Competing risks analysis of external versus internal radiation in patients with hepatocellular carcinoma after controlling for immortal time bias.

PURPOSE: In cohort studies on liver cancer, there are often immortal time bias and interference of competing risk events. This study proposes to explore the role of internal and external radiotherapy for hepatocellular carcinoma using SEER data, using a competing risk model and controlling immortal time bias. METHODS: Data of SEER from 2004 till 2015 was included. To analyze whether there was a difference in survival between HCC (hepatocellular carcinoma) patients receiving external radiation and internal radiation, we used a competing risk analysis after excluding immortal time bias, and created a nomogram to assess the risk of cancer-specific death (CSD) in hepatocellular carcinoma patients receiving radiotherapy. RESULTS: Potential confounding factors adjusted, there was no significant difference in CSD between external and internal radiation therapy [HR and its 95% CI = 1.098 (0.874-1.380)]. The constructed nomogram performed better than the traditional AJCC model. The AUC and calibration curve results showed that this well-calibrated nomogram could be used to make clinical decisions regarding the prognosis and personalized treatment of hepatocellular carcinoma treated. There was no difference in the cumulative risk of death between patients with liver cancer treated with external radiation therapy and internal radiation therapy. CONCLUSION: There is no difference in the cumulative risk of death between patients with liver cancer treated with external radiation therapy and internal radiation therapy. The nomogram predicts the results more accurately. These results can be used to guide the choice of treatment options for patients with HCC and to predict their survival prognosis.

[Effects of Nutrient Inputs on Changes of Phosphorus Forms and Phytoplankton Growth in Taihu Lake].

In order to determine the effects of nutrient inputs on changes of phosphorus forms and phytoplankton growth in large shallow lakes, an enrichment bioassay was conducted using surface lake water collected from the Meiliang Bay of Taihu Lake in spring. The concentration of different phosphorus forms, phytoplankton biomass (chlorophyll a) and alkaline phosphatase activity (APA) was analyzed after the addition of different concentrations of inorganic nutrients. The results showed that the phytoplankton biomass increased significantly with the addition of phosphorus (P), but with no primary effect from nitrogen (N), which suggested the phytoplankton growth was mainly limited by P. The maximum growth rate and the highest concentration of chlorophyll both occurred in the SRP 0.015 mg x L(-1) treatment. Nitrate addition could improve the bioavailability of phosphorus, accelerate the phosphorus cycling process and promote the growth of APA. There was an induction-repression mechanism resulting in a negative relationship between APA and orthophosphate concentration. The APA was obviously stimulated under PO4(3-) -P ≤ 0.025 mg x L(-1). This paper researches the transformation and cycling process of phosphorus in water and the induction-repression mechanism between the APA and orthophosphate concentration. The result can help to reveal the compensation path of nutrients in algae growth process and provide a theoretical basis for the further reveal of the mechanism of algae outbreaks.