Menstrual timing of breast cancer surgery

Timing of breast cancer surgery, menstrual phase, and prognosis: Systematic review and meta-analysis

BACKGROUND

For over 25 years, there has been a debate revolving around the timing of breast cancer surgery, menstrual cycle, and prognosis.

METHODS

This systematic review synthesizes and evaluates the body of evidence in an effort to inform evidence-based practice. A keyword and reference search was performed in PubMed and Web of Science to identify human studies that met the inclusion criteria. A total of 58 studies (48 international and 10 U.S.-based) were identified. We provided a narrative summary on study findings and conducted a meta-analysis on a subset of studies where quantitative information was available.

RESULTS

Findings from both qualitative and quantitative analyses were inconclusive regarding performing breast cancer surgery around a specific phase of the menstrual cycle.

CONCLUSION

Based on the Institute of Medicine criteria, evidence is insufficient to recommend a change in current primary breast cancer surgery practice based on menstrual phase.

An interferon signature identified by RNA-sequencing of mammary tissues varies across the estrous cycle and is predictive of metastasis-free survival

The concept that a breast cancer patient's menstrual stage at the time of tumor surgery influences risk of metastases remains controversial. The scarcity of comprehensive molecular studies of menstrual stage-dependent fluctuations in the breast provides little insight. To gain a deeper understanding of the biological changes in mammary tissue and blood during the menstrual cycle and to determine the influence of environmental exposures, such as low-dose ionizing radiation (LDIR), we used the mouse to characterize estrous-cycle variations in mammary gene transcripts by RNA-sequencing, peripheral white blood cell (WBC) counts and plasma cytokine levels. We identified an estrous-variable and hormone-dependent gene cluster enriched for Type-1 interferon genes. Cox regression identified a 117-gene signature of interferon-associated genes, which correlated with lower frequencies of metastasis in breast cancer patients. LDIR (10cGy) exposure had no detectable effect on mammary transcripts. However, peripheral WBC counts varied across the estrous cycle and LDIR exposure reduced lymphocyte counts and cytokine levels in tumor-susceptible mice. Our finding of variations in mammary Type-1 interferon and immune functions across the estrous cycle provides a mechanism by which timing of breast tumor surgery during the menstrual cycle may have clinical relevance to a patient's risk for distant metastases.

The Relationship between Surgery and Phase of the Menstrual Cycle Affects Survival in Breast Cancer

PURPOSE

The impact of time of surgery based on the menstrual cycle is a controversial issue. Two decades after the first interest in this topic, a number of studies with conflicting results have not helped to resolve this problem. This study aimed to prospectively evaluate the impact of timing of surgery based on the menstrual cycle on survival rates of breast cancer patients, and various clinical and hormonal classifications of the menstrual cycle were compared in order to determine the phase of the menstrual cycle which showed the highest degree of surgical survival.

METHODS

Premenopausal breast cancer patients treated with curative surgery between 1998 and 2002 were prospectively included in this study. Patients were divided into different groups according to the first day of their last menstrual cycle using three different classifications (clinical, Hrushesky, Badwe), and were also grouped according to their serum hormone levels. Serum levels of follicle stimulating hormone, luteinizing hormone, estrogen, and progesterone were measured on the day of surgery.

RESULTS

Ninety patients were included in the study. Median follow-up time was 90 months. Nineteen patients (21.1%) had loco-regional recurrence and/or distant metastases while 12 patients (13.3%) died during follow-up. Five-year (78.6% vs. 90.6%) and 10-year (66.7% vs. 90.6%) disease-free survival (DFS) rates of patients in the clinically defined follicular phase were significantly decreased compared to luteal phase. On the other hand, hormonally determined phases of the menstrual cycle and grouping of patients according to clinical classifications did not show an impact on prognosis.

CONCLUSION

In the current study performing surgery in the follicular phase of the menstrual cycle decreased DFS in premenopausal patients. According to these results, performing surgery during the luteal phase of the menstrual cycle might have a beneficial effect on survival.

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.

Timing of breast cancer surgery in relation to the menstrual cycle--the rise and fall of a hypothesis

It has been claimed that the timing of surgery in relation to the menstrual cycle can significantly influence the prognosis among premenopausal women with primary breast cancer. The literature on the subject is reviewed. The results are heterogeneous, and the quality of the studies is in general low. Many studies suffer from statistical problems concerning small sample sizes and sub-group analyses. In all, the scientific basis for the hypothesis seems weak.

Estrous cycle modulates ovarian carcinoma growth

PURPOSE

The effects of reproductive hormones on ovarian cancer growth are not well understood. Here, we examined the effects of estrous cycle variation and specific reproductive hormones on ovarian cancer growth.

EXPERIMENTAL DESIGN

We investigated the role of reproductive hormones in ovarian cancer growth using both in vivo and in vitro models of tumor growth.

RESULTS

In vivo experiments using the HeyA8 and SKOV3ip1 ovarian cancer models showed that tumor cell inoculation during proestrus significantly increased tumor burden (251-273%) compared with injection during the estrus phase. Treatment of ovariectomized mice with 17beta-estradiol resulted in a 404% to 483% increase in tumor growth compared with controls. Progestins had no significant effect, but did block estrogen-stimulated tumor growth. Tumors collected from mice sacrificed during proestrus showed increased levels of vascular endothelial growth factor (VEGF) and microvessel density compared with mice injected during estrus. HeyA8, SKOV3ip1, and mouse endothelial (MOEC) cells expressed estrogen receptor alpha and beta and progesterone receptor at the protein and mRNA levels, whereas 2774 ovarian cancer cells were estrogen receptor-negative. In vitro assays showed that 17beta-estradiol significantly increased ovarian cancer cell adhesion to collagen in estrogen receptor-positive, but not in estrogen receptor-negative cells. Additionally, 17beta-estradiol increased the migratory potential of MOEC cells, which was abrogated by the mitogen-activated protein kinase (MAPK) inhibitor, PD 09859. Treatment with 17beta-estradiol activated MAPK in MOEC cells, but not in HeyA8 or SKOV3ip1 cells.

CONCLUSION

Our data suggest that estrogen may promote in vivo ovarian cancer growth, both directly and indirectly, by making the tumor microenvironment more conducive for cancer growth.

Discovery of candidate genes and pathways that may help explain fertility cycle stage dependent post-resection breast cancer outcome

Breast cancer relapse and death occur more often and sooner among young pre-menopausal women. Breast cancer resected during luteal phase cures about a quarter more women than if the operation is performed during follicular phase. We have identified candidate breast cancer gene signatures that may point to the potential mechanisms of cycle stage-dependent surgical cure. We performed whole murine genome microarrays on mammary tumors resected during pre-ovulatory (diestrus, follicular) and post-ovulatory (estrus, luteal) phases of the estrous cycle with known post-surgical cure or relapse (pulmonary metastasis) outcome. A set of genes whose expressions are differentially modulated by fertility cycle stage of tumor resection and also associate with prognosis were identified. These identified genes were validated by qRT-PCR. From two independent microarray studies, we identified 90 genes in mammary tumors whose expressions change significantly (up to 100-fold) across the estrous cycle, 69 genes that are associated with cure/relapse independent of cycle stage at resection, and 24 genes that change significantly (up to 12-fold) across the estrous cycle and also associate with the outcome. The mRNA expression patterns of these 24 identified genes were 100% validated by qRT-PCR in the same samples. We have identified candidate breast cancer genes and pathways that may point to the potential mechanisms by which the post-resection breast cancer outcome is influenced by the menstrual cycle phase of cancer resection. Since human breast cancer outcome is influenced by the menstrual cycle phase of breast cancer resection, we consider this study in a mouse breast cancer model to be a proof of principle that such signatures may well exist in human premenopausal breast cancer. It remains to be determined in human breast cancer whether woman to woman and/or tumor to tumor variability will mask cycle phase dependent and outcome predictive genomic signatures in human premenopausal breast cancer. The pathways identified by these studies are potential targets for the development of peri-surgical neoadjuvant therapies, which may delay or prevent relapse by preventing dormant micrometastatic tumor cells from escaping that dormant state post-operatively.

The effects of surgery on tumor growth: a century of investigations

A few clinical investigations suggest that while primary breast cancer surgical removal favorably modifies the natural history for some patients, it may also hasten the metastatic development for others. The concepts underlying this disease paradigm, i.e. tumor homeostasis, tumor dormancy and surgery-driven enhancement of metastasis development, have a long history that is reviewed. The review reveals the context in which these concepts were conceived and structured to explain experimental data and shows that they are not so new and far fetched. The idea that surgical cancer resection has both beneficial and adverse effects upon cancer spread and growth that result from the modulation of tumor dormancy by the resection should be considered a potentially fruitful working hypothesis.

Timing of breast cancer surgery in relation to menstrual cycle phase: no effect on 3-year prognosis: the ITS Study

The effect of breast cancer surgery timing during the menstrual cycle on prognosis remains controversial. We conducted a multicentre prospective study to establish whether timing of interventions influences prognosis. We report 3-year overall and disease-free survival (OS/DFS) results for ‘primary analysis’ patients (regular cycles, no oral contraceptives within previous 6 months). Data were collected regarding timing of interventions in relation to patients’ last menstrual period (LMP) and first menstrual period after surgery (FMP). Hormone profiles were also measured. Cox's proportional hazards model incorporated LMP in continuous form. Exploratory analyses used menstrual cycle categorisations of Senie, Badwe and Hrushesky. Hormone profiles with LMP and FMP data were also used to define menstrual cycle phase. Four hundred and twelve ‘primary analysis’ patients were recruited. Three-year OS from first surgery was 90.7, 95% confidence interval (CI) [87.9, 93.6%]. Menstrual cycle according to LMP was not statistically significant (OS: hazard ratio (HR)=1.02, 95%CI [0.995,1.042], P=0.14; DFS: HR=1.00, 95%CI [0.980,1.022], P=0.92). Timing of surgery in relation to menstrual cycle phase had no significant impact on 3-year survival. This may be due to 97% of patients receiving some form of adjuvant therapy. Survival curves to 10 years indicate results may remain true for longer-term survival.

Seasonal modulation of post-resection breast cancer metastasis

BACKGROUND

Human breast cancer incidence, histopathologic grade, invasiveness, and mortality risk vary significantly throughout each year. In order to better understand this seasonal cancer biology, we investigated the circannual pattern of post-resection breast cancer metastasis, under genetically and environmentally controlled conditions.

METHODS

Over a span of 14 consecutive years, we conducted 22 similar experiments to investigate metastatic biology of breast cancer among 1,214 C3HeB/FeJ female mice. All mice were kept in temperature-controlled environment with 12 h light:12 h dark photoperiod, with food and water freely available, from birth until death. At 10-13 weeks of age, each mouse received 20,000 viable syngeneic mammary cancer cells subcutaneously and the tumor bearing leg was resected 10-12 days after tumor inoculation for potential cure. Once 10% of resected mice were found moribund, due to autopsy proven pulmonary metastases, all remaining mice were sacrificed and metastatic lung nodules were counted.

RESULTS

The incidence of post-resection pulmonary metastasis was not randomly distributed throughout the year, but peaked prominently in Summer and Winter. Although tumor volume at resection was strongly associated with metastatic potential, a significantly higher probability of pulmonary metastasis was observed if surgery was performed in Summer and Winter, regardless of tumor volume at resection, compared to Spring and Fall.

CONCLUSION

These results support the likelihood that human breast cancer seasonality is real and of biological origin. There are implications of this cancer chronobiology for breast cancer prevention, screening, diagnosis, and treatment.

Perioperative endocrine status and prognosis in early breast cancer

Although the relationship between breast cancer and hormones has been known for almost two centuries, it is only during the last 16 years that evidence suggesting the hormonal profile of the patient at the time of surgery can affect the outcome, came to light. A series of studies investigated the hypothesis that unopposed estrogen (observed during the follicular phase of the cycle) may adversely affect the overall and/or disease-free survival of women operated on at that time. The findings have been, at times, contradictory. The retrospective nature of the studies, poor recording of last menstrual period, small study size, and the possible effect of the timing of the diagnostic procedures (cytology or core biopsy) on the outcome may be responsible for the conflicting results. Despite this, more sophisticated studies based on pathological or hormonal observations/measurements, confirmed the relation of luteal phase surgery to better outcome. Estrogen-induced increased protease activity activates a cascade of proteolysis and allows the more discohesive tumor cells to gain access to the circulation. Moreover, disseminated cells might be able to proliferate easier because of several estrogen-dependent growth factors. Diminished immune function during the follicular phase, because of natural killer cell activity and mononuclear cell phagocytic activity down-regulation may also be implicated in the dissemination of viable tumor cells. Taken together these findings provide a framework for explaining the observation that luteal phase surgery can lead to an improved outcome. By altering the perioperative hormonal milieu it may be possible to reduce deaths from breast cancer in a simple and nontoxic manner.

Estradiol and medroxyprogesterone acetate regulated genes in T47D breast cancer cells

Many mammary tumors express estrogen receptors (ER) and progesterone receptors (PR), and there is increasing evidence that progestins influence gene expression of breast tumor cells. To analyse the impact of progestins on breast cancer cells, we compared (a) the expression of two cytokines, involved in tumor progression, and searched (b) for differentially regulated genes by a microarray, containing 2400 genes, on T47D breast cancer cells cultured for 6 days with 17beta-estradiol (E2) or E2+medroxyprogesterone acetate (E2+MPA). Lower amounts of PDGF and TNFalpha were found in culture supernatants of E2+MPA treated T47D cells. MPA addition induced a 2.8-3.5-fold increase of the mRNA expression of (a) tristetraprolin, which is involved in the posttranscriptional regulation of cytokine biosynthesis, and (b) zinc-alpha2-glycoprotein and Na, K-ATPase alpha1-subunit, which both resemble differentiation markers of breast epithelium. In contrast, the mRNA expression of lipocalin 2, which promotes matrixmetalloproteinase-9 activity, was decreased five-fold in E2+MPA treated cells. Our data show that the expression of genes from various functional gene families is regulated differentially by E2 and E2+MPA treatment in T47D cells. This suggests that exogenous progestins applied for therapy and endogenous changes of the progesterone levels during the menstrual cycle both influence breast cancer pathophysiology.

Sex cycle modulates cancer growth

HYPOTHESIS

Among premenopausal women, both post-resection metastatic potential and tumor growth rate are influenced by the menstrual cycle. There is strong support for the former in large retrospective studies of surgical resection timing within the menstrual cycle and the following experiments were conducted to critically evaluate the latter.

METHODS

We studied a transplantable breast cancer of C3HeB/FeJ mice (3 studies), and a transplantable methylcholantherene A induced sarcoma of CD2F1 mice (2 studies). We concurrently measured local cancer size and estrous cycle stage up to twice and at least once each day. There is a natural individual variability in the average length of normal estrus (3-1/2 to 7 days) cycle in mice. We assessed the effect of the cycle stage and cycle duration on tumor size.

RESULTS

We found identical estrous cycle stage coordination of cancer size, and identical effects of cycling frequency across all studies in each of these two tumors, both of which express both estrogen receptor alpha and progesterone receptor. Little or no change in cancer size occurs during proestrus (preovulatory phase) and estrus (periovulatory phase); tumor size increases several fold during diestrus (post-ovulatory phase); and the tumor shrinks partially as the next proestrus phase is approached. Across both mouse strains and tumor types, mice whose average cycle length is briefer (faster cyclers), have slower average tumor growth rate than those with longer cycles (slower cyclers) who have faster tumor growth rates.

CONCLUSION

The virtually identical modulation of tumor size and cancer growth rate, in each of two very different transplantable cancers (one, classically sex-hormone-dependent, and the other, never previously recognized as hormone dependent) growing in two unrelated inbred mouse strains, indicates that the fertility cycle related host factors affect cancer size and growth rate. These experimental findings suggest that cancer cell proliferation of both breast and non-breast cancers in premenopausal women may be meaningfully coordinated by the menstrual cycle. If this proves to be the case, then any therapeutic strategy targeting proliferating cancer cells should be most effective against cancer of cycling women when given during the follicular phase of their menstrual cycles.

Period3 Structural Variation: A Circadian Biomarker Associated with Breast Cancer in Young Women

Circadian disruption has been indicated as a risk factor for breast cancer in recent epidemiologic studies. A novel finding in circadian biology is that genes responsible for circadian rhythm also regulate many other biological pathways, including cell proliferation, cell cycle regulation, and apoptosis. Therefore, mutations in circadian genes could conceivably result in deregulation of these processes and contribute to tumor development, and be markers for susceptibility to human cancer. In this study, we investigated the association between an exonic length variation in a circadian gene, Period3 (Per3), and breast cancer risk using blood samples collected from a recently completed breast cancer case-control study in Connecticut. There were 389 Caucasian cases and 432 Caucasian controls included in our analysis. We found that the variant Per3 genotype (heterozygous + homozygous 5-repeat alleles) was associated with an increased risk of breast cancer among premenopausal women (odds ratio, 1.7; 95% confidence interval, 1.0-3.0). Our finding suggests that the circadian genes might be a novel panel of potential biomarkers for breast cancer and worth further investigation.

Models of Breast Cancer Growth and Investigations of Adjuvant Surgical Oophorectomy

Clinical observations of the natural history of breast cancer and its response to a variety of therapeutic interventions have contributed to changing concepts about the growth and metastatic spread of this disease. Increased attention has been given to tumor cell dormancy and the occurrence of greatly delayed metastatic disease development, which has been important to rethinking therapy. Although gene profiling of breast tumors recently has highlighted the importance of individual tumor characteristics in patients' prognosis, considerable data also support the concept of breast cancer as a problem of macro- and microenvironmental regulatory imbalance and dynamic chaos. Observations of unexpectedly large survival benefits from adjuvant surgical oophorectomy done in the luteal phase of the menstrual cycle in premenopausal women are consistent with an interpretation that extratumoral interactions in the host environment are important in prognosis. These observations also suggest that a treatment paradigm shift from an exclusive focus on cell kill and specific tumor cell molecular targets to one focused also on broad host regulatory control may be useful. Clinical trials and laboratory mechanistic investigations based on these data and observations can determine the potential impact of therapeutic interventions targeting host system macro and micro tumor cell environments.

CREATION OF A STABLE MAMMARY TUMOR CELL LINE THAT MAINTAINS FERTILITY-CYCLE TUMOR BIOLOGY OF THE PARENT TUMOR

A mammary tumor cell line, designated MTCL, was successfully established from a mouse primary mammary tumor (MTP). The MTCL cells retain cytokeratin and both estrogen receptor (ER) and progesterone receptor (PR) in vitro. In vitro exposure of MTCL cells to progesterone causes a decrease in the cellular (3)H-thymidine uptake, indicating an inhibition by progesterone on MTCL cellular deoxyribonucleic acid synthesis, whereas exposure of the cells to a high dose of estrogen (15 pg/ml) for 48 h causes an increase of (3)H-thymidine uptake. We inoculated both MTP or MTCL tumor cells into normal cycling female C(3)HeB/FeJ mice and demonstrated that the post-resection metastatic recurrence of MTCL tumors, like the original MTP tumors, depends on the time of tumor resection within the mouse estrous-cycle stage. Both MTCL and MTP tumors have similar histological appearances with the exception of less extensive tumor necrosis and higher vascularity in MTCL tumors. Equivalent levels of sex hormone receptors (ER alpha, ER beta, and PR), epithelial growth hormone receptors (Her2/neu, EGFR1), tumor suppressors (BRCA1, P53), and cell apoptosis-relevant protein (bcl-xl) were found in these in vivo tumors by immunohistochemistry. Cyclin E protein, however, was significantly higher in MTP tumors compared with MTCL tumors. Our results indicate that MTCL cells retain many of the biologic features of the original MTP primary tumor cells, and to our knowledge, it is the first in vitro cell line that has been shown to maintain the estrous-cycle dependence of in vivo cancer metastasis.

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.

Upregulation of HER-2/neu by Ovarian Ablation: Results of a Randomized Trial Comparing Leuprorelin to CMF as Adjuvant Therapy in Node-positive Breast Cancer Patients

PURPOSE

HER-2/neu oncogene expression is modulated by an estrogen-sensitive binding site in the HER-2/neu promoter. Utilizing the circulating antigen of HER-2/neu in serum (sHER-2/neu) as a surrogate marker we investigated whether ovarian ablation by adjuvant therapy leads to an upregulation of HER-2/neu in breast cancer patients.

PATIENTS AND METHODS

The analysis was done on sera from premenopausal, node-positive, hormone-receptor positive patients randomized in a multi-center trial. The study was designed with patients receiving either 11.25 mg of leuprorelin s.c. every 3 months over 2 years or CMF chemotherapy for 6 cycles. Sera, available from 80 patients in the leuprorelin arm and from 53 patients in the CMF arm, were collected at 0, 3, 6, 12, 18, 24 and 30 months. sHER-2/neu was measured using a standardized ELISA assay that has an upper limit of normal of 15 ng/ml. sHER-2/neu results were correlated to the levels of LH, FSH and estradiol as indicators of ovarian ablation and to the tumor marker, CA 27.29.

RESULTS

During estradiol deprivation, sHER-2/neu levels increased significantly by more than one third from 8.1 ng/ml to 11.0 ng/ml (p < 0.0001) in both treatment arms. The most pronounced relative increase occurred within the first 3 months (p < 0.001). In only 2.7% (16/587) of sHER-2/neu measurements, the sHER-2/neu results were elevated above 15 ng/ml, confirming the upper limit of normal for breast cancer patients irrespective of their menopausal status. At month 30, the sHER-2/neu level started to decrease in the leuprorelin arm, reflecting reversible castration and estradiol reconstitution. Conversely, CA 27.29 levels did not show a trend over time, indicating that sHER-2/neu changes were of a regulatory nature and were not merely a reflection of increasing residual disease.

CONCLUSION

Our study demonstrates the upregulation of HER-2/neu during ovarian ablation. These results are consistent with data showing that the percentage of HER-2/neu positive tumors, evaluated by standardized immunohistochemistry on the primary tumor, is significantly increased during the follicular phase of the menstrual cycle (Balsari et al., Am J Pathol 155: 1543-1547, 1999). Regulatory processes at the HER-2/neu gene should be considered when prescribing specific therapy for breast cancer.

Fertility cycle influence on surgical breast cancer cure

Cancer growth and spread is an intricate process dependent upon both tumor and host. This laboratory is interested in the role of the fertility cycle, specifically cyclic changes in steroid hormone levels, in tumor growth and metastases. Our previous studies, using a murine model, have documented that breast cancer growth rate and post-resection metastatic behavior each change reproducibly during the estrous cycle, and that post-resection cancer spread depends upon the time within the estrous cycle that an advanced transplanted cancer is resected. Twelve to thiry-two percent cure rates were seen in these studies. That early work described estrous cycle stages just prior and near to putative ovulation to be superior while those stages farther from ovulation were disadvantageous times for surgery. Data presented here confirm the role of the estrous cycle in post-resection metastatic spread. This current work validates vaginal smear determined estrous cycle stage with uterine weight. A primary, transplantable, mammary carcinoma, which metastasizes to the lungs, was resected for surgical cure in cycling C3HeB/FeJ female mice at each fertility cycle stage. A group of oophorectomized (ovx) animals was also used. In two large, independent studies resecting much earlier stage cancers than in prior studies, a 96% surgical cure frequency was documented when the tumor is resected during estrus. The second best surgical cure rate is achieved when tumors are resected during metestrus (79% overall cure rate). Cure frequency in ovx animals is intermediate. These results further support a probable role for circulating E2 and P4 levels in modulating the metastatic process. We conclude that the timing of surgical resection within the estrous cycle affects the cancer's metastatic potential and that the optimal timing of resection may also depend to some extent upon the size (stage) of the resected cancer.

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

The timing of surgery in relation to menstrual phase might affect the progress of disease in premenopausal women with operable breast cancer. In the present study, the records were examined of 28 such cases treated between 1990 and 1999, and compared for recurrence-free survival with reference to the phases of the menstrual cycle defined by Hrushesky and Senie. During the follow-up period, breast cancer relapse occurred in five patients, and one patient died of another disease unconnected with recurrent breast cancer. The recurrence rate was not significantly different between two phases classified by either Hrushesky or Senie. However, patients with early-stage breast cancer operated during the perimenstrual phase and those with advanced breast cancer which was resected during the peri-ovulatory phase appeared to have a better prognosis than patients operated on during the other phases. Since the prognosis for breast cancer patients is dependent not only on the menstrual cycle but also on many other factors, it is concluded that the menstrual cycle cannot constitute an absolute prognostic factor.

Tumour dormancy: findings and hypotheses from clinical research on breast cancer

Breast cancer metastatic development is commonly considered as resulting from continuous tumour growth from tumour seeding until clinical recurrence is documented. Continuous growth model inferences, however, fail to explain clinical findings concerning local recurrences, as well as the time-distribution of first treatment failure and mortality for patients undergoing mastectomy. The tumour dormancy hypothesis is considered to provide a more reasonable description of the natural history of breast cancer, while primary tumour removal is believed to be a potential perturbing factor for metastasis development. A new model of the natural history of operable breast cancer, incorporating tumour dormancy and starting signals from surgery for micrometastatic growth is proposed.

Timing of breast cancer surgery in relation to the menstrual cycle: an update of developments

It is well-established that hormones have multiple effects on breast cancer. Some, but not all studies indicate that the phase of the menstrual cycle (and hence hormonal status) at the time of breast surgery may influence survival. In this paper we review the literature in this area, explore how it is possible that such an association may occur, and note that randomised studies which unambiguously determined the phase of the cycle at the time of the operation are lacking. We go on to describe an ongoing self-randomised trial designed to address this problem and present preliminary results which show that only about 75% of the women ovulated during the cycle in which the operation took place, and that the established prognostic factor Ki-67 varied with the phase of the cycle in women who ovulated. It is too early to assess the significance of this finding.

Predictability of monthly and yearly rhythms of breast cancer features

In order to evaluate if breast cancer biological characteristics undergo significant menstrual and seasonal variations, we analysed in a consecutive series of 905 breast cancer patients, steroid receptor level (ER and PgR by DCC assay), proliferative activity (3H-Thymidine Labeling Index, 3H-TLI) and size of primary tumour in relation to calendar date and day of menstrual cycle at the time of the surgical procedure. For data analysis, the method of time series construction and classical spectral analyses with Bartlett Kolmogorov-Smirnov test for white noise (BKS test) was utilised. For what concerns menstrual variations, 3H-TLI showed a significant periodicity (t = 0.3146, p < 0.01 by BKS test) with peaks at day 12nd and day 18th; ER showed a significant periodicity (t = 0.3605, p < 0.01 by BKS test) with more evident peak at day 27th; PgR, a significant periodicity (t = 0.160, p = 0.05 by BKS test) with peaks at day 15th and day 24th, similar to that observed for tumour size (t = 0.19, p < 0.05 by BKS test). With respect to yearly fluctuations, 3H-TLI showed only a trend for a significant rhythm (t = 0.16, p = 0.06 by BKS test) with peaks in May and November; ER a significant periodicity (t = 0.2099, p < 0.05 by BKS test) with two evident peaks in January and April; also for PgR a significant periodicity (t = 0.3161, p < 0.05 by BKS test) was demonstrated with a peak in July; finally, tumour size showed a significant rhythm (t = 0.335, p < 0.01) paralleling 3H-TLI behaviour. Finally, the analysis of variance with interaction of menstrual and seasonal timings showed that only the seasonal timing was able to independently influence the 3H-TLI variations (3H-TLI higher in spring). We confirmed that breast biology has significant menstrual and seasonal variations and that the seasonality is probably the timing factor more relevant in periodicity determination.

Premenopausal status accelerates relapse in node positive breast cancer: hypothesis links angiogenesis, screening controversy

Much attention has been given to determining the benefit of mammographic screening to reduce breast cancer mortality. Eight randomized clinical trials have been conducted in four countries: the US, Canada, Scotland and Sweden. Trials report an early and stable 30% reduction in breast cancer mortality for women aged 50-59. For women under 50, unexpectedly, the early years of screening produce a disadvantage to the screened population. Only in later years does an advantage appear. To help understand this, we studied relapse patterns using a breast cancer database of 1,173 pre- and postmenopausal, node negative and positive patients treated with surgery only and having 16-20 years of follow-up. This approach is relevant since at least five of the eight screening trials began before the widespread use of adjuvant chemotherapy in the 1980s. Surgical cure rates were independent of menopausal status. However, a major difference in early relapse rate was found. In premenopausal and node positive patients, 27% of all distant relapses occurred within the first 10 months following resection. This is twice the early relapse frequency of any other clinical group. Using computer simulation, we interpret that these early relapses probably result from a disadvantage induced at surgery. A disinhibition or surgery/wounding induced angiogenic surge might be responsible. Disinhibition is known to occur in animal models such as Lewis lung where lung metastases are avascular and dormant until the primary is removed. Sudden outgrowth of tumor after wounding has been observed for a century. According to the simulation, in breast cancer this induction apparently accelerates inevitable relapses by a median of two years. This is offset in later years with a balancing reduction in relapses. These data suggest that the angiogenic switch may be upregulated more frequently among premenopausal women, perhaps depending upon the sex hormones. The acceleration would cause 0.11 deaths per 1,000 screened aged 40-49 subjects in years 2-3, a value comparable to the early year excess mortality in trials of a significant 0.15 deaths per 1,000 subjects. Equal screening advantage is predicted for node negative (but not node positive) pre- and postmenopausal patients. The acceleration of relapse after surgery may explain the paradoxical effect of mammographic screening for women under 50.

Timing within the menstrual cycle, sex, and the use of oral contraceptives determine adrenergic suppression of NK cell activity

Physiological responses that involve adrenergic mechanisms, such as stress-induced changes in cardiovascular indices, were reported to fluctuate along the menstrual cycle. Metastatic development following surgery was also reported to vary according to the menstrual phase during which a primary breast tumour was removed. Natural killer (NK) cells are believed to play an important role in controlling metastases. Our recent studies in rats demonstrated that adrenergic suppression of NK activity and of resistance to metastasis is more profound during oestrous phases characterized by high levels of oestradiol. In the current study in humans, we examined the in vitro impact of a beta-adrenergic agonist, metaproterenol (MP), on NK activity, comparing blood drawn from (a) women tested at 3-4 different phases of their menstrual cycle (n = 10), (b) women using oral contraceptives (OC) (n = 10), and (c) men (n = 7). NK activity in each blood sample was assessed in the presence of 5 different concentrations of MP (10(-8)M to 10(-6)M), and in its absence (baseline). The results indicated marked group differences in the magnitude of NK suppression by MP: EC(50)was 2. 6-fold lower in the luteal phase compared to the follicular phase, and 1.8-fold lower in OC users compared to men, who were least susceptible to the effects of MP. No significant group differences or menstrual effects in baseline levels of NK activity were evident. These findings provide the first empirical evidence for menstrual regulation of adrenergic impact on cellular immune competence. Relevance of these findings to the relation between the timing of breast cancer excision within the menstrual cycle and survival rates is discussed.

Biological time and in vivo research: a field guide to pitfalls

Biological rhythmicity is a fundamental characteristic of all life forms, from primitive bacteria to man. The molecular biology, genetics, and the neurobiology of the biological clock(s) are being elucidated. Daily (circadian) statistically significant fluctuations occur in all of the normal biological variables studied in the experimental animal and the human. Many researchers, however, are not aware of the negative impact biological rhythmicity can have on experimental design and/or data interpretation. This article serves not as a review, but as a "field guide" to the pitfalls that can occur when research is performed in the absence of an understanding of biological rhythmicity. The major topics discussed are: 1) data transfer from the diurnally in-active/resting/sleeping lab animal to the diurnally active human, 2) frequency of sampling, 3) free-running vs. synchronization, 4) alternating periods of resistance and susceptibility, 5) phase shifting of a rhythm, 6) the assumption that one mean +/- S.E. from control animals can be "stretched" across an experimental time span, and 7) plotting data on an "hours after treatment" format vs. a "time of day" format. The hope is that by avoiding the pitfalls, biological time will become an ally in the endeavor to understand human biology.

Menses and breast cancer: does timing of mammographically directed core biopsy affect outcome?

BACKGROUND AND OBJECTIVES

Studies have shown molecular, genetic and cellular changes in breast cancer during the menstrual cycle. Changes in proliferative and metastatic potential of breast cancer cells during menses could explain improved survival when tumors are surgically removed in the luteal phase. This study examined if timing of mammography/core biopsy (MAM-CB) also affected breast cancer prognosis (histological tumor grade).

METHODS

Eighty-five premenopausal women undergoing MAM-CB at one clinic between March 1995 and February 1998 were retrospectively studied. All patients had Stage I or II breast cancer surgically treated. Patients were grouped by phase of menses at MAM-CB: follicular (F, Days 0-14) or luteal (L, Days 15-35). Groups were comparable in age, menarche, family history, nulliparity, breastfeeding, and total percentage of clinically palpable tumors. Pathological characteristics of the tumors (tumor size, tumor type, estrogen and progesterone receptor status, axillary lymph node status, the presence of lymphatic or vascular invasion and extranodal metastasis) was also comparable across the 2 groups.

RESULTS

Low-grade tumors were more frequent in the MAM-CB group L, whereas high-grade tumors were more common in the MAM-CB group F (P = 0.002, chi2(4) = 17.06).

CONCLUSIONS

Timing of MAM-CB in relation to menses may be a factor influencing breast cancer outcome. Future studies examining the effect of menses on the outcome of breast cancer should consider the potential effect of the timing of MAM-CB.

Variations in prognostic factors in primary breast cancer throughout the menstrual cycle

AIMS

We investigated whether menstrual cycle dependent variations in prognostic factors are detectable in malignant breast tissue.

METHODS

Since 1977 the Danish Breast Cancer Cooperative Group has collected population-based information about primary clinical data, treatment regimens and follow-up status on Danish women with breast cancer. Information about last menstrual periods prior to surgery was obtained from files recorded at the time of admission for primary surgery. Included in this study were 1060 patients self-reported to be regularly menstruating and with a menstrual period within 6 weeks of surgery and who were operated in a single-step procedure. None of the patients were current users of exogenous hormones at the time of surgery. Variations of prognostic factors throughout the menstrual cycle were evaluated.

RESULTS

Overall, no significant correlation between endogenous hormone fluctuations and oestrogen receptor (ER) status and progesterone receptor (PgR) status were found. Furthermore, we observed no cycle-dependent variation for mitotic index, lymph node involvement or tumour size.

CONCLUSIONS

The classical prognostic factors in breast cancer did not differ significantly throughout the menstrual cycle in the present study.

Fluctuation of HER2 expression in breast carcinomas during the menstrual cycle

The hormonal milieu at time of tumor surgery seems to have a significant impact on survival in premenopausal breast cancer patients. Indeed, surgery performed during the follicular phase of the menstrual cycle was suggested to correlate with a poor prognosis. To investigate the relationship between prognosis and menstrual cycle at time of surgery, we analyzed the expression of some markers associated with tumor aggressiveness, such as the hormone receptors, HER2, p53, Bcl2, and cathepsin D in breast carcinomas obtained from 198 premenopausal women who underwent surgery during different phases of the menstrual cycle. HER2 overexpression was found to fluctuate in hormone receptor-positive tumors. In actual fact, 20% of the tumors removed during the follicular phase scored HER2-positive, versus 8% of those removed during the luteal phase. Similarly, a number of hormone receptor-positive tumor specimens, obtained from the same patients during follicular and luteal phases, were scored HER2-positive when the sample was removed during the follicular phase and HER2-negative when removed in the luteal phase. Southern blot analysis of the HER2 gene indicated that, in hormone receptor-positive cases, the overexpression of HER2 is often not associated with gene amplification. The finding that overexpression of the HER2 gene, associated with tumor aggressiveness, can fluctuate according to the hormonal milieu may explain the increased survival of patients operated during the luteal phase. It is also relevant to the selection and treatment of patients most likely to benefit from anti-HER2 antibody therapy.

Lack of correlation between timing of surgery in relation to the menstrual cycle and prognosis of premenopausal patients with early breast cancer

In a retrospective cohort of a randomised study of adjuvant endocrine, chemotherapy and chemoendocrine therapy, we investigated the correlation between timing of mastectomy and relapse-free survival (RFS) and overall survival (OS) in 721 premenopausal patients with early breast cancer. The median follow-up was 10.1 years (range: 6.1-19.1 years). We grouped the patients by three kinds of classification according to Badwe, Senie, and Hrushesky. The logrank test after the Kaplan-Meier curves showed that there were no significant differences between the categorised menstrual phase in cycle and RFS or OS, except for RFS using Badwe's classification, where the patients whose timing of operation was in the follicular phase had a better RFS compared with those in the luteal phase. These were confirmed by the Cox proportional hazard model. These results suggest that a positive result might be a chance finding, dependent upon the cut-off levels in the menstrual cycle.

Vascular endothelial growth factor A (VEGF-A) mRNA expression levels decrease after menopause in normal breast tissue but not in breast cancer lesions

We hypothesized that the regulation of microvascular functions and angiogenesis in breast tissue, a well known target of ovarian steroid action, is dependent on the hormonal exposure of the breast. Relative expression levels of VEGF-A (vascular endothelial growth factor A), a putative key regulator of angiogenesis in breast cancer, were analysed in the tumour and the adjacent non-neoplastic breast tissue of 19 breast cancer patients by quantitative reverse transcriptase polymerase chain reaction. In non-neoplastic breast specimens the expression levels of all detected VEGF-A-isoforms (189, 165, 121) were significantly higher in premenopausal compared to post-menopausal women (P = 0.02) and were inversely correlated with the patient's age (P = 0.006). In contrast, in cancerous tissues menopausal status had no influence on VEGF-A-expression levels. Benign and malignant tissues exhibited a similar expression pattern of VEGF-A-isoforms relative to each other. Thus, the regulation of the vasculature in normal breast tissue, as opposed to breast cancer tissue, appears to be hormonally dependent. Endogenous and therapeutically used hormonal steroids might, therefore, cause clinically relevant changes of the angiogenic phenotype of the human breast.