The clinical utilization of radiation therapy in Korea between 2009 and 2013

Trends in medical care utilization in patients with cancer: An analysis of real-world data in a tertiary hospital in Korea, 2014-2019

BACKGROUND

Rising costs of cancer treatments challenge even areas with universal health coverage. There's a need to assess current medical care utilization trends among patients with cancer to guide public health policy, resource allocation, and set informed healthcare goals.

METHODS

We analyzed the latest trends in medical care utilization by cancer patients in four areas-drugs, radiation therapy (RT), surgery, and diagnostic procedures-using clinical databases extracted from electronic medical records of a tertiary hospital in Korea between 2014 and 2019. Compound adjusted growth rates (CAGR) were computed to capture the annual growth over the study period.

RESULTS

A total of 74,285 cancer patients were identified, with 40.3% (29,962), 14.2% (10,577), 31.1% (23,066), and 92.6% (68,849) of patients having received at least one anticancer agent, RT, surgery, and diagnostic procedure, respectively, over the period. We observed a 1.7-fold increase in the use of targeted · immune-oncology agents (from 6.8% to 11.6%) and a 21-fold increase (from 3.0% in 2014 to 65.7%) in intensity-modulated RT (IMRT) use over the period. In contrast, we observed a continuous decrease in the proportion of patients who underwent surgical treatment from 12.2% in 2014 to 10.9% in 2019. This decrease was particularly noticeable in patients with colon cancer (from 28.5% to 24.2%) and liver cancer (from 4.1% to 2.9%).

CONCLUSION

From 2014 to 2019, there was a significant rise in the use of targeted · immune-oncology agents and IMRT, alongside a decline in surgeries. While targeted · immune-oncology agents and IMRT may offer promising outcomes, their financial impact and potential for overuse necessitate careful oversight and long-term cost-effectiveness studies.

Operational Definitions of Colorectal Cancer in the Korean National Health Insurance Database

OBJECTIVES

We reviewed the operational definitions of colorectal cancer (CRC) from studies using the Korean National Health Insurance Service (NHIS) and compared CRC incidence derived from the commonly used operational definitions in the literature with the statistics reported by the Korea Central Cancer Registry (KCCR).

METHODS

We searched the MEDLINE and KoreaMed databases to identify studies containing operational definitions of CRC, published until January 15, 2021. All pertinent data concerning the study period, the utilized database, and the outcome variable were extracted. Within the NHIS-National Sample Cohort, age-standardized incidence rates (ASRs) of CRC were calculated for each operational definition found in the literature between 2005 and 2019. These rates were then compared with ASRs from the KCCR.

RESULTS

From the 62 eligible studies, 9 operational definitions for CRC were identified. The most commonly used operational definition was "C18-C20" (n=20), followed by "C18-C20 with claim code for treatment" (n=3) and "C18-C20 with V193 (code for registered cancer patients' payment deduction)" (n=3). The ASRs reported using these operational definitions were lower than the ASRs from KCCR, except for "C18-C20 used as the main diagnosis." The smallest difference in ASRs was observed for "C18-C20," followed by "C18- C20 with V193," and "C18-C20 with claim code for hospitalization or code for treatment."

CONCLUSIONS

In defining CRC patients utilizing the NHIS database, the ASR derived through the operational definition of "C18-C20 as the main diagnosis" was comparable to the ASR from the KCCR. Depending on the study hypothesis, operational definitions using treatment codes may be utilized.

Clinical utilization of radiation therapy in Korea between 2017 and 2019

PURPOSE

This study aimed to evaluate the clinical infrastructure and utilization of radiotherapy (RT) services in Korea between 2017 and 2019.

MATERIALS AND METHODS

We extracted the data of patients who underwent RT between 2017 and 2019 from the Health Insurance Review and Assessment Service. We further analyzed this data according to the diagnosis and treatment modalities of patients diagnosed with International Classification of Disease 10 (ICD-10) diagnostic codes C00-C97 and D00-D48. In addition, we collected statistics on RT facilities in Korea using a nationwide survey.

RESULTS

The total number of patients who received RT in 2017, 2018, and 2019 were 77,901, 81,849, and 87,460, respectively. The number of patients diagnosed with ICD 10 C- and D-codes in 2019 was 86,339, of whom 39,467 were men and 46,872 women. The rate of utilization of RT among cancer patients was 30.4% in 2017 and 2018 and 30.9% in 2019. In 2019, the most common types of cancers treated with RT were breast, lung, prostate, colorectal, and liver cancers. Regarding the RT infrastructure in Korea, there were 95 radiation oncology centers, 237 megavoltage (MV) teletherapy units, 35 brachytherapy units, and two proton accelerators in 2019. There were 4.5 MV teletherapy machines per million.

CONCLUSION

The number of patients treated with RT has increased consistently from 2017 to 2019. As the number of patients with cancer increases, it is expected that the RT infrastructure will be further expanded in Korea.

Efficacy of an Integrated Mobile Application System for Patients with Radiation Therapy: A Pilot Study

The use of IT applications for patients undergoing radiotherapy is limited. This study aimed to develop an integrated system for communication between patients and radiation oncologists using IT technology and report the first test results for the system “Assisted Radiation Oncology Mobile Application” (AROMA). This system consisted of a manager program, a server running on a PC, and a mobile application on a smartphone. A prospective survey was conducted to evaluate the usefulness of this system from October 2020 to January 2021. The survey consisted of a specific questionnaire on basic information and application use by the patients. The management program was designed such that the user (doctor) edits the treatment schedule, member (patient and doctor) information, self-management, disease information, and side effect questionnaire. The mobile application for patients consisted of the current schedule, treatment schedule calendar, side effect questionnaire, side effect management method, and disease information entered by the doctor. A total of 41 patients were enrolled in this study. The mean adverse event response time was 4.4 days. In the survey, the mobile application received positive views (8.6/10 points). Most responses related to the side effect reporting function (94%) and communication using the application (91%) were positive. Satisfaction with the application design and each menu item was high, with an average of ≥8 and ≥8.5 points in most cases, respectively. The survey showed good satisfaction with the design, operability, and reporting system. Therefore, the system can facilitate communication between patients and radiation oncologists in the future.

Risk perception of radiation emergency medical staff on low-dose radiation exposure: Knowledge is a critical factor

Radiation emergency medical (REM) staff respond to many types of disasters such as radiological and nuclear accidents as well as environmental radioactivity exposure. The objective of this study was to evaluate the risk perception of REM staff on radiation exposure in various situations and to analyze the factors that affect their risk perception. A questionnaire was given to 284 REM staff affiliated with various organizations, including nuclear power generation, nuclear fuel manufacturing, large-scale irradiation, and radiation-waste disposal facilities, as well as research and development institutions. To determine the substantially influential factors for risk perception, we analyzed the questionnaire responses using ordinal logistic regression, Kruskal-Wallis, and Spearman correlation analyses. It was generally perceived by REM staff that low-dose radiation exposure in daily life and work environments does not pose any health risks. A higher level of radiation knowledge was tightly associated with a lower risk perception of REM staff on extremely low-dose (several mSv) radiation exposure, thus exhibiting an inverse correlation. In contrast to radiation researchers, the work experience of REM staff was not a contributing factor to their risk perception. In our study, REM staff with a high level of radiation knowledge did not have any health concerns in their work environments. Efforts to enhance the radiation knowledge of REM staff through proper education and training would result in analytical risk evaluation, which may also improve their willingness to help meet surge capacity needs in large-scale radiological events.

Clinical utilization of radiation therapy in Korea, 2016

Radiotherapy (RT) is one of the primary cancer treatment modalities. To estimate the actual utilization of RT and infrastructure in Korea, the current study was performed. Data from 2012 to 2016 were extracted from the Health Insurance Review and Assessment Service. In addition, a nationwide survey was conducted to collect the statistics of RT facilities, equipment and human resources in Korea. The total number of patients treated with RT was 72 563 in 2016. The five cancers that were most commonly treated with RT in 2016 were breast, lung, colorectal, liver and prostate cancer. According to analyses of specific treatment modalities, the number of patients treated with intensity-modulated radiotherapy (IMRT), stereotactic radiation therapy (SRT) and proton therapy increased from 6670, 6306 and 50 in 2012 to 21584, 9048 and 703 in 2016, respectively. Ninety radiation oncology centers were working in 2015 and there were a total of 213 megavoltage teletherapy machines. In 2015, 310 patients were treated per megavoltage RT machine, 246 patients per radiation oncologist, 501 patients per medical physicist and 111 patients per radiotherapy technologist. In conclusion, the number of patients who underwent RT in Korea has increased steadily from 2012 to 2016. The IMRT utilization rate remarkably increased in 2016, and the number of patients treated with advanced treatment modalities such as IMRT, SRT and proton therapy is expected to increase.

Patterns of Practice in Radiotherapy for Breast Cancer in Korea

Adjuvant radiotherapy (RT) is a well-established treatment for breast cancer. However, there is a large degree of variation and controversy in practice patterns. A nationwide survey on the patterns of practice in breast RT was designed by the Division for Breast Cancer of the Korean Radiation Oncology Group. All board-certified members of the Korean Society for Radiation Oncology were sent a questionnaire comprising 39 questions on six domains: hypofractionated whole breast RT, accelerated partial breast RT, postmastectomy RT (PMRT), regional nodal RT, RT for ductal carcinoma in situ, and RT toxicity. Sixty-four radiation oncologists from 54 of 86 (62.8%) hospitals responded. Twenty-three respondents (35.9%) used hypofractionated whole breast RT, and the most common schedule was 43.2 Gy in 16 fractions. Only three (4.7%) used accelerated partial breast RT. Five (7.8%) used hypofractionated PMRT, and 40 (62.5%) had never used boost RT after chest wall irradiation. Indications for regional nodal RT varied; ≥pN2 (n=7) versus ≥pN1 (n=17) versus ≥pN1 with pathologic risk factors (n=40). Selection criteria for internal mammary lymph node (IMN) irradiation also varied; only four (6.3%) always treated IMN when regional nodal RT was administered and 30 (46.9%) treated IMN only if IMN involvement was identified through imaging. Thirty-one (48.4%) considered omission of whole breast RT after breast-conserving surgery for ductal carcinoma in situ based on clinical and pathologic risk factors. Fifty-two (81.3%) used heart-sparing techniques. Overall, there were wide variations in the patterns of practice in breast RT in Korea. Standard guidelines are needed, especially for regional nodal RT and omission of RT for ductal carcinoma in situ.

Estimation of the medical need for carbon-ion radiotherapy in Korea

The Korea Heavy Ion Medical Accelerator project focuses on the development of medical accelerator facilities for delivering carbon-ion beams to cancer patients. The purpose of the present study was to estimate the clinical need for carbon-ion therapy in Korea. Seven tumor sites, namely head and neck, liver, lung, colon and rectum, prostate, bone and soft tissue, and pancreas were selected as eligible sites for receiving carbon-ion radiotherapy (RT) by radiation oncologists of the Korea Institute of Radiological and Medical Sciences. Cancer incidence data for the selected tumor sites were obtained from the Korea National Cancer Incidence Database in order to estimate the potential medical need for carbon-ion RT. The carbon-ion RT adaption rate was assessed based on the clinical experience of other carbon-ion therapy facilities. An estimation model was constructed for estimating the medical need for carbon-ion RT, and from this, 25 606 patients were deemed to be potential candidates for carbon-ion RT. This estimated potential need corresponded to 10% of newly diagnosed cancer patients in Korea. The realistic estimation was calculated as ranging between 4000 and 6300 patients, depending on the carbon-ion RT adaptation rate. This estimated medical need corresponded to 2-3% of newly diagnosed cancer patients in Korea. Taken together, our findings suggest that there is a clear medical need for carbon-ion RT in Korea, with at least 4000 potential patients per year.

Which Patients with Left Breast Cancer Should be Candidates for Heart-Sparing Radiotherapy?

Purpose

This study aimed to identify risk factors that have significant interaction with radiation exposure to the heart, and thus to determine candidates for heart-sparing radiotherapy (RT) among women with left breast cancer.

Methods

We identified 4,333 patients who received adjuvant RT following breast-conserving surgery for ductal carcinoma in situ or invasive breast cancer from 1996 to 2010. Incidence rates of cardiovascular disease were compared between left-sided and right-sided RT, and stratified by age and risk factors such as body mass index (BMI), smoking, hyperlipidemia, hypertension, diabetes, administration of anthracycline, and trastuzumab.

Results

In all patients, the cumulative incidence of cardiovascular disease was greater in patients treated with left-sided RT than in those treated with right-sided RT, but the difference was not significant (p=0.428). Smoking (hazard ratio [HR], 5.991; 95% confidence interval [CI], 2.109-17.022; p=0.002) and hyperlipidemia (HR, 5.567; 95% CI, 3.235-9.580; p<0.001) were the most powerful risk factors for cardiovascular disease. There was no significant factor that further increased the risk of cardiovascular disease after left breast RT compared to right breast RT.

Conclusion

Although hyperlipidemia and smoking are risk factors for cardiovascular disease, they have not been proven to increase the risk of RT-related cardiovascular disease in Korean women.

A Survey of Radiation Therapy Utilization in Korea from 2010 to 2016: Focusing on Use of Intensity-Modulated Radiation Therapy

BACKGROUND

This study aimed to assess the recent changes of radiation therapy (RT) modalities in Korea. In particular, we focused on intensity-modulated radiation therapy (IMRT) utilization as the main index, presenting the application status of advanced RT.

METHODS

We collected information from the Korean Health and Insurance Review and Assessment Service data based on the National Health Insurance Service claims and reimbursements records by using treatment codes from 2010 to 2016. We classified locating region of each institution as capital vs. non-capital areas and metropolitan vs. non-metropolitan areas to assess the regional difference in IMRT utilization in Korea.

RESULTS

IMRT use has been steadily increased in Korea, with an annual increase estimate (AIE) of 37.9% from 2011 to 2016 (P < 0.001) resulting in IMRT being the second most common RT modality following three-dimensional conformal radiotherapy. In general, an increasing trend of IMRT utilization was observed, regardless of the region. The rate of AIE in the capital areas or metropolitan areas was higher than that in non-capital areas or non-metropolitan areas (40.7% vs. 31.9%; P < 0.001 and 39.7% vs. 29.4%; P < 0.001, respectively).

DISCUSSION

The result of our survey showed that IMRT has become one of the most common RT modalities. IMRT is becoming popular in both metropolitan and non-metropolitan areas, while metropolitan area has faster AIE possibly due to concentration of medical resources and movement of advanced patients.

Breast Conservation Therapy Versus Mastectomy in Patients with T1-2N1 Triple-Negative Breast Cancer: Pooled Analysis of KROG 14-18 and 14-23

Purpose

The aim of this study is to compare the treatment outcomes of breast conserving surgery (BCS) plus radiotherapy (RT) versus mastectomy for patients with pT1-2N1 triple-negative breast cancer (TNBC).

Materials and Methods

Using two multicenter retrospective studies on breast cancer, a pooled analysis was performed among 320 patients with pT1-2N1 TNBC. All patients who underwent BCS (n=212) receivedwhole breast RTwith orwithoutregional nodal RT,while nonewho underwent mastectomy (n=108)received it. All patients received taxane-based adjuvant chemotherapy. The median follow-up periods were 65 months in the BCS+RT group, and 74 months in the mastectomy group.

Results

The median age of all patients was 48 years (range, 24 to 70 years). Mastectomy group had more patients with multiple tumors (p < 0.001), no lymphovascular invasion (p=0.001), higher number of involved lymph node (p=0.028), and higher nodal ratio ≥ 0.2 (p=0.037). Other characteristics were not significantly different between the two groups. The 5-year locoregionalrecurrence-free, disease-free, and overall survivalrates of BCS+RT group versus mastectomy group were 94.6% versus 87.7%, 89.5% versus 80.4%, and 95.0% versus 87.8%, respectively, and the differences were statistically significant after adjusting for covariates (p=0.010, p=0.006, and p=0.005, respectively).

Conclusion

In pT1-2N1 TNBC, breast conservation therapy achieved better locoregional recurrencefree, disease-free, and overall survival rates compared with mastectomy.

Selective Radiation Therapy for Ductal Carcinoma In Situ Following Breast-Conserving Surgery According to Age and Margin Width: Korean Radiation Oncology Group 11-04 and 16-02 Studies

Purpose

The optimal indications for omitting adjuvant radiation therapy (RT) after breast-conserving surgery are still controversial in ductal carcinoma in situ (DCIS) of the breast. The purpose of this study was to validate the role of postoperative RT in DCIS patients aged ≤50 years and with tumor margin widths of <1 cm, both of which have been proven to be high-risk features for recurrence in cohorts not receiving RT.

Methods

Using two multicenter retrospective studies on DCIS, a pooled analysis was performed among patients aged ≤50 years and with margin widths <1 cm. All patients underwent breast-conserving surgery. Two hundred thirty-two patients received postoperative RT, while 54 did not. The median follow-up period was 77 months (range, 2-190 months) and 70 months (range, 5-166 months) in the patients who received RT and those who did not, respectively.

Results

The patients who received RT had larger tumors (p<0.001), higher nuclear grade (p<0.001), closer margin width (p<0.001), and negative estrogen receptor expression (p=0.010) compared with those who did not receive RT. During the follow-up period, there were 17 ipsilateral breast tumor recurrences (IBTRs) as follows: invasive carcinoma in 10 patients and DCIS in seven. In the univariate analysis, the treatment with RT and human epidermal growth factor receptor 2 (HER2) status were significant risk factors for IBTR. The 7-year IBTR rates with and without postoperative RT were 3.6% and 13.1%, respectively (p=0.008). HER2-positive tumors had a higher IBTR rate than the HER2-negative tumors (7-year rate, 13.6% vs. 3.9%; p=0.003).

Conclusion

Postoperative RT following breast-conserving surgery significantly reduced the 7-year IBTR rate in the DCIS patients aged ≤50 years and with margin widths <1 cm. HER2 positivity was associated with increased IBTR in these patients.

Value of imaging study in predicting pelvic lymph node metastases of uterine cervical cancer

PURPOSE

To evaluate the diagnostic accuracy of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) in predicting pelvic lymph node (LN) metastases in patients with cervical cancer.

MATERIALS AND METHODS

From January 2009 to March 2015, 114 patients with FIGO stage IA1-IIB uterine cervical cancer who underwent hysterectomy with pelvic lymphadenectomy and took CT, MRI, and PET/CT before surgery were enrolled in this study. The criteria for LN metastases were a LN diameter ≥1.0 cm and/or the presence of central necrosis on CT, a LN diameter ≥1.0 cm on MRI, and a focally increased FDG uptake on PET/CT. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for pelvic LN metastases were estimated.

RESULTS

The sensitivity, specificity, PPV, NPV, and accuracy for detection of pelvic LN metastases were 51.4%, 85.9%, 41.3%, 90.1%, and 80.3% for CT; 24.3%, 96.3%, 56.3%, 86.8%, and 84.6% for MRI; and 48.6%, 89.5%, 47.4%, 90.0%, and 82.9% for PET/CT, respectively. The sensitivity of PET/CT and CT was higher than that of MRI (p=0.004 and p= 0.013, respectively). The specificity of MRI was higher than those of PET/CT and CT (p=0.002 and p=0.001, respectively). The difference of specificity between PET/CT and CT was not statistically significant (p=0.167).

CONCLUSION

These results indicate that preoperative CT, MRI, and PET/CT showed low to moderate sensitivity and PPV, and moderate to high specificity, NPV, and accuracy. More efforts are necessary to improve sensitivity of imaging modalities in order to predict pelvic LN metastases.

Valproic Acid Sensitizes Hepatocellular Carcinoma Cells to Proton Therapy by Suppressing NRF2 Activation

Although efficacy of combined histone deacetylase (HDAC) inhibitors and conventional photon radiotherapy is being tested in clinical trials, their combined effect with proton beam radiotherapy has yet to be determined. Here, we compared combined effect of valproic acid (VPA), a class I and II HDAC inhibitor and antiepileptic drug with proton and photon irradiation in hepatocellular carcinoma (HCC) cells in vitro and in vivo. We found that VPA sensitized more Hep3B cells to proton than to photon irradiation. VPA prolonged proton-induced DNA damage and augmented proton-induced apoptosis. In addition, VPA further increased proton-induced production of intracellular reactive oxygen species and suppressed expression of nuclear factor erythroid-2-related factor 2 (NRF2), a key transcription factor regulating antioxidant response. Downregulation of NRF2 by siRNA transfection increased proton-induced apoptotic cell death, supporting NRF2 as a target of VPA in radiosensitization. In Hep3B tumor xenograft models, VPA significantly enhanced proton-induced tumor growth delay with increased apoptosis and decreased NRF2 expression in vivo. Collectively, our study highlights a proton radiosensitizing effect of VPA in HCC cells. As NRF2 is an emerging prognostic marker contributing to radioresistance in HCC, targeting NRF2 pathway may impact clinical outcome of proton beam radiotherapy.

Quality assurance for a multicenter Phase II study of stereotactic ablative radiotherapy for hepatocellular carcinoma ≤5 cm: a planning dummy run

Objective

The Korean Radiation Oncology Group (12-02) investigated the outcome of stereotactic ablative radiotherapy for hepatocellular carcinoma ≤5 cm using 60 Gy in three fractions. To evaluate dosimetric differences and compliance in a multicenter trial, a planning dummy run procedure was performed.

Methods

All six participating institutions were provided the contours of two dummy run cases. Plans were performed following the study protocol to cover the planning target volume with a minimum of 90% of the prescription dose and to satisfy the constraints for organs at risk. We assessed the institutional variations in plans using dose-volume histograms.

Results

Different planning techniques were applied: static intensity-modulated radiotherapy in two institutions, CyberKnife in two institutions and RapidArc in two institutions. The conformity index of all 12 plans was ≤1.2. In terms of the planning target volume coverage, all participants followed our study protocol. For the second dummy run case, located in Segment 8 near the heart, the minimum dose of the planning target volume (D99%: dose covering 99% of the planning target volume) was variable because there was no mention of constraints of D99% of the planning target volume in the study protocol. As an important organ at risk, the normal liver volumes receiving <17 Gy in all 12 plans were >700 ml.

Conclusions

Dosimetric parameters showed acceptable compliance with the study protocol. However, we found the possibility of underdose to the planning target volume if the hepatocellular carcinoma lesion was located near organs at risk such as the heart. Based on this dummy run, we will conduct individual case reviews to minimize the effects of study protocol deviation.

On-site audits to investigate the quality of radiation physics of radiation therapy institutions in the Republic of Korea

PURPOSE

To investigate and improve the domestic standard of radiation therapy in the Republic of Korea.

METHODS

On-site audits were performed for 13 institutions in the Republic of Korea. Six items were investigated by on-site visits of each radiation therapy institution, including collimator, gantry, and couch rotation isocenter check; coincidence between light and radiation fields; photon beam flatness and symmetry; electron beam flatness and symmetry; physical wedge transmission factors; and photon beam and electron beam outputs.

RESULTS

The average deviations of mechanical collimator, gantry, and couch rotation isocenter were less than 1mm. Those of radiation isocenter were also less than 1mm. The average difference between light and radiation fields was 0.9±0.6mm for the field size of 20cm×20cm. The average values of flatness and symmetry of the photon beams were 2.9%±0.6% and 1.1%±0.7%, respectively. Those of electron beams were 2.5%±0.7% and 0.6%±1.0%, respectively. Every institutions showed wedge transmission factor deviations less than 2% except one institution. The output deviations of both photon and electron beams were less than ±3% for every institution.

CONCLUSIONS

Through the on-site audit program, we could effectively detect an inappropriately operating linacs and provide some recommendations. The standard of radiation therapy in Korea is expected to improve through such on-site audits.

Intensity-modulated radiotherapy for hepatocellular carcinoma: dosimetric and clinical results

Since the introduction of 3-dimensional conformal radiotherapy (3DCRT), new radiotherapy techniques have expanded the indication of radiotherapy for the treatment of hepatocellular carcinoma (HCC), from the hitherto palliative to a now curative-intent purpose. Intensity-modulated radiotherapy (IMRT), currently the most advanced radiotherapy technique, is considered an attractive option for the treatment of HCC, and is more widely applied because it can deliver a higher dose to the tumor than 3DCRT while sparing surrounding normal organs. However, the advantages and potential disadvantages of IMRT for treating HCC have not been fully established. This article deals with three different IMRT techniques, including static IMRT and volumetric modulated arc therapy using conventional multileaf collimator (MLC) mounted linear accelerators, and helical IMRT using binary MLC mounted helical tomotherapy machine. We review dosimetric and clinical studies for these IMRT techniques for the treatment of HCC.

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.

Possible benefits from post-mastectomy radiotherapy in node-negative breast cancer patients: a multicenter analysis in Korea (KROG 14-22)

PURPOSE

This study was performed to identify a subset of patients who may benefit from post-mastectomy radiotherapy (PMRT) among node-negative breast cancer patients.

MATERIALS AND METHODS

We retrospectively reviewed 1,828 patients with pT1-2N0 breast cancer, treated with mastectomy without PMRT from 2005 to 2010 at 10 institutions. Univariate and multivariate analyses for locoregional recurrence (LRR) and any first recurrence (AFR) were performed according to clinicopathologic factors and biologic subtypes.

RESULTS

During a median follow-up period of 5.9 years (range: 0.7-10.4 years), 98 patients developed AFR (39 isolated LRR, 13 LRR with synchronous distant metastasis, and 46 isolated distant metastasis), and 52 patients developed LRR. The 7-year LRR and AFR rates were 3.8% and 6.7%, respectively. Multivariate analysis revealed that age of ≤ 40 years (p<0.001) and T2 stage (p=0.013) were independent risk factors for LRR. The 7-year LRR rates were 2.5% with no risk factors, 4.5% with one risk factor, and 12.4% with two risk factors. Multivariate analysis for AFR revealed that age of ≤ 40 years (p<0.001), T2 stage (p<0.001), and triple-negative biological subtype (p=0.045) were independent risk factors for AFR. The 7-year AFR rates were 3.9% with no risk factors, 8.4% with one risk factor, and 15.7% with two to three risk factors.

CONCLUSIONS

Mastectomy without PMRT is a sufficient local treatment for pT1-2N0M0 breast cancer. Nevertheless, PMRT might be considered for patients with two or three risk factors, among those of young age, with T2 tumors, and with the triple-negative biological subtype based on LRR and AFR.

Locoregional relapse after gastrectomy with D2 lymphadenectomy for gastric cancer

BACKGROUND

Risk for and site of locoregional relapse have not been well studied in patients undergoing gastrectomy with D2 lymphadenectomy for gastric cancer.

METHODS

Patients who had undergone gastrectomy with D2 lymphadenectomy for gastric cancer between 2004 and 2007 were identified from an institutional database. The locoregional relapse rate was estimated by competing risk analysis, and risk groups were derived according to locoregional relapse risk using recursive partitioning analysis (RPA). The locations of nodal relapses were evaluated according to Japanese Classification of Gastric Carcinoma criteria.

RESULTS

Some 2618 patients were included. With a median follow-up of 78·0 (range 28·5-122·6) months, relapse was diagnosed in 471 of 2618 patients (18·0 per cent). The cumulative incidence of locoregional relapse at 5 years was 8·5 (95 per cent c.i. 7·4 to 9·6) per cent. The 5-year locoregional recurrence rates for high-risk (N3), intermediate-risk (N1-2) and low-risk (N0) groups were 32·4, 12·3 and 1·7 per cent respectively (P < 0·001). Among patients with regional relapse, 90·4 per cent had involvement outside the D2 dissected area, and the most commonly involved site was station 16b1. This pattern was maintained in the RPA risk groups (P = 0·329).

CONCLUSION

Locoregional relapse at 5 years after gastrectomy with D2 lymphadenectomy was 8·5 per cent, and was most often seen outside the D2 dissected area.

Recurrence outcomes after omission of postoperative radiotherapy following breast-conserving surgery for ductal carcinoma in situ of the breast: a multicenter, retrospective study in Korea (KROG 16-02)

PURPOSE

To evaluate the loco-regional recurrence (LRR) rate after breast-conserving surgery without postoperative radiotherapy (RT) for ductal carcinoma in situ (DCIS) of the breast.

METHODS

Between 2000 and 2010, 311 DCIS patients from 9 institutions were analyzed retrospectively. The median age was 47 (range, 20-82). The median tumor size was 7 mm (range, 0.01-76). Margin width was <1 cm in 85 patients (27.3%), and nuclear grade was high in 37 patients (11.9%). Two hundred and three patients (65.3%) received tamoxifen.

RESULTS

With a median follow-up of 74 months (range, 5-189), there were 11 local recurrences (invasive carcinoma in 6 and DCIS in 5) and 1 regional recurrence. The 7-year LRR rate was 3.8%. On univariate analysis, age and margin width were significant risk factors influencing LRR (p = 0.017 and 0.014, respectively). When age and margin width were combined among 211 patients whose margin width were available, the 7-year LRR rates were as follows (p < 0.001): (1) 0% in patients with age >50 years and any margin width status (n = 64), (2) 1.2% in age ≤50 years and margin width ≥1 cm (n = 93), (3) 13.1% in age ≤50 years and margin width <1 cm (n = 54).

CONCLUSIONS

The LRR rate was very low in selected DCIS patients treated with breast-conserving surgery without postoperative RT. However, adjuvant RT should be considered for those with age ≤50 years and margin width <1 cm.

Incorporating Risk Factors to Identify the Indication of Post-mastectomy Radiotherapy in N1 Breast Cancer Treated with Optimal Systemic Therapy: A Multicenter Analysis in Korea (KROG 14-23)

PURPOSE

In a recent meta-analysis, post-mastectomy radiotherapy (PMRT) reduced any first recurrence (AFR) and improved survival in N1 and N2 patients. We investigated risk factors for AFR in N1 after optimal systemic therapy without PMRT, to define a subgroup of patients who may benefit from PMRT.

MATERIALS AND METHODS

One thousand three hundred eighty-two pT1-2N1M0 breast cancer patients treated with mastectomy without PMRT between 2005 and 2010 were retrospectively analyzed. Only 0.6% had no systemic therapy.

RESULTS

After a median follow-up of 5.9 years, there were 173 AFR (53 loco-regional recurrence [LRR] without distant metastases [DM], 38 LRR with DM, and 82 DM without LRR). The 5-year LRR and AFR rates were 6.1% and 12.0%, respectively. Multivariate analysis revealed that close resection margin (p=0.001) was the only independent risk factor for LRR. Multivariate analysis for AFR revealed that age < 35 years (p=0.025), T2 stage (p=0.004), high tumor grade (p=0.032), close resection margin (p=0.035), and triple-negative biological subtype (p=0.031) were independent risk factors. Two or three positive lymph nodes (p=0.078) were considered a marginally significant factor. When stratified by these six factors, the 5-year LRR rates were 3.6% with 0-1 (n=606), 7.5% with 2-3 (n=655), and 12.7% with 4-6 (n=93) risk factors. The 5-year AFR rates were 7.1% with 0-1, 15.0% with 2-3, and 24.5% with 4-6 risk factors.

CONCLUSION

Patients with pT1-2N1M0 breast cancer who underwent mastectomy and optimal systemic therapy showed excellent loco-regional control and disease control. The patients with four or more risk factors may benefit from PMRT, and those with two or three risk factors merit consideration of PMRT.