Breast Cancer in Young Women: The University of New Mexico Cancer Center (UNMCC) Experience

Background: While only a small proportion of breast cancer is attributable to hereditary susceptibility, identifying high-risk individuals is essential for appropriate medical management. Furthermore, identifying individuals with inherited breast cancers have significant impact on both patient and their family. Beyond early age of onset, family history of multiple cancers may warrant a referral to cancer genetics professional. However, in a busy oncology practice, documentation of a full family history can be time consuming and referral opportunities for genetic counseling may be missed. In this study, we evaluated the strength of family history documentation in breast cancer patients' charts, and whether or not appropriate referrals to the Hereditary Cancer Assessment Program (HCAP) were made. Racial differences in these referral patterns were also assessed.Materials and Methods: All charts of patients last known to be living as of 03/29/06 per the UNMCC Tumor Registry with an invasive breast cancer who were 40 years old or younger at the time of diagnosis were reviewed. Baseline data included patient age at diagnosis, self-reported ethnicity, histology, bilaterality and cancer status. The presence or absence of family history of breast and other cancers, and referral to the HCAP was documented. Descriptive statistics were performed on baseline data. Correlative analyses were conducted to note any racial differences in referral to HCAP.Results: A total of 211 women met inclusion criteria. Patients in the Tumor Registry were seen at diagnosis at UNMCC from 01/01/67 through 12/31/04. Mean age was 35. Racial distribution was similar to that of the New Mexican population: 44% Caucasian, 41% Hispanic, 10% Native American (NA) and 3% African American. Predominant histology was infiltrating ductal carcinoma (79%); 10% of women had a second breast primary. 63% of women had a positive family history of cancer; however, family history was not recorded in 17%. After HCAP was established, 109 women were eligible for referral, yet 68 (62%) of women had not been referred for genetic counseling. Only 39% of Caucasian, 40% of Hispanic and 34% of NA eligible women were referred.Discussion: Women under the age of 40 at time of breast cancer diagnosis are more likely to have a hereditary cancer syndrome. In our population, 17% of women had no documentation of family history, and almost 70% were never referred for hereditary counseling. There was no difference in referral patterns among different racial/ethnic backgrounds. On the basis of this review, quality improvement initiatives were undertaken to improve referral patters of young women with breast cancer for genetic counseling and potential genetic testing.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4079.

Estimated capacity of object files in visual short-term memory is not improved by retrieval cueing

Visual short-term memory (VSTM) has been claimed to maintain three to five feature-bound object representations. Some results showing smaller capacity estimates for feature binding memory have been interpreted as the effects of interference in memory retrieval. However, change-detection tasks may not properly evaluate complex feature-bound representations such as triple conjunctions in VSTM. To understand the general type of feature-bound object representation, evaluation of triple conjunctions is critical. To test whether interference occurs in memory retrieval for complete object file representations in a VSTM task, we cued retrieval in novel paradigms that directly evaluate the memory for triple conjunctions, in comparison with a simple change-detection task. In our multiple object permanence tracking displays, observers monitored for a switch in feature combination between objects during an occlusion period, and we found that a retrieval cue provided no benefit with the triple conjunction tasks, but significant facilitation with the change-detection task, suggesting that low capacity estimates of object file memory in VSTM reflect a limit on maintenance, not retrieval.

Feature binding in visual working memory evaluated by type identification paradigm

Memory for feature binding comprises a key ingredient in coherent object representations. Previous studies have been equivocal about human capacity for objects in the visual working memory. To evaluate memory for feature binding, a type identification paradigm was devised and used with a multiple-object permanence tracking task. Using objects defined by shape and color, observers identified types of changes in feature combinations across an occlusion event, and the effects of object motion and number of switches were investigated. With only one switch, task performance was impaired even under stationary conditions, suggesting highly limited capacity of binding memory. Second switch improved performance only in the stationary condition, suggesting that object motion strongly disrupts feature binding. Further analyses and experiments suggest that improvement by the second switch reflects transition of binding memory by selective attention.

A neural network implementation of a saliency map model

The saliency map model proposed by Itti and Koch [Itti, L., & Koch, C. (2000). A saliency-based search mechanism for overt and covert shifts of visual attention. Vision Research, 40, 1489-1506] has been a popular model for explaining the guidance of visual attention using only bottom-up information. In this paper we expand Itti and Koch's model and propose how it could be implemented by neural networks with biologically realistic dynamics. In particular, we show that by incorporating synaptic depression into the model, network activity can be normalized and competition within the feature maps can be regulated in a biologically plausible manner. Furthermore, the dynamical nature of our model permits further analysis of the time course of saliency computation, and also allows the model to calculate saliency for dynamic visual scenes. In addition to explaining the high saliency of pop-out targets in visual search tasks, our model explains attentional grab by sudden-onset stimuli, which was not accounted for by previous models.