***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: Completed randomised trials were not found. There is one trial that is currently ongoing in Italy; the results have yet to be published. Two prospective observational studies had data on recurrence-free survival. One study reported an odds ratio for recurrence rate at one year (where > 1 favours the luteal phase) of 0.86 (95% confidence interval (CI) 0.69 to 1.08); 0.87 at two years (95% CI 0.69 to 1.09); 0.95 at three years (95% CI 0.75 to 1.21); 1.12 at four years (95% CI 0.87 to 1.43); and 1.12 at five years (95% CI 0.87 to 1.43). Another study reported a hazard ratio for overall survival of 1.02 (95% CI 0.995 to 1.04, P = 0.14) and for disease-free survival of 1.00 (95% CI 0.98 to 1.02, P = 0.92) at three years based on the last and first menstrual period. The results were not significant. There was no difference in the recurrence rate whether the surgery was done during the follicular or luteal phase of the menstrual cycle. In the absence of RCTs, this review provides evidence from large prospective observational studies that timing of surgery does not show a significant effect on survival.
Output:

Of the three prospective observational studies, one reported no survival differences between menstrual cycle groups after stratification by lymph node status at a mean follow-up of 48 months. The results showed a lack of prognostic value (recurrence-free survival and overall survival) of timing of surgery in relation to the menstrual period or to oestrogen and progesterone levels in premenopausal breast carcinoma patients. One study gave no data on mean survival time or recurrence-free survival and the third study reported no significant difference in the overall survival of patients when surgery was done in either the follicular or luteal phase of the menstrual cycle. A large randomised controlled trial would be ideal to establish the influence of timing of surgery in relation to the menstrual cycle (follicular phase or luteal phase) on the prognosis of breast cancer. However, in the absence of this, the information available from the prospective observational studies shows that there is no difference in disease-free survival and overall survival in non-metastatic breast cancer patients irrespective of whether the surgery was done during the follicular or the luteal phase.