Iterative Network Pricing for Ridesharing Platforms

Ridesharing platforms match riders and drivers, using dynamic pricing to balance supply and demand. The origin-based "surge pricing", however, does not take into consideration market conditions at trip destinations, leading to inefficient driver flows in space and incentivizes drivers to strategize. In this work, we introduce the Iterative Network Pricing mechanism, addressing a main challenge in the practical implementation of optimal origin-destination (OD) based prices, that the model for rider demand is hard to estimate. Assuming that the platform's surge algorithm clears the market for each origin in real-time, our mechanism updates the OD-based price adjustments week-over-week, using only information immediately observable during the same time window in the prior weeks. For stationary market conditions, we prove that our mechanism converges to an outcome that is approximately welfare-optimal. Using data from the City of Chicago, we illustrate (via simulation) the iterative updates under our mechanism for morning rush hours, demonstrating substantial welfare improvements despite significant fluctuations of market conditions from early 2019 through the end of 2020

Familial Associations of Colorectal Cancer with Other Cancers

Colorectal cancer (CRC) has a strong familial component which extends to discordant cancers (ie non-CRC tumors). This is best seen in cancer syndromes such as hereditary non-polyposis colorectal cancer (HNPCC) which predisposes to several tumor types. Population-based family studies have also found discordant associations for CRC but they have included cancers which manifest in HNPCC, and there is no convincing evidence of discordant associations beyond the known syndromes. We address familial associations of non-CRC tumors with CRC using the resources of the Swedish Family-Cancer Database and applying a powerful approach of assessing familial relative risks in families of increasing numbers of patients with discordant cancers. Among 1.8 million cancer patients and over 200,000 CRC cases consistent familial associations of CRC was observed for several HNPCC related cancers. However, for small intestinal, pancreatic and nervous system cancers RRs remained essentially unchanged when potential HNPCC families were excluded, suggesting involvement of genes not related to HNPCC. Two independent associations of CRC were found for melanoma, thyroid and eye cancers and these appeared not to be related to known syndromes. A number of other cancers associated with CRC in single analyses and independent studies are required to assess the relevance of such findings.Peer reviewe

Familial Associations of Colon and Rectal Cancers With Other Cancers

BACKGROUND: Many studies have indicated that colon and rectal cancers differ in etiology and histology. OBJECTIVE: The aim of this study was to investigate whether the associations of colon and rectal cancers with any other (discordant) cancer were site specific. DESIGN: A novel approach was implemented in which cancer risks were analyzed in families with increasing numbers of family members diagnosed with defined cancers. The novel assumption was that, for a true familial association, the risk should increase by the number of affected family members. In separate analyses, familial risks were calculated after the exclusion of putative families with hereditary nonpolyposis colorectal cancer. SETTINGS: The study was conducted using the Swedish Family-Cancer Database. MAIN OUTCOME MEASURES: The outcome measure was relative risk. RESULTS: Relative risks of colorectal cancer and colon cancer were higher when family members were diagnosed with colon cancer than when family members were diagnosed with rectal cancer (incidence rate ratio for colorectal: 1.82 (95% Cl, 1.74-1.90) vs 1.61 (95% Cl, 1.51-1.71); incidence rate ratio for colon: 1.92 (95% Cl, 1.83-2.02) vs 1.56 (95% CI, 1.45-1.69)). Relative risks for 10 discordant cancers were increased in colon or rectal cancer families, whereas none of the relative risks differed significantly between colon and rectal cancers. After deleting hereditary nonpolyposis colorectal cancer families, the relative risks of endometrial and ovarian cancers were no longer significant. LIMITATIONS: Genetic data are unavailable in the database. CONCLUSIONS: Our results suggested that familial risks for colon cancer were higher than risks for rectal cancer in families of patients with colorectal cancer and colon cancer. The relationships of lung cancer and nervous system cancer with colorectal cancer were site specific. The associations of colon and rectal cancers with lung cancer, myeloma, and cancer of unknown primary appeared not to point out known syndromes and may suggest involvement of a novel predisposition.Peer reviewe

Common cancers share familial susceptibility : implications for cancer genetics and counselling

Background It has been proposed that cancer is more common in some families than in others, but the hypothesis lacks population level support. We use a novel approach by studying any cancers in large three-generation families and thus are able to find risks even though penetrance is low. Methods Individuals in the nation-wide Swedish Family-Cancer Database were organised in three generations and the relative risk (RR) of cancer was calculated to the persons in the third generation by the numbers of patients with cancer in generations 1, 2 and 3. Results The RRs for any cancer in generation 3 increased by the numbers of affected relatives, reaching 1.61 when at least seven relatives were diagnosed. The median patient had two affected relatives, and 7.0% had five or more affected relatives with an RR of 1.46, which translated to an absolute risk of 21.5% compared with 14.7% in population by age 65 years. For prostate cancer, the RR was 2.85 with four or more affected family members with any cancer, and it increased to 14.42 with four or more concordant cancers in family members. RRs for prostate cancer were approximately equal (2.70 vs 2.85) if a man had one relative with prostate cancer or four or more relatives diagnosed with any cancer. Conclusions A strong family history of cancer, regardless of tumour type, increases cancer risk of family members and calls for mechanistic explanations. Our data provide tools for counselling of patients with cancer with both low and high familiar risks.Peer reviewe

Concordant and discordant familial cancer : Familial risks, proportions and population impact

Relatives of cancer patients are at an increased risk of the same (concordant) cancer but whether they are at a risk for different (discordant) cancers is largely unknown - beyond well characterized hereditary cancer syndromes - but would be of major scientific and clinical interest. We therefore decided to resolve the issue by analyzing familial risks when family members were diagnosed with any discordant cancers. We compared the population impact of concordant to discordant familial cancer. The Swedish Family-Cancer Database (FCD) was used to calculate familial relative risks (RRs) for family members of cancer patients, for the 27 most common cancers. Population attributable fractions (PAFs) were estimated for concordant and discordant family histories. Discordant cancers in the family were detected as significant risk factors for the majority of cancers, although the corresponding RRs were modest compared to RRs for concordant cancers. Risks increased with the number of affected family members with the highest RRs for pancreatic (2.31), lung (1.69), kidney (1.98), nervous system (1.79) and thyroid cancers (3.28), when 5 or more family members were diagnosed with discordant cancers. For most cancers, the PAF for discordant family history exceeded that for concordant family history. Our findings suggest that there is an unspecific genetic predisposition to cancer with clinical consequences. We consider it unlikely that shared environmental risk factors could essentially contribute to the risks for diverse discordant cancers, which are likely driven by genetic predisposition. The identification of genes that moderately increase the risk for many cancers will be a challenge.Peer reviewe

Familial Associations in Testicular Cancer with Other Cancers

Familial risks for testicular cancer (TC) are among the highest of all cancers. However, data are limited for histological types of TC and for possible familial associations of TC with other cancers. We used the nationwide Swedish Family-Cancer Database for years 1958 to 2015 to analyse familial relative risks (RR) for 11,138 TC patients when first-degree relatives were diagnosed with TC or other cancer in reference to those without a family history. A total of 191 familial TCs were found, which accounted for 2.0% of all TC. The RR was 5.06 when one family member was diagnosed with TC with no significant difference between seminoma and nonseminoma. However, the risk for nonseminoma was 33.59 when two family members were affected. Internally consistent familial associations of TC, particularly of seminoma, were found with breast and nervous system cancers and melanoma. Individual significant associations were found for a number of sites, including ovarian, endometrial and prostate cancers. Our results suggest that nonseminoma may have a stronger genetic background than seminoma but seminoma shares more familial associations with discordant cancers. Clustering of TC with hormone-dependent cancers of the breast, ovary, endometrium and prostate may suggest mechanistic links and possibly gene-environment interactions.Peer reviewe

Familial Ovarian Cancer Clusters with Other Cancers

Familial risk of ovarian cancer is well-established but whether ovarian cancer clusters with other cancers and the clusters differ by histology remains uncertain. Using data from the Swedish Family-Cancer Database, we explored familial associations of ovarian cancer with other cancers with a novel approach; relative risk for (histology-specific) ovarian cancer was estimated in families with patients affected by other cancers, and conversely, risks for other cancers in families with (histology-specific) ovarian cancer patients. Eight discordant cancers were associated with ovarian cancer risk, of which family history of breast cancer showed a dose-response (P-trendPeer reviewe

Familial associations of male breast cancer with other cancers

Male breast cancer is associated with female breast cancer in families but whether male breast cancer clusters with other discordant cancers has not been studied. As concordant male breast cancers are utterly rare, discordant associations of male breast cancer with other cancers may reveal genetic and possible environmental risk factors contributing to male breast cancer susceptibility. We calculated relative risks (RRs) for male breast cancer in families with discordant cancers, and conversely, for discordant cancers in families of male breast cancer patients, based on 15.7 million individuals in the Swedish Family-Cancer Database. Among 1428 male breast cancer patients, 16.2% had a female relative diagnosed with breast cancer. Ovarian and female anal cancers showed the strongest associations with male breast cancer (p value <0.0005). The other significant associations included colorectal, small intestinal, and thyroid cancers, cancer of unknown primary and non-Hodgkin lymphoma but these were each based on a single positive association with male breast cancer. The RRs for male breast cancer were increased in families in which multiple patients were diagnosed with diverse cancers, reaching an RR of 2.58 when three or more family members were affected. The results suggest that male breast cancer shares susceptibility with a number of other cancers but confirmation is needed in other datasets.Peer reviewe

Multiple myeloma: family history and mortality in second primary cancers

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