High incidence of micrometastases in breast cancer sentinel nodes.

BACKGROUND: Sentinel lymph node biopsy (SLNB) is being investigated as an alternative to formal axillary dissection in early breast cancer. Avoiding the morbidity of unnecessary axillary dissection is seen as the main potential benefit of SLNB. Sentinel lymph node biopsy also allows enhanced pathological analysis. A series of 62 sentinel node (SN) biopsies demonstrating a high incidence of micrometastases is presented here. METHODS: All SN were initially examined and reported by H&E staining. All negative SN were analysed after staining with polyclonal anticytokeratin antibody. RESULTS: Sixty-two patients underwent SLNB at Royal Melbourne Hospital between May 1998 and February 2000. One or more SN was identified in 51/62 patients. A total of 10/51 contained metastases identified after H&E staining. There was one false negative. A total of 10/41 patients with H&E-negative SN had micrometastases identified on immunohistochemistry (IHC). Micrometastases were more common in patients with larger tumours, with disease found in the H&E-negative SN of 1/17 T1a and T1b (1-10 mm), 4/15 T1c (11-20 mm), and 5/9 T2 (20-50 mm) tumours. CONCLUSION: Sentinel lymph node biopsy can accurately assess the axilla in most patients with early breast cancer. A significant proportion of histologically negative SN will have micrometastases identifiable with IHC. Although the clinical significance of such metastases is uncertain, the available evidence suggests that these patients have a poorer prognosis than other patients with negative lymph nodes.

Circulating radioimmunoassayable inhibin during periods of transient follicle-stimulating hormone rise: secondary surge and unilateral ovariectomy.

We have measured changes in circulating immunoreactive (ir-) inhibin in male and female rats using an RIA with an antiserum raised against porcine inhibin alpha (1-26)-Gly-Tyr. The same synthetic peptide was used for standards and for the preparation of tracer. Serum ir-inhibin levels were significantly higher in intact female than in intact male rats (p less than 0.001). Immunoreactive inhibin was significantly reduced in both sexes 24 h after bilateral gonadectomy (p less than 0.0001). Unilateral ovariectomy (ULO) of female rats on metestrus caused a transient decrease in serum inhibin 8 h after surgery, but levels were not significantly different from those of sham-operated controls at later times after surgery. Increases in serum FSH and LH were observed for 8-18 h after ULO. Serum ir-inhibin levels were also measured on the early morning of estrus during the secondary FSH surge. At this time, ir-inhibin levels were low, while FSH levels were high and LH levels were low. These results show that serum ir-inhibin levels in rats are decreased at times when serum FSH levels are high.

Acute effects of ovariectomy and sham ovariectomy on pituitary-ovarian phenomena in the mouse.

Four- and 5-day cyclic mice housed with and without males, respectively, were autopsied at 10 a.m. on proestrus (P) or estrus (E) after no treatment, or after ovariectomy (Ovax) or sham Ovax at 10 a.m. or 4 p.m. on one of the preceding 3 days. Results indicate the ovarian must be in situ between 4 p.m. the day before P and 10 a.m. the day of P for a normal proestrous uterine weight increase to occur in both 4- and 5-day cyclic mice. For estrous cornification to occur, ovaries must be in situ between 10 a.m. and 4 p.m. on diestrus (D) in 4-day cyclic mice, and between 4 p.m. on D-I and 10 a.m. on D-II in 5-day cyclic mice. Sham Ovax tended to inhibit ovulation in both 4- and 5-day cyclic mice. The effects of both Ovax and sham Ovax on proestrous and estrous pituitary LH values were variable. ttiming of the feedback relationship between ovary and hypothalamus-pituitary in mice may be imprecise, leading to easy disruption of the estrous cycle in this species.