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G Vlastos

Publications and source records attributed to G Vlastos.

28 records · Page 2Linked to original sources
PubMed2000

Presentation, management and outcome of axillary recurrence from breast cancer.

BACKGROUND: The impact of axillary node dissection on breast cancer survival is unclear. Limited axillary surgery has been proposed but may increase regional recurrence rates. Optimal management for axillary recurrence is poorly understood. METHODS: Axillary recurrences were initial treatment failure sites in 44 of 4,255 breast cancer patients (1%) seen at M.D. Anderson Cancer Center, 1982 to 1992. RESULTS: Twenty-one patients (48%) had early stage disease (0, I, II) at diagnosis. With 70.8 months median follow-up, complete control of axillary recurrence was achieved in 31 patients (71%). Distant metastases developed in 50% and were more likely with uncontrolled axillary recurrences. Failure to receive multimodality therapy and failure to undergo surgery for the recurrence correlated with resistant axillary disease. CONCLUSIONS: Axillary recurrence from breast cancer is uncommon but may follow any stage of disease. One half of affected patients develop distant metastases. Durable disease control is best achieved with multimodality therapy including a surgery component.

Adult↗
PubMed2000

Prophylactic mastectomy.

The Society of Surgical Oncology has developed a position statement54 that lists conditions warranting consideration of prophylactic mastectomy (Table 4). It must be stressed that there are no absolute indications for prophylactic mastectomy. The data are limited about the efficacy of prophylactic mastectomy in humans, but recent studies suggest that it results in up to 90% reduction in the risk for breast cancer. Total mastectomy is technically a more definitive procedure, although reported series have had a predominance of patients undergoing subcutaneous, nipple-sparing procedures. Prophylactic mastectomy may improve longevity in BRCA mutation carriers, but this must be balanced against the impact on quality of life. The benefits of prophylactic mastectomy relative to chemoprevention are unclear because there are no prospective randomized studies comparing these two strategies. Contralateral prophylactic mastectomy in patients with a unilateral cancer is unlikely to improve survival, but this approach may be considered for high-risk or difficult-to-observe patients, to facilitate breast reconstruction, and for the psychologic benefits. Patients considering prophylactic mastectomy should be well informed of risk-reduction alternatives and the limitations in the efficacy and cosmetic results of the procedure.

Animals↗
PubMed1999

Primary tumor response to induction chemotherapy as a predictor of histological status of axillary nodes in operable breast cancer patients.

BACKGROUND: Routine use of axillary lymph node dissection is being questioned, especially in clinically NO patients. The goal of this study was to determine whether primary tumor response to induction chemotherapy (IC) can predict the histological volume of residual axillary disease in patients who were candidates for breast conservation surgery after IC. METHODS: Forty-seven patients with stage II or IIIA breast cancer who received breast conservation surgery were selected from a population of patients randomized to receive four cycles of IC. Largest clinical tumor size before and after IC was determined by physical examination, mammography, and breast ultrasound. Clinical nodal status was determined by physical examination and axillary ultrasound and compared with histological findings. RESULTS: In patients with at least 50% reduction in primary tumor size after IC, 12 of 14 (86%) NO patients and 11 of 17 (65%) N1 patients were histologically negative. In patients with a less than 50% reduction, 0 of 3 NO patients and 2 of 13 (15%) N1 patients were histologically negative. CONCLUSIONS: There is significantly less axillary disease in responders than in nonresponders after IC. For NO responders, axillary irradiation may be an acceptable alternative to axillary lymph node dissection, and could easily be incorporated into the postsurgical radiotherapy that is standard protocol for breast conservation therapy. The more aggressive disease in nonresponders is best treated by axillary lymph node dissection, pending further study.

Adult↗
PubMed1998

Shear stress related hemolysis and its modelling by mechanical degradation of polymer solutions.

Human or animal blood is normally used as a test fluid for in vitro evaluation of hemolysis by artificial organs. However, blood has some disadvantages (no transparence for visualization of the flow field, large biological variability and problems with cleaning the devices). For that reason, it would be of advantage to have a reproducibile transparent technical fluid with blood like flow characteristics and that exhibits similar shear depending destruction. We have shown that solutions of long-chaining polymer molecules are destroyed by heart valve prostheses in a similar manner as blood corpuscules. In the presented study, a direct comparison between erythrocyte destruction of bovine blood and degradation of Polyacrylamid molecules in a 300 ppm solution is given. A uniform shear field was applied to the fluid using a plate-plate geometry shear device. This device allows a variation of shear stress and shear time in the range of 15-500 N/m2 and 64-516 ms, respectively A correlation between the index of hemolysis (ratio of free plasma hemoglobin to total hemoglobin) and the percentage viscosity decrease (derived from low shear viscosity at a shear rate of 0.01/s) was found. Thus, PAA solutions are suitable model fluids for in vitro estimation of the damaging effects of artificial devices.

Acrylic Resins↗
PubMed1996

Is maternal serum creatine kinase actually a marker for early diagnosis of ectopic pregnancy?

OBJECTIVE: Our purpose was to investigate whether serum creatine kinase (CK) levels could be used as an early marker of ectopic pregnancy. Student's t-test was used for statistical analysis. STUDY DESIGN: In a prospective study we therefore measured serum progesterone, beta hCG and CK levels in 30 women with ectopic pregnancies, 30 women with ongoing pregnancies and 30 women with missed abortion. RESULTS: The mean serum CK concentration for patients with an ectopic pregnancy, ongoing pregnancy, and the women with missed abortion was 81.4 +/- 66.2, 81.5 +/- 40.3, 84.8 +/- 49.3, respectively. No relationship was found between CK level and the location of the pregnancy. CONCLUSION: Conversely to the first report of Lavie et al. (Am J Obstet Gynecol 1993; 169: 1149), our data suggest that serum CK level is not discriminative in the early diagnosis of tubal pregnancy.

Abortion, Missed↗
PubMed1996

[Distal tubal surgery: a critical review of 104 laparoscopic distal tuboplasties].

MATERIALS AND METHODS: Between January 1988 and June 1993, laparoscopic distal tuboplasty was carried out on 104 patients. The mean age of the patients was 32 years: the duration of infertility was 3.2 years; infertility was primary for 44 patients (42.3%) and secondary for 60 patients (57.7%). The patients were classified according to the French cooperative tubal scoring system: stage 1: 21 patients, stage II: 49 patients, stage III: 22 patients, stage IV: 12 patients; 37 patients underwent a fimbrioplasty (35%) whereas 67 patients underwent a neosalpingostomy (65%). No complications were observed either during or after the operation. All patients were discharged two or three days after the operative procedure. Antibiotic and antiinflammatory treatments were systematically administered post-operatively. RESULTS: Thirty-four patients obtained intrauterine pregnancies (32.5%) and 5 patients obtained ectopic pregnancies (4.8%); 76% of the intrauterine pregnancies were obtained within the 1st postoperative year. The pregnancy outcome was directly correlated to the tubal scoring system. Intrauterine pregnancy rate decreased with the severity of the tubal damage: stage 1: 12/21 (57%), stage II: 19/49 (38.7%), stage III: 3/22 (13.6%), stage IV: 0/12. CONCLUSION: Laparoscopic surgery represents the first-choice treatment of distal tubal occlusion in stage I and II. In stage IV, IVF should be suggested immediately. In stage III, the choice of treatment is more difficult: the main prognostic factor might be the tubal mucosal appearance.

Adult↗
PubMedDate not supplied

MR imaging: breast cancer staging and screening.

This review describes the current knowledge and challenges of breast cancer staging and screening with MRI of the breast. Assessment of local disease extent, including tumor size, multicentricity, and chest wall invasion, can be obtained more accurately with MRI than with mammography. Moreover, international experts have established standardized reporting of MRI staging results, taking into account tumor size measurements and the number of breast quadrants involved. Results from MRI assessment of the axilla and skin are promising, but need further refinement. Preliminary results of the use of breast MRI in patients at high risk for breast cancer demonstrated a superiority of breast MRI over the combined use of mammography and high-frequency ultrasound. The role of MRI in this subset of patients may be confirmed by ongoing larger multicenter trials. Strict protocol conditions are mandatory to maintain a high standard of quality. Confirming the nature of "MRI-only" lesions with MRI-guided biopsy systems will allow changes in treatment planning. More accurate tumor diagnosis and tumor volume evaluation may allow minimally invasive treatment strategies.

Breast Neoplasms↗
PubMedDate not supplied

The superposition of steady on oscillatory shear and its effect on the viscoelasticity of human blood and a blood-like model fluid.

To understand the pulsatility of human blood flow in vivo, it is necessary to separately investigate (1) steady shear and oscillatory flow, and (2) the superposition of steady shear flow on oscillatory flow performed under in vitro conditions. In this study a variable steady shear rate was superimposed in parallel on oscillatory shear at a constant frequency (0.5 Hz) for human blood (45% hematocrit), and an aqueous polyacrylamide polymer solution (AP 30E, concentration 300 ppm). The effect of superposition of the above two shear flows on the viscoelasticity of blood was more pronounced for the elastic (eta") than for the viscous (eta') component of viscoelasticity. With increasing superimposed shear rate, both eta' and eta" decreased, especially at the low shear region. This behavior can be explained by the viscoelastic properties of blood and the phenomenon of blood aggregation and disaggregation. Quantitatively, the dependence of the viscous component of complex viscosity on superimposed shear for both blood and polymer solution is described by a modified Carreau equation. The elastic component of complex viscosity decreased exponentially with increasing superimposed shear, and it is described by an exponential model.

Blood Viscosity↗