Incidence and treatment outcomes of ovarian carcinosarcoma from the national cancer registry of Korea.

OBJECTIVE: To investigate the incidence and survival outcomes of ovarian carcinosarcoma in Korea between 1999 and 2018. METHODS: Patients diagnosed with ovarian carcinosarcoma between 1999 and 2018 were identified from the Korea Central Cancer Registry (KCCR) and their information was collected. Age-standardized incidence rates (ASRs), annual percent changes (APC), and relative survival rates of ovarian carcinosarcoma were calculated and compared to those of epithelial ovarian cancer. RESULTS: According to the KCCR, 458 cases of ovarian carcinosarcoma were detected, and accounted for 1.5% (458/30,679) of all epithelial ovarian cancers in Korea between 1999 and 2018. The ASR of ovarian carcinosarcoma between 1999 and 2018 was 0.064 per 100,000 women. The incidence rate of ovarian carcinosarcoma increased during the study period, with an ASR of 0.029 per 100,000 in 1999 and 0.073 per 100,000 in 2018. The APC of ovarian carcinosarcoma during 1999-2018 was 5.86 (p<0.001). The median overall survival (OS) of patients with ovarian carcinosarcoma was 39 months, and the 5-year OS rate was 42.5%. Among ovarian carcinosarcomas, patients with localized stages showed better clinical outcomes than those with regional or distant stages (5-year OS, 60.8%, 57.9%, and 32.8%, respectively; p<0.001). In addition, younger (<50 years) patients showed better OS than older (≥50 years) patients (5-year OS, 52.6% vs. 40.2%; p<0.001). CONCLUSION: Our nationwide registry-based study demonstrated that the incidence of ovarian carcinosarcoma increased from 1999 to 2018 in Korea. Patients with advanced-stage disease and older age (≥50 years) had poorer survival outcomes.

Trends in the incidence and survival outcomes of endometrial cancer in Korea: a nationwide population-based cohort study.

OBJECTIVE: To evaluate trends in the incidence and survival outcomes of endometrial cancer (EC) based on the year of diagnosis, stage, age, and histologic types. METHODS: Women with primary EC diagnosed between 1999 and 2018, and who were followed up with until 2019, were identified from the Korea Central Cancer Registry using the International Classification of Diseases, 10th revision. The age-standardized rates (ASRs) of incidence, annual percent changes (APCs), and survival were estimated according to age, stage, histology, and year of diagnosis. RESULTS: The ASR for EC increased from 2.38 per 100,000 in 1999 to 7.29 per 100,000 in 2018 across all histologic types (APCs of 9.82, 15.97, and 7.73 for endometrioid, serous, and clear cell, respectively, p<0.001). There were significant differences in the 5-year survival rates based on histology (90.9%, 55.0%, and 68.5% for endometrioid, serous, and clear cell, respectively, p<0.001), stage (93.4%, 77.0%, and 31.0% for localized, regional, and distant, respectively, p<0.001), and age (93.0% for <50 years and 80.6% for ≥50 years, p<0.001). The 5-year survival was significantly better in the group diagnosed between 2000 and 2018 (85.9%) than that in the 1999-2008 group (83.3%) (p<0.001). This trend was only observed for endometrioid cancer (p<0.001). CONCLUSION: The incidence of EC increased across the all 3 subtypes. Survival of patients with endometrioid histology improved over the past two decades, but remained static for serous or clear cell histology. Healthcare strategies to prevent EC incidence in at-risk populations and apply effective treatments for high-risk histology are needed.

Clinical Trials for Oral, Inhaled and Intravenous Drug Delivery System for Lung Cancer and Emerging Nanomedicine-Based Approaches.

Lung cancer is one of the most common malignant tumors worldwide and is characterized by high morbidity and mortality rates and a poor prognosis. It is the leading cause of cancer-related death in the United States and worldwide. Most patients with lung cancer are treated with chemotherapy, radiotherapy, or surgery; however, effective treatment options remain limited. In this review, we aim to provide an overview of clinical trials, ranging from Phase I to III, conducted on drug delivery systems for lung cancer treatment. The trials included oral, inhaled, and intravenous administration of therapeutics. Furthermore, the study also talks about the evolving paradigm of targeted therapy and immunotherapy providing promising directions for personalized treatment. In addition, we summarize the best results and limitations of these drug delivery systems and discuss the potential capacity of nanomedicine.

Characteristics of second primary breast cancer after ovarian cancer: a Korea central cancer registry retrospective study.

Background: Second primary cancer has become an important issue among cancer survivors. This study sought to determine the differences in clinicopathologic outcomes between second primary breast cancer (SPBC) after ovarian cancer and primary breast cancer (PBC) in the Republic of Korea. Methods and materials: We searched the Korea Central Cancer Registry and identified 251,244 breast cancer cases that were diagnosed between 1999 and 2017. The incident rate and standardized incidence ratio (SIR) were calculated. Demographic and clinical characteristics and overall survival (OS) rates were estimated according to age, histological type, and cancer stage. Results: Among the 228,329 patients included, 228,148 were patients with PBC, and 181 patients had SPBC diagnosed after ovarian cancer (OC). The mean ages at diagnosis were 56.09 ± 10.81 years for SPBC and 50.65 ± 11.40 years for PBC. Patients with SPBC were significantly less likely than patients with PBC to receive adjuvant radiotherapy (14.92% vs. 21.92%, p = 0.02) or adjuvant chemotherapy (44.75% vs. 55.69%, p < 0.01). Based on the age-standardized rate (ASR), the incidence of SPBC after OC was 293.58 per 100,000 ovarian cancer patients and the incidence of PBC was 39.13 per 100,000 women. The SIR for SPBC was 1.27 (1.09-1.46, 95% Confidence interval) in the patients overall. The 5-year OS rates were 72.88% and 89.37% for SPBC and PBC (p < 0.01). The OS rate in SPBC decreased significantly with advanced stage and older age. Conclusion: The incidence of breast cancer is about 1.27 times higher in ovarian cancer patients than in healthy people. The survival outcomes were worse for SPBC than for PBC and were related to older age and advanced stage. Active screening for breast cancer is necessary in ovarian cancer patients.

Exocrine pancreatic cancer as a second primary malignancy: A population-based study.

Backgrounds/Aims: Although cancer survivors are at higher risk of developing second primary malignancies, cancer surveillance strategies for them have not yet been established. This study aimed to identify first primary cancers that had high risks of developing second primary exocrine pancreatic cancer (EPC). Methods: Data on individuals diagnosed with primary cancers between 1993 and 2017 were obtained from the Korea Central Cancer Registry. The standardized incidence ratios (SIRs) of second primary EPCs were analyzed according to the primary tumor sites and follow-up periods. Results: Among the 3,205,840 eligible individuals, 4,836 (0.15%) had second primary EPCs, which accounted for 5.8% of the total EPC patients in Korea. Between 1 and 5 years after the diagnosis of first primary cancers, SIRs of second primary EPCs were increased in patients whose first primary cancers were in the bile duct (males 2.99; females 5.03) in both sexes, and in the small intestine (3.43), gallbladder (3.21), and breast (1.26) in females. Among those who survived 5 or more years after the diagnosis of first primary cancers, SIRs of second primary EPCs were elevated in patients whose first primary cancers were in the bile duct (males 2.61; females 2.33), gallbladder (males 2.29; females 2.22), and kidney (males 1.39; females 1.73) in both sexes, and ovary (1.66) and breast (1.38) in females. Conclusions: Survivors of first primary bile duct, gallbladder, kidney, ovary, and female breast cancer should be closely monitored for the occurrence of second primary EPCs, even after 5 years of follow-up.

Incidence and treatment outcomes of uterine cervical cancer in Korea 1999-2018 from the national cancer registry.

OBJECTIVE: To describe the incidence and survival outcomes of uterine cervical cancer during 1999-2018. METHODS: Patients who were diagnosed with cervical cancer during 1999-2018 were identified in the Korea Central Cancer Registry. Age-standardized incidence rates (ASRs) and annual percent changes (APCs) were calculated. Survival rates by histology, year of diagnosis (1999-2008 vs. 2009-2018), stage, and age at diagnosis were analyzed. RESULTS: The absolute incidence of cervical cancer decreased over 20 years from 4,488 in 1999 to 3,500 in 2018, with an APC of -3.42% (p<0.0001). While ASR of squamous cell carcinoma (SCCA) more than halved from 13.27 per 100,000 in 1999 to 6.16 in 2018 (APC, -4.04%), adenocarcinoma continued to rise (ASR, 1.30 per 100,000 to 1.92; APC, 1.52%; p<0.0001). Patients with adenocarcinoma were younger than those with SCCA (mean, 49.9±12.7 vs. 52.9 ±14.6 years; p<0.0001). Five-year survival rate of cervical cancer patients overall was 78.0%. Adenocarcinoma had poorer survival than SCCA (5-year survival rate, 76.8% vs. 79.8%; p<0.0001). There was no survival difference between patients who were diagnosed between 1999-2008 and 2009-2018. Earlier-stage disease had better survival (5-year survival rate for localized, regional, and distant disease, 90.0% vs. 69.9% vs. 26.5%; p<0.0001). Younger patients aged <50 years had better survival than those aged ≥50 years (87.1% vs. 69.8%; p<0.0001). CONCLUSION: The incidence of SCCA of the uterine cervix declined while adenocarcinoma continued to increase slowly but significantly from 1999 to 2018 in Korea. Adenocarcinoma was diagnosed at a younger age, but had poorer survival outcome than SCCA.

Trend Analysis and Prediction of Hepatobiliary Pancreatic Cancer Incidence and Mortality in Korea.

BACKGROUND: This study aimed to analyze the current trends and predict the epidemiologic features of hepatobiliary and pancreatic (HBP) cancers according to the Korea Central Cancer Registry to provide insights into health policy. METHODS: Incidence data from 1999 to 2017 and mortality data from 2002 to 2018 were obtained from the Korea National Cancer Incidence Database and Statistics Korea, respectively. The future incidence rate from 2018 to 2040 and mortality rate from 2019 to 2040 of each HBP cancer were predicted using an age-period-cohort model. All analyses, including incidence and mortality, were stratified by sex. RESULTS: From 1999 to 2017, the age-standardized incidence rate (ASIR) of HBP cancers per 100,000 population had changed (liver, 25.8 to 13.5; gallbladder [GB], 2.9 to 2.6; bile ducts, 5.1 to 5.9; ampulla of Vater [AoV], 0.9 to 0.9; and pancreatic, 5.6 to 7.3). The age-standardized mortality rate (ASMR) per 100,000 population from 2002 to 2018 of each cancer had declined, excluding pancreatic cancer (5.5 to 5.6). The predicted ASIR of pancreatic cancer per 100,000 population from 2018 to 2040 increased (7.5 to 8.2), but that of other cancers decreased. Furthermore, the predicted ASMR per 100,000 population from 2019 to 2040 decreased in all types of cancers: liver (6.5 to 3.2), GB (1.4 to 0.9), bile ducts (4.3 to 2.9), AoV (0.3 to 0.2), and pancreas (5.4 to 4.7). However, in terms of sex, the predicted ASMR of pancreatic cancer per 100,000 population in females increased (3.8 to 4.9). CONCLUSION: The annual incidence and mortality cases of HBP cancers are generally predicted to increase. Especially, pancreatic cancer has an increasing incidence and will be the leading cause of cancer-related death among HBP cancers.

Distinct prognosis of biliary tract cancer according to tumor location, stage, and treatment: a population-based study.

Biliary tract cancer (BTC) has been inconsistently identified according to its location in epidemiological and clinical studies. This study retrospectively reviewed the treatment pattern and prognosis of BTC according to tumor location using the Korea Central Cancer Registry data of 97,676 patients with BTC from 2006 to 2017. The proportion of localized and regional Surveillance, Epidemiology, and End Results (SEER) stage was the highest in ampulla of Vater (AoV, 78.2%) cancer, followed by extrahepatic bile duct (BD, 68.3%), gallbladder (GB, 52.6%), and intrahepatic BD (49.5%) cancers. Overall, the "no active anti-cancer treatment" rate was the highest in intrahepatic BD (52.8%), followed by extrahepatic BD (49.5%), GB (39.6%), and AoV cancers (28.9%). The 5-year relative survival rate was the highest in AoV (48.5%), followed by GB (28.5%), extrahepatic BD (19.9%), and intrahepatic BD (10.8%) cancers, which significantly improved over time, except for intrahepatic BD cancer. In the localized and regional stage, older patients had a higher risk of receiving no active anti-cancer treatment in each tumor location after adjusting for period and sex. BTC statistics should be reported separately according to tumor location due to its distinct SEER stage distribution, treatment pattern, and prognosis. Care should be taken in elderly patients to reduce the rate of no active anti-cancer treatment.

Trends in the Incidence and Survival Rates of Primary Ovarian Clear Cell Carcinoma Compared to Ovarian Serous Carcinoma in Korea.

Objective: To compare the incidence and survival rates of primary ovarian clear cell carcinoma (OCCC) and ovarian serous carcinoma (OSC) from a nationwide collected database. Methods: We extracted information of patients with primary OCCC and OSC from the Korea Central Cancer Registry recorded between 1999 and 2018, including age at diagnosis and the Surveillance, Epidemiology, and End Results summary stage. Age-standardized incidence rates (ASRs) and annual percent changes (APCs) were calculated. Baseline characteristics and overall survival (OS) were compared between the OCCC and OSC groups. Results: Overall, the incidence rate of primary OCCC increased markedly from 1999 (ASR, 0.16/100,000) to 2018 (0.76/100,000) (APC, 7.85%; P<0.0001). Patients with OCCC were significantly younger and had early-stage disease more frequently than those with OSC. Patients diagnosed with OCCC before the age of 50 showed better OS than those diagnosed after the age of 50 (P=0.0048). The 5-year OS of the OCCC group did not differ by study period [73.5% (1999-2008) vs. 75.4% (2009-2018), P=0.3187], whereas the 5-year OS of the OSC group improved from 54.4% to 58% (P=0.0003). Conclusions: Our nationwide registry-based study demonstrated that the incidence of OCCC in Korea increased significantly from 1999 to 2018. Early-stage OCCC had a relatively good prognosis, but advanced-stage OCCC had a worse OS than advanced-stage OSC. Therefore, the development of optimal treatment strategies for OCCC is warranted.

Incidence and mortality projections for major cancers among Korean men until 2034, with a focus on prostate cancer.

PURPOSE: The Korean population is rapidly aging, and the cancer burden is expected to change significantly. This study aimed to generate projections of incidence and mortality of major cancers among men in Korea until 2034, with a special focus on prostate cancer. MATERIALS AND METHODS: Cancer incidence data from 1999 to 2016 were obtained from the Korea National Cancer Incidence Database. Mortality data were obtained from Statistics Korea. The most common cancers among Korean men (stomach, colorectum, liver, lung and prostate) were analyzed. To predict the future trends of these cancers, the age-period-cohort method was conducted and extrapolated up to 2034. RESULTS: In Korean men, prostate cancer was the fourth most commonly diagnosed cancer in 2016. Based on newly diagnosed cases, the leading cancer site in the year 2034 is expected to be the lung, and the prostate is expected to be the second most frequently diagnosed cancer among Korean men. Age-standardized incidence rates of the most common cancers in men, except prostate cancer, are expected to decrease until 2034. Lung cancer is projected to remain the most common cause of cancer-related mortality until 2034, and the highest estimated change in cancer deaths is expected to be for prostate cancer. CONCLUSIONS: In Korea, the incidence and mortality of prostate cancer is expected to increase markedly in the period up to 2034, particularly in older men. Concerted efforts in screening, diagnosis, and treatment strategies should be considered by healthcare planners and providers.

Cancer Statistics in Korea: Incidence, Mortality, Survival, and Prevalence in 2019.

PURPOSE: The current study provides national cancer statistics and their secular trends in Korea, including incidence, mortality, survival, and prevalence in 2019. MATERIALS AND METHODS: Incidence, survival, and prevalence rates of cancer were calculated using the Korea National Cancer Incidence Database, from 1999 to 2019, with survival follow-up until December 31, 2020. Deaths from cancer were assessed using causes-of-death data obtained from Statistics Korea. RESULTS: In 2019, newly diagnosed cancer cases and deaths from cancer were reported as 254,718 (ASR, 275.4 per 100,000) and 81,203 (ASR, 72.2 per 100,000), respectively. For the first time, lung cancer (n=29,960) became the most frequent cancer in Korea, excluding thyroid cancer. The overall cancer incidence rates increased by 3.3% annually from 1999 to 2012, and decreased by 5.3% annually from 2012 to 2015, thereafter, followed by nonsignificant changes. The incidence of thyroid cancer increased again from 2016 (annual percentage change, 6.2%). Cancer mortality rates have been decreasing since 2002, with more rapid decline in recent years (annual decrease of 2.7% from 2002 to 2013; 3.3% from 2013 to 2019). The 5-year relative survival between 2015 and 2019 was 70.7%, which contributed to prevalent cases reaching over 2 million in 2019. CONCLUSION: Cancer survival rates have improved over the past decades, but the number of newly diagnosed cancers is still increasing, with some cancers showing only marginal improvement in survival outcomes. As the number of cancer survivors increases, a comprehensive cancer control strategy should be implemented in line with the changing aspects of cancer statistics.

Prediction of Cancer Incidence and Mortality in Korea, 2022.

PURPOSE: This study aimed to report the projected cancer incidence and mortality for the year 2022 to estimate Korea's current cancer burden. MATERIALS AND METHODS: Cancer incidence data from 1999 to 2019 were obtained from the Korea National Cancer Incidence Database, and cancer mortality data from 1993 to 2020 were acquired from Statistics Korea. Cancer incidence and mortality were projected by fitting a linear regression model to observed age-specific cancer rates against their respective years and then by multiplying the projected age-specific rates by the anticipated age-specific population for 2022. A joinpoint regression model was used to determine the year in which the linear trend changed significantly; we only used the data of the latest trend. RESULTS: In total, 274,488 new cancer cases and 81,277 cancer deaths are expected to occur in Korea in 2022. The most common cancer site is expected to be the thyroid, followed by the lung, colon and rectum, breast, and stomach. These five cancers are expected to represent half of the overall burden of cancer in Korea. The most common type of cancer leading to death is expected to be lung cancer, followed by liver, colorectal, pancreatic, and gallbladder cancers. CONCLUSION: The incidence rates for all types of cancer in Korea are estimated to gradually decrease. These up-to-date estimates of the cancer burden in Korea could be an important resource for planning and evaluating cancer-control programs.

Cause of death and cause-specific mortality for primary liver cancer in South Korea: A nationwide population-based study in hepatitis B virus-endemic area.

BACKGROUND/AIMS: Primary liver cancer is one of the leading causes of cancer mortality worldwide. However, the causes of death have not been studied in detail in patients with liver cancer. METHODS: The causes of death and cause-specific mortality risks in patients with primary liver cancer, diagnosed during 2000-2016, were investigated using the nationwide population-based cancer registry data in South Korea (n=231,388). The cumulative incidence function and Fine-Gray models were used to estimate the cause-specific mortality under the competing risks. Risks of non-cancer deaths relative to the general population were compared by standardized mortality ratios (SMRs). RESULTS: Among 179,921 total deaths, 92.4%, 1.7%, and 6.0% of patients died of primary liver cancer, cancer from other sites, and non-cancer illnesses, respectively. Proportionate mortality from liver cancer remained high. The 5-year competing risks probability of death from liver cancer varied by tumor stage, from 42% to 94%, and it remained high 10 years after the diagnosis (61-95%). Competing mortality from other causes has continuously increased. The most common non-cancer causes of death were underlying liver diseases (SMR, 15.6; 95% confidence interval [CI], 15.1-16.1) and viral hepatitis (SMR, 46.5; 95% CI, 43.9-49.2), which demonstrated higher mortality risks compared to the Korean general population. Higher mortality risks of suicide (SMR, 2.6; 95% CI, 2.4-2.8) was also noted. CONCLUSION: Patients with liver cancer are most likely to die from liver cancer and related liver disease, even 10 years after the diagnosis, highlighting a need for specialized long-term follow-up care.

First Course of treatment and Prognosis of Exocrine Pancreatic Cancer in Korea from 2006 to 2017.

PURPOSE: Hospital-based clinical studies have limitations in holistic assessment of cancer treatment and prognosis, as they omit out-of-hospital patients including elderly individuals. This study aimed to investigate trends in initial treatment and corresponding prognosis of patients with exocrine pancreatic cancer (EPC) in Korea. MATERIALS AND METHODS: The Korea Central Cancer Registry data of patients with EPC from 2006 to 2017 were retrospectively reviewed. We defined the first course of treatment (FT) as the cancer-directed treatment administered within four months after cancer diagnosis according to the Surveillance, Epidemiology, and End Results (SEER) program. RESULTS: Among 62,209 patients with EPC, localized and regional (LR) SEER stage; patients over 70 years old; and ductal adenocarcinoma excluding cystic or mucinous (DAC) accounted for 40.6%, 50.1%, and 95.9%, respectively. "No active treatment" (NT, 46.5%) was the most frequent, followed by non-surgical FT (28.7%) and surgical FT (22.0%). Among 25,198 patients with LR EPC, surgical FT increased (35.9% to 46.3%) and NT decreased (45.0% to 29.5%) from 2006 to 2017. The rate of surgical FT was inversely related to age (55.1% [< 70 years], 37.3% [70-79 years], 10.9% [≥ 80 years]). Five-year relative survival rates of LR DAC were higher after surgical FT than after NT in localized (46.1% vs. 12.9%) and regional stage (23.6% vs. 4.9%) from 2012 to 2017. CONCLUSION: Less than half of overall patients with LR EPC underwent surgical FT, and this proportion decreased significantly in elderly individuals. Clinicians should focus attention on elderly patients with EPC to provide appropriate medical advice.

Incidence Patterns and Outcomes of Ewing Sarcoma in South Korea (1999-2017): A Retrospective Analysis Using Korea Central Cancer Registry Data.

PURPOSE: Due to low incidence, epidemiologic data of Ewing sarcoma in the Asian population are scarce. We aimed to examine the incidence pattern and outcome of patients with Ewing sarcoma in the Republic of Korea. MATERIALS AND METHODS: Data of patients with Ewing sarcoma diagnosed between 1999 and 2017 were obtained from the Korea Central Cancer Registry (KCCR). Incidence, clinical characteristics, and survival rates were analyzed and compared between different age groups. RESULTS: There were 788 cases (459 males, 329 females), with a median age at diagnosis of 20 years. The age-standardized rate of Ewing sarcoma was 1.01. The number of cases and incidence rates in each age group were as follows: children, 1.6; adolescents and young adults (AYA), 0.93; adults, 0.44; and elderly, 0.53. There were more male cases in children and the AYA group (p < 0.001). Extraskeletal tumors (p < 0.001), primary sites other than extremity (p=0.007), and presence of metastasis at diagnosis (p=0.031) were more frequent in the adults and elderly group. With a median survival time of 78 months, the 5-year overall survival (OS) rate of the entire cohort was 52%. Children fared best (5-year OS, 75%), and the 5-year OS of AYA patients (51%) approximated the OS of the entire cohort. A two-fold difference of 5-year OS was observed between adults and elderly patients (42% vs. 19%). On univariate and multivariate analyses, age ≥ 15 years and presence of metastasis were adverse prognostic factors. CONCLUSION: This was the first epidemiologic study of Ewing sarcoma using the KCCR data. With a similar incidence to other Asian countries, the survival rate was slightly lower than that of Euro-American cases. Collaborative clinical studies are necessary to improve the outcome of Ewing sarcoma in low-incidence populations.

Cause-specific mortality rate of ovarian cancer in the presence of competing risks of death: a nationwide population-based cohort study.

OBJECTIVE: This nationwide cohort study aimed to evaluate the cause-specific mortality (probability of death by ovarian cancer, probability of death by other causes) under the competing risks of death in women with ovarian cancer. METHODS: The Korea Central Cancer Registry was searched to identify women with primary ovarian cancer diagnosed between 2006 and 2016. Epithelial ovarian cancer cases were identified using the International Classification of Diseases for Oncology 3rd edition. We estimated the cause-specific mortality according to age (<65 years, ≥65 years), stage (local, regional, and distant), and histology (serous, mucinous, endometrioid, clear cell, and others) under the competing risks framework; moreover, cumulative incidences were estimated. RESULTS: We included 21,446 cases. Cause-specific mortality continuously increased throughout 10 year follow-up. Compared with women aged <65 years, ovarian cancer-specific mortality (5-year, 28.9% vs. 61.9%; 10-year, 39.0% vs. 68.6%, p<0.001) and other cause mortality (5-year, 1.7% vs. 4.8%; 10-year, 2.8% vs. 8.2%, p<0.001) increased in women aged ≥65 years. This trend was consistent across all the stages and histological types. There was a substantial increase in competing risks from 1.1% in women aged <65 years to 8.0% in women aged ≥65 years in patients with early-stage (p<0.001) non-serous ovarian cancer (p<0.001). CONCLUSION: Older age at diagnosis is associated with increasing ovarian cancer-specific mortality and competing risks. Given the substantial effect of competing risks on elderly patients, there is a need for assessment tools to balance the beneficial and harmful effects to provide optimal treatment.

Osteosarcoma in Adolescents and Young Adults.

The epidemiology of osteosarcoma in adolescents and young adults (AYA) remains unclear. We aimed to assess and compare the clinical features of osteosarcoma between AYA and other age groups. We retrieved osteosarcoma cases diagnosed between 1999 and 2017 from the Korea Central Cancer Registry. We compared survival trends and clinical characteristics between AYA and other age groups. AYA comprised 43.3% (1309/3022) of the osteosarcoma cases. Compared to other age groups, the male-to-female ratio was highest in AYA (1.61:1). The proportion of tumors located in an extremity was 80.3% in AYA, which was lower than in young children (92.5%) or pubertal children (93.8%) but higher than in adults (55.7%) or the elderly (47.5%). As for treatments, 71.2% of AYA received local treatment and systemic chemotherapy, and 28.8% received only local treatment (surgery: 261, radiotherapy: 9, surgery and radiotherapy: 5). The 5-year overall survival (OS) was lower in AYA (68%) than in young children (78%) or pubertal children (73%) but higher than in adults (47%) or the elderly (25%). When AYA were divided into five subgroups by age, patients aged 15-19 years constituted the largest proportion (45.4%, n = 594). Additionally, the proportion of patients with a non-extremity tumor increased in an age-dependent manner, from 10.3% in AYA aged 15-19 years to 35.3% in AYA aged 35-39 years. OS did not significantly differ among the different age subgroups of AYA. The clinical characteristics and OS of the AYA were more similar to those of children than to those of adults. There is a need for cooperation between pediatric and adult oncologists for effective osteosarcoma treatment in AYA.

Incidence and treatment outcomes of ovarian sarcoma compared to epithelial ovarian cancer from the national cancer registry.

PURPOSE: To investigate the incidence and survival outcomes of primary ovarian sarcoma compared to those of epithelial ovarian cancer. METHODS: Data on primary ovarian sarcoma patients (n = 1361) and epithelial ovarian cancer patients (n = 30,366) between 1999 and 2017 were obtained from the Korea Central Cancer Registry, and their respective age-standardized incidence rate (ASR) and relative survival rate were calculated and compared. RESULTS: Based on the ASR, the incidence of epithelial ovarian cancer was 4.75 per 100,000 women, while that of primary ovarian sarcoma was 0.22 per 100,000 women. The ASR ratio was 21.94 without significant change of ASR during the study period. Primary ovarian sarcoma had a better survival curve compared with epithelial ovarian cancer, though the difference was not statistically significant (5 yr overall survival 64.0% vs. 61.5%; p = 0.6030). In addition, among the pure sarcomas, the fibrosarcoma histologic subtype showed the best overall survival, and that of liposarcomas and stromal cell sarcoma were behind that (5 yr overall survival 85.0%, 76.7%, and 72.7%; p < 0.0001). CONCLUSIONS: The incidence of primary ovarian sarcoma is quite low, with an ASR of 0.22/100,000 during the last 20 years. There were no significant differences between survival rates of primary ovarian sarcoma and epithelial ovarian cancer.

Descriptive epidemiology of cancer of unknown primary in South Korea, 1999-2017.

BACKGROUND: Cancers of unknown primary (CUPs) are tumors found after metastasizing from unidentified primary sites; these tumors generally have unknown treatment strategies, expected treatment results, and prognosis. We assessed the epidemiological characteristics of CUPs in Korea. METHODS: We extracted records for 1999 through 2017 from the Korea Central Cancer Registry using the International Statistical Classification of Diseases and Related Health Problems (10th revision) codes for CUP as defined by the International Agency for Research on Cancer. Age-standardized rates and relative survival rates were calculated. RESULTS: The CUPs constituted 2.1 % of the total number of cancer registrations in 1999, declining to 0.7 % in 2017. The incidence rate decreased for both sexes (5.35 to 2.20 for men, 3.15 to 1.77 for women). Patients aged 80 years and older had the highest incidence rate at 40.2, and 86.3 % of CUPs occurred in those 50 years of age or older. The cases of retroperitoneum and peritoneum sites increased over time. Cases diagnosed by microscopic methods and death certification only were 62.3 % and 7.9 %, respectively. The malignant neoplasm of the retroperitoneum and peritoneum and unknown primary site had the highest and lowest survival rates, respectively. The 5-year relative survival rate increased over time from 14.2 % (1999-2002) to 27.3 % (2013-2017). CONCLUSIONS: Our analysis of data from the Korea Central Cancer Registry found decreasing rates of CUP, although with consistent disparities by patient age and sex. Advancements in diagnostic technology may be decreasing the number of CUP diagnoses. Expanding the amount of information recorded in the registry may further improve diagnostic accuracy.