Discussion
This study describes BS as a promising component in the fertility sparing treatment for patients who have early EC. This is the first study discussing this topic in the local setting, and one of the few studies worldwide describing using BS in this context.
Morbid obesity is the underlying biological factor that drives the development of endometroid EC in young patients in the reproductive age group. Addressing this underlying factor with BS is a logical treatment strategy that can potentially improve the regression rates and reduce recurrence rates of EC. Indeed, we see two patients who had EC previously and had cancer regression with hormonal therapy. They had recurrence a few years after treatment. Another patient had a long treatment period with hormonal therapy, without regression of EC. This could possibly be because obesity, as the underlying driving factor for cellular proliferation and carcinogenesis, had not been addressed. Long term follow-up and data is necessary to demonstrate if weight loss induced by BS results in reduced EC recurrence and survival benefit.
In addition, weight loss induced by BS improves the chances of fertility, both via natural conception or via ART, reduces maternal and fetal complications antenatally and reduces risks in the peri-partum period. We see that one of the patients had successfully conceived with IVF and had no maternal or fetal complications during the antenatal follow up period. Once the other patients pass the first 12 months after BS, where weight loss is rapid and extensive, they would be counselled to undergo ART to aid in conception.
The improvement in physical and psychological health after BS provides additional benefit to this group of patients. Total weight loss is between 25 to 30%, which is consistent with other large-scale studies. We also saw resolution of obesity related comorbidities, which could lead to improved health outcomes and reduced complications from cardiovascular diseases in the long term (12, 27).
The limitations of this case series include the retrospective nature of the study design, the lack of a control group, the short follow-up time and the small number of patients in the study group. The retrospective nature of the study design makes it prone to selection and measurement bias. The patients included in this study are only those that are treated in the centers in which the authors are based. In addition, the early cancer regression in this group of patient who chose to undergo BS may be due to other factors like higher compliance to the fertility sparing treatment or increased health seeking behavior. Measurement bias can also result from incomplete or heterogeneous data from a lack of standard study protocol. This is partially mitigated by the fact that all the treatment received by the patient (both fertility sparing treatment for EC and BS) were according to a standard pathway, and all data collected were from the same comprehensive EMR system used in both public healthcare institutions. The outcomes measured were also objective in nature e.g. histology proving that EC has regressed and weight loss measured in the outpatient clinic during follow-up appointments. The lack of a control group prevents us from inferring a causal relationship between EC regression and BS. We are also unable to draw any conclusions about the longevity of the cancer regression due to the short follow-up period.