The development of microwave breast cancer detection and treatment techniques has been driven by reports of substantial contrast in the dielectric properties of malignant and normal breast tissues. However, definitive knowledge of the dielectric properties of normal and diseased breast tissues at microwave frequencies has been limited by gaps and discrepancies across previously published studies. To address these issues, we conducted a large-scale study to experimentally determine the ultrawideband microwave dielectric properties of a variety of normal, malignant and benign breast tissues, measured from 0.5 to 20 GHz using a precision open-ended coaxial probe. Previously, we reported the dielectric properties of normal breast tissue samples obtained from reduction surgeries. Here, we report the dielectric properties of normal (adipose, glandular and fibroconnective), malignant (invasive and non-invasive ductal and lobular carcinomas) and benign (fibroadenomas and cysts) breast tissue samples obtained from cancer surgeries. We fit a one-pole Cole-Cole model to the complex permittivity data set of each characterized sample. Our analyses show that the contrast in the microwave-frequency dielectric properties between malignant and normal adipose-dominated tissues in the breast is considerable, as large as 10:1, while the contrast in the microwave-frequency dielectric properties between malignant and normal glandular/fibroconnective tissues in the breast is no more than about 10%.

ObjectiveA prospective multi-institutional randomized surgical trial involving 740 stage and 11 melanoma patients was conducted by the Intergroup Melanoma Surgical Program to determine whether elective (immediate) lymph node dissection (ELND) for intermediate-thickness melanoma (1-4 mm) improves survival rates compared with clinical observation of the lymph nodes. A second objective was to define subgroups of melanoma patients who would have a higher survival with ELND. MethodsThe eligible patients were stratified according to tumor thickness, anatomic site, and ulceration, and then were prerandomized to either ELND or nodal observation. Femoral, axillary, or modified neck dissections were performed using standardized surgical guidelines. ResultsThe median follow-up was 7.4 years. A multifactorial (Cox regression) analysis showed that the following factors independently influenced survival: tumor ulceration, trunk site, tumor thickness, and patient age. Surgical treatment results were first compared based on randomized intent. Overall 5-year survival was not significantly different for patients who received ELND or nodal observation. However, the 552 patients 60 years of age or younger (75% of total group) with ELND had a significantly better 5-year survival. Among these patients, 5-year survival was better with ELND versus nodal observation for the 335 patients with tumors 1 to 2 mm thick, the 403 patients without tumor ulceration, and the 284 patients with tumors 1 to 2 mm thick and no ulceration. In contrast, patients older than 60 years of age who had ELND actually had a lower survival trend than those who had nodal observation. When survival rates were compared based on treatment actually received (i.e., including crossover patients), the patients with significantly improved 5-year survival rates after ELND included those with tumors 1 to 2 mm thick, those without tumor ulceration, and those 60 years of age or younger with tumors 1 to 2 mm thick or without ulceration. 255

These long-term survival rates from patients treated at 77 institutions demonstrate that ulceration and tumor thickness are dominant predictive factors that should be used in the staging of stages I and II melanomas, and confer a survival advantage for these subgroups of prospectively defined melanoma patients.

As students progress through medical school their attitude scores decline. The reasons for the shift in attitude scores are not clear but they may relate to a ceiling of high attitude scores at entry, loss of idealism and the impact of the unintended curriculum. Further study of the impact of medical education on student attitudes is warranted.

Margins of excision can be safely reduced to 2 cm for patients with intermediate-thickness melanomas. The narrower margins significantly reduced the need for skin grafting and shortened the hospital stay.

This prospective study identifies that delay in presentation accounts for the majority of perforated appendices. Clinical evaluation is effective for identifying patients with more advanced disease. Indiscriminate appendectomy as an attempt to decrease perforation is not supported by these data. Hospital perforation rates likely reflect patient factors, illness attitude, and access to medical care.

For this group of melanoma patients, a local recurrence is associated with a high mortality rate, a 2-cm margin of excision is safe and ulceration of the primary melanoma is the most significant prognostic factor heralding an increased risk for a local recurrence.

The science of surgical technique can be better measured by this unique instrument and will create accountability in surgery.