Endometrial cancer is the most common gynecological malignancy among women, and its incidence has increased considerably over recent decades. Surgical treatment, chemotherapy, radiotherapy, and hormone therapy are frequently associated with psychological distress, impaired social functioning, and reduced quality of life. The present study aimed to examine changes in quality of life among women with endometrial cancer across different stages of treatment and rehabilitation, as well as to assess changes associated with a psychotherapeutic intervention combining individual and group psychological counseling with art therapy and body-oriented psychotherapy techniques. The study included 40 women diagnosed with endometrial cancer who completed the WHOQOL-BREF questionnaire at three time points: before treatment, after completion of the main treatment, and during the rehabilitation period. Treatment-related factors, including the type of surgery (laparoscopic total hysterectomy, radical hysterectomy, or no surgery), chemotherapy, radiotherapy, and hormone therapy, were also evaluated. Statistical analysis demonstrated significant improvements in self-perception (p < 0.001) and social wellbeing (p = 0.002) during the rehabilitation period compared with the intermediate stage of treatment, while physical and psychological wellbeing remained relatively stable. Patients who did not receive adjuvant chemotherapy showed significantly better quality-of-life outcomes during the intermediate stage, whereas these differences largely diminished over time. During rehabilitation, women who underwent laparoscopic total hysterectomy demonstrated higher levels of self-perception and microsocial support, while the absence of hormone therapy was associated with better self-perception and social wellbeing. These findings demonstrate changes in quality-of-life indicators across the treatment and rehabilitation trajectory in women with endometrial cancer. Improvements in self-perception and social functioning were observed during rehabilitation; however, because the study did not include a control group, these changes cannot be attributed specifically to the psychotherapeutic intervention. Natural recovery, adaptation to the disease, completion of active treatment, and treatment-related factors may also have contributed to the observed dynamics. The results support the need for larger controlled studies of integrative psycho-oncological rehabilitation programs. Because subgroup sizes were small and multiple exploratory comparisons were performed, treatment-related findings should be interpreted as preliminary.