Psychological distress and breast cancer : a bidirectional link

Psychological distress is one of the six vital signs among patients with cancer. An increased risk of psychiatric disorders has also been reported among cancer patients, compared with the general population. On the other hand, psychological distress might also influence the initiation and progression of cancer. As breast cancer is the most common cancer, and females are more vulnerable to psychiatric disorders than men, we further investigated the bidirectional link between psychological distress and breast cancer. The potential mechanisms linking together psychological distress and breast cancer include inflammation, neuroendocrine pathways, behavioral factors, and reproductive and hormonal factors. In this thesis, we studied various response processes and consequences of psychological distress in relation to the risk, prognosis, and diagnostic workup of breast cancer, including stress coping ability, anti-inflammatory drug use, and genetic determinants of different stress pathways, to comprehensively investigate such a link. In Study I, we examined whether sense of coherence (SoC), as a measure of resilience to psychological distress, reduced the risk of breast cancer. We included all women who had answered the SoC-13 questionnaire when enrolled in the Karolinska Mammography Project for Risk Prediction of Breast Cancer (KARMA) cohort, and identified incident cases of breast cancer after enrollment of these women through cross-linkages with Swedish national registers. We used the SoC score measured at enrollment as the main exposure because SoC is believed to be stable. We estimated the hazard ratio (HR) and 95% confidence interval (CI) of breast cancer in relation to SoC, based on Cox proportional hazards models, after adjustment for potential confounders. We found no evidence to support an association between SoC and risk of breast cancer (HR: 1.08; 95% CI: 0.90-1.29). In Study II, considering that inflammation is a critical component in both cancer development and stress response (especially chronic stress response), we assessed whether use of non-steroidal anti-inflammatory drugs (NSAIDs) reduced the risk of breast cancer. We used a nested case-control design within the general female population of Sweden as well as within the KARMA cohort. Conditional logistic regression models were used to estimate HRs and 95% CIs, adjusted for potential confounders. We did not find use of aspirin to be associated with the risk of breast cancer. However, use of non-aspirin NSAIDs was associated with a slightly increased risk of early-stage breast cancer (HR: 1.05; 95% CI: 1.02-1.08), a decreased risk of advanced-stage breast cancer (HR: 0.80; 95% CI: 0.73-0.88), and a decreased risk of breast cancer in general among women with dense breasts (HR: 0.72; 95% CI: 0.59-0.89). In study III, we aim to understand the potential genetic determinants of the link between psychological distress and breast cancer prognosis. We assessed whether somatic mutations and gene expression of the neuroendocrine pathways, namely the adrenergic, cholinergic, dopaminergic, glucocorticoid, and serotonergic pathways, which are directly involved in stress response, were associated with breast cancer prognosis. We used a matched extreme case-control design based on two cohorts of breast cancer patients from China, US, and other countries. Somatic mutations and gene expression data were derived from whole exome sequencing (WES) and RNA sequencing on tumor and paired normal breast tissues. Logistic regression was used to estimate the odds ratio of invasive disease-free survival (iDFS). A two-fold increase of somatic mutation burden in genes of the glucocorticoid pathway was associated with a 17% (95% CI: 2%-35%) elevated odds of reaching iDFS endpoints. This association might be regulated through differential gene expression of the glucocorticoid pathway in tumor tissue. In Study IV, we compared the risk of psychiatric disorders potentially related to psychological distress among cancer patients with or without pre-diagnostic use of NSAIDs. We conducted a cohort study including all cancer patients diagnosed during July 2006 to December 2013 in Sweden and followed them for an incident diagnosis of anxiety, depression, or stress-related disorders. Cox proportional hazards models were used to estimate the HR and 95% CI, adjusted for potential confounders. We found a reduced risk of anxiety, depression, and stress-related disorders among cancer patients with pre-diagnostic use of aspirin (HR: 0.88; 95% CI: 0.81-0.97) and contrastingly an increased risk of these psychiatric disorders among patients with pre-diagnostic use of non-aspirin NSAIDs (HR: 1.24; 95% CI: 1.15-1.32). A more prominent risk decreased in relation to aspirin use was found among females and patients with breast cancer. Taken together, the knowledge gained through this thesis work helps to improve our understanding on the role of psychological distress in the risk and prognosis of cancer and supports intervention of severe psychological distress subsequent to a cancer diagnosis. In the long run, such knowledge should also help pave the way for the development of innovative measures for the prevention of cancer and cancer-related morbidity and mortality

WeStore or AppStore: How we shop differently in mobile apps vs. social commerce

In the dynamic world of e-commerce, social commerce has emerged as a revolutionary force, transforming the ways consumers interact, explore, and purchase products online. This paper investigates the differences in customers' search and purchase patterns between a prominent online retailer's burgeoning social commerce channel—WeChat mini-program—and its native mobile app. We study customers' entire journey through a sequential search model that captures decisions from channel selection to which products to search, search termination, and final purchase. Our research contributes to the search model literature by being the first to estimate both fixed and marginal search costs in a sequential search model that leverages an omnichannel retail environment and search path data. We calculate fixed search costs, marginal search costs, and preferences for each channel and uncover differences in customers' search and purchase behaviors across channels. Our findings indicate that customers experience higher fixed search costs on WeChat, but lower marginal search costs compared to the mobile app. Additionally, customer characteristics such as historical spending levels and time of search influence their search costs. Based on these insights, we suggest two strategies tailored to each channel that leverages the differences in customers' search costs. The first strategy involves encouraging search initiation by lowering fixed search costs through peer-to-peer link sharing in the WeChat channel, while the second strategy aims to reduce marginal search costs using search-triggering coupons in the App channel. Implementing these approaches leads to a significant increase in conversion rates and profits for the online retailer. Our paper is one of the first to explore the differences between traditional retail channels and emerging social commerce channels

WeStore or AppStore: how customers shop differently in mobile apps vs. social commerce

In the dynamic e-commerce environment, social commerce has emerged as a revolutionary force, transforming how consumers interact and transact online. This paper investigates the differences in customers’ search and purchase patterns between a prominent online retailer’s burgeoning social commerce channel, the WeChat mini-program, and its native mobile app. We analyze the customers’ entire journey through a sequential search model that encapsulates decisions from channel selection to product search, search termination, and the final purchase. This study contributes to the search model literature by being the first to estimate both fixed and marginal search costs in a sequential search model in an omnichannel retail environment. We calculate fixed search costs, marginal search costs, and preferences for each channel, revealing differences in customers’ behaviors across channels. Our analysis shows that customers’ fixed search costs are higher, but marginal costs are lower on WeChat channel compared to the App channel. Also, customer characteristics like historical spending levels and search timing influence their search costs. From these insights, we suggest strategies tailored to each channel capitalizing on the differences in customers’ search costs. The first strategy encourages search initiation by lowering fixed search costs through peer-to-peer link sharing in the WeChat channel. The second strategy aims to minimize marginal search costs using search-triggering coupons in the App channel. Implementing these strategies significantly boosts conversion rates and profits for the online retailer. This research is one of the first to explore the differences between traditional retail channels and emerging social commerce channels

An interpolation matched interface and boundary method for elliptic interface problems

AbstractAn interpolation matched interface and boundary (IMIB) method with second-order accuracy is developed for elliptic interface problems on Cartesian grids, based on original MIB method proposed by Zhou et al. [Y. Zhou, G. Wei, On the fictious-domain and interpolation formulations of the matched interface and boundary method, J. Comput. Phys. 219 (2006) 228–246]. Explicit and symmetric finite difference formulas at irregular grid points are derived by virtue of the level set function. The difference scheme using IMIB method is shown to satisfy the discrete maximum principle for a certain class of problems. Rigorous error analyses are given for the IMIB method applied to one-dimensional (1D) problems with piecewise constant coefficients and two-dimensional (2D) problems with singular sources. Comparison functions are constructed to obtain a sharp error bound for 1D approximate solutions. Furthermore, we compare the ghost fluid method (GFM), immersed interface method (IIM), MIB and IMIB methods for 1D problems. Finally, numerical examples are provided to show the efficiency and robustness of the proposed method

Investigating esophageal sarcomatoid carcinoma and its comparison with esophageal squamous cell carcinoma on clinicopathological characteristics, prognosis, and radiomics features: a retrospective study

IntroductionEsophageal sarcomatoid carcinoma (ESC) is a rare pathological subtype of esophageal carcinomas, wherein its epithelial component typically demonstrates squamous cell carcinoma (SCC). However, the clinicopathological features and prognosis of ESC remain unclear, alongside its unique aspects compared to esophageal SCC (ESCC).MethodsBetween January 2008 and December 2018, we retrospectively reviewed 67 ESC patients treated at West China Hospital. Among them, 51 patients with resected ESC were matched with 98 resected ESCC patients over the same period using propensity score matching at 1:2. The survival time and radiomics features of the two groups were compared.ResultsA total of 59 patients with resected ESC and eight patients with non-resected ESC were enrolled. Progression-free survival (PFS) and overall survival (OS) were significantly different in patients with different TNM stages (p < 0.001). A multivariate analysis showed that length of tumor was an independent factor for OS in resetable ESC (p = 0.041). Among matched ESC and ESCC patients, OS was significantly longer for patients with ESC than those with ESCC (5-year OS, 61.1% vs. 43.6%; HR 0.59, 95% CI 0.35–0.96; p = 0.032). A Rad-score for discriminating ESC from ESCC containing two CT-derived radiomics features was developed [area under the curve: 0.823 (95% CI 0.732–0.913) in the training cohort and 0.828 (95% CI 0.636–1.000) in the validation cohort, respectively].ConclusionsESC has a better prognosis when compared with ESCC. By developing a radiomics prediction model, we provide reliability and convenience for the differential diagnosis of ESC from ESCC