Y.S. Seo

Stereotactic Body Radiation Therapy in Patients with Pelvic Recurrence from Rectal Carcinoma

OBJECTIVE To investigate the clinical applications of stereotactic body radiation therapy (SBRT) using the CyberKnife system for pelvic recurrence from rectal cancer with a focus on survival and toxicity. METHODS Between 2002 and 2006, 23 patients with recurrent rectal cancer were treated with SBRT at our institution. The median follow-up was 31 months. Sites of recurrence were pre-sacral in seven patients and the pelvic wall in 16. SBRT doses ranged from 30 to 51 Gy (median 39 Gy) and were delivered in three fractions. Response to treatment was assessed by computed tomography. Overall and local progression-free survival and toxicities were recorded. RESULTS Four-year overall survival and local control rates were 24.9 and 74.3%, respectively. No prognostic factor was found to affect patient survival or local progression. One patient developed a severe radiation-related toxicity, but recovered completely after treatment. CONCLUSIONS SBRT for pelvic recurrence was found to be comparable with other modalities with respect to overall survival and complication rates. Further studies are needed to confirm these preliminary results.

Stereotactic body radiation therapy boost in locally advanced pancreatic cancer.

PURPOSE To investigate the clinical application of a stereotactic body radiation therapy (SBRT) boost in locally advanced pancreatic cancer patients with a focus on local efficacy and toxicity. METHODS AND MATERIALS We retrospectively reviewed 30 patients with locally advanced and nonmetastatic pancreatic cancer who had been treated between 2004 and 2006. Follow-up duration ranged from 4 to 41 months (median, 14.5 months). A total dose of 40 Gy was delivered in 20 fractions using a conventional three-field technique, and then a single fraction of 14, 15, 16, or 17 Gy SBRT was administered as a boost without a break. Twenty-one patients received chemotherapy. Overall and local progression-free survival were calculated and prognostic factors were evaluated. RESULTS One-year overall survival and local progression-free survival rates were 60.0% and 70.2%, respectively. One patient (3%) developed Grade 4 toxicity. Carbohydrate antigen 19-9 response was found to be an independent prognostic factor for survival. CONCLUSIONS Our findings indicate that a SBRT boost provides a safe means of increasing radiation dose. Based on the results of this study, we recommend that a well controlled Phase II study be conducted on locally advanced pancreatic cancer.

Robotic system-based fractionated stereotactic radiotherapy in locally recurrent nasopharyngeal carcinoma

PURPOSE We reviewed survival, local control, and toxicity in patients with locally recurrent nasopharyngeal carcinoma (NPC) who had been treated with fractionated stereotactic radiotherapy (FSRT). MATERIALS AND METHODS Between June 2002 and March 2008, we retrospectively reviewed 35 patients with locally recurrent NPC treated using FSRT with CyberKnife. Gross tumor volumes ranged from 2.6 to 64.0 ml (median, 7.9 ml). Radiation doses were prescribed at the isodose line (75-84% of the maximum dose; median, 80%). The prescribed dose of FSRT ranged from 24 to 45 Gy (median, 33 Gy) in three or five fractions. RESULTS The overall survival (OS) rate, local failure-free survival (LFFS) rate, and disease progression-free survival (DPFS) rate at 5 years were 60%, 79%, and 74%, respectively. Twenty-three patients achieved complete response after FSRT. Only T stage at recurrence was an independent prognostic factor for OS and DPFS. Five patients exhibited severe late toxicity (Grade 4 or 5). CONCLUSIONS With regard to OS and LFFS, our study provided favorable outcomes. The incidence of severe late toxicities was acceptable in our study. FSRT would be considered as the alternative treatment of choice in re-irradiation for locally recurrent NPC.

Nomogram Prediction of Overall Survival After Curative Irradiation for Uterine Cervical Cancer

PURPOSE The purpose of this study was to develop a nomogram capable of predicting the probability of 5-year survival after radical radiotherapy (RT) without chemotherapy for uterine cervical cancer. METHODS AND MATERIALS We retrospectively analyzed 549 patients that underwent radical RT for uterine cervical cancer between March 1994 and April 2002 at our institution. Multivariate analysis using Cox proportional hazards regression was performed and this Cox model was used as the basis for the devised nomogram. The model was internally validated for discrimination and calibration by bootstrap resampling. RESULTS By multivariate regression analysis, the model showed that age, hemoglobin level before RT, Fédération Internationale de Gynécologie Obstétrique (FIGO) stage, maximal tumor diameter, lymph node status, and RT dose at Point A significantly predicted overall survival. The survival prediction model demonstrated good calibration and discrimination. The bootstrap-corrected concordance index was 0.67. The predictive ability of the nomogram proved to be superior to FIGO stage (p=0.01). CONCLUSIONS The devised nomogram offers a significantly better level of discrimination than the FIGO staging system. In particular, it improves predictions of survival probability and could be useful for counseling patients, choosing treatment modalities and schedules, and designing clinical trials. However, before this nomogram is used clinically, it should be externally validated.

Salvage stereotactic body radiotherapy for locally recurrent uterine cervix cancer at the pelvic sidewall: Feasibility and complication.

To determine the feasibility of stereotactic body radiotherapy (SBRT) in patients with pelvic sidewall recurrence of uterine cervical cancer after radical hysterectomy or definitive radiotherapy.

Long term follow-up results of external beam radiotherapy as primary treatment for retinoblastoma.

The authors reviewed their experiences of external beam radiotherapy (EBR) as an initial treatment in retinoblastoma patients to determine its long-term effect on subsequent tumor control and complications. A total of 32 eyes in 25 patients that underwent EBR for retinoblastoma were reviewed retrospectively. The patients consisted of 21 boys and 4 girls of median age at treatment of 7.1 months. Radiation doses ranged from 35 to 59.4 Gy. The 10-yr ocular and patient survivals were 75.4% and 92.3%, respectively. Nine of the 32 eyes progressed; 7 of these were enucleated and 2 were salvaged by focal treatment. According to the Reese-Ellsworth classification, 4 of 5 eyes of Group II, 13 of 16 Group III eyes, 2 of 4 Group IV eyes, and 5 of 7 Group V eyes were retained, and of the 32 eyes, 13 had visual acuity better than 20/200. Eleven patients experienced a radiation-induced complication. No patient developed a second malignancy during follow-up. Despite the limited number of patients enrolled, EBR may provide a mean of preserving eyeball and vision for some advanced lesions.

Association of Metformin Use With Cancer-Specific Mortality in Hepatocellular Carcinoma After Curative Resection: A Nationwide Population-Based Study.

AbstractMany preclinical reports and retrospective population studies have shown an anticancer effect of metformin in patients with several types of cancer and comorbid type 2 diabetes mellitus (T2DM). In this work, the anticancer effect of metformin was assessed in hepatocellular carcinoma (HCC) patients with T2DM who underwent curative resection.A population-based retrospective cohort design was used. Data were obtained from the National Health Insurance Service and Korea Center Cancer Registry in the Republic of Korea, identifying 5494 patients with newly diagnosed HCC who underwent curative resection between 2005 and 2011. Crude and adjusted hazard ratios (HRs) were calculated using Cox proportional hazard models to estimate effects. In the sensitivity analysis, we excluded patients who started metformin or other oral hypoglycemic agents (OHAs) after HCC diagnosis to control for immortal time bias.From the patient cohort, 751 diabetic patients who were prescribed an OHA were analyzed for HCC-specific mortality and retreatment upon recurrence, comparing 533 patients treated with metformin to 218 patients treated without metformin. In the fully adjusted analyses, metformin users showed a significantly lower risk of HCC-specific mortality (HR 0.38, 95% confidence interval [CI] 0.30–0.49) and retreatment events (HR 0.41, 95% CI 0.33–0.52) compared with metformin nonusers. Risks for HCC-specific mortality were consistently lower among metformin-using groups, excluding patients who started metformin or OHAs after diagnosis.In this large population-based cohort of patients with comorbid HCC and T2DM, treated with curative hepatic resection, metformin use was associated with improvement of HCC-specific mortality and reduced occurrence of retreatment events.

Stereotactic Body Radiotherapy for Oligometastases Confined to the Para-Aortic Region: Clinical Outcomes and the Significance of Radiotherapy Field and Dose

We retrospectively reviewed 88 patients with oligometases in the para-aortic region from any controlled primary tumor site who were treated with stereotactic body radiotherapy (SBRT). The 5-year local control, disease-free survival, and overall survival rates were 83%, 31%, and 41%, respectively. A 90% tumor-control probability was predicted at a biological effective dose of 90 Gy. Severe gastrointestinal toxicities (grade ≥3) were observed in 2 of 88 patients (1%). The results of this study are limited by the retrospective nature of the study but could serve as the background and rationale for future prospective trials on SBRT-based treatment for oligometastses.

Radiofrequency ablation versus stereotactic body radiotherapy for small hepatocellular carcinoma: a Markov model‐based analysis

The aim of this study is to compare radiofrequency ablation (RFA) with stereotactic body radiotherapy (SBRT) for hepatocellular carcinomas (HCC) smaller than 3 cm. A Markov cohort model was developed to simulate a cohort of patients aged 60–65 years with small HCCs who had undergone either RFA or SBRT and were followed up over their remaining life expectancy. The inclusion criteria were: (1) HCC ≤3 cm in diameter with ≤ 3 nodules; (2) absence of extrahepatic metastasis or portal/hepatic vein invasion; (3) Child‐Pugh Class A or B. Twenty thousand virtual patients were randomly assigned to undergo RFA or SBRT. Predicted life expectancy was 6.452 and 6.371 years in the RFA and SBRT groups, respectively. The probability distributions of the expected overall survival were nearly identical. The 95% confidence intervals were 6.25–6.66 and 6.17–6.58 years for RFA and SBRT, respectively. The difference between RFA and SBRT was insignificant (P = 0.2884). Two‐way sensitivity analysis demonstrated that if the tumor is 2–3 cm, SBRT is the preferred treatment option. Our Markov model has shown that expected overall survival of SBRT is nearly identical to RFA in HCCs smaller than 3 cm, but SBRT may have an advantage for tumors 2 cm and larger. A randomized trial is required to confirm these findings.

The Clinical Utilization of Radiation Therapy in Korea between 2011 and 2015

Purpose The purpose of this study was to estimate the clinical utilization of radiation therapy (RT) in Korea between 2011 and 2015. Materials and Methods We analyzed the claims data from the Health Insurance Review and Assessment Service to estimate the clinical utilization of RT. The source population consisted of all patients who had any of the International Classification of Diseases 10th revision cancer diagnoses (C00-C97) and those with diagnostic codes D00-D48, who were also associated with at least one of the procedure codes related to RT. Results The total number of patients who received RT in 2011, 2012, 2013, 2014, and 2015 were 54,810, 59,435, 61,839, 64,062, and 66,183, respectively. Among them, the total numbers of male and female patients were 24,946/29,864 in 2011, 27,211/32,224 in 2012, 28,111/33,728 in 2013, 29,312/34,750 in 2014, and 30,266/35,917 in 2015. The utilization rate of RT in cancer patients has also increased steadily over the same period from 25% to 30%. The five cancers that were most frequently treated with RT between 2011 and 2012 were breast, lung, colorectal, liver, and uterine cervical cancers. However, the fifth most common cancer treated with RT that replaced uterine cervical cancer in 2013 was prostate cancer. More than half of cancer patients (64%) were treated with RT in the capital area (Seoul, Gyeonggi, and Incheon). Conclusion The total number of patients who underwent RT increased steadily from 2011 to 2015 in Korea. The utilization rate of RT in cancer patients is also increasing.