Background: In Japan cancer has been the most 1c common cause of deaths since 1981 [1]. However, as a result of an extensive national effort to provide measures to combat cancers, the five-year survival rate has improved to 62.1% [2]. Among female cancers, the incidence of uterine cancer was the fifth most common with relatively good prognoses in the various clinical stages [2]. With the improvement in treatment methods, treatment may now be conducted at patient homes, rather than as previously by hospitalization. As the length of hospitalizations has been shortened, there are many patients who are discharged from the hospital without having adequate knowledge and skills to prevent the onset of postoperative complications however. To maintain and improve the postoperative quality of life (QOL), it is indispensable for patients to perform self-management activities to prevent lymphedema development. Secondary lymphedema is among the complications arising after gynecological cancer surgery. The incidence of lymphedema is reported to be between 27.2% [3] and 42% [4] in Japan. Once lymphedema develops, it is difficult to cure, making prevention of the onset an important issue. Purpose: This study aims to conduct an intervention program to promote self-management of lymphedema prevention for patients who have undergone gynecological cancer surgery (cervical and endometrial cancer), and to establish the effect of the interventions at two years after the start of implementation. Methods: The study design is a randomized controlled trial. Participants were gynecologic cancer patients who had undergone lymph node dissection in five participating hospitals. Inclusion criteria are patients aged between 20 and 74, and who are able to participate in all of the two-year program. The study was approved by the ethics review committee of the university the authors belong to and that of participating hospitals. Study protocol: Three to five days after surgery, we provided instruction for the intervention group: about the causes and symptoms of lymphedema, details of self-management to prevent lymphedema, and methods for coping with abnormal symptoms. Similar instructions were also provided for the staff at the hospitals where the participants in the intervention group were hospitalized. The participants were provided similar instructions twice from the hospital staff and researchers, instructing them to measure the femoral circumference at the roots of the right and left legs and body weight, observe for the presence of edemas weekly until 6 months after surgery, and to record the measurement and observation results in a form provided by the researcher. Following this, measurements and observations were conducted at 12 and 24 months after the surgery. Until 6 months after surgery, we provided the participants with health instruction once a month by phone. For the control group, the measurement, observation, and recording were conducted at 6, 12, and 24 months after the surgery. We handed out the questionnaire and the form for record-keeping to participants in both groups 3 to 5 days after surgery, and requested them to return the completed questionnaire and recording form to the researchers by post in a franked return envelope we provided. We used SPSS for Windows ver. 25 for the statistical analysis. Multiple logistic analysis was performed to calculate the descriptive statistical values of the participants, to compare the groups, and to explore the factors affecting lymphedema development. Results: We explained the study purpose and methods to the patients 3 to 5 days after surgery, and 108 expressed consent to participate. We randomly divided the patients into two groups: 56 as an intervention group, and 52 as a control group. For the demographics, there were statistically significantly more participants who were working in the intervention group. However, there were no differences in other items. Twelve months after the surgery, the numbers of participants in the intervention and control groups were 38 and 33. The social relations score of the QOL of the intervention group was significantly stronger than the control group. The right femoral circumference and body weight of the control group were significantly lower than that of the intervention group. There was no difference in the incidence of lymphedema of the two groups. Because the development of lymphedema is diagnosed by comparing the circumference of the lower extremity in this longitudinal study, and 1 to 2 cm is considered mild lymphedema, we performed a multiple logistic regression analysis using patients where the right femoral circumference increased 1 to 2 cm (mild lymphedema) as the objective variable. Body weight was identified as a factor affecting mild right femoral lymphedema. Sixty-three point two percent of patients with increases in the right femoral circumference are 1.057 times more likely to develop mild right femoral lymphedema. Discussion: When cancer is detected and treatment is started in the early stage, the 5-year relative survival rate improves, and this also holds for uterine cancer. For this reason, patients need to conduct self-management for long periods following cancer treatment, as in the case of chronic diseases. A previous study that investigated educational hospitalization effects on patients with diabetes reported a significant improvement in blood glucose control 12 months after being discharged, but the mean value of the HgA1c control after 12 months was poor [6] This suggests the necessity for nurses to assist patients to raise the awareness of blood glucose control again before the intervention effect declines. From the results it can be inferred that self-semanagement (observing the lymphedema symptoms including measuring and recording of femoral circumferences and body weight by patients themselves) influenced the promotion of self-management [7]. It is worthwhile making and recording measurements customarily and continuously. As patients who show increases in body weight are 1.057 times more likely to develop lymphedema, it is suggested that the body weight measurement is an effective tool as an index to evaluate the presence or absence of lymphedema, easily and simply. This study proposes weight measurement as an index for self-assessment of lymphedema, and through such efforts, we can expect intervention effects to be present even 2 years after surgery. The social relations score of QOL of the intervention group was significantly higher than that of the control group. This suggests that the increases in circumference of the lower extremity and body weight may affect participation in community activities. Lymphedema development after gynecological cancer surgery appears about 2.6 months after surgery and chronic lymphedema often appears around 9.7 months after surgery [8]. It can be inferred that patients were not aware of the development of lymphedema due to the temporary improvement of lymphatic reflux after the improvement of edema. Conclusions: In this study we conducted an intervention program to promote self-management of lymphedema as a prevention measure for patients who have undergone gynecological cancer surgery, and examined the effect of the interventions two years after the start of implementation of the program. The right femoral circumference and body weight of the control group were significantly lower than the intervention group. The social relations element in the QOL of the intervention group was significantly higher than that of the control group. We performed a multiple logistic regression analysis using patients where the right femoral circumference increased 1 to 2 cm (suggesting mild right femoral lymphedema) as an objective variable, and identified body weight as a factor related to mild right femoral lymphedema. [ABSTRACT FROM AUTHOR]