County-based demographics, patterns of treatment seeking, and disease burden for malignant tumor patients in China
Introduction
World Health Organization (WHO) estimates suggest there were 18.1 million new cases of cancer and 9.6 million deaths worldwide in 2018 (1). In 2015, 4.3 million new cancer cases were reported in China, ranking this country first in the world (2), and more than 2.8 million people died of malignant tumors, accounting for 32% of the total cancer deaths worldwide (3). The 5 leading causes of cancer death among both men and women are cancers of the lung and bronchus, stomach, liver, esophagus, and colorectum, accounting for about three-quarters of all cancer deaths (2). From 2000 to 2015, the age-standardized incidence rate for esophageal cancer, gastric cancer and liver cancer decreased significantly, while the age-standardized incidence rate for colorectal cancer in whole population and for lung cancer, breast cancer, cervix cancer, uterus cancer and thyroid cancer in females increased significantly (4). The incidence rate in rural areas of China in 2015 was significantly higher than that in city areas (213.6 per 100,000 vs. 191.5 per 100,000), and the standardized mortality rate of malignant tumors in rural areas was higher than urban areas (149.0 per 100,000 vs. 109.5 per 100,000).
This regional difference may be caused by many factors, in which the higher smoking rate of rural populations in comparison to their urban counterparts likely to play a leading role (5,6). Smoking is highest in the southwest of China, which also has a standardized incidence rate of malignant tumors of (226.7 per 100,000) and mortality rate of (170.2 per 100,000), which is significantly higher than other parts of the country (7). The uneven distribution of medical resources in China, different degrees of access to and quality of cancer diagnosis and treatment, and the fact that most patients in rural and underdeveloped areas are in the middle and late stage of cancer when they are diagnosed, also contribute to the higher rate in these areas. This high prevalence creates a significant burden on patients, their families and the community at large. With the aging of the Chinese population and the increase of unhealthy behaviors and lifestyles related to cancer, the prevention and treatment of malignant tumors requires an increase in government health resources, especially in county and rural areas.
Yun County in Yunnan is in the southwest of China and has a permanent population of 460,000 and total population of 700,000 (8,9). In April 2014, the county was selected to be part of a trial of a comprehensive reform of county-level public hospitals, and a new medical health system focusing on an integral combination of medical treatment and health services started in June of that year. The new hospital system included two higher level hospitals, 13 township central hospitals, a center for disease control, and a maternity and child health hospital, and was designed to provide full coverage for health services and promote the implementation of hierarchical medical treatment. In 2019, the new insurance reform, diagnosis related groups (DRG), was initiated (10), and in 2020, to promote the development of the system, accelerate the construction of hierarchical treatment, and enhance the prevention for the critical diseases such as malignant tumors, a strategy of early screening and early treatment was implemented.
This study aimed to investigate the demographics, treatment pattern, and disease burden of patients with malignant tumors, and explore changes which occurred after the introduction of the new medical system. The results may provide evidence for the further construction of prevention and early treatment resources for cancer patients. We present the following article in accordance with the STROBE reporting checklist (available at https://dx.doi.org/10.21037/apm-21-2075).
Methods
Study design
A retrospective analysis was performed to extract data from the records of patients with malignant tumors who presented to Yun County medical health care units including two higher level hospitals (Yun County People’s Hospital and Yun County Chinese Medicine Hospital), and 13 township central hospitals, from 1st Jul 2017 to 30th Aug 2020. Patients with incomplete medical records and those under 18 years of age were excluded. All medical records including outpatient, inpatient, and emergency visits were extracted for the analysis. This study was approved by the ethics committee of Yun County People’s Hospital (approval number: 2021-02). All procedures performed in this study involving human participants were in accordance with the Declaration of Helsinki (as revised in 2013). Individual consent for this retrospective analysis was waived.
Demographic information including gender, age, ethnicity, marriage status, and medical insurance status were analyzed, as were the tumor types and treatment. Referral rates and patterns between higher level hospitals and county health centers were investigated, as was the disease burden for patients including health resource consumption and treatment costs. Moreover, all-cause visits and malignant tumor-specific visits were assessed separately.
Statistical analysis
Continuous variables were presented as minimum, maximum, mean, standard deviance (SD), median, and interquartile range (IQR) per group, while categorical variables were expressed as frequency and percentages. Analyses were conducted with the R statistical package v.2.13.1 (R Foundation for Statistical Computing, Vienna, Austria).
Results
Demographics
A total of 3,912 patients with malignant tumors were enrolled. Two patients were excluded due to missing key baseline information, and a further 118 were excluded because of missing cost information, resulting in 3,792 patient records used for further analysis (Figure 1).
Based on the results shown in Table 1, the mean age of patients was 56.4 (14.5) years old and male patients numbered slightly more than females. Most patients were Han ethnics. About 80% of patients were married, and over 85% had medical insurance coverage. The most common tumors, in order, were thyroid, lung, liver, and stomach, and were each found in over 10% of patients. Once diagnosed, 16.5% of patients received chemotherapy, 4.6% patients had surgery, and only 0.1% and 1.4% patients received radiation and target or immunization therapy, respectively.
Table 1
| Characteristics | Result (n=3,792) |
|---|---|
| Age (years), mean ± SD | 56.4±14.5 |
| Gender, n (%) | |
| Male | 1,963 (51.8) |
| Female | 1,829 (48.2) |
| Ethics, n (%) | |
| Han | 3,252 (85.8) |
| Non-Han | 345 (9.1) |
| Missing | 195 (5.1) |
| Marriage status, n (%) | |
| Married | 3,060 (80.7) |
| Single | 88 (2.3) |
| Widowed | 25 (0.7) |
| Divorced | 2 (0.1) |
| Others | 10 (0.3) |
| Unspecified | 607 (16.0) |
| Medical insurance, n (%) | |
| Covered | 3,333 (87.9) |
| Self-pay | 459 (12.1) |
| Target lesion, n (%) | |
| Thyroid | 419 (11.0) |
| Lung | 416 (11.0) |
| Liver | 392 (10.3) |
| Stomach | 391 (10.3) |
| Rectum | 297 (7.8) |
| Breast | 293 (7.7) |
| Blood | 238 (6.3) |
| Colon | 209 (5.5) |
| Esophagus | 189 (5.0) |
| Cervix | 142 (3.7) |
| Bladder | 114 (3.0) |
| Nasopharynx/throat | 80 (2.1) |
| Ovarium | 47 (1.2) |
| Prostate | 35 (0.9) |
| Treatment pattern for primary tumor, n (%) | |
| Surgery | 1,173 (4.6) |
| Chemo | 6,624 (16.5) |
| Radiation | 55 (0.1) |
| Targeted/immunization | 552 (1.4) |
SD, standard deviance.
Tumor prevalence
We also calculated the tumor prevalence in different target lesions in 2018 and 2019. The statistical results (Table 2) show that tumors occurring in the thyroid, lung, liver, stomach, and rectum were the most common. The prevalence of thyroid cancer was 35.4 patients per 100,000 persons, for lung 33.6% and for liver cancer 32.6%. However, in 2019, the prevalence of lung tumors was highest (30.6 patients/100,000), followed by thyroid and stomach tumors (27.0 and 28.7 patients/100,000, respectively).
Table 2
| Target lesion (patients/100,000) | 2018 (n=466,700), n (%) | 2019 (n=466,790), n (%) |
|---|---|---|
| Thyroid | 165 (35.4) | 126 (27.0) |
| Lung | 157 (33.6) | 143 (30.6) |
| Liver | 152 (32.6) | 91 (19.5) |
| Stomach | 137 (29.4) | 134 (28.7) |
| Rectum | 128 (27.4) | 72 (15.4) |
| Breast | 110 (23.6) | 90 (19.3) |
| Blood | 94 (20.1) | 64 (13.7) |
| Colon | 77 (16.5) | 61 (13.1) |
| Esophagus | 72 (15.4) | 56 (12.0) |
| Cervix | 67 (14.4) | 31 (6.6) |
| Bladder | 39 (8.4) | 34 (7.3) |
| Nasopharynx/throat | 36 (7.7) | 24 (5.1) |
| Ovarium | 25 (5.4) | 24 (5.1) |
| Prostate | 11 (2.4) | 18 (3.9) |
Pattern of treatment seeking
We investigated the treatment rate per year in thirteen township central hospitals (Table 3) and this showed 10,726 visits occurred in county health centers, with 29.9% of these all-cause visits, while tumor-specific visits were seen in 1,603 (23.2%) of patients visiting township central hospitals. The analysis result for all-cause visits showed a huge increase in treatment rates in township central hospitals, rising from 5.3% in the period between Jul 2017 and Dec 2017 to 34.1% in 2020. The treatment rate for tumor-specific visits in township central hospitals also showed a large increase from 2017 to 2020, while the rise was less across 2018, 2019, and 2020, with 25.2%, 23.8%, and 22.4%, respectively.
Table 3
| Year | All-cause | Tumor-specific | |||
|---|---|---|---|---|---|
| Total visits | Visits in county health centers, n (%) | Total visits | Visits in county health centers, n (%) | ||
| Total | 35,835 | 10,726 (29.9) | 11,237 | 2,603 (23.2) | |
| 2017.7–2017.12 | 1,672 | 89 (5.3) | 468 | 39 (8.3) | |
| 2018.1–2018.12 | 10,976 | 3,048 (27.8) | 3,240 | 818 (25.2) | |
| 2019.1–2019.12 | 14,180 | 4,516 (31.8) | 4,419 | 1,050 (23.8) | |
| 2020.1–2020.8 | 9,007 | 3,073 (34.1) | 3,110 | 696 (22.4) | |
Total visits: total visits in Yun County medical health care units.
For the referral rate analysis, we investigated the yearly rate from 2017 to 2020 in the Yun County medical community, and three referral patterns for all-cause and tumor-specific visits were assessed separately. We defined the two higher level hospitals as the top units and the 13 township central hospitals as down units. Table 4 shows 1,154 and 294 patients were referred for all-cause visits and tumor-specific visits, respectively, while for or all-cause visits, 199 patients (17.2%) experienced “up-to-down” referral, 130 patients (11.3%) experienced “down-to-top” pattern, and 825 patients (71.5%) experienced bidirectional referral. For tumor-specific visits, 125 patients (42.5%) had “up-to-down” referral, 25 patients (8.5%) were referred “down-to-up”, and 144 patients (49.0%) received referral in both directions. In addition, in the yearly analysis result, “down-to-up” referral increased from 2017 to 2020 for all-cause or tumor-specific visits, while “up-to-down” referral was similar in 2018, 2019, and 2020 with 34.7%, 34.2% and 31.7% for all-cause visits, and 30.4%, 35.2%, and 33.6% are for tumor-specific in 2018, 2019, and 2020, respectively. Finally, most bidirectional referral occurred in 2019.
Table 4
| Year | All-cause (n=1,154), n (%) | Tumor-specific (n=294), n (%) | |||||
|---|---|---|---|---|---|---|---|
| Up-to-down | Down-to-up | Both | Up-to-down | Down-to-up | Both | ||
| Overall (number of patients) | 199 (17.2) | 130 (11.3) | 825 (71.5) | 125 (42.5) | 25 (8.5) | 144 (49.0) | |
| 2017.7–2017.12 | 1 (0.5) | 0 (0.0) | 12 (1.5) | 1 (0.8) | 0 (0.0) | 2 (1.4) | |
| 2018.1–2018.12 | 69 (34.7) | 23 (17.7) | 382 (46.3) | 38 (30.4) | 8 (32.0) | 47 (32.6) | |
| 2019.1–2019.12 | 68 (34.2) | 51 (39.2) | 547 (66.3) | 44 (35.2) | 6 (24.0) | 79 (54.9) | |
| 2020.1–2020.8 | 61 (31.7) | 56 (43.1) | 489 (59.3) | 42 (33.6) | 11 (44.0) | 63 (43.8) | |
Disease burden
We also assessed medical resource consumption for all-cause and tumor-specific visits. The medical resource consumption results (Table 5) indicated that the mean number of outpatient visits was 9.99 visits/person for all-cause visits and 3.94 visits/person for tumor-specific visits, while across the time of analysis, the mean outpatient visit was 8.00 visits per person per year for all-cause visits, and 5.13 for tumor-specific visits. The mean interval for outpatient visits was 64.02 days for all-cause visits, and 68.08 for tumor-specific visits for patients having at least two visits.
Table 5
| Characteristics | All-cause (n=3,792) | Tumor-specific (n=3,792) |
|---|---|---|
| Outpatient | ||
| Visits (visits/person) | 9.99±13.50 | 3.94±8.59 |
| Visits (visits/person, year) | 8.00±7.96 | 5.13±7.49 |
| Visits ≥2, n (%) | 3,132 (87.30) | 1,425 (48.0) |
| Outpatient interval (days) | ||
| Mean ± SD | 64.02±79.83 | 68.08±95.20 |
| Median (Q1–Q3) | 40.10 (19.80–77.40) | 34.50 (12.00–81.45) |
| Inpatient | ||
| Visits/person | ||
| Mean ± SD | 2.56±2.57 | 2.19±2.34 |
| Median (Q1–Q3) | 1.00 (1.00–3.00) | 1.00 (1.00–2.00) |
| Length of hospital stay (days) | ||
| Mean ± SD | 8.62±6.22 | 9.25±7.05 |
| Median (Q1–Q3) | 7.20 (5.00–10.40) | 7.80 (5.00–11.00) |
| Length of hospital stay (days/person, year) | 13.45±12.80 | 16.06±14.6 |
| Visits ≥2, n (%) | 1,179 (49.91) | 653 (33.6) |
| Inpatient interval (days) | ||
| Mean ± SD | 137.78±166.27 | 94.09±136.53 |
| Median (Q1–Q3) | 72.98 (28.24–178.65) | 36.82 (21.52–97.02) |
| Readmission in 12 months after initial diagnosis, n (%) | 2,317 (98.09) | 1,923 (98.9) |
| Length of hospital stay (days/visit) | ||
| Mean ± SD | 8.10±6.82 | 8.20±7.32 |
| Median (Q1–Q3) | 6.00 (3.90–10.00) | 6.00 (3.80–10.00) |
| Length of hospital stay (readmission in 12 months after initial diagnosis, days/visit) | ||
| Mean ± SD | 8.28±6.96 | 8.39±7.46 |
| Median (Q1–Q3) | 6.00 (4.00–10.10) | 6.00 (3.90–10.10) |
SD, standard deviance.
The mean number of inpatient visits was 2.56 and 2.19 visits/person for all-cause and tumor-specific visits, respectively, and the mean length of hospital stay was 8.62 and 9.25 days for all-cause visits and tumor-specific visits, respectively. The mean interval for inpatient visits was 137.78 and 94.09 days for all-cause and tumor-specific visits, respectively in patients having at least two visits. Almost all patients had readmission in 12 months after initial diagnosis, and the length of hospital stay for readmission were 8.28 and 8.39 days for all-cause and tumor-specific patients, respectively.
Analysis of the economic burden in 2018 and 2019 in Yun County (Table 6) showed the total cost of all-cause visits in 2018 was 14.471 million, the outpatient and inpatient cost for these years were 1.556 and 12.915 million, respectively, and medical insurance covered 71.7% of the total cost. In 2019, the total cost for all-cause visits was 20.29 million, with 2.37 and 17.91 million for outpatient and inpatient visit costs, respectively, and medical insurance covered 73% for all costs, with 32.3% and 78.4% for outpatient and inpatient costs, respectively. For tumor-specific visits, the total costs were 9.933 and 15.088 million in 2018 and 2019, and the percentages for insurance coverage were the same with 76.6% in 2018 and 2019.
Table 6
| Cost [10,000] | 2018 | 2019 | |||||
|---|---|---|---|---|---|---|---|
| Total cost | Outpatient | Inpatient | Total cost | Outpatient | Inpatient | ||
| All-cause | |||||||
| Total | 1,447.1 | 155.6 | 1,291.5 | 2,029.0 | 237.1 | 1,791.9 | |
| Reimbursement, n (%) | 1,037.8 (71.7) | 28.2 (18.1) | 1,009.7 (78.2) | 1,480.6 (73.0) | 76.5 (32.3) | 1,404.1 (78.4) | |
| Self-pay, n (%) | 409.3 (28.3) | 127.5 (81.9) | 281.8 (21.8) | 548.4 (27.0) | 160.6 (67.7) | 387.8 (21.6) | |
| Tumor-specific | |||||||
| Total | 993.3 | 43.6 | 949.7 | 1,508.8 | 85.4 | 1,423.5 | |
| Reimbursement, n (%) | 761.3 (76.6) | 9.7 (22.2) | 751.6 (79.1) | 1,155.0 (76.6) | 35.1 (41.1) | 1,119.9 (78.7) | |
| Self-pay, n (%) | 232.1 (23.4) | 33.9 (77.8) | 198.1 (20.9) | 353.8 (23.4) | 50.2 (58.9) | 303.6 (21.3) | |
We also assessed the median total cost, outpatient cost, and inpatient cost per person (Table 7) and median costs per visit (Table 8) by year. The median costs per person in the first year (from July 2017 to June 2018) were ¥1,307.4 and ¥1,605.4 all-cause and tumor-specific visits, respectively, while for the second year these were ¥1,273.2 and ¥1,218.0. The median total costs per person increased to ¥2,086.0 and ¥2,300.6 for all-cause and tumor-specific, respectively, in the third year.
Table 7
| Median cost/person | All-cause | Tumor-specific | |||||
|---|---|---|---|---|---|---|---|
| Total cost | Outpatient cost | Inpatient cost | Total cost | Outpatient cost | Inpatient cost | ||
| 2017.7–2018.6 | 1,307.4 (229.2–6,462.5) | 299.6 (112.5–715.8) | 6,730.0 (3,811.0–6,730.0) | 1,605.4 (114.2–6,951.4) | 104.4 (29.4–317.9) | 6,828.0 (3,853.0–16,671.0) | |
| 2018.7–2019.6 | 1,273.2 (1,273.2–6,880.9) | 441.4 (166.5–1,048.3) | 7,174.0 (4,112.0–14,950.0) | 1,218.0 (145.0–7,182.4) | 193.0 (61.2–555.1) | 7,538.4 (4,225.7–16,231.5) | |
Table 8
| Median cost/visit | All-cause | Tumor-specific | |||||
|---|---|---|---|---|---|---|---|
| 2017.7–2018.6 | 2018.7–2019.6 | 2019.7–2020.6 | 2017.7–2018.6 | 2018.7–2019.6 | 2019.7–2020.6 | ||
| Total cost | 167.3 (44.3–616.4) | 116.0 (42.6–335.6) | 134.7 (43.6–416.0) | 203.8 (37.1–4,095.4) | 152.7 (41.3–1,534.9) | 201.7 (60.5–2,996.1) | |
| Outpatient cost | 91.7 (35.9–207.6) | 88.0 (37.6–205.0) | 90.00 (38.9–218.5) | 55.7 (21.0–170.0) | 84.82 (29.8–195.4) | 111.81 (41.56–255.00) | |
| Inpatient cost | 4,599.0 (3,328.0–6,518.0) | 4,820.0 (3,248.0–6,972.0) | 5,212.8 (588.4–7,933.4) | 4,691.0 (3,552.0–6,586.0) | 5,056.0 (3,949.0–7,429.0) | 5,499.4 (4,068.4–8,726.0) | |
| Examination fee | 340.0 (120.0–1,581.0) | 260.0 (107.0–1472.0) | 284.0 (107.0–1,483.0) | 1,402.0 (540.0–2,300.0) | 1,302.0 (195.0–2,313.0) | 926.5 (177.0–2,329.8) | |
| Drug cost | 135.15 (9.46–651.66) | 82.0 (29.9–251.4) | 85.0 (33.1–366.8) | 169.0 (31.3–1,670.4) | 111.2 (31.8–884.9) | 203.5 (59.1–1,544.6) | |
| Surgery fee | 138.0 (130.0–630.0) | 230.0 (120.0–990.0) | 220.0 (10.0–800.0) | 130.0 (130.0–630.0) | 230.0 (130.0–2,078.0) | 60.0 (10.0–1,319.0) | |
An increasing trend in median inpatient costs per visit was observed (Table 8), while other costs, including outpatient costs, examination fees, drug costs and surgery fees, showed no change.
Discussion
This retrospective study explored the electronic medical records of patients with malignant tumors in Yun County. The study analyzed the patient demographics, treatment patterns, referral patterns, medical resource consumption, and economic burden in a real-world setting.
The mean age of the 3,792 patients was 56.4 years old and there were more males than females (51.8% vs. 48.2%). Han ethnics dominated the study population, and over 80% of patients were covered by medical insurance. Thyroid tumors were the most common cancer, followed by lung, liver, and stomach. The high prevalence of thyroid cancer seen may be because of its less serious nature, making it relatively easy to treat in local centers, and not requiring referral to tertiary hospitals outside the region. The initial treatment for malignant tumors was chemotherapy, followed by surgery, with a small number of patients receiving radiation, target, or immunization therapy. This too may be because sophisticated procedures, such as radiation and immunotherapy, are less likely to be practiced at smaller hospitals.
The number of individuals seeking care for malignant tumors increased yearly, whether all-cause or tumor-specific visits. Moreover, the treatment rate in township central hospitals increased yearly for all-cause visits, while the treatment rate for tumor-specific visits decreased yearly. The results indicated that cancer patients preferred to attend higher level hospitals for treatment, while other patients choose to seek care at local centers. In addition, referral between higher level hospital and township central hospitals for cancer patients was high, whether all-cause visits or tumor-specific visits, with bidirectional referral occurring the most.
The mean number of outpatient visits per person for all-cause and tumor-specific visits were 9.99 and 3.94 visits, respectively, and the median interval for outpatient visits for all-cause and tumor-specific patients were 40.10 and 34.50 days, respectively. The mean number of inpatient visits per person was 2.56 visits, and the mean length of hospital stay per person was 8.62 days for all-cause visits and 2.19 visits and 9.25 days for tumor-specific visits.
The total cost of care showed a large increase in 2019 compared with 2018, in both all-cause visits and tumor-specific visits. Moreover, medical insurance coverage increased yearly, both in total reimbursement cost and the percentage covered. In addition, while an obvious increase in the year-to-year outpatient and inpatient costs per person was observed, there was no trend in the cost of outpatient and inpatient per visits. This suggests reforms to the medical system may have resolved issues around overtreatment or over examination and may have assisted in controlling the cost of care for patients.
As this study was limited to one county and across a 3-year period only, the results may not be more generally applicable, and studies involving additional counties and across longer periods of time are required. As a part of a trial of a comprehensive reform of county-level public hospitals, the experience and pattern of Yun County will be promoted and popularized to other county areas, thus, more clinical cases, longer research time, the comparison with other regions would be feasible in the future.
Conclusions
Dealing with cancer is time consuming and brings significant financial and emotional stress to individuals, their families, and the community at large. In addition to prevention and early detection, early treatment for cancer patients is crucial. Changes to the medical environment in Yun County, including medical system reform and medical insurance, have greatly decreased the disease burden for cancer patients.
Acknowledgments
Funding: None.
Footnote
Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://dx.doi.org/10.21037/apm-21-2075
Data Sharing Statement: Available at https://dx.doi.org/10.21037/apm-21-2075
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/apm-21-2075). The authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was approved by the ethics committee of Yun County People’s Hospital (approval number: 2021-02). All procedures performed in this study involving human participants were in accordance with the Declaration of Helsinki (as revised in 2013). Individual consent for this retrospective analysis was waived.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
References
- Bray F, Ferlay J, Soerjomataram I, et al. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin 2018;68:394-424. Erratum in: CA Cancer J Clin 2020;70:313. [Crossref] [PubMed]
- Chen W, Zheng R, Baade PD, et al. Cancer statistics in China, 2015. CA Cancer J Clin 2016;66:115-32. [Crossref] [PubMed]
- Chen W, Zheng R, Zeng H, et al. The incidence and mortality of major cancers in China, 2012. Chin J Cancer 2016;35:73. [Crossref] [PubMed]
- Zhang S, Sun K, Zheng R, et al. Cancer incidence and mortality in China, 2015. Journal of the National Cancer Center 2021;1:2-11. [Crossref]
- Li Q, Hsia J, Yang G. Prevalence of smoking in China in 2010. N Engl J Med 2011;364:2469-70. [Crossref] [PubMed]
- Yang T, Wu J, Rockett IR, et al. Smoking patterns among Chinese rural-urban migrant workers. Public Health 2009;123:743-9. [Crossref] [PubMed]
- Zeng H, Zheng R, Guo Y, et al. Cancer survival in China, 2003-2005: a population-based study. Int J Cancer 2015;136:1921-30. [Crossref] [PubMed]
- Yun County 2018 Statistical Bulletin. 2019. (Accessed Jan 27, 2021). Available online: http://www.ynyx.gov.cn/yxrmzf/zwdt78/tzgg63/305765/index.html
- Yun County 2019 Statistical Bulletin. 2020. (Accessed Jan 29, 2021). Available online: http://www.ynyx.gov.cn/yxrmzf/zdlygk66/sjxx0/535453/index.html
- Notice for implementation of basic medical insurance DRG payment reform in Yun County. 2019. (Accessed Jan 27, 2021). Available online: http://www.ynyx.gov.cn/yxrmzf/zwdt78/tzgg63/298047/index.html
(English Language Editor: B. Draper)
