Relation between surgery-induced prolactin increase and the menstrual cycle phase at time of surgery in premenopausal breast cancer.

It has been suggested that both the menstrual cycle phase and postoperative changes in prolactin (PRL) secretion at the time of surgery may influence the prognosis of breast cancer. The present study was carried out to evaluate the relation between menstrual cycle period and surgery-induced PRL variations. We evaluated 32 premenopausal women with operable breast carcinoma; 17 were in perimenstrual phase (days 1-6 and 21-28) and 15 were in the mid-cycle (days 7-20) period at the time of surgery. To investigate serum levels of PRL, venous blood samples were collected before and 7 days after surgery. Postoperative hyperprolactinemia occurred in 17/32 patients and it was statistically more frequent in patients surgically treated during the perimenstrual phase than in the mid-cycle phase (12/17 vs 5/15; p less than 0.05), while no other parameter (including axillary node and estrogen receptor status) showed a significant influence on hyperprolactinemia rate. The results suggest that in premenopausal breast cancer patients surgery-induced hyperprolactinemia may be influenced by the menstrual cycle phase at the time of surgery.

Pineal gland and tumor cell kinetics: serum levels of melatonin in relation to Ki-67 labeling rate in breast cancer.

Recent observations showed that host may regulate either endocrinologically or immunologically tumor growth and differentiation, perhaps by modulating oncogene expression. Within the endocrine system, the pineal hormone, melatonin, seems to play an important antineoplastic role. To investigate its secretion in relation to tumor growth, we have evaluated the daily serum levels of melatonin in a group of 25 untreated breast cancer patients with a locally limited disease. Tumor cell proliferation was established by measuring Ki-67 labeling rate. As controls, 46 healthy women were considered. Breast cancer patients showed significantly higher mean values of melatonin than controls. Moreover, patients with negative Ki-67 labeling rate had significantly higher levels of the pineal hormone than those with a positive Ki-67 rate. Since tumors with high growth fraction present a worse prognosis, this study would suggest that the relief of an increased melatonin secretion represents a favorable prognostic sign, because of its association with less proliferating breast cancers.

Postoperative hyperprolactinaemia and early recurrence rate in breast cancer.

Serum levels of prolactin before and after surgery were measured in 90 women with breast cancer until the 5th postoperative month. Surgery-induced hyperprolactinaemia occurred in 51 patients, without significant correlation to any other clinical variable. After a median follow-up of 39 months, irrespective of each other variable (i.e. nodal involvement, oestrogen receptor status, adjuvant therapies), patients with postoperative hyperprolactinaemia had a significantly lower recurrence rate than those in whom surgery was not followed by an abnormal increase in prolactin secretion (3/51 vs. 13/39, P less than 0.001). These results suggest that, despite the stimulatory role of prolactin on mammary tumours, the lack of postoperative hyperprolactinaemia is an unfavourable prognostic factor because of its association with a higher relapse rate.

The pineal gland and breast cancer: serum levels of melatonin in patients with mammary tumors and their relation to clinical characteristics.

Several studies have suggested that the pineal gland hormone melatonin may influence the growth of breast cancer. The importance of melatonin blood concentrations in the clinical history of human breast cancer, however, has still to be defined. To further investigate this problem, we used a RIA method to assay serum levels of the pineal hormone in 74 untreated breast cancer patients, clinical stage T1-3 NO-2 MO, and in 46 age-matched healthy women as controls. Mean serum melatonin levels were significantly higher in patients than in controls. Melatonin concentrations were highest in breast cancer patients with the best prognosis (i.e. estrogen receptor-positive/node-negative cases). Mean levels of melatonin were significantly higher in estrogen receptor-positive patients than in the negative ones. They were also higher in node-negative than in node-positive cases, and in progesterone receptor-positive patients than negative ones, but none of these differences was statistically significant. No difference was observed in relation to menopausal status and to tumor histotype. These results suggest that melatonin plays a role in the hormone-dependency of human breast cancer.

Effects of radical mastectomy on prolactin blood levels in patients with breast cancer.

The role played by PRL in human breast cancer is still obscure. Several observations, however, demonstrated that antitumor therapies for breast cancer are associated with changes in PRL secretion, clinical significance of which remains to be determined. The present investigation was carried out to further clarify the effects of mastectomy on PRL levels in breast cancer women. The study included 34 patients at clinical stage T1-2N0-2M0 treated with radical mastectomy. In each patient, venous blood samples were drawn before, and 15 days, 1 month, 45 days, 2 months and 3 months after surgery to determine PRL serum levels. As controls, 14 women surgically treated for reasons other than neoplastic disease were included in the study. Mastectomy was followed by hyperprolactinemia in 18 of the 34 cases (52.9%). PRL remained elevated for at least 1 month, and it became normal within 2 months. On the contrary, no PRL increase was seen in controls. Among breast cancer women, PRL increase was irrespective of the type of surgery, the histology of the tumor and the menopausal status. In contrast, PRL increase was significantly higher in patients without node involvement and with negative hormonal receptors, with respect to that observed in cases with node involvement and positive receptors, respectively. The mechanisms by which mastectomy induces enhanced PRL secretion are still obscure. They might depend, however, on changes in feed-back systems operating in the regulation of PRL secretion, due to the removal of a target organ for PRL itself. Longitudinal studies, by evaluating the percentage of relapse either in patients with surgery-induced hyperprolactinemia or in those with normal hormonal values, will be needed to clarify the prognostic significance of the enhanced PRL secretion induced by mastectomy.