Design and evaluation of electron beam energy degraders for breast boost irradiation.

Background: For breast cancer patients who require electron boost energies between 6 and 9 MeV, an energy degraders (ED) in the 9 MeV beamline was specially designed and manufactured to increase the skin dose of 6 MeV and to reduce the penetration depth of 9 MeV beams.

Methods: We used Monte Carlo (MC) techniques as a guide in the design of ED for use with linear accelerators. In order to satisfy percent depth dose (PDD) characteristics and dose profile uniformity in water, the shape and thickness of Lucite® ED in the 9 MeV beamline was iteratively optimized and then manufactured.

Delayed Numerical Chromosome Aberrations in Human Fibroblasts by Low Dose of Radiation.

Radiation-induced genomic instability refers to a type of damage transmitted over many generations following irradiation. This delayed impact of radiation exposure may pose a high risk to human health and increases concern over the dose limit of radiation exposure for both the public and radiation workers. Therefore, the development of additional biomarkers is still needed for the detection of delayed responses following low doses of radiation exposure.

Concurrent Chemoradiotherapy Versus Chemotherapy Alone for Unresectable Locally Advanced Pancreatic Cancer: A Retrospective Cohort Study.

Purpose: The optimal treatment strategy for locally advanced pancreatic cancer (LAPC), particularly the role of concurrent chemoradiotherapy (CCRT), remains debatable. We compared the clinical outcomes of CCRT and palliative chemotherapy alone (CA) in patients with unresectable LAPC.

Materials And Methods: Patients with LAPC who were consecutively treated between 2003 and 2010 were included.

Effect of Time Interval between Breast-Conserving Surgery and Radiation Therapy on Outcomes of Node-Positive Breast Cancer Patients Treated with Adjuvant Doxorubicin/Cyclophosphamide Followed by Taxane.

Purpose: This study evaluated the effect of surgery-radiotherapy interval (SRI) on outcomes in patients treated with adjuvant radiotherapy (RT) after breast-conserving surgery (BCS) and adjuvant four cycles of doxorubicin/cyclophosphamide (AC) followed by four cycles of taxane.

Materials And Methods: From 1999 to 2007, 397 eligible patients were diagnosed. The effect of SRI on outcomes was analyzed using a Cox proportional hazards model, and a maximal chi-square method was used to identify optimal cut-off value of SRI for each outcome.

Outcome analysis in patients with uterine sarcoma.

Purpose: To analyze the prognostic factors for survivals and to evaluate the impact of postoperative whole pelvic radiotherapy (WPRT) on pelvic failure in patients with uterine sarcoma treated with radical surgery.

Materials And Methods: We retrospectively analyzed 75 patients with uterine sarcoma who underwent radical surgery with (n = 22) or without (n = 53) radiotherapy between 1990 and 2010. There were 23 and 52 patients with carcinosarcoma and non-carcinosarcoma (leiomyosarcoma, 22; endometrial stromal sarcoma, 25; others, 5), respectively.

A New Isolated Mediastinal Lymph Node or Small Pulmonary Nodule Arising during Breast Cancer Surveillance Following Curative Surgery: Clinical Factors That Differentiate Malignant from Benign Lesions.

Purpose: A newly isolated mediastinal lymph node (LN) or a small pulmonary nodule, which appears during breast cancer surveillance, may pose a diagnostic dilemma with regard to malignancy. We conducted this study to determine which clinical factors were useful for the differentiation of malignant lesions from benign lesions under these circumstances.

Materials And Methods: We enrolled breast cancer patients who were presented with a new isolated mediastinal LN or small pulmonary nodule that arose during surveillance, and whose lesions were pathologically confirmed.

Influence of boost radiotherapy in patients with ductal carcinoma in situ breast cancer: a multicenter, retrospective study in Korea (KROG 11-04).

To estimate the effect of boost radiotherapy on local recurrence-free survival (LRFS) in patients with ductal carcinoma in situ (DCIS) breast cancer. We included patients from nine institutions who met the following criteria: having Tis, age 18 years or older, having breast conserving surgery (BCS) and radiotherapy within 12 weeks after surgery. From 1995 through 2006, 728 patients were analyzed retrospectively by the Korean Radiation Oncology Group.

The effect of photon energy on intensity-modulated radiation therapy (IMRT) plans for prostate cancer.

Purpose: To evaluate the effect of common three photon energies (6-MV, 10-MV, and 15-MV) on intensity-modulated radiation therapy (IMRT) plans to treat prostate cancer patients.

Materials And Methods: Twenty patients with prostate cancer treated locally to 81.0 Gy were retrospectively studied.

The influence of adjuvant radiotherapy on patterns of failure and survivals in uterine carcinosarcoma.

Purpose: To evaluate the impact of postoperative radiotherapy (PORT) on patterns of failure and survivals in uterine carcinosarcoma patients treated with radical surgery.

Materials And Methods: Between October 1998 and August 2010, 19 patients with stage I-III uterine carcinosarcoma received curative hysterectomy and bilateral salpingo-oophorectomy with or without PORT at Seoul National University Hospital. Their hospital medical records were retrospectively reviewed.

Phase II clinical trial of induction chemotherapy with fixed dose rate gemcitabine and cisplatin followed by concurrent chemoradiotherapy with capecitabine for locally advanced pancreatic cancer.

Purpose: 5-FU-based concurrent chemoradiotherapy (CRT) has been the mainstay of treatment for locally advanced pancreatic cancer (LAPC) for the past decades, but the prognosis remains dismal.

Methods: Patients with pathologically confirmed LAPC of the pancreas, an ECOG PS of 0-2 and no prior chemo- or radiotherapy were eligible. The treatment consisted of induction (IND) chemotherapy with a fixed dose rate gemcitabine 1,000 mg/m(2) on days 1 and 8 and CDDP 60 mg/m(2) on day 1 every 3 weeks for 3 cycles.

Changes in biologic markers of oxidative stress and plasma endotoxin levels in gynecologic cancer patients treated with pelvic radiotherapy: a pilot study.

Objective: We conducted a pilot study to evaluate the effects of pelvic radiotherapy on biologic markers of oxidative stress and plasma endotoxin levels, and to assess the relationship between the changes of such factors and radiotherapy-related complications.

Methods: Twelve gynecologic cancer patients who were treated via pelvic radiotherapy with or without concurrent chemotherapy were enrolled in this study. Biologic markers of oxidative stress, such as glutathione (GSH) and oxidized glutathione (GSSG), as well as endotoxin levels, were measured weekly during treatment.

Definitive radiotherapy for treatment of primary vaginal cancer: effectiveness and prognostic factors.

Objective: This study was performed to evaluate treatment outcomes and define prognostic factors for primary vaginal cancer treated with definitive radiotherapy.

Materials And Methods: We retrospectively analyzed 38 patients with primary vaginal cancer who received radiotherapy with curative intent between January 1981 and August 2008. Of these 38 patients, 6 were excluded from this analysis because of other uncontrolled malignancy (n = 1), uncommon histology (n = 4), or insufficient medical records (n = 1).

Phase II trial of preoperative paclitaxel, gemcitabine, and trastuzumab combination therapy in HER2 positive stage II/III breast cancer: the Korean Cancer Study Group BR 07-01.

An addition of trastuzumab preoperatively to chemotherapy for human epidermal growth factor receptor 2 (HER2) positive breast cancer improved relapse-free survival (RFS). This study was designed to evaluate the efficacy and safety of preoperative paclitaxel, gemcitabine, and trastuzumab (PGH) combination for HER2-positive breast caner. Pathologically, proven node positive stage II/III breast cancer patients with adequate organ function and no history of anti-cancer therapy were eligible.

The dosimetric effect of mixed-energy IMRT plans for prostate cancer.

We investigated the effect of mixing high- and low-energy photon beams on the quality of intensity-modulated radiation therapy (IMRT) plans for patients with prostate cancer. Three different plans for each of twenty patients were generated using either 6 MV or 15 MV alone, and both 6 and 15 MV beams. All the planning parameters, goals, and constraints were set to be identical except beam energy.

Dosimetry of a new P-32 ophthalmic applicator.

Purpose: The potential of P-32 ophthalmic applicator irradiation after pterygium excision has been demonstrated as an alternative to Sr∕Y-90 irradiation. This study aimed to provide the clinical dosimetry for this new applicator.

Methods: The prototype of a cylindrical P-32 applicator was fabricated according to the Monte Carlo (MC)-based design study.

Clinical outcome of central nervous system metastases from breast cancer: differences in survival depending on systemic treatment.

Central nerve system (CNS) metastases are a feared complication of breast cancer and are associated with poor prognosis. The purpose of this study is to investigate the clinical characteristics of CNS metastases and to clarify the prognostic factors after CNS metastases in breast cancer at a single institution over a long time period. We retrospectively reviewed the medical records of breast cancer patients diagnosed at Seoul National University Hospital from 1981 to 2009 and identified the patients who experienced CNS metastases.

Treatment outcomes and prognostic factors of gallbladder cancer patients after postoperative radiation therapy.

Backgrounds/aims: To investigate survival rates and prognostic factors of patients with gallbladder cancer who were treated with surgery and postoperative radiation therapy.

Methods: Seventeen gallbladder cancer patients who received surgery and postoperative radiotherapy from October 1989 to April 1998 were included in this retrospective study. Five patients had stage II, 8 patients had stage III, and 4 patients had stage IV disease according to the 1997 American Joint Committee on Cancer (AJCC) staging.

Diagnostic performance of contrast enhanced CT and 18F-FDG PET/CT in suspicious recurrence of biliary tract cancer after curative resection.

Background: Because of the late clinical presentation of biliary tract cancer (BTC), only 10% of patients are eligible for curative surgery. Even among those patients who have undergone curative surgery, most patients develop recurrent cancer. This study is to determine the clinical role of 18F-FDG PET/CT during post-operative surveillance of suspected recurrent BTC based on symptoms, laboratory findings and contrast-enhanced CT (ceCT) findings.

Statistical analysis of IMRT dosimetry quality assurance measurements for local delivery guideline.

Purpose: To establish our institutional guideline for IMRT delivery, we statistically evaluated the results of dosimetry quality assurance (DQA) measurements and derived local confidence limits using the concept confidence limit of |mean|+1.96σ.

Materials And Methods: From June 2006 to March 2009, 206 patients with head and neck cancer, prostate cancer, liver cancer, or brain tumor were treated using LINAC-based IMRT technique.

Outcomes of positron emission tomography-staged clinical N3 breast cancer treated with neoadjuvant chemotherapy, surgery, and radiotherapy.

Purpose: To evaluate the treatment outcome and efficacy of regional lymph node irradiation after neoadjuvant chemotherapy (NCT) and surgery in positron emission tomography (PET)-positive clinical N3 (cN3) breast cancer patients.

Methods And Materials: A total of 55 patients with ipsilateral infraclavicular (ICL), internal mammary (IMN), or supraclavicular (SCL) lymph node involvement in the absence of distant metastases, as revealed by an initial PET scan, were retrospectively analyzed. The clinical nodal stage at diagnosis (2002 AJCC) was cN3a in 14 patients (26%), cN3b in 12 patients (22%), and cN3c in 29 patients (53%).

The value of preoperative staging chest computed tomography to detect asymptomatic lung and liver metastasis in patients with primary breast carcinoma.

Little is known about the benefits of preoperative staging chest computed tomography (CT) in patients with asymptomatic breast cancer. We therefore investigated the clinical value of preoperative chest CT in detecting lung and liver metastases by retrospectively reviewing the records of 1,703 patients who underwent preoperative chest CT in a single institution between January 2006 and June 2009. Abnormal CT findings, including suspected metastases and indeterminate nodules in the lung or liver, were found in 266 patients (15.

Triple negativity and young age as prognostic factors in lymph node-negative invasive ductal carcinoma of 1 cm or less.

Background: Whether a systemic adjuvant treatment is needed is an area of controversy in patients with node-negative early breast cancer with tumor size of ≤1 cm, including T1mic.

Methods: We performed a retrospective analysis of clinical and pathology data of all consecutive patients with node-negative T1mic, T1a, and T1b invasive ductal carcinoma who received surgery between Jan 2000 and Dec 2006. The recurrence free survival (RFS) and risk factors for recurrence were identified.

Prognostic factors for recurrent breast cancer patients with an isolated, limited number of lung metastases and implications for pulmonary metastasectomy.

Background: The aim of this study was to evaluate the clinical treatment outcomes of recurrent breast cancer with a limited number of isolated lung metastases, and to evaluate the role of pulmonary metastasectomy.

Methods: The authors consecutively enrolled 140 recurrent breast cancer patients with isolated lung metastasis from 1997 to 2007 in Seoul National University Hospital and retrospectively analyzed 45 patients who had <4 metastatic lesions.

Results: Fifteen patients had pulmonary metastasectomy followed by systemic treatment (pulmonary metastasectomy group), and 30 received systemic treatment alone (nonpulmonary metastasectomy group).

The sequencing of chemotherapy and radiotherapy in breast cancer patients after mastectomy.

Background: The purpose of the study was to retrospectively evaluate the outcome according to the sequencing of radiotherapy and chemotherapy after mastectomy in high-risk patients with breast cancer.

Methods: From January 1986 through September 2000, 275 women with stage I-IIIB breast cancer were treated with chemotherapy and radiotherapy after mastectomy. The patients were divided into four groups.