Importance of neuroanatomical data from domestic animals to the development and testing of the KNDy hypothesis for GnRH pulse generation

Work during the last decade has led to a novel hypothesis for a question that is half a century old: how is the secretory activity of GnRH neurons synchronized to produce episodic GnRH secretion. This hypothesis posits that a group of neurons in the arcuate nucleus (ARC) that contain kisspeptin, neurokinin B (NKB), and dynorphin (known as KNDy neurons) fire simultaneously to drive each GnRH pulse. Kisspeptin is proposed to be the output signal to GnRH neurons with NKB and dynorphin acting within the KNDy network to initiate and terminate each pulse, respectively. This review will focus on the importance of neuroanatomical studies in general and, more specifically, on the work of Dr Marcel Amstalden during his postdoctoral fellowship with the authors, to the development and testing of this hypothesis. Critical studies in sheep that laid the foundation for much of the KNDy hypothesis included the report that a group of neurons in the ARC contain both NKB and dynorphin and appear to form an interconnected network capable of firing synchronously, and Marcel's observations that the NKB receptor is found in most KNDy neurons, but not in any GnRH neurons. Moreover, reports that almost all dynorphin-NKB neurons and kisspeptin neurons in the ARC contained steroid receptors led directly to their common identification as "KNDy" neurons. Subsequent anatomical work demonstrating that KNDy neurons project to GnRH somas and terminals, and that kisspeptin receptors are found in GnRH, but not KNDy neurons, provided important tests of this hypothesis. Recent work has explored the time course of dynorphin release onto KNDy neurons and has begun to apply new approaches to the issue, such as RNAscope in situ hybridization and the use of whole tissue optical clearing with light-sheet microscopy. Together with other approaches, these anatomical techniques will allow continued exploration of the functions of the KNDy population and the possible role of other ARC neurons in generation of GnRH pulses.

Kisspeptin, gonadotrophin-releasing hormone and oestrogen receptor α colocalise with neuronal nitric oxide synthase neurones in prepubertal female sheep

Puberty is a process that integrates multiple inputs ultimately resulting in an increase in gonadotrophin-releasing hormone (GnRH) secretion. Although kisspeptin neurones play an integral role in GnRH secretion and puberty onset, other systems are also likely important. One potential component is nitric oxide (NO), a gaseous neurotransmitter synthesised by nitric oxide synthase (NOS). The present study aimed to neuroanatomically characterise neuronal NOS (nNOS) in prepubertal female sheep and determine whether oestradiol exerts effects on this system. Luteinising hormone secretion was reduced by oestradiol treatment in prepubertal ovariectomised ewes. Neurones immunoreactive for nNOS were identified in several areas, with the greatest number present in the ventrolateral portion of the ventromedial hypothalamus, followed by the ventromedial hypothalamus, preoptic area (POA) and arcuate nucleus (ARC). Next, we determined whether nNOS neurones contained oestrogen receptor (ER)α and could potentially communicate oestradiol (E₂ ) feedback to GnRH neurones. Neuronal NOS neurones contained ERα with the percentage of coexpression (12%-40%) depending upon the area analysed. We next investigated whether a neuroanatomical relationship existed between nNOS and kisspeptin or nNOS and GnRH neurones. A high percentage of kisspeptin neurones in the POA (79%) and ARC (98%) colocalised with nNOS. Kisspeptin close contacts were also associated with nNOS neurones. A greater number of close contacts were observed in the ARC than the POA. A high percentage of POA GnRH neurones (79%) also expressed nNOS, although no GnRH close contacts were observed onto nNOS neurones. Neither the numbers of nNOS neurones in the POA or hypothalamus, nor the percentage of nNOS coexpression with GnRH, kisspeptin or ERα were influenced by oestradiol. These experiments reveal that a neuroanatomical relationship exists between both nNOS and kisspeptin and nNOS and GnRH in prepubertal ewes. Therefore, nNOS may act both directly and indirectly to influence GnRH secretion in prepubertal sheep.

Does Dynorphin Play a Role in the Onset of Puberty in Female Sheep?

Puberty onset involves increased gonadotrophin-release (GnRH) release as a result of decreased sensitivity to oestrogen (E₂ )-negative feedback. Because GnRH neurones lack E₂ receptor α, this pathway must contain interneurones. One likely candidate is KNDy neurones (kisspeptin, neurokinin B, dynorphin). The overarching hypothesis of the present study was that the prepubertal hiatus in luteinising hormone (LH) release involves reduced kisspeptin and/or heightened dynorphin input. We first tested the specific hypothesis that E₂ would reduce kisspeptin-immunopositive cell numbers and increase dynorphin-immunopositive cell numbers. We found that kisspeptin cell numbers were higher in ovariectomised (OVX) lambs than OVX lambs treated with E₂ (OVX+ E₂ ) or those left ovary-intact. Very few arcuate dynorphin cells were identified in any group. Next, we hypothesised that central blockade of κ-opioid receptor (KOR) would increase LH secretion at a prepubertal (6 months) but not postpubertal (10 months) age. Luteinising hormone pulse frequency and mean LH increased during infusion of a KOR antagonist, norbinaltorphimine, in OVX + E₂ lambs at the prepubertal age but not in the same lambs at the postpubertal age. We next hypothesised that E₂ would increase KOR expression in GnRH neurones or alter synaptic input to KNDy neurones in prepubertal ewes. Oestrogen treatment decreased the percentage of GnRH neurones coexpressing KOR (approximately 68%) compared to OVX alone (approximately 78%). No significant differences in synaptic contacts per cell between OVX and OVX + E₂ groups were observed. Although these initial data are consistent with dynorphin inhibiting pulsatile LH release prepubertally, additional work will be necessary to define the source and mechanisms of this inhibition.

Impact of psychosocial stress on gonadotrophins and sexual behaviour in females: role for cortisol?

This review focuses on the importance of cortisol in mediating the inhibitory effects of psychosocial stress on reproduction in females. In particular, we have summarized our research in sheep where we have systematically established whether cortisol is both sufficient and necessary to suppress reproductive hormone secretion and inhibit sexual behaviour. Our findings are put into context with previous work and are used to develop important concepts as well as to identify productive further lines of investigation. It is clear that cortisol is necessary to inhibit some, but not all, aspects of reproduction in female sheep. These actions vary with reproductive state, and there are important interactions with gonadal steroids. The impact of cortisol on the tonic secretion of gonadotrophin-releasing hormone and luteinizing hormone has been investigated extensively, but less is known about the surge secretion of these hormones and their effects on sexual behaviour. Furthermore, there are separate effects of cortisol in the brain (hypothalamus) and at the anterior pituitary, illustrating that there are different mechanisms of action. Thus, although cortisol is important in mediating some of the effects of stress on reproduction, we need to look beyond cortisol and investigate some of the other mechanisms and mediators that relay the effects of stress on reproduction. In this regard, we propose that a group of neurons in the hypothalamus that co-synthesize kisspeptin, neurokinin B and dynorphin, termed KNDy cells, play important roles in mediating the effects of cortisol on reproduction. This hypothesis needs to be rigorously tested.

Surge-Like Luteinising Hormone Secretion Induced by Retrochiasmatic Area NK3R Activation is Mediated Primarily by Arcuate Kisspeptin Neurones in the Ewe

The neuropeptides neurokinin B (NKB) and kisspeptin are potent stimulators of gonadotrophin-releasing hormone (GnRH)/luteinsing hormone (LH) secretion and are essential for human fertility. We have recently demonstrated that selective activation of NKB receptors (NK3R) within the retrochiasmatic area (RCh) and the preoptic area (POA) triggers surge-like LH secretion in ovary-intact ewes, whereas blockade of RCh NK3R suppresses oestradiol-induced LH surges in ovariectomised ewes. Although these data suggest that NKB signalling within these regions of the hypothalamus mediates the positive-feedback effects of oestradiol on LH secretion, the pathway through which it stimulates GnRH/LH secretion remains unclear. We proposed that the action of NKB on RCh neurones drives the LH surge by stimulating kisspeptin-induced GnRH secretion. To test this hypothesis, we quantified the activation of the preoptic/hypothalamic populations of kisspeptin neurones in response to POA or RCh administration of senktide by dual-label immunohistochemical detection of kisspeptin and c-Fos (i.e. marker of neuronal activation). We then administered the NK3R agonist, senktide, into the RCh of ewes in the follicular phase of the oestrous cycle and conducted frequent blood sampling during intracerebroventricular infusion of the kisspeptin receptor antagonist Kp-271 or saline. Our results show that the surge-like secretion of LH induced by RCh senktide administration coincided with a dramatic increase in c-Fos expression within arcuate nucleus (ARC) kisspeptin neurones, and was completely blocked by Kp-271 infusion. We substantiate these data with evidence of direct projections of RCh neurones to ARC kisspeptin neurones. Thus, NKB-responsive neurones in the RCh act to stimulate GnRH secretion by inducing kisspeptin release from KNDy neurones.

Neurokinin-3 receptor activation in the retrochiasmatic area is essential for the full pre-ovulatory luteinising hormone surge in ewes

Neurokinin B (NKB) is essential for human reproduction and has been shown to stimulate luteinising hormone (LH) secretion in several species, including sheep. Ewes express the neurokinin-3 receptor (NK3R) in the retrochiasmatic area (RCh) and there is one report that placement of senktide, an NK3R agonist, therein stimulates LH secretion that resembles an LH surge in ewes. In the present study, we first confirmed that local administration of senktide to the RCh produced a surge-like increase in LH secretion, and then tested the effects of this agonist in two other areas implicated in the control of LH secretion and where NK3R is found in high abundance: the preoptic area (POA) and arcuate nucleus (ARC). Bilateral microimplants containing senktide induced a dramatic surge-like increase in LH when given in the POA similar to that seen with RCh treatment. By contrast, senktide treatment in the ARC resulted in a much smaller but significant increase in LH concentrations suggestive of an effect on tonic secretion. The possible role of POA and RCh NK3R activation in the LH surge was next tested by treating ewes with SB222200, an NK3R antagonist, in each area during an oestradiol-induced LH surge. SB222200 in the RCh, but not in the POA, reduced the LH surge amplitude by approximately 40% compared to controls, indicating that NK3R activation in the former region is essential for full expression of the pre-ovulatory LH surge. Based on these data, we propose that the actions of NKB in the RCh are an important component of the pre-ovulatory LH surge in ewes.

Abstract P6-13-01: Lyso-thermosensitive liposomal doxorubicin + local hyperthermia for radiation-pretreated chest wall recurrence

Background: Chest wall recurrence (CWR) causes much morbidity when not controlled by local measures. Lyso-thermosensitive liposomal doxorubicin (LTLD) provides accelerated release of doxorubicin (Dox) at ≥ 39° C, and is being studied for CWR based on the pioneering thermochemotherapy work of Dewhirst and colleagues at Duke. We now report on its tolerance, pharmacology, and preliminary antitumor effects in a dose-escalation study combined with local hyperthermia (LH) for radiation-refractory CWR. LH selectively increases liposomal permeability in tumor microvasculature, and promotes release of Dox from LTLD, and Dox tumor uptake, in addition to LH anti-tumor effects.

Methods: This phase I study entered patients (pts) with CWRs < 3 cm deep failing all standard Tx including surgery, radiation, and chemotherapy: pts received up to 6 LTLD/LH treatments every 21 days at a starting dose of 40 mg/m2 (cohort 1) and escalated to 50 mg/m2 (cohort 2). LTLD was infused IV over 30 minutes (min); followed within 30 min by microwave or ultrasound LH. The thermal dose goal was 40°C-42°C for 60 min. Pharmacokinetic samples for total plasma Dox and doxorubicinol (Doxol) were taken at 0.5, 5, 10 and 24 hours after starting infusion. Left ventricular ejection fraction was monitored every other cycle.

Results: Eleven pts with a median of 4 prior chemotherapy regimens (range 2 — 12) were enrolled; all but one had prior anthracycline (AC). All pts received ≥ 2 cycles. The within subject variability in Dox and Doxol exposure was small with mean Cycle 2 vs Cycle 1 ratios ranging from 0.99 to 1.06.

Cmax/dose (ng/ml)/(mg/m2) Cycle 1 Cycle 2

Dox 499.82 512.00

Doxol 0.46 0.45

AUClast/dose ((ng*hr/ml)/(mg/m2)

Dox 1338.12 1381.82

Doxol 7.96 8.04

Grade 3 and 4 toxicities included reversible neutropenia in 17 (40.5%) and one case (each) of mucositis (grade 1), chest wall thermal burn, and chest wall cellulitis (both grade 4); these occurred in only ≥ 5% of 42 cycles given. No cardiomyopathy or hand-foot toxicity occurred. The rate of clinically-significant (≥ 6 point) QoL improvement on the FACT-B after 2 cycles was 54.5% (95% CI: 25.1%–83.9%), including 1 lasting > 3 months. The local objective response rate was encouraging: 45.5% (95% CI: 16.1%–74.9%), with 1 complete and 4 partial local responses.

Conclusion: LTLD + LH is safe in CWR after prior radiation and doxorubicin. A phase II study is planned for pharmacologic evaluations and to add pts with less or no anthracycline treatment.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-13-01.

Neural systems mediating seasonal breeding in the ewe

Seasonal reproduction in ewes is caused by a dramatic increase in response to oestradiol (E(2)) negative feedback during the nonbreeding (anoestrous) season. Considerable evidence supports the hypothesis that A15 dopaminergic neurones in the retrochiasmatic area (RCh) play a key role in these seasonal changes. These A15 neurones are stimulated by E(2) and inhibit gonadotrophin-releasing hormone (GnRH) secretion in anoestrus, but not the breeding season. Because A15 neurones do not contain oestrogen receptors-alpha (ER alpha), it is likely that E(2)-responsive afferents stimulate their activity when circulating E(2) levels increase during anoestrus. Retrograde tract tracing studies identified a limited set of ER alpha-containing afferents primarily found in four areas [ventromedial preoptic area, RCh, ventromedial and arcuate (ARC) nuclei]. Pharmacological and anatomical data are consistent with GABA- and glutamate-containing afferents controlling A15 activity in anoestrus, with E(2) inhibiting GABA and stimulating glutamate release at this time of year. Tract tracing demonstrated that A15 efferents project posteriorly to the median eminence and the ARC, suggesting possible direct actions on GnRH terminals or indirect actions via kisspeptin neurones in the ARC to inhibit GnRH in anoestrus. Identification of this neural circuitry sets the stage for the development of specific hypotheses for morphological or transmitter/receptor expression changes that would account for seasonal breeding in ewes.

Colocalisation of dynorphin a and neurokinin B immunoreactivity in the arcuate nucleus and median eminence of the sheep

Dynorphin A (DYN)-containing cells play a key role in conveying the negative feedback influence of progesterone upon pulsatile gonadotrophin-releasing hormone (GnRH) secretion in the ewe. A very high percentage of DYN cells in the arcuate nucleus express the progesterone receptor; another population of arcuate nucleus cells that also express steroid receptors in the sheep are those that express the tachykinin peptide, neurokinin B (NKB). Both DYN and NKB fibres have been shown to form close contacts with ovine GnRH cells. Therefore, the present study tested the hypothesis that neurones expressing NKB and DYN represent the same neuronal population in the arcuate nucleus. Confocal microscopic analysis of brain sections processed for dual immunofluorescence revealed that a large majority of DYN neurones in the arcuate nucleus were also immunoreactive for NKB. Likewise, a similar majority of NKB neurones in the arcuate nucleus were immunoreactive for DYN. By contrast, DYN cells in the preoptic area and anterior hypothalamus did not colocalise with NKB, nor did DYN cells in the paraventricular or supraoptic nuclei. Fibres that stained positively for both DYN and NKB were seen in the arcuate nucleus, where they formed close appositions with DYN/NKB-positive neurones, and in the external zone of the median eminence. Taken together with previous findings, these data suggest that a subpopulation of arcuate nucleus neurones coexpressing DYN and NKB mediate the negative feedback influence of progesterone on pulsatile GnRH secretion in the ewe and may also be involved in other feedback actions of gonadal steroids.

Immunocytochemical colocalization of GABA-B receptor subunits in gonadotropin-releasing hormone neurons of the sheep

GABA has been shown to play an important role in the control of gonadotropin-releasing hormone (GnRH) and luteinizing hormone secretion in many mammals. In sheep, seasonal differences in the ability of GABA-B receptor antagonists to alter pulsatile luteinizing hormone secretion have led to the hypothesis that this receptor subtype mediates the increased inhibitory effects of estradiol on GnRH and luteinizing hormone pulse frequency seen during the non-breeding season (anestrus). The aim of the present study was to use multiple-label immunocytochemistry to determine if ovine GnRH neurons contain the GABA-B receptor subunits R1 and/or R2, and to determine whether there are seasonal differences in the colocalization of these subunits in GnRH neurons. A majority of GnRH cells in the preoptic area, anterior hypothalamic area, and medial basal hypothalamus of both breeding season and anestrous ewes contained either GABA-B R1 or R2 subunits; a subset of GnRH neurons in breeding season (42%) and anestrous ewes (60%) contained both subunits. In contrast to colocalization within cell bodies, GnRH fibers in the median eminence did not colocalize GABA-B receptor subunits. Although the percentage of GnRH neurons expressing GABA-B receptor subunits tended to be higher in anestrus than in the breeding season, there were no significant seasonal differences in R1 and R2 subunit colocalization in GnRH cell bodies. Thus, while GABA may act directly on GnRH cell bodies via GABA-B receptors in the sheep, any role that GABA-B receptors may play in seasonal reproductive changes is likely mediated by other neurons afferent to GnRH cells.

Distribution of preprodynorphin mRNA and dynorphin-a immunoreactivity in the sheep preoptic area and hypothalamus

Endogenous opioid peptides (EOP) are important modulators in a variety of neuroendocrine systems, including those mediating reproduction, energy balance, lactation, and stress. Recent work in the ewe has implicated the EOP, dynorphin (DYN), in the inhibitory effects of progesterone on pulsatile gonadotropin releasing hormone secretion. Although DYN is involved in a number of hypothalamic functions in the sheep, little is known regarding the localization of preprodynorphin (PPD) expression and its major product DYN A (1-17). In this study, we determined the distribution of PPD mRNA and DYN A-containing cell bodies in the brains of ovary-intact, luteal ewes. To detect PPD mRNA, an ovine PPD mRNA was subcloned by reverse transcription-polymerase chain reaction from sheep hypothalamus and used to create a (35)S-labeled riboprobe for in situ hybridization. Neurons that expressed PPD mRNA and DYN A immunoreactivity were widely distributed in the ovine preoptic area and hypothalamus. PPD mRNA-expressing cells were seen in the supraoptic nucleus, paraventricular nucleus, preoptic area, anterior hypothalamus area, bed nucleus of the stria terminalis, ventromedial nucleus (VMN), dorsomedial nucleus of the hypothalamus, and the arcuate nucleus. All of these regions also contained DYN A-positive cell bodies except for the VMN, raising the possibility that PPD is preferentially processed into other peptide products in the VMN. In summary, based on the expression of both mRNA and peptide, DYN cells are located in a number of key hypothalamic regions involved in the neuroendocrine control of homeostasis in sheep.

Neuroendocrine control of pulsatile GnRH secretion during the ovarian cycle: evidence from the ewe

This article reviews the neuroendocrine control of episodic GnRH secretion during the ovine oestrous cycle. There is general agreement that endogenous opioid peptides (EOPs) mediate the negative feedback action of progesterone on GnRH pulse frequency during the luteal phase of the ovarian cycle and recent preliminary data have implicated the dynorphin-kappa-receptor system in this effect of progesterone. Progesterone also acutely inhibits GnRH pulse frequency via a non-EOP mechanism, as naloxone does not block the rapid effects of this steroid. The effects of bicuculline, 3alpha-hydroxy-5alpha-pregnan-20-one and RU486 consistently indicated that the gamma-aminobutyric acid A (GABA-A) receptor is also not involved in the acute actions of progesterone. Thus, the neural system mediating this effect remains to be determined. Oestradiol has several actions on episodic GnRH secretion. The most well characterized action is inhibition of GnRH pulse amplitude, which is probably mediated by noradrenergic neurones. Oestradiol also increases the response to progesterone negative feedback, alters GnRH pulse shape and increases GnRH pulse frequency. The first two of these actions may involve EOPs, whereas the mechanisms underlying GnRH pulse frequency are currently unknown. Finally, there is also evidence that EOPs play a physiological role in synchronizing the firing of the GnRH neurones responsible for episodic release. Specifically, the effects of naloxone on the GnRH pulse shape lead to the hypothesis that EOP tone contributes to the termination of each GnRH pulse and prevents random firing of these GnRH neurones between pulses. Thus, it appears that EOPs play an important role in controlling several different aspects of pulsatile GnRH release during the ovine oestrous cycle.

Seasonal plasticity in the brain: the use of large animal models for neuroanatomical research

Seasonally breeding mammals display an annual cycle of fertility that is associated with both structural neuroplasticity and functional changes in the activity of the GnRH neurones in the brain. Sheep are valuable models for understanding the hormonal and environmental cues that regulate seasonal reproduction, as well as the brain circuitry that underlies this response. As a result of the large size of sheep, we can tightly correlate the anatomy of GnRH cells and their patterns of gene expression with direct measurements of their neurosecretory output. Tract tracing studies have begun to reveal the pathways by which seasonal changes in response to oestradiol negative feedback affect the function of the reproductive system. Electron microscopic studies have shown that synaptic inputs on to ovine GnRH cells undergo marked seasonal rearrangements that are independent of hormonal changes and may reflect the intrinsic seasonality of the brain. Recent work indicates that the polysialylated form of neural cell adhesion molecule (PSA-NCAM), a marker of neuroplasticity, is well positioned anatomically to contribute to seasonal structural and functional alterations. Applying state-of-the-art neuroanatomical techniques to this model has allowed us to delineate the neural pathways responsible for the seasonal shut down of reproduction in sheep, as well as to begin to uncover the cellular mechanisms underlying seasonal neuroplasticity in the adult mammalian brain.

Case report: myopic shift in a stable corneal graft following high altitude exposure

Refractive changes in patients after radial keratotomy who are exposed to high altitudes have been reported previously. Hypoxic environments may cause corneal curvature changes in surgically altered corneas that result in refractive error shifts. We report a patient who experienced a partially reversible myopic shift in a previously stable corneal transplant after prolonged exposure to high altitude.

Oestradiol microimplants in the ventromedial preoptic area inhibit secretion of luteinizing hormone via dopamine neurones in anoestrous ewes

Oestradiol exerts a season-specific negative feedback effect on the GnRH/LH neurosecretory system of the Suffolk ewe. This neuroendocrine suppression is mediated in part by dopamine A15 neurones, but these neurones do not possess the oestrogen receptor. Based on indirect evidence, we hypothesized that oestrogen receptor-containing neurones in the ventromedial preoptic area (vmPOA) may be the initial step in a neuronal system whereby oestradiol suppresses GnRH secretion during the non-breeding season. To test this, three experiments were conducted using ovariectomized ewes receiving either empty or oestradiol-containing bilateral microimplants directed at the vmPOA or s.c. subcutaneous oestradiol-containing implants. In the first experiment, LH pulse frequency was measured on days 0, 1, 7 and 14 of treatment during seasonal anoestrus. In vmPOA oestradiol and s.c. oestradiol groups only, LH pulse frequency was suppressed on days 7 and 14, with maximal suppression evident by day 7. In the second experiment, this protocol was repeated during the breeding season, with LH pulses examined on days 0 and 7; LH pulse frequency did not change in any group. The third experiment tested if the effect of vmPOA oestradiol during anoestrus could be overcome by an injection of the dopamine-D2 receptor antagonist (-)-sulpiride. The vmPOA microimplants and s.c. oestradiol implants again suppressed LH pulse frequency and this was reversed by sulpiride in vmPOA oestradiol ewes. We conclude that oestradiol acts on cells in the vmPOA to stimulate a system involving dopamine neurones that inhibits GnRH/LH pulsatility in the anoestrous ewe.

The relationship between radiation fields and regional lymph nodes in carcinoma of the breast

PURPOSE

To examine the relationships between tangential, anterior, and posterior radiation fields and regional lymph nodes, including Levels I-III axillary and supraclavicular lymph nodes.

METHODS AND MATERIALS

Fifty-five patients underwent computed tomography (CT) scanning in the supine treatment position, and radiation fields were developed to treat appropriate breast and lymphatic regions. After conventional fields had been selected, Levels I-III axillary and supraclavicular lymph nodes were identified on multiple CT slices performed at 3-5-mm intervals and their depths to the anterior skin surface and the anterior-posterior separations at multiple levels were measured.

RESULTS

The mean depths of the Levels I-III axillary nodes were 4.6, 5.1, and 3.6 cm, respectively. The mean depth of the supraclavicular nodes was 3.9 cm. The mean anterior-posterior separations at these levels were 15.4, 15.2, 15.2, and 14.6 cm. The mean depths of the nodes, therefore, were well anterior to the midline. In the two-field treatment group, Level I axillary nodes appeared in the tangential portals in 9/9 patients, either alone or with other lymph node groups. In the three-field group, Level I axillary nodes were in 16/16 tangential fields either alone or with level II nodes (8 patients). In 8 patients, Level III and the supraclavicular nodes were included in the anterior field and in the other 8, Levels II, III, and the supraclavicular nodes were in the anterior field. There was considerable variation in the nodal groups present in the posterior axillary boost field. No nodal groups were observed in 6 patients.

CONCLUSION

There is considerable variation both in the depth of supraclavicular and axillary lymph nodes and the fields in which these nodal groups appear. To be certain that nodal groups which one plans to treat are actually treated, as well as to minimize nodal treatment when such treatment is not planned, it is recommended that before the placement of radiation fields, the nodal groups be outlined on a CT scan much as one would outline a tumor volume in other disease sites.

Estradiol increases multiunit electrical activity in the A15 area of ewes exposed to inhibitory photoperiods

Seasonal anestrus in ewes results from an increase in response to the negative feedback action of estradiol (E(2)). This increase in the inhibitory effects of E(2) is controlled by photoperiod and appears to be mediated, in part, by dopaminergic neurons in the retrochiasmatic area of the hypothalamus (A15 group). This study was designed to test the hypothesis that E(2) increases multiunit electrical activity (MUA) in the A15 during inhibitory long days. MUA was monitored in the retrochiasmatic area of 14 ovariectomized ewes from 4 h before to 24 h after insertion of an E(2)-containing implant subcutaneously. In six of these ewes, MUA activity was also monitored before and after insertion of blank implants. Three of the 14 ewes were excluded from analysis because E(2) failed to inhibit LH. When MUA was recorded within the A15, E(2) produced a gradual increase in MUA that was sustained for 24 h. Blank implants failed to increase MUA in the A15 area, and E(2) did not alter MUA if recording electrodes were outside the A15. These data demonstrate that E(2) increases MUA in the A15 region of ewes and are consistent with the hypothesis that these neurons mediate E(2) negative feedback during long photoperiods.

The ability of estradiol to induce Fos expression in a subset of estrogen receptor-alpha-containing neurons in the preoptic area of the ewe depends on reproductive status

In the ewe, seasonal anestrus results from a change in the hypothalamic responsiveness to estradiol (E2) negative feedback. Considerable evidence has implicated a specific group of dopaminergic neurons (the A15 group) in this seasonally dependent E2 effect, but these neurons do not appear to contain estrogen receptor-alpha (ERalpha). This apparent discrepancy raises the possibility that at least one other neural system is also involved in mediating E2 inhibition. The purpose of this study was to determine whether ERalpha-containing neurons are activated by the negative feedback action of E2 in anestrus. In Exp 1, we examined the effects of E2 on expression of the immediate early gene products, Fos and Fos-related antigens, in ERalpha-positive cells in anestrous ewes. ERalpha and Fos/Fos-related antigens were colocalized using a dual immunofluorescence procedure in sections throughout the hypothalamus from ovariectomized and E2-treated ovariectomized anestrous ewes. A low dose E2 treatment that inhibited LH pulse frequency and induced Fos in A15 dopaminergic neurons in a previous study significantly increased the percentage of ERalpha-containing neurons expressing Fos (17.8% vs. 1.7%) in the medial preoptic area, but not in other hypothalamic areas. In Exp 2, we determined whether there was a seasonal difference in the effect of E2 on Fos/ERalpha colocalization in this region. E2 treatment produced a 3-fold increase in the percentage of ERalpha-positive cells expressing Fos (15.1% vs. 3.4%) in anestrus, but failed to increase ERalpha/Fos colocalization (1.8% vs. 3.5%) during the breeding season. These data raise the possibility that a subset of ERalpha-containing neurons in the medial preoptic area plays a role in the seasonal change in response to E2 negative feedback in the ewe.

A subset of gonadotropin-releasing hormone neurons in the ovine medial basal hypothalamus is activated during increased pulsatile luteinizing hormone secretion

GnRH neurons active in the preovulatory LH surge have been identified in several species using the early intermediate gene product, Fos, but the GnRH neurons active during episodic LH secretion remain unknown. In this study, we have used Fos and Fos-related antigens (FRA) to determine whether a subset of GnRH neurons is active when pulsatile LH secretion is acutely stimulated in sheep. In experiment 1, episodic LH secretion was stimulated in five of six ewes by injection of an opioid antagonist to luteal phase ewes. These five ewes had a 6-fold increase in the percentage of GnRH neurons in the medial basal hypothalamus (MBH) expressing Fos/FRA, compared with control ewes that had no LH pulses before death. Fos/FRA expression was not increased in GnRH neurons found in any other area. In experiment 2, episodic LH secretion was induced in rams by introduction of estrous ewes. This treatment increased Fos/FRA expression in MBH GnRH neurons approximately 10-fold compared with control rams. Again, this increase in Fos/FRA expression in GnRH neurons was limited to the MBH. This selective activation of MBH GnRH neurons could reflect the preferential inhibition of these perikarya by endogenous opioid peptides. It also raises the possibility that a subset of GnRH neurons in the MBH may be responsible for episodic GnRH secretion in sheep.

A new method for simultaneous demonstration of anterograde and retrograde connections in the brain: co-injections of biotinylated dextran amine and the beta subunit of cholera toxin

In studying reciprocally connected brain networks, it is advantageous to use techniques that allow simultaneous visualization of both efferent and afferent connections from a single injection site. We report on a new technique to achieve this using pressure injections of a mixture of biotinylated dextran amine (BDA) and the beta subunit of cholera toxin (Ctb). Adult male hamsters (n = 12) received 20-30-nl injections of either a 1:1 mixture of BDA (Sigma, 10%) and Ctb (List Biological, 0.5%), or each tracer by itself, into the medial amygdala. Adult female sheep (n = 4) received 200-300 nl of the combined tracer into the A15 region of the hypothalamus. After 1 (hamster) or 2 weeks' (sheep) survival, animals were perfused with 4% paraformaldehyde. Sections were double-labeled, first for BDA histochemistry using nickel-enhanced DAB, then for Ctb using a PAP technique and unenhanced DAB. In all animals, combined injections resulted in clear and consistent patterns of both anterograde and retrograde labeling. Ctb immunoreactivity was distinct and easily distinguished from BDA labeling. There was no evidence for loss of sensitivity of either tracer due to the combined delivery; no differences were seen between combined or single tracer injections in numbers of retrogradely-labeled cells or in the distribution of anterogradely-labeled fibers. In summary, the combined delivery of BDA and Ctb is an easy and reliable technique for simultaneous afferent and efferent tract tracing in both small and large animals; it could potentially be combined with immunocytochemistry to determine the neurochemical content of labeled cells or fibers.

The negative feedback actions of progesterone on gonadotropin-releasing hormone secretion are transduced by the classical progesterone receptor

Progesterone (P) powerfully inhibits gonadotropin-releasing hormone (GnRH) secretion in ewes, as in other species, but the neural mechanisms underlying this effect remain poorly understood. Using an estrogen (E)-free ovine model, we investigated the immediate GnRH and luteinizing hormone (LH) response to acute manipulations of circulating P concentrations and whether this response was mediated by the nuclear P receptor. Simultaneous hypophyseal portal and jugular blood samples were collected over 36 hr: 0-12 hr, in the presence of exogenous P (P treatment begun 8 days earlier); 12-24 hr, P implant removed; 24-36 hr, P implant reinserted. P removal caused a significant rapid increase in the GnRH pulse frequency, which was detectable within two pulses (175 min). P insertion suppressed the GnRH pulse frequency even faster: the effect detectable within one pulse (49 min). LH pulsatility was modulated identically. The next two experiments demonstrated that these effects of P are mediated by the nuclear P receptor since intracerebroventricularly infused P suppressed LH release but 3alpha-hydroxy-5alpha-pregnan-20-one, which operates through the type A gamma-aminobutyric acid receptor, was without effect and pretreatment with the P-receptor antagonist RU486 blocked the ability of P to inhibit LH. Our final study showed that P exerts its acute suppression of GnRH through an E-dependent system because the effects of P on LH secretion, lost after long-term E deprivation, are restored after 2 weeks of E treatment. Thus we demonstrate that P acutely inhibits GnRH through an E-dependent nuclear P-receptor system.

The GnRH system of seasonal breeders: anatomy and plasticity

Seasonal breeders, such as sheep and hamsters, by virtue of their annual cycles of reproduction, represent valuable models for the study of plasticity in the adult mammalian neuroendocrine brain. A major factor responsible for the occurrence of seasonal reproductive transitions is a striking change in the responsiveness of gonadotropin-releasing hormone (GnRH) neurons to the inhibitory effects of gonadal steroids. However, the neural circuitry mediating these seasonal changes is still relatively unexplored. In this article, we review recent findings that have begun to define that circuitry and its plasticity in a well-studied seasonal breeder, the ewe. Tract tracing studies and immunocytochemical analyses using Fos and FRAs as markers of activation point to a subset of neuroendocrine GnRH neurons in the MBH as potential mediators of pulsatile GnRH secretion. Because the vast majority of GnRH neurons lack estrogen receptors, seasonal changes in responsiveness to estradiol are most probably conveyed by afferents. Two possible mediators of this influence are dopaminergic cells in the A14/A15 cell groups of the hypothalamus, and estrogen receptor-containing cells in the arcuate nucleus that project to the median eminence. The importance of GnRH afferents in the regulation of season breeding is underscored by observations of seasonal changes in the density of synaptic inputs onto GnRH neurons. Thyroid hormones may participate in this remodeling, because they are important in seasonal reproduction, influence the morphology of other brain systems, and thyroid hormone receptors are expressed within GnRH neurons. Finally, in the hamster, neonatal hypothyroidism affects the number of caudally placed GnRH neurons in the adult brain, suggesting that thyroid hormones may influence development of the GnRH system as well as its reproductive functions in the adult brain.

Dopaminergic A14/A15 neurons are activated during estradiol negative feedback in anestrous, but not breeding season, ewes

A major factor responsible for seasonal anestrus in sheep is a striking increase in the ability of estradiol (E) to inhibit pulsatile GnRH and LH secretion. Previous studies suggest that dopaminergic neurons in the A14 and A15 groups of the ovine hypothalamus play a key role in conveying the inhibitory effects of E in anestrous ewes. The present study tested the hypothesis that A14/A15 neurons in anestrous ewes are activated in response to E, and that this activation is specifically related to seasonal changes in E negative feedback. Expression of the immediate early gene products, Fos and the Fos-related antigens (FRAs), was used as a marker of neuronal activation. Ovariectomized anestrous ewes received either blank implants (no E) or 0.5-cm long E implants sc and were killed 6 h later (E+6h) or 7 days later (E+7d and no E groups). During the breeding season, two additional groups of ovariectomized ewes were perfused 7 days after insertion of either blank or E implants. During anestrus, E completely suppressed LH pulses in the E+7d group, but had no effect in the E+6h group. In the E+7d anestrous group, there was also a significant increase in the mean percentage of tyrosine hydroxylase (TH)-positive cells that expressed nuclear Fos/FRAs in A14 and A15 areas compared to that in either the no E or E+6h group. By contrast, during the breeding season, E had no effect on LH pulse frequency, and there were relatively few TH-positive cells in A14 and A15 that coexpressed Fos/FRAs in either the no E or E+7d group. No significant steroidal or seasonal differences in Fos/FRA expression were seen in other hypothalamic dopaminergic cell groups (A12 and A13) or in the preoptic area-anterior hypothalamus or suprachiasmatic nucleus. Furthermore, E did not alter the total number of TH-positive neurons in A14/A15 or other cell groups. There were seasonal differences in the number of TH-positive neurons, with a significantly greater number of cells in the A13 and A15 of breeding season animals compared to anestrous ewes. Thus, E increased Fos/FRA expression in A14/A15 neurons only during anestrus at a time when it also inhibited LH pulse frequency. These findings are consistent with the view that activation of dopaminergic cells in A14 and A15 is a critical link in the chain of events leading to seasonal shifts in sensitivity to E negative feedback in the ewe.

Alpha adrenergic neurons inhibit luteinizing hormone pulse amplitude in breeding season ewes

It is now clear that estradiol acts in the brain to inhibit LH pulse amplitude in breeding season ewes, but the neural mechanisms underlying this action of estradiol have yet to be determined. In this study, we performed four experiments to examine the role of alpha-adrenergic neurons in the control of LH pulse amplitude in the ewe. In the first experiment, implantation of the alpha-adrenergic antagonist phenoxybenzamine into the preoptic area (POA) during the follicular phase of the ovine estrous cycle significantly increased LH pulse amplitude. A similar stimulatory effect of POA implants of this antagonist was observed in estradiol-treated ovariectomized (OVX+E) ewes, but phenoxybenzamine implants had no effect in the absence of estradiol. In contrast, systemic administration of phenoxybenzamine decreased LH pulse amplitude in both OVX and OVX+E ewes. Finally, POA implants of the alpha 1-adrenergic antagonist, prazosin, increased LH pulse amplitude in OVX+E ewes, whereas the alpha 2-adrenergic antagonist, yohimbine, had no effect in these animals. These results suggest that a noradrenergic (or adrenergic) system acts in the POA via alpha 1-adrenergic receptors to inhibit LH pulse amplitude in the ewe. They also raise the possibility that this system may be involved in the negative feedback action of estradiol during the breeding season.

Neural systems mediating the negative feedback actions of estradiol and progesterone in the ewe

The ewe shows a marked seasonal variation in the effects of ovarian steroids on pulsatile GnRH secretion. In the breeding season, progesterone inhibits GnRH pulse frequency, while estradiol suppresses pulse amplitude. In anestrus, both steroids inhibit pulse frequency. The effects of progesterone in both seasons are mediated by endogenous opioid peptides (EOP) that act in the preoptic area (POA) and medial basal hypothalamus (MBH). However, knife cut studies indicate that actions in the MBH are most important. Moreover, blockade of EOP receptors activates (e.g., induces Fos) GnRH perikarya in the MBH, but not those in the POA. Thus interactions between EOP and GnRH neurons within the MBH may be critical for progesterone negative feedback. The neural systems mediating estradiol suppression of GnRH pulse amplitude in the breeding season are largely unknown, although alpha-adrenergic neurons may be involved. The seasonal variation in inhibition of GnRH pulse frequency by estradiol is postulated to be mediated by a group of dopaminergic (DA) neurons that have three important properties: (1) they inhibit GnRH pulse frequency; (2) their activity is stimulated by estradiol; and (3) they are functional in anestrus, but not the breeding season. Recent work examining the effects of lesions of DA neurons and the ability of estradiol to induce Fos in DA cells strongly suggests that DA neurons in the retrochiasmatic area (A15) and POA (A14) have all three characteristics. We thus propose that these DA neurons are responsible for the seasonal variation in the ability of estradiol to inhibit GnRH pulse frequency.

Endogenous opioid peptides control the amplitude and shape of gonadotropin-releasing hormone pulses in the ewe

This study was designed to test the hypothesis that endogenous opioid peptides (EOP) mediate the negative feedback action of estradiol on GnRH pulse size in breeding season ewes. If this hypothesis is correct, one would predict that an EOP antagonist should increase GnRH pulse size in estradiol-treated ovariectomized (OVX+E), but not in OVX, ewes. We, therefore, examined the effects of naloxone on GnRH pulse profiles in the hypophyseal portal blood of OVX and OVX+E ewes (n = 6/group). Samples were collected every 10 min for 6 h before, 6 h during, and 4 h after naloxone infusion. Estradiol treatment decreased GnRH pulse size and increased GnRH pulse frequency. Naloxone treatment had no effect on GnRH pulse frequency, but significantly increased GnRH pulse size. However, this stimulatory action of naloxone on GnRH pulse size was evident in both OVX and OVX+E ewes. These results are thus not consistent with the hypothesis that EOP mediate the negative feedback action of estradiol. Interestingly, naloxone not only increased GnRH pulse amplitude, but also prolonged the duration of GnRH release during a pulse. To obtain a more precise characterization of the effects of naloxone on the dynamics of GnRH release, pulse profiles in six OVX ewes were examined in hypophyseal portal blood sampled every minute for 4 h before and 4 h during naloxone infusion. Naloxone again increased both the amplitude and duration of GnRH pulses. The increase in GnRH pulse duration was caused by a prolongation of both the plateau and declining phases of the GnRH pulse. In addition to these effects on GnRH release during a pulse, naloxone increased the amount of GnRH collected between pulses in both experiments. The stimulatory effects of naloxone on GnRH release in OVX ewes indicate that the role of EOP in the control of GnRH is not limited to mediating the feedback actions of steroids. In particular, the dramatic effects of naloxone on GnRH pulse shape and interpulse GnRH levels raise the possibility that EOP play an important role in synchronizing the activity of the GnRH neurons involved in episodic GnRH secretion.

Is the inhibitory action of estradiol on luteinizing hormone pulse frequency in anestrous ewes mediated by noradrenergic neurons in the preoptic area?

This study tested the hypothesis that estradiol inhibits luteinizing hormone (LH) pulse frequency in anestrous ewes by increasing the activity of an inhibitory noradrenergic (NE) system that acts in the ovine preoptic area (POA). The effects of estradiol on the release of NE and other neurotransmitters in the POA were determined using intracranial microdialysis. Microdialysis probes (5 mm membrane length) were inserted via chronic guide tubes into the POA. Ringer's solution was pumped through the probes at a rate of 2 microliters/min for 8 h, the alpha-adrenergic antagonist phenoxybenzamine (PBZ; 60 micrograms/ml of Ringer's solution) was then administered via the probe from hours 8 to 12, and Ringer's solution alone was given the last 4 h. The outflow from the dialysis probes was collected every 20 min from 2 to 16 h and concentrations of aminergic transmitters and gamma aminobutyric acid determined by high-performance liquid chromatography. Blood samples were collected every 10 min throughout the experiment and the LH pulse patterns determined. Dialysis was done in the same neural area twice in each ewe, without (ovariectomy only) and with estradiol treatment (ovariectomy and a 1.5-cm-long Silastic capsule filled with crystalline estradiol placed subcutaneously for 2 days); the order of dialysis was randomized. As expected, estradiol decreased the LH pulse frequency. This negative feedback action of estradiol was associated with a decrease in mean NE concentrations in dialysate samples and an increase in the intra-animal variability of NE. Estradiol had no effect on any other neurotransmitter measured.(ABSTRACT TRUNCATED AT 250 WORDS)

The importance of mammographic screening relative to the treatment of women with carcinoma of the breast

BACKGROUND

The use of mammographic screening for the early detection of breast cancer has been shown to reduce the mortality from breast cancer. However, the impact of mammographic screening relative to the local treatment of the breast (ie, breast-conservation treatment vs mastectomy) is not well established.

METHODS

An analysis was performed of 206 newly diagnosed and treated breast cancers in 201 women identified in 1989 from a health maintenance organization (US Healthcare, Blue Bell, Pa). The 206 breast cancers were evaluated for eligibility for and actual local treatment of the breast with breast-conserving surgery and definitive breast irradiation as a function of mammographic screening for the early detection of breast cancer.

RESULTS

Eligibility for local treatment of the breast with breast-conserving surgery and definitive breast irradiation was significantly increased for the breast cancers detected in women who had undergone mammographic screening compared with the breast cancers detected in women who had not undergone mammographic screening (88% vs 60%, respectively; P < .0001). For the breast cancers that were eligible on chart review for treatment with breast-conserving surgery and definitive breast irradiation, there was no significant difference in the actual local treatment of the breast with breast-conserving surgery and definitive breast irradiation for the eligible breast cancers detected in women who had undergone mammographic screening compared with the eligible breast cancers detected in women who had not undergone mammographic screening (44% vs 37%, respectively; P = .40); however, there was a statistically significant difference for the subgroup of women aged 50 years or more (49% vs 21%, respectively; P = .016).

CONCLUSIONS

These results show that breast cancers detected in women who had undergone mammographic screening were more likely to be eligible for breast-conserving surgery and definitive breast irradiation compared with breast cancers detected in women who had not undergone mammographic screening. For women aged 50 years or more, there was a significant increase in the use of breast-conserving surgery and definitive breast irradiation for eligible breast cancers detected in women who had undergone mammographic screening compared with eligible breast cancers detected in women who had not undergone mammographic screening.

Dopaminergic structures in the ovine hypothalamus mediating estradiol negative feedback in anestrous ewes

This study examined the role of two dopaminergic (DA) cell groups, the A-14 and A-15 DA groups, in the seasonal shift in the response of LH to estradiol negative feedback in ewes. Radiofrequency lesions were placed bilaterally, in the area of the A-15 or the ventromedial A-14 cell groups of ovariectomized ewes, while control animals underwent sham neurosurgery. The effect of estrogen was tested in anestrus by analyzing LH pulse patterns before and 3 and 10 days after the insertion of estradiol implants. To evaluate the effects of these lesions on DA inhibition of LH secretion, LH pulse patterns were compared before and after an iv injection of the DA antagonist pimozide on day 3 of estradiol treatment. LH pulses were also examined in these ewes during the breeding season before and 3 days after the insertion of estradiol implants. Also, the effect of the DA receptor agonist apomorphine was tested to determine any effect of lesions on DA receptors inhibitory to LH. Lesions in either the A-14 or A-15 area decreased, but did not completely abolish, estradiol inhibition of LH pulse frequency in anestrus. Both types of lesions also blocked the stimulatory effects of pimozide on LH pulse frequency in estradiol-treated ovariectomized anestrous ewes. During the breeding season, estrogen decreased LH pulse amplitude, but not frequency, in all groups. The DA receptor agonist apomorphine decreased LH pulse frequency in all groups. Furthermore, immunohistochemistry for tyrosine hydroxylase revealed catecholaminergic fibers apparently connecting the caudal A-14 and the rostral A-15 areas. These results suggest that both the A-14 and A-15 DA cell groups are involved in the inhibition of LH by estradiol in anestrous, but not breeding season, ewes. Seasonal shifts in the activity of these DA neurons may, thus, play a role in the annual reproductive cycle of the ewe.

Effect of anterior hypothalamic deafferentation on the negative feedback of gonadal steroids on luteinizing hormone pulse frequency in the ewe

Three experiments were performed to determined the effect of anterior hypothalamic deafferentation (AHD) on the inhibitory actions of estradiol and progesterone on luteinizing hormone (LH) pulse frequency in ovariectomized ewes during the anestrous season. The first experiment tested the effects of AHD on LH secretion in the absence of gonadal steroids. AHD was accomplished by a 180 degree knife cut (Halasz knife) placed at the posterior border of the optic chiasm (n = 4). Control ewes received sham cuts or no surgery (n = 6). LH pulses were monitored in blood samples taken every 12 min for 4 hr before and after surgery. AHD reduced LH pulse amplitude (pre 7.4 +/- 2.9 ng/ml; post 1.2 +/- 0.3 ng/ml), but had no effect on LH pulse frequency (pre 3.5 +/- 0.3/4 hr; post 3.3 +/- 0.3/4 hr) in ovariectomized ewes. In the second experiment all ewes were given a Silastic implant containing estradiol (1 cm long) and 2 d later bled at 12 min intervals for 4 hr before and after administration of pimozide (PIM, 0.08 mg/kg), a dopamine antagonist. Estradiol decreased LH pulse frequency in controls (2.8 +/- 0.4 to 1.5 +/- 0.3/4 hr) and this was reversed by PIM (2.5 +/- 0.4/4 hr). In contrast, estradiol did not decrease pulse frequency in AHD ewes (3.3 +/- 0.3 to 2.8 +/- 0.5/4 hr) and PIM did not increase it (2.7 +/- 0.7/4 hr). In the third experiment, all ewes were given Silastic implants containing progesterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of a claims database for the identification of patients with carcinoma of the breast

To develop and optimize algorithms for the identification of newly diagnosed and treated cases of women with carcinoma of the breast, an analysis was performed of cases identified from the claims database of a large health maintenance organization (U.S. Healthcare). An initial algorithm was developed from the patterns of claims which suggested common clinical presentations of carcinoma of the breast, and the positive predictive value was 88% (411/469). To attempt to improve upon the positive predictive value, multiple modifications of the initial algorithm were performed. The best identified modification of the initial algorithm yielded a positive predictive value of 93% (400/432) with a loss of only 3% (11/411) of the true positive cases. These results demonstrate that logic-based algorithms can be used as a valid and efficient method of identifying large numbers of cases from claims data with specific clinical characteristics. The best algorithm identified provides a powerful and accurate tool to perform health care analysis and research on large populations of women with newly diagnosed and treated carcinoma of the breast.

A new technique for positioning tangential fields

PURPOSE

A technique that eliminates the use of a mechanical "breast-bridge" for positioning tangential fields for treatment of the intact breast or chest wall has been developed.

METHODS AND MATERIALS

Treatment set-up parameters are determined using measuring capabilities (gantry angles and source-skin distances) available on a standard simulator unit. A programmable scientific calculator is used to determine field geometry from polar coordinates for various points on the patient's skin. The calculator program determines the field size, a depth and lateral shift from a skin reference point to the isocenter for the tangential fields, and the gantry angles. The program provides additional information which facilitates the simulation process: First, the coordinates of the isocenter for the tangential fields are expressed relative to couch coordinates for an initial arbitrary isocenter so that the "auto go to" capability available on some simulators can be used. Second, the coordinates of the medial and lateral entry points can be edited when the first set of tangents are not accepted. This part of the program allows quick and efficient adjustment of the fields to obtain adequate treatment volume coverage and a minimum of irradiated lung or heart.

RESULTS

Simulation of more than 300 patients has shown the technique to be a practical and efficient method for positioning tangential fields for breast or chest wall irradiation.

CONCLUSION

The technique described here takes full advantage of the capabilities of the new generation of computer controlled simulators, and offers an alternative to previous methods employing a mechanical "breast-bridge."

Immunocytochemical localization of beta endorphin and gonadal steroid regulation of proopiomelanocortin messenger ribonucleic acid in the ewe

In the ewe, estradiol and progesterone inhibit luteinizing hormone (LH) secretion during the breeding season. Endogenous opioid peptides (EOP) are also inhibitory to LH secretion, and both estrogen and progesterone have been reported to enhance EOP inhibition of LH release. Which EOP are involved in this inhibition is unclear. In this study, we concentrated on beta-endorphin because evidence for its ability to inhibit LH secretion exists in ewes. We first studied the distribution of beta-endorphin-immunoreactive neurons in 4 cycling ewes using immunocytochemistry. Cell bodies were found only within the medial basal hypothalamus (MBH) and were concentrated in arcuate nucleus and mammillary recess of the third ventricle, with a few in the median eminence. Extensive fiber tracts were seen in preoptic area (POA) and median eminence. We next tested the hypothesis that gonadal steroids increase the synthesis of EOP by measuring levels of mRNA for proopiomelanocortin (POMC), the precursor to beta-endorphin. Ovariectomized ewes were treated with no steroids (n = 7) or given subcutaneous Silastic implants containing either estradiol (n = 6) or progesterone (n = 6). After 4 days of treatment, EOP inhibition of LH secretion was measured by determining the LH response to WIN 44,441-3 (WIN), an EOP antagonist. LH pulse frequency and pulse amplitude were determined in blood samples collected at 12-min intervals for 3 h before and after intravenous administration of 12.5 mg WIN. WIN injection increased (p < 0.01) the LH pulse-frequency only in progesterone-treated and pulse amplitude only in estradiol-treated ewes. After blood sampling, the ewes were killed, and POA, MBH, and pituitary gland were removed. Total RNA was extracted from these tissues and dot blotted onto nitrocellulose membranes for hybridization with a DNA probe complementary to the POMC mRNA. The resulting autoradiographs were quantified densitometrically. Levels of POMC mRNA in the MBH were increased (p < 0.01) by both estradiol and progesterone as compared with the no steroid group. There was no detectable POMC mRNA in the POA. These results suggest that estrogen and progesterone enhance EOP inhibition of LH secretion by increasing POMC mRNA levels and thus synthesis of beta-endorphin.

Conservative surgery and radiation therapy in black women with early stage breast cancer. Patterns of failure and analysis of outcome

Between 1977 and 1986, 75 black and 615 white women with American Joint Committee (AJC) Stages I and II breast cancer were treated with excisional biopsy, axillary dissection, and radiation therapy for breast conservation. Cyclophosphamide, methotrexate, and 5-fluorouracil, with and without prednisone and tamoxifen, was given to 92% of premenopausal, 83% of perimenopausal, and 63% of postmenopausal node-positive women; 20 of 106 (19%) postmenopausal node-positive women received tamoxifen only. The clinical characteristics of the similarly treated patients were compared. The 5-year actuarial local only first failure rate was 5% for black women and 6% for white women (P = 0.53). Regional only failure as the first site of failure was 9% for blacks versus 1% for whites (P = 0.002), with regional recurrence as any component of first failure being 16% for blacks and 4% for whites (P = 0.001). The supraclavicular fossa was identified as the primary site of regional recurrence in black patients with either pathologically positive or negative axillae. Distant metastases as the only site of first failure were significantly greater in the black population with a 20% 5-year actuarial failure rate versus 11% in white patients (P = 0.01). The 5-year actuarial overall survival for the black patients was 82% versus 91% for the white patients (P = 0.01), with no-evidence-of-disease (NED) survival being 64% and 83% (P = 0.0002) and relapse-free survival (RFS) being 61% and 77% (P = 0.01), respectively. Black patients younger than 40 years of age or with pathologically positive axillary nodes had significantly worse NED, RFS, and overall survival compared with similarly staged white patients. Cosmetic results were analyzed at 3 and 5 years after completion of therapy. Although significantly fewer black patients had an excellent-to-good cosmetic result at 3 years compared with white patients, the results were not significantly different at 5 years. These results show that appropriately selected black patients with early stage breast cancer have excellent local control after conservative surgery and radiation therapy and should continue to be offered breast preservation as an alternative to mastectomy. Patterns of failure, however, demonstrated higher regional and distant recurrence rates and lower NED, RFS, and overall survival rates in most subsets of black patients reviewed.

Evaluation of multileaf collimator design for a photon beam

Various aspects of multileaf collimator (MLC) design are examined relative to clinical requirements. The characteristics studied included: (a) irregular field edge definition or "effective" penumbra, (b) optimum field coverage for the multileaf portion of the field, and (c) leaf velocity. A film dosimetry technique was developed to measure the rapid 2-dimensional change in dose at an edge defined by a multileaf collimator with the segments staggered. The method applies a correction factor which allows for the changing ratio of scattered to primary photons at the field edge so that the energy dependence of the film is corrected. Stepped lead alloy blocks were irradiated with 6 MV photons to obtain films simulating a double-focused multileaf collimator, and the results were compared to films of fields shaped with standard divergent blocks. The effect of the shape of the leaf face (the end of the leaf) on penumbra was also studied. Proper shaping of the leaf ends may eliminate the need to exactly match beam divergence so that the mechanical of the collimator system is simplified. Leaves having several different end shapes and moving horizontally to intercept a vertical beam were compared to the divergent design where a straight face moves along an arc. The measurements showed that the "effective" penumbra (measured as the distance from the 80 to 20% isodose lines) for the multileaf collimator is a function of the angle between the direction of leaf motion and the edge defined by the leaves. In addition, all leaf end shapes showed some increase in penumbra compared to standard divergent blocking and also had increasing penumbra width as they moved over or back from the field center line. A total of 459 treatment fields and six disease sites were examined to determine the percentage of fields potentially shaped by multileaf segments of specified length. This study showed 93% of the fields had lengths of 30 cm or less and 99% had widths of 25 cm or less. A study conducted to determine the required leaf velocity to shape various target volume configurations during complete rotation (at 1 RPM) showed that a leaf speed of at least 1.5 cm/sec at isocenter is needed for dynamic conformal treatment.

Microinvasive ductal carcinoma of the breast treated with breast-conserving surgery and definitive irradiation

An analysis was performed of 39 consecutive women with microinvasive ductal carcinoma of the breast treated with breast-conserving surgery and definitive irradiation during the period 1977 to 1988. Microinvasive ductal carcinoma was defined as predominantly intraductal carcinoma with microscopic or early invasion. Surgical treatment of the primary tumor included excisional biopsy or wide resection. Axillary lymph node staging showed that 37 patients were pathologically node negative and two patients were pathologically node positive, each with only one positive lymph node. The median follow-up was 55 months (mean = 65 months; range = 25-135 months). The 5-year actuarial rate of overall and cause-specific survival were both 97%. The 5-year actuarial rate of freedom from distant metastases was 93%. Nine patients developed a recurrence in the breast; eight of the nine patients had isolated local only first failures, and one of the nine patients had a local recurrence simultaneously with distant metastases. The median time to local failure was 42 months (mean = 53 months; range = 20-116 months). Of the eight patients with local only first failure, seven patients have been salvaged with further treatment and remain free of disease at the time of last follow-up, and one patient has died of subsequent distant metastatic disease. Median follow-up after salvage treatment was 29 months (mean = 27 months; range = 0-54 months). Comparison of the patients with microinvasive ductal carcinoma with two control groups of intraductal carcinoma and invasive ductal carcinoma was performed. Although the rate of local failure was significantly higher for patients with microinvasive ductal carcinoma as compared to the two control groups, the rates of survival and freedom from distant metastases for patients with microinvasive ductal carcinoma were intermediate to the two control groups. Because of the high rates of survival and freedom from distant metastases and because of the ability to salvage patients with local recurrence, breast-conserving surgery and definitive irradiation should continue to be considered as an alternative to mastectomy for appropriately selected and staged patients with microinvasive ductal carcinoma of the breast.

Endogenous opioid suppression of luteinizing hormone pulse frequency and amplitude in the ewe: hypothalamic sites of action

Evidence suggests that endogenous opioid peptides (EOP) inhibit pulsatile luteinizing hormone (LH) secretion during both the luteal and follicular phases of the ovine estrous cycle. Further data from sheep and other species indicate that the hypothalamus is the primary site of action for this EOP inhibition. The purpose of the following experiments was to determine which areas of the hypothalamus are involved in the EOP inhibition of pulsatile LH secretion. Regularly cycling ewes (n = 10) were stereotaxically implanted with guide tubes into the preoptic area (POA) and medial basal hypothalamus (MBH). Implants containing the EOP antagonist WIN 44,441-3 (WIN) were placed into each of these areas. Blood samples were collected at 12-min intervals for 3 h before and during WIN administration in the luteal phase and for 4 h before and during WIN administration in the follicular phase of the estrous cycle. During the luteal phase, WIN implants in either area increased (p less than 0.01) LH pulse frequency (POA 1.4 +/- 0.3/3 h before vs. 3.1 +/- 0.4/3 h during; MBH 1.1 +/- 0.2/3 h before vs. 2.8 +/- 0.5/3 h during). There was no effect on LH pulse amplitude. In contrast, during the follicular phase, WIN implants selectively increased (p less than 0.01) LH pulse frequency when implanted in the POA (3.2 +/- 0.4/4 h before vs. 5.2 +/- 0.6/4 h during) while increasing (p less than 0.05) only LH pulse amplitude when placed in the MBH (0.7 +/- 0.2 ng/ml before vs. 1.4 +/- 0.3 ng/ml during).(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacologic erection with intracavernosal injection for men with sexual dysfunction following irradiation: a preliminary report

Impotence is a possible consequence of treatment of pituitary adenomas and prostatic carcinomas. Following pituitary irradiation, the effect has been attributed to decreased gonadotrophins, while a variety of mechanisms, primarily vascular and neurogenic, have been proposed to explain the impotence following irradiation of prostatic carcinomas. Men with impotence of any etiology have been entered on a program to evaluate prospectively the efficacy of intracavernosal injection of vasoactive compounds in producing a satisfactory erection with pharmacologic means. Ten of these men had developed impotence following therapy for pituitary adenomas (2) or prostatic carcinomas (8). Test doses of 0.1 to 0.5 ml of a phentolamine (1 mg/ml) and papaverine (30 mg/ml) mixture were used; the dose was titrated to produce an erection deemed sufficient for vaginal penetration. All patients achieved a satisfactory response (i.e., tumescence and rigidity) lasting 10 minutes to 3 hours. Seven patients have continued in the pharmacologic erection program, with six patients functioning normally, and the remaining patient noting decreased tumescence after 18 months of treatment, but adequate erections are maintained with supplemental penile ring. Two patients have discontinued intracavernosal injections due to inconvenience, and one patient was lost to follow-up. Recent substitution of prostaglandin E1 (PGE1) has produced similar results and has replaced the phentolamine-papaverine combination. These preliminary results indicate that pharmacologic erection can be achieved in patients with impotence related to the treatment of pituitary and prostatic neoplasms and represents a reasonable alternative to implanted penile prostheses.

Patterns of circulating gonadotropins and ovarian steroids during the first periovulatory period in the developing sheep

This report provides evidence that an increment in serum gonadotropin levels occurs at puberty in the sheep and that this reflects the critical hormonal event culminating in first ovulation in this species. Blood samples were collected from 6 female lambs at 4-h intervals for a period of approximately 2 mo around the expected time of puberty (32 wk of age) until behavioral estrus was observed and ovulation was verified by assay of serum progesterone. Patterns of circulating LH, FSH, progesterone, and estradiol concentrations were characterized during the peripubertal period for each lamb. A rise in serum levels of both LH and FSH began approximately 7-10 days before the first preovulatory surge of gonadotropins. Although the increase in gonadotropin levels occurred gradually over several days, serum estradiol levels rose only during the final 40-60 h prior to the preovulatory surge of gonadotropin. Serum progesterone profiles revealed, however, that normal (14-16-day) luteal phases were induced in only 2 of 6 females as a result of the first surge. In four lambs, a short luteal phase of 2.5 days' duration occurred, which was followed by another estradiol rise and a preovulatory surge that then resulted in a full luteal phase of 14 days' duration. These data demonstrate clearly that the precipitating event at puberty in the female sheep is an increase in circulating gonadotropin levels and that the estradiol secreted from the newly stimulated follicle provides the signal for the first preovulatory surge.

Ten year results of conservative surgery and irradiation for stage I and II breast cancer

Between 1977 and 1985, 697 women with clinical Stage I or II invasive breast cancer underwent excisional biopsy, axillary dissection, and definitive irradiation. Reexcision of the primary was performed in 330 and residual tumor was identified in 57% of these patients. Margins of resection were assessed in 50% and 257 had final margins of resection that were negative. Four hundred eighty patients had negative axillary dissections and 217 had histologically positive axillary nodes. Median follow-up was 58 months. The 10-year actuarial survival for the entire group was 83% with an NED survival of 73%. The 10-year actuarial survival was 87% for clinical Stage I and 77% for clinical Stage II patients with an NED survival of 79% and 67%, respectively. Patients with histologically negative axillary nodes had a 10-year overall survival of 86% (NED 78%) compared to 74% (NED 66%) for patients with positive nodes. Sixty-one patients developed a recurrence in the treated breast and in seven of these it was associated with simultaneous distant metastases. The cumulative probability of an isolated breast recurrence was 6% at 5 years and 16% at 10 years. The overall breast recurrence rate (+/- distant metastasis) was 8% at 5 years and 18% at 10 years. Breast recurrence was unrelated to T size, clinical stage, or histologic nodal status. The addition of adjuvant chemotherapy significantly decreased the risk of an isolated breast recurrence both at 5 and 10 years; however, there was no significant impact on the overall risk of a breast recurrence. Complications of treatment included moderate arm edema (5%), symptomatic pneumonitis (less than 1%), rib fraction (1%), pericarditis (0%), and brachial plexopathy (less than 1%). Cosmesis was judged to be good to excellent in 93% of patients in 10 years. These results have been achieved in a series of patients who for the most part have been treated by contemporary standards, that is, pathologic assessment of the axilla in all patients, reexcision in 47%, and adjuvant chemotherapy in 77% of node positive patients. Assessment of resection margins, however, was not performed in all patients (50%) and further follow-up in the group of patients with margin assessment will provide long term information on breast recurrence rate in this group of patients.

The significance of the pathology margins of the tumor excision on the outcome of patients treated with definitive irradiation for early stage breast cancer

To evaluate the significance of the pathology margins of the tumor excision on the outcome of treatment, an analysis was performed of 697 consecutive women with clinical Stage I or II invasive carcinoma of the breast treated with breast-conserving surgery and definitive irradiation. Complete gross excision of the primary tumor was performed in all cases, and an axillary staging procedure was performed to determine pathologic axillary lymph node status. The 697 patients were divided into four groups based on the final pathology margin from the primary tumor excision or from the re-excision if performed. These four groups were: (a) 257 patients with a negative margin (greater than 2 mm), (b) 57 patients with a positive margin, (c) 37 patients with a close margin (less than or equal to 2 mm), and (d) 346 patients with an unknown margin. The patients with positive final pathology margins were focally positive on microscopic examination. Patients with grossly positive margins or with diffusely positive microscopic margins were treated with conversion to mastectomy. There was a significant difference in the total radiation dose for the four groups (median dose of 6000 vs 6500 vs 6400 vs 6240 cGy, respectively; p less than .0001). There was no significant difference among the four groups for 5-year actuarial overall survival (p = .19), no evidence of disease (NED) survival (p = .95), or relapse-free survival (p = .80). There was no significant difference among the four groups for five year actuarial local or regional control (all p greater than or equal to .29). Subset analyses did not identify any poor outcome subgroups. These results have demonstrated that selected patients with focally positive or close microscopic pathology margins can be adequately treated with definitive breast irradiation. Patient selection and the technical delivery of radiation treatment including a boost may have been important contributing factors to the good outcome in these patients.

The results of radiation therapy for isolated local regional recurrence after mastectomy

Between 1967 and 1988 128 patients with isolated local-regional recurrence of breast cancer after mastectomy were treated with definitive radiation therapy. Recurrence was confined to a single site in 108 patients and multiple sites in 20. The chest wall was the most common location (86) and the supraclavicular region was the second most common (20). Surgical treatment for recurrence prior to irradiation consisted of excision of all gross disease in 78 patients and incisional biopsy in 49 patients. Irradiation was directed to the entire chest wall in 19% of patients with isolated chest wall recurrences and to the chest wall and regional nodes in 81%. In patients with isolated nodal failures, treatment was directed to the nodal site and chest wall in 87% and to the regional site alone in 13%. Patients with multiple sites received treatment to the chest wall and regional nodes in all cases. Electively treated sites usually received 4500-5000 cGy. Following excision of chest wall disease, the median dose was 6000 cGy. Gross disease on the chest wall received a median dose of 6100 cGy. Gross disease in nodal sites received a median dose of 5600 cGy; 66 patients received systemic therapy at recurrence. The 5-year actuarial local-regional control was 43%. In a multivariate analysis only the estrogen receptor status of the recurrence remained significant (p = .002). The 5-year actuarial survival was 49% with a relapse-free survival of 24%. In a multivariate analysis for survival, the disease-free interval (p = .007), local regional control (p = .006), and excisional biopsy for recurrence (p = .03) remained significant. In a multivariate analysis for relapse-free survival, the disease-free interval (p = .03), excisional biopsy (p = .0001), and the extent of axillary nodal involvement (p = .007) remained significant. In the subgroup of patients with a disease-free interval greater than or equal to 24 months, excisional biopsy, and local regional control, the 5-year survival was 61% with a relapse-free survival of 59%. This subgroup represents 18% of the entire group and has a relatively good prognosis after recurrence.

Hypothalamic sites of catecholamine inhibition of luteinizing hormone in the anestrous ewe

Norepinephrine (NE) and dopamine (DA) actively inhibit the release of LH in anestrous ewes. This can be detected as an increase in LH pulse frequency following i.v. injection of NE and DA antagonists. The objective of this study was to determine the sites of these inhibitory actions in the ovine hypothalamus by using local administrations of the NE antagonist, phenoxybenzamine (PBZ), or the DA antagonist, pimozide (PIM), into specific hypothalamic areas. Each neurotransmitter antagonist was administered via a chronically implanted steel guide tube into either the preoptic area (POA), retrochiasmatic area (RCh), or the median eminence region (ME). Blood samples were taken every 15 min for 2 h before and 4 h during implantation of these drugs and were analyzed for LH and prolactin by RIA. Control (no treatment) samples were obtained similarly from the same animals on another day. Placement of PBZ into the POA significantly increased LH pulse frequency and mean LH concentrations over control values whereas PIM did not. In contrast, PIM significantly increased LH pulse frequency and mean LH concentrations when placed in the ME or in the RCh, but PBZ did not. No effects of PIM on prolactin concentrations were detected. These results suggest that an NE neural system operates in the POA and that a DA system acts in the medial basal hypothalamus (RCh or ME) to suppress GnRH pulse frequency in the ovary-intact anestrous ewe.

Results of the 1983 patterns of care process survey for definitive breast irradiation

This report has documented the U.S.A. national averages for the results of the Process Survey for the 1983 Patterns of Care Study (PCS) for the processes of evaluation, work-up, and treatment for definitive breast irradiation. All women had been treated with definitive irradiation following breast-conserving surgery for early stage breast cancer. The data were collected from 191 patient charts which were randomly selected from five strata of radiotherapy practice to represent the U.S.A. national averages. Clinical and pathological characteristics of the primary tumor and regional lymph node status were similar to reported series as of 1983. Analysis of this Process Survey showed high compliance with the 1983 PCS standards of best current management of breast cancer. However, there was a wide variation in the technical delivery of the radiation fields and radiation doses used. There was good compliance with the use of documentation of the radiation treatments with simulation films, port films, implant films, and field descriptions. No systematic difference was seen amongst the various strata of radiotherapy practice. Although compliance with the majority of the parameters was relatively high, the small but important areas of lack of compliance with the standards of best current management document an incomplete transfer of technology to the radiation oncology community as a whole in 1983. Separate analysis for the outcome of treatment for these cases will be necessary to correlate process with outcome.

A role for catecholaminergic neurons in the suppression of pulsatile luteinizing hormone secretion in the prepubertal ewe lamb

These experiments tested the hypothesis that inhibitory catecholaminergic neural systems suppress tonic luteinizing hormone (LH) secretion in the prepubertal ewe lamb, as they do in the adult anestrous ewe. This was done by determining the effects of the alpha-adrenergic antagonist, phenoxybenzamine, and the dopaminergic antagonist, pimozide. In the first experiment, pimozide at 0.24 mg/kg increased LH plus frequency in 28-week-old lambs, but not in 17-week-old animals. Phenoxybenzamine (0.8 mg/kg) had no effect at either age. In experiment 2, a dose-response curve for pimozide (0.008, 0.08, 0.8 mg/kg) and a high dose of phenoxybenzamine were tested at two ages. The highest dose of pimozide and phenoxybenzamine stimulated LH release at both 22 and 28 weeks, although the magnitude of the response was blunted in older lambs. In the third experiment, we tested whether age or time of year determined the response to pimozide by using two groups of lambs born 5 weeks apart. Two doses of pimozide (0.24 and 0.8 mg/kg) were tested at the same time of year in these lambs. The highest dose of pimozide again stimulated LH secretion in 22-week-old lambs, but not in 17-week-old animals; the lower dose produced a partial (not statistically significant) response only in older lambs. These data suggest that inhibitory catecholaminergic (probably dopaminergic) neurons contribute to the suppression of tonic LH secretion prior to puberty in the ewe lamb, but that this neural system only becomes functional between 17 and 22 weeks of age.

Definitive irradiation for intraductal carcinoma of the breast

During the period from 1978 to 1985, 51 women with intraductal carcinoma of the breast were treated with definitive irradiation following breast-conserving surgery. Surgical treatment of the primary tumor in all patients consisted of excisional biopsy or wide resection. In general, definitive irradiation consisted of conventional breast tangents to 4500-5000 cGy followed by a breast boost to a total dose of 6000-6600 cGy (median = 6000 cGy; range = 4200-6600 cGy). No patient was treated with radiation to a supraclavicular or axillary field. For the 51 patients, the median follow-up was 68 months (range = 25-126 months). The 5-year actuarial rate of local failure was 6%. A total of five patients failed in the breast at 19, 35, 40, 79, and 119 months following definitive irradiation. Salvage treatment in these five patients consisted of mastectomy in all five patients plus adjuvant tamoxifen in one patient. All five of the patients with breast failures are alive and NED (no evidence of disease), although with limited follow-up (median = 12 months; range = 6-68 months). These results suggest that definitive irradiation is an acceptable alternative to conventional mastectomy for appropriately selected and staged patients with intraductal carcinoma of the breast. In view of the long natural history of this disease, prolonged and careful follow-up of these patients is required.

Breast recurrence following conservative surgery and radiation: patterns of failure, prognosis, and pathologic findings from mastectomy specimens with implications for treatment

Between 1978 and 1986, 1030 women with clinical Stage I or II breast cancer underwent excisional biopsy, axillary dissection (948 patients), and definitive irradiation. Sixty-five patients developed a recurrence in the treated breast, 9 of which were associated with simultaneous (8) or antecedent (1) distant metastases. Detection was by mammography alone in 29%, physical exam alone in 50%, and both in 21%. The median interval to recurrence was 34 months. Overall, 65% of the recurrences were in the vicinity of the original tumor; however, as the interval to recurrence increased, the percentage of operable recurrences in a separate quadrant increased. For those recurring after 5 years, 54% were in a separate quadrant. Ninety-five percent of the recurrences unassociated with distant metastases were operable and pathology revealed non-invasive cancer only in 10%. Fifty-two patients underwent salvage mastectomy. Thirteen patients had no residual tumor following excisional biopsy at the time of mastectomy. None of the following factors were predictive for no residual tumor: initial age, method of detection, interval to recurrence, location of recurrence, or histology. Local-regional control following mastectomy was 95%. The 5-year actuarial overall and disease-free survivals for salvage mastectomy patients were 84% and 59%, respectively. The only significant prognostic factor for survival was the initial clinical tumor size, which was related to the extent of the recurrence. Based on the inability to identify factors which would predict for a localized recurrence pathologically, we recommend mastectomy as the preferred surgical treatment for an isolated breast recurrence. Adjuvant chemotherapy may be beneficial in patients with an unfavorable prognosis.