Interpreting the number of ramified covering of a Riemann surface by Riemann surfaces as the relative Gromov-Witten invariants and applying a gluing formula, we derive a recursive formula for the number of ramified covering of a Riemann surface by Riemann surface with elementary branch points and prescribed ramification type over a special point.

Background Pulmonary sclerosing pneumocytoma is a kind of rare benign pulmonary tumor with potential malignancy. The clinical features, risk factors for prognosis, and optimal treatment have not been identified yet. This study aimed to investigate the clinical features and prognosis of pulmonary sclerosing pneumocytoma. Methods We retrospectively performed a review of pulmonary sclerosing pneumocytoma patients in West China Hospital from 2009 to 2019. The basic characteristics, treatment regimens, operation detail, postoperative variables, and follow-up time were recorded for each case. Differences in features between patients undergoing lobectomy and segmentectomy were compared. We also performed a case review and summarized reported clinical features in former studies. Results Altogether 61 pulmonary sclerosing pneumocytoma patients were retrospectively reviewed. Fifty-six patients were female and 5 were male. The patients’ median age was 51 (23-73). Seven (11.48%) patients had smoking history. Twenty tumors were located in the right lung [upper lobe (n = 7), middle (n = 2), and lower (n = 11)] and 41 in the left [upper (n = 12) and lower (n = 29)]. The median tumor size was 2 (0.9-7) cm. Thirty-six (59.02%) patients underwent sublobectomy (segmentectomy or wedge resection) whereas 25 (40.98%) underwent lobectomy. All patients recovered uneventfully, and no perioperative mortality was identified. Sublobectomy showed a trend towards reduced chest tube duration and shorter postoperative hospital stays compared with lobectomy. Conclusions The findings showed good prognosis of pulmonary sclerosing pneumocytoma and proved its benign characteristics. Sublobectomy showed advanced efficacy regarding chest tube duration and postoperative hospital stay compared with lobectomy.

The availability and affordability of medicines remain major health challenges around the world. In March 2019, the Chinese government introduced a pilot National Centralized Drug Procurement (NCDP) program in order to reduce drug prices and improve the affordability of effective and safe medicines. This study aimed to assess the impact of NCDP policy on health expenditures of cancer patients. Using inpatient discharge records from a large hospital in the pilot city, we performed a difference-in-differences design to estimate the change in health expenditures before and after the policy. We found that the implementation of NCDP was associated with a significant decrease in total expenditures (14.13%) and drug expenditures (20.75%) per inpatient admission. There were also significant reductions in non-drug-related expenditures, including a 7.65% decrease in health service expenditures, a 38.28% decrease in diagnosis expenditures, and a 25.31% decrease in consumable material expenditures per inpatient admission. However, the NCDP implementation was associated with a 107.97% increase in the traditional Chinese medicine expenditures. Overall, the study provided evidence that the NCDP policy has achieved its goals of high-quality and affordable healthcare. The drug expenditures of lung cancer patients revealed a continuous decline, and the policy may have spillover effects on other healthcare expenditures. Further studies are needed to evaluate the long-term effects of NCDP on policy-related expenditures and health outcomes.

BackgroundUniportal video-assisted thoracoscopic surgery (UniVATS) was utilized with a rapid growth. The evidence is sparse, however, on whether to add external suction to water-seal drainage for chest drainage after UniVATS. This retrospective propensity score-matched study aimed to identify the necessity of adding external suction to chest drainage after UniVATS.MethodsPatients with lung cancer who underwent UniVATS were included from our prospectively maintained database. Patients were divided into two cohorts based on the addition of external suction to postoperative water-seal drainage or not. Propensity score-matched analysis was performed to identify the impact of suction on chest tube duration, incidence of persistent air leak, hospital stay, and hospitalization cost. Multivariable model with interaction terms was constructed to identify impact of covariables on effect of suction.ResultsThe two cohorts matched well on baseline characteristics (nonsuction: 173; suction: 96). Compared with nonsuction group, suction group showed longer median chest tube duration (3 vs. 2 days, p = 0.003), higher incidences of persistent air leak (9.4% vs. 1.2%, p = 0.003), persistent drainage (16.8% vs. 5.8%, p = 0.007), and reduced drainage volume within first 3 postoperative days (386.90 vs. 504.78 ml, p = 0.011). Resection extent was identified to mediate the relationship between suction and chest tube drainage.ConclusionsThese findings discouraged adding external suction to water-seal drainage after UniVATS regarding longer chest tube duration and more persistent air leak. Patients undergoing lobectomy would benefit more from water-seal drainage without external suction compared with those doing sublobectomy.