Correlation between timing of surgery in relation to the menstrual cycle and prognosis of premenopausal breast cancer patients

Timing of breast cancer surgery during the menstrual cycle-is there an optimal time of the month?

An intriguing relationship between menstrual cycle phase at the time of breast cancer surgery and clinical outcomes was first proposed in the late 1980s. Despite a number of clinical studies conducted to address this, as well as meta-analyses and systematic reviews, there remains significant controversy surrounding the effect of menstrual cycle phase at time of surgery on the prognosis of premenopausal breast cancer. While some studies have suggested that surgery performed during the luteal phase results in the most favourable outcome, other studies report the follicular phase is more favourable, and others show no association. Given the conflicting results, there remains insufficient evidence to determine whether there is an optimal time of the month to perform surgery. This issue has dogged breast cancer surgery for decades; knowledge of an optimal time of the month to conduct surgery would be a simple approach to improving patient outcomes. This review explores the potential biological mechanisms through which the hormonal milieu might contribute to differences in prognosis, and why clinical findings are so variable. It is concluded that a significant problem with current clinical research is the lack of insight from mechanistic studies. While there are a number of plausible biological mechanisms that could lead to altered survival, supporting evidence is limited. There are also variable approaches to defining the menstrual cycle phase and hormone receptor status of the tumour and few studies controlled for prognostic factors such as tumour size and stage, or addressed the impact of adjuvant treatments. Elucidation of the specific confounding factors, as well as biological mechanistic pathways that could explain the potential relationship between timing of surgery and survival, will greatly assist in designing robust well-controlled prospective clinical studies to evaluate this paradigm.

Timing of breast surgery in premenopausal breast cancer patients

BACKGROUND

The majority of women diagnosed with breast cancer undergo a multidisciplinary treatment with surgical intervention and radiotherapy or chemotherapy, or both. The importance of timing of tumour removal in relation to the menstrual cycle and its influence on disease-free survival and overall survival has been studied by researchers since 1989 but still remains speculative.

OBJECTIVES

To determine if surgery performed either during the follicular or luteal phase of the menstrual cycle affects the overall and disease-free survival of premenopausal breast cancer patients.

SEARCH STRATEGY

We searched the Cochrane Breast Cancer Group Trials Register (January 2009), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 1), MEDLINE (1966 to January 2009), EMBASE (1974 to September 2006) and the WHO International Clinical Trials Registry Platform (ICTRP) search portal (July 2010). We checked references of articles and communicated with authors.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing breast surgery during the follicular phase of the menstrual cycle with the luteal phase in premenopausal women. Prospective non-RCTs or observational studies were considered if randomised studies were lacking.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data and assessed trial quality.

MAIN RESULTS

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.

AUTHORS' CONCLUSIONS

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.

Does the timing of surgery for breast cancer in relation to the menstrual cycle or geomagnetic activity affect prognoses of premenopausal patients?

We examined the records in 36 breast cancer patients treated between 1990 and 2001, and compared them for relapse-free survival with reference to the phases of menstrual cycle defined by Hrushesky et al. and Senie et al. During the follow-up period, seven patients suffered a relapse and one died of another disease without relapsed breast cancer. The recurrence rate and relapse-free survival were not significantly different with the menstrual timing of surgery. However, patients with early breast cancer operated during the follicular phase and those with advanced breast cancer resected during the luteal phase appeared to show better prognosis than corresponding controls operated during the other phases. On the other hand, the correlation between geomagnetic activity and prognosis of breast cancer was also investigated. High geomagnetic activity during operation significantly affected the prognosis of the disease in an adverse fashion. This adverse influence was more marked in the patients operated during the luteal period. Since the menstrual cycle has no clear relation to the prognosis of breast cancer, the geomagnetic activity might affect them via other pathways than the menstrual cycle.