Kyung Sik Lee

P-glycoprotein: The intermediate end point of drug response to induction chemotherapy in locally advanced breast cancer

Expression and clinical relevance of p-glycoprotein (p-gp) were evaluated in 31 cases of locally advanced breast cancer and 9 cases involving inflammatory breast cancer after induction chemotherapy. The de novo p-gp expression rate was 26% and increased up to 58% (p = 0.03) with the FAC (5-fluorouracil, adriamycin, cyclophosphamide) regimen. Although more clinically complete responders were found in the secondary p-gp negative group (p = 0.02), this difference was not found in pathological tumor response. Moreover, as the grade of the secondary p-gp expression increased, the chemotherapeutic effect decreased, suggesting an inverse relationship between p-gp expression and drug effect (p = 0.04). When we subgrouped the patients into 4 groups using these two parameters, p-gp negative patients presenting with a high drug effect showed a low recurrence rate (p = 0.05) and marginal survival benefits (p = 0.09) as opposed to patients with a low drug effect. But in p-gp positive groups, the recurrence rate was the same between the two groups regardless of the drug effect. Thus, in the p-gp negative patient with a high drug effect, adjuvant chemotherapy with the same regimen as induction chemotherapy may induce more prognostically favorable results. Therefore, clinical application of the secondary p-gp detection can be used as an intermediate endpoint in evaluating drug response for an induction regimen.

Regression of uveal melanoma after ru-106 brachytherapy and thermotherapy based on metabolic activity measured by positron emission tomography/computed tomography.

Purpose: To evaluate regression rates of uveal melanoma after combined Ru-106 plaque radiotherapy and thermotherapy according to metabolic activity measured by positron emission tomography/computed tomography imaging. Methods: A retrospective medical chart review was conducted on 26 patients with uveal melanoma who underwent pretreatment whole-body positron emission tomography/computed tomography and received combined plaque radiotherapy and thermotherapy between 2006 and 2011. Tumors were classified as metabolically active and inactive based on the positron emission tomography/computed tomography imaging and compared with tumor height regression rates after treatment. Results: Before treatment, the median tumor thickness was 8.8 mm for metabolically active tumors (7 eyes) and 5.0 mm for metabolically inactive tumors (19 eyes). The median tumor thicknesses with respect to the original thickness at 3, 6, and 12 months after treatment were 88%, 78%, and 64% for metabolically active tumors and 95%, 89%, and 81% for metabolically inactive tumors, respectively. The monthly tumor regression rates during the first 3 months (4.2% vs. 1.7%, P = 0.022) and the overall monthly tumor regression rates (3.0% vs. 1.5%, P = 0.041) were significantly higher for metabolically active tumors versus inactive tumors. Two patients with positive metabolic activity developed metastatic diseases 2 years after treatment, whereas no patient with negative metabolic activity developed metastatic disease during the study period. Conclusion: Positive metabolic activity of uveal melanoma based on the positron emission tomography/computed tomography was significantly associated with rapid initial tumor regression after combined plaque radiotherapy and thermotherapy, suggesting a prognostic value for this diagnostic approach.

Risk of Retinal Vein Occlusion in Patients With End-Stage Renal Disease: A 12-Year, Retrospective, Nationwide Cohort Study in South Korea

Purpose The present study aimed to evaluate the risk of retinal vein occlusion (RVO) in Korean patients with end-stage renal disease (ESRD). Methods In this retrospective, nationwide, propensity score-matched cohort study, subjects were randomly enrolled from the 12-year longitudinal Korean National Health Insurance Service-National Sample Cohort 2002-2013 database comprising 1 million subjects. The ESRD group comprised 988 patients newly diagnosed with ESRD from 2003 onward by washing out data from 2002. The comparison group comprised 4940 (5 for each patient with ESRD) randomly selected propensity score-matched individuals not diagnosed with ESRD. Each sampled patient was tracked until 2013 for RVO development. Multiple conditional Cox regression analysis was performed to compare the risk of RVO between the two groups. Results The mean follow-up period was 7.37 years. The incidence of RVO was 3.95% in the ESRD group and 2.17% in the comparison group (P = 0.001). ESRD was associated with greater risk of RVO development after adjustment for possible confounders (adjusted hazard ratio [HR], 2.122; 95% confidence interval [CI], 1.396-3.226; P = 0.0004). The 50- to 60-year (adjusted HR, 2.635; 95% CI, 1.100-6.313; P = 0.0297) and 60- to 70-year (adjusted HR, 2.544; 95% CI, 1.059-6.110; P = 0.0368) age groups exhibited higher risk of RVO compared with the <40-year age group. Hyperlipidemia (adjusted HR, 1.670; 95% CI, 1.176-2.371; P = 0.0042) and hypertension (adjusted HR, 1.896; 95% CI, 1.165-3.086; P = 0.01) were also associated with RVO. Conclusions An association between ESRD and subsequent RVO development was found after adjustment for possible confounding factors.