Hyung Sik Lee

A multicenter retrospective cohort study of practice patterns and clinical outcome on radiotherapy for hepatocellular carcinoma in Korea

Aim: To determine the national practice processes of care and outcomes of radiotherapy for hepatocellular carcinoma (HCC) in Korea.

Combination of external beam irradiation and high-dose-rate intraluminal brachytherapy for inoperable carcinoma of the extrahepatic bile ducts

PURPOSEnTo assess the feasibility and therapeutic benefits of a combination of external beam radiotherapy (EBRT) and high-dose-rate intraluminal brachytherapy (ILBT) for treating patients with inoperable carcinoma of the extrahepatic bile ducts.nnnMETHODS AND MATERIALSnOf 31 patients who received RT at the Yonsei Cancer Center, Yonsei University College of Medicine in Seoul, Korea between 1986 and 1995, 17 patients underwent EBRT alone (Group 1) and 14 patients were treated with EBRT in combination with high-dose-rate ILBT (Group 2). After external drainage, EBRT was delivered with a total dose ranging from 36 to 55 Gy (median 50.4) in both groups. High-dose-rate ILBT for the patients in Group 2 was performed using a high-intensity (192)Ir source (Gamma-med remote afterloading system) within the expandable intrabiliary prosthesis (Gianturco stent), inserted transhepatically at the site of the obstruction. The radiation dose of the high-dose-rate ILBT was prescribed at 1.5 cm from the center of the source with a single daily dose of 5 Gy to a total of 15 Gy given in three fractions. The response rate, patterns of treatment failure, treatment morbidity, and survival data in the two groups were compared.nnnRESULTSnAlthough locoregional recurrence was the most common pattern of failure in both groups, no statistically significant difference was found in the recurrence rates between those who did and did not receive ILBT (53% for Group 1 vs. 36% for Group 2; p > 0.05). However, a prolongation of the median time to tumor recurrence was observed in the Group 2 patients (5 months for Group 1 vs. 9 months for Group 2; p = 0.06). When the EBRT dose delivered was >50 Gy, most patients experienced various degrees of GI symptoms, but the frequency of radiation-induced complications in the two groups was similar. No enhancement in treatment morbidity was attributed to the addition of high-dose-rate ILBT to EBRT. With a median follow-up of 12 months, the overall actuarial 2-year survival rate for Group 2 patients was significantly better than that for Group 1 patients (0% for Group 1 vs. 21% for Group 2; p = 0.015).nnnCONCLUSIONnGiven these observations, we believe that the combined use of EBRT and high-dose-rate ILBT is a beneficial, relatively safe, and effective method of improving the treatment outcome in selected patients with inoperable carcinoma of the extrahepatic bile ducts.

The role of postmastectomy radiation therapy after neoadjuvant chemotherapy in clinical stage II-III breast cancer patients with pN0: A multicenter, retrospective study (KROG 12-05)

PURPOSEnThe purpose of this study was to investigate the role of postmastectomy radiation therapy (PMRT) after neoadjuvant chemotherapy (NAC) in clinical stage II-III breast cancer patients with pN0.nnnMETHODS AND MATERIALSnWe retrospectively identified 417 clinical stage II-III breast cancer patients who achieved an ypN0 at surgery after receiving NAC between 1998 and 2009. Of these, 151 patients underwent mastectomy after NAC. The effect of PMRT on disease-free survival (DFS), locoregional recurrence-free survival (LRRFS), and overall survival (OS) was evaluated by multivariate analysis including known prognostic factors using the Kaplan-Meier method and compared using the log-rank test and Cox proportional regression analysis.nnnRESULTSnOf the 151 patients who underwent mastectomy, 105 (69.5%) received PMRT and 46 patients (30.5%) did not. At a median follow-up of 59 months, 5 patients (3.3%) developed LRR (8 sites of recurrence) and 14 patients (9.3%) developed distant metastasis. The 5-year DFS, LRRFS, and OS rates were 91.2, 98.1, and 93.3% with PMRT and 83.0%, 92.3%, and 89.9% without PMRT, respectively (all P values not significant). By univariate analysis, only age (≤40 vs >40 years) was significantly associated with decreased DFS (P=.027). By multivariate analysis, age (≤40 vs >40 years) and pathologic T stage (0-is vs 1 vs 2-4) were significant prognostic factors affecting DFS (hazard ratio [HR] 0.353, 95% confidence interval [CI] 0.135-0.928, P=.035; HR 2.223, 95% CI 1.074-4.604, P=.031, respectively). PMRT showed no correlation with a difference in DFS, LRRFS, or OS by multivariate analysis.nnnCONCLUSIONSnPMRT might not be necessary for pN0 patients after NAC, regardless of clinical stage. Prospective randomized clinical trial data are needed to assess whether PMRT can be safely omitted in pN0 patients after NAC and mastectomy for clinical stage II-III breast cancer.

Influence of Environmental pH on G2-Phase Arrest Caused by Ionizing Radiation

Abstract Park, H. J., Lee, S. H., Chung, H., Rhee, Y. H., Lim, B. U., Ha, S. W., Griffin, R. J., Lee, H. S., Song, C. W. and Choi, E.;thK. Influence of Environmental pH on G2-Phase Arrest Caused by Ionizing Radiation. Radiat. Res. 159, 86–93 (2003). We investigated the effects of an acidic environment on the G2/M-phase arrest, apoptosis, clonogenic death, and changes in cyclin B1-CDC2 kinase activity caused by a 4-Gy irradiation in RKO.C human colorectal cancer cells in vitro. The time to reach peak G2/M-phase arrest after irradiation was delayed in pH 6.6 medium compared to that in pH 7.5 medium. Furthermore, the radiation-induced G2/M-phase arrest decayed more slowly in pH 6.6 medium than in pH 7.5 medium. Finally, there was less radiation-induced apoptosis and clonogenic cell death in pH 6.6 medium than in pH 7.5 medium. It appeared that the prolongation of G2-phase arrest after irradiation in the acidic environment allowed for greater repair of radiation-induced DNA damage, thereby decreasing the radiation-induced cell death. The prolongation of G2-phase arrest after irradiation in the acidic pH environment appeared to be related at least in part to a prolongation of the phosphorylation of CDC2, which inhibited cyclin B1-CDC2 kinase activity.

Effect of omental pedicle hammock in protection against radiation-induced enteropathy in patients with rectal cancer

PURPOSE: The aim of this nonrandomized study was to assess effects against radiation-induced enteropathy by constructing an omental pedicle hammock, thus isolating the small bowel outside the pelvis. METHODS: Since 1991, 32 patients received the omental pedicle hammock procedure as an adjunct to definitive cancer surgery, and the perioperative experiences and toxic effects of radiation therapy were evaluated and compared with 25 patients who received pelvic floor reperitonealization only. RESULTS: There were no surgical complications related to the omental hammock procedure. Contrary to control cases that showed the bowel to adhere deeply in the pelvis, exclusion of the small bowel from the pelvic cavity demonstrated by contrast study was successful in all except four cases of a segment of bowel loop descent within the radiation portals. According to acute and late radiation morbidity scoring criteria, 26 patients (81 percent) scored Grade 0 in the treatment group, whereas only 3 patients (12 percent) scored Grade 0 in the control group (P<0.01) in the acute phase, and 28 patients (88 percent) of Grade 0 in the former group and 15 (60 percent) in the latter (P<0.025) in late phase. There has been no case of radiation-induced enteropathy requiring surgical treatment. CONCLUSION: The technique of bowel exclusion by pedicle omental hammock would make it possible to use higher doses of postoperative pelvic radiation therapy without fear of complications from radiation-induced enteropathy.

Efficacy of hepatic arterial infusion chemotherapy in advanced hepatocellular carcinoma

AIMnTo investigate the efficacy of hepatic arterial infusion chemotherapy (HAIC) using floxuridine (FUDR) in patients with advanced hepatocellular carcinoma (HCC) confined to the liver.nnnMETHODSnThirty-four patients who had advanced HCC with unresectability or unsuccessful previous therapy in the absence of extrahepatic metastasis were treated with intra-arterial FUDR chemotherapy at our hospital between March 2005 and May 2008. Among the 34 patients, 9 patients were classified as Child class C, and 18 patients had portal vein tumor thrombus (PVTT). One course of chemotherapy consisted of continuous infusion of FUDR (0.3 mg/kg during day 1-14) and dexamethasone (10 mg on day 1, 4, 7 and 11), and this treatment was repeated every 28 d.nnnRESULTSnTwo patients (5.9%) displayed a complete response, and 12 patients (35.3%) had a partial response. The tumor control rate was 61.8%. The median overall survival times were 15.3 mo, 12.4 mo and 4.3 mo for the patients who were classified as Child class A, Child class B and Child class C, respectively (P = 0.0392). The progression-free survival was 12.9 mo, 7.7 mo and 2.6 mo for the patients who were classified as Child class A, Child class B and Child class C, respectively (P = 0.0443). The cumulative survival differed significantly according to the Child-Pugh classification and the presence of PVTT. In addition to hepatic reserve capacity and PVTT, the extent of HCC was an independent factor in determining a poor prognosis. The most common adverse reactions to HAIC were mucositis, diarrhea and peptic ulcer disease, but most of these complications were improved by medical treatment and/or a delay of HAIC.nnnCONCLUSIONnThe present study demonstrates that intra-arterial FUDR chemotherapy is a safe and effective treatment for advanced HCC that is recalcitrant to other therapeutic modalities, even in patients with advanced cirrhosis.

Is elective nodal irradiation beneficial in patients with pathologically negative lymph nodes after neoadjuvant chemotherapy and breast-conserving surgery for clinical stage II–III breast cancer? A multicentre retrospective study (KROG 12-05)

Background:To evaluate the effects of elective nodal irradiation (ENI) in clinical stage II–III breast cancer patients with pathologically negative lymph nodes (LNs) (ypN0) after neoadjuvant chemotherapy (NAC) followed by breast-conserving surgery (BCS) and radiotherapy (RT).Methods:We retrospectively analysed 260 patients with ypN0 who received NAC followed by BCS and RT. Elective nodal irradiation was delivered to 136 (52.3%) patients. The effects of ENI on survival outcomes were evaluated.Results:After a median follow-up period of 66.2 months (range, 15.6–127.4 months), 26 patients (10.0%) developed disease recurrence. The 5-year locoregional recurrence-free survival and disease-free survival (DFS) for all patients were 95.5% and 90.5%, respectively. Pathologic T classification (0−is vs 1 vs 2–4) and the number of LNs sampled (<13 vs ⩾13) were associated with DFS (P=0.0086 and 0.0012, respectively). There was no significant difference in survival outcomes according to ENI. Elective nodal irradiation also did not affect survival outcomes in any of the subgroups according to pathologic T classification or the number of LNs sampled.Conclusions:ENI may be omitted in patients with ypN0 breast cancer after NAC and BCS. But until the results of the randomised trials are available, patients should be put on these trials.

Enhancement of radiation effect using beta-lapachone and underlying mechanism

Beta-lapachone (β-Lap; 3,4-dihydro-2, 2-dimethyl-2H-naphthol[1, 2-b]pyran-5,6-dione) is a novel anti-cancer drug under phase I/II clinical trials. β-Lap has been demonstrated to cause apoptotic and necrotic death in a variety of human cancer cells in vitro and in vivo. The mechanisms underlying the β-Lap toxicity against cancer cells has been controversial. The most recent view is that β-Lap, which is a quinone compound, undergoes two-electron reduction to hydroquinone form utilizing NAD(P)H or NADH as electron source. This two-electron reduction of β-Lap is mediated by NAD(P)H:quinone oxidoreductase (NQO1), which is known to mediate the reduction of many quinone compounds. The hydroquinone forms of β-Lap then spontaneously oxidizes back to the original oxidized β-Lap, creating futile cycling between the oxidized and reduced forms of β-Lap. It is proposed that the futile recycling between oxidized and reduced forms of β-Lap leads to two distinct cell death pathways. First one is that the two-electron reduced β-Lap is converted first to one-electron reduced β-Lap, i.e., semiquinone β-Lap (SQ)·- causing production of reactive oxygen species (ROS), which then causes apoptotic cell death. The second mechanism is that severe depletion of NAD(P)H and NADH as a result of futile cycling between the quinone and hydroquinone forms of β-Lap causes severe disturbance in cellular metabolism leading to apoptosis and necrosis. The relative importance of the aforementioned two mechanisms, i.e., generation of ROS or depletion of NAD(P)H/NADH, may vary depending on cell type and environment. Importantly, the NQO1 level in cancer cells has been found to be higher than that in normal cells indicating that β-Lap may be preferentially toxic to cancer cells relative to non-cancer cells. The cellular level of NQO1 has been found to be significantly increased by divergent physical and chemical stresses including ionizing radiation. Recent reports clearly demonstrated that β-Lap and ionizing radiation kill cancer cells in a synergistic manner. Indications are that irradiation of cancer cells causes long-lasting elevation of NQO1, thereby sensitizing the cells to β-Lap. In addition, β-Lap has been shown to inhibit the repair of sublethal radiation damage. Treating experimental tumors growing in the legs of mice with irradiation and intraperitoneal injection of β-Lap suppressed the growth of the tumors in a manner more than additive. Collectively, β-Lap is a potentially useful anti-cancer drug, particularly in combination with radiotherapy.

Dummy run of quality assurance program in a phase 3 randomized trial investigating the role of internal mammary lymph node irradiation in breast cancer patients: Korean Radiation Oncology Group 08-06 study

PURPOSEnThe Korean Radiation Oncology Group (KROG) 08-06 study protocol allowed radiation therapy (RT) technique to include or exclude breast cancer patients from receiving radiation therapy to the internal mammary lymph node (IMN). The purpose of this study was to assess dosimetric differences between the 2 groups and potential influence on clinical outcome by a dummy run procedure.nnnMETHODS AND MATERIALSnAll participating institutions were asked to produce RT plans without irradiation (Arm 1) and with irradiation to the IMN (Arm 2) for 1 breast-conservation treatment case (breast-conserving surgery [BCS]) and 1 mastectomy case (modified radical mastectomy [MRM]) whose computed tomography images were provided. We assessed interinstitutional variations in IMN delineation and evaluated the dose-volume histograms of the IMN and normal organs. A reference IMN was delineated by an expert panel group based on the study guidelines. Also, we analyzed the potential influence of actual dose variation observed in this study on patient survival.nnnRESULTSnAlthough physicians intended to exclude the IMN within the RT field, the data showed almost 59.0% of the prescribed dose was delivered to the IMN in Arm 1. However, the mean doses covering the IMN in Arm 1 and Arm 2 were significantly different for both cases (P<.001). Due to the probability of overdose in Arm 1, the estimated gain in 7-year disease-free survival rate would be reduced from 10% to 7.9% for BCS cases and 7.1% for MRM cases. The radiation doses to the ipsilateral lung, heart, and coronary artery were lower in Arm 1 than in Arm 2.nnnCONCLUSIONSnAlthough this dummy run study indicated that a substantial dose was delivered to the IMN, even in the nonirradiation group, the dose differences between the 2 groups were statistically significant. However, this dosimetric profile should be studied further with actual patient samples and be taken into consideration when analyzing clinical outcomes according to IMN irradiation.

Postoperative adjuvant chemoradiotherapy in D2-dissected gastric cancer: Is radiotherapy necessary after D2-dissection?

Studies from the Far East have demonstrated that D2-dissection is superior to D0/1-dissection. The effect of postoperative chemoradiotherapy (CRT) after D2-dissection has not been accepted due to the lack of D2-dissection in Western countries, as well as the potential harmful effect of radiotherapy. In the current NCCN guideline, adjuvant chemotherapy alone is recommended in D2-dissected patients. However, three recent prospective randomized controlled trials in South Korea and China (ARTIST, NCC and Multicenter IMRT Trials) demonstrated that adjuvant CRT can be safely administered to D2-dissected patients with notable benefits. To identify the role of radiotherapy (RT) in the D2-dissected postoperative setting, clinical research attempts should include (1) identification of high-risk patients for loco-regional recurrence who might benefit from CRT; (2) modification of RT target volume based on the findings that failure patterns should be different after D1- and D2-dissection; and (3) integration of new RT techniques to decrease treatment-related toxicity. The present paper is a review of recent studies addressing these fields. Well-designed prospective randomized studies are needed to clearly define the role of adjuvant CRT in D2-dissected gastric cancer, however, future clinical studies should also focus on answering these questions.