with reduced disease-free survival (p<0.001) and overall survival (p<0.003). Multivariate analysis showed that a larger tumor volume had an impact as an independent factor on recurrence (OR: 1.019, 95% CI: 1.005-1.032) and survival (OR 1.027, 95% CI: 1.009-1.046). Regarding the preoperative concordance; MRI underestimated FIGO stage in 12.6% of cases, with poor agreement (κ=0.082) and low sensitivity (14.3%) for serous infiltration. The cut-off values established through the volume parameters had an adequate estimate with high sensitivity (70-83%) and specificity (64-84%) for all histopathological variables. Excellent agreement was found in all volume parameters for the identification of deep myometrial invasion (0.71), cervical stromal infiltration (0.80), serosal infiltration (0.81), and nodal metastases (0.81). Conclusions: This study shows a significant correlation between MRI tumor volume and poor prognostic factors. Preoperative tumor volume on MRI is a valuable biomarker that should be considered for EC evaluation. Lymphadenectomy can be omitted in patients with EC who do not have any of the following risk factors: high histologic grade, elevated Ca 125 (>28), and MRI tumor volume >25cm3. Tumor volume could predict lymph node status in EC and could provide information on surgical treatment. Tumor volume measurements have a good predictive ability to detect histopathologic findings that affect final tumor staging and could play a crucial role in the preoperative evaluation of endometrial cancer patients in the future.