Colorectal cancer (CRC) incidence has decreased over the past three decades, due largely to screening efforts. Relatively little is known about CRC incidence among the young adult (YA) population ages 20-39, as screening typically commences at age 50 for average-risk individuals. We examined CRC incidence with a focus on YAs in order to identify high-risk subgroups. We analyzed 231,544 incident CRC cases from 1988-2009 (including 5617 YAs 20-39 years of age) from the California Cancer Registry. We assessed age-specific incidence rates by race/ethnicity, gender, and colorectal tumor location, and calculated the biannual percent change (BAPC) to monitor change in incidence over the 22-year study period. The absolute incidence of CRC per 100,000 was low among YAs 20-29 and 30-39 years old (ranging from 0.7 per 100,000 among Hispanic and African American females aged 20-29 up to 5.0 per 100,000 among Asian/Pacific Islander males aged 30-39). However, we observed increasing CRC incidence rates over time among both males and females in the YA population, particularly for distal colon cancer in Hispanic females aged 20-29 (BAPC=+15.9%; <0.042). The absolute incidence of CRC remains far lower for YAs than among adults aged 50 and over. However, CRC incidence is increasing among young adults, in contrast to the decreasing rates observed for adults in the screened population (aged 50 and above). More research is needed to better characterize YAs at increased risk for CRC.

The toxicity of diesel exhaust particles (DEP) can be due to the particle itself, extractable components, or both. Many studies focus on the biological properties of DEP-extractable components although it is possible that chemical properties inherent to the DEP itself can lead to toxicity. Thus, an examination of the chemistry inherent to DEP was carried out. Herein, we report that DEP are capable of catalyzing the consumption of O2 (monitored using a Clarke electrode) by ascorbate and thiols leading to the generation of reactive oxygen species. Consistent with the idea that DEP are capable of catalyzing the generation of reactive oxygen species, they were also found to catalyze DNA strand breakage via an O2- and reductant-dependent process. Significantly, extraction of DEP with either organic solvent (methylene chloride) or acid (aqueous HCl) did little to abrogate this chemistry. Finally, using electron paramagnetic spectrometry (EPR), DEP were found to have paramagnetic properties. The paramagnetic character of DEP may be important to their ability to catalyze the formation of reactive oxygen species and at least partially responsible for their toxicity. These findings indicate that studies that primarily consider or examine particle extracts as the toxic components of DEP may be insufficient in describing the toxicity associated with DEP exposure.

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To identify risk factors that may predispose patients with a diagnosis of obstructive sleep apnea (OSA) to fail treatment with positive airway pressure (PAP) owing to noncompliance.

Introduction Persistent lymph node positive disease after preoperative radiotherapy for rectal cancer is associated with adverse outcomes. We quatified mortality risks of persistent pathologic lymph nodes in lymph node positive rectal cancer patients treated with preoperative versus postoperative chemoradiation. Methods This was a retrospective population-based analysis of 2,038 patients with stage III rectal cancer diagnosed 1994–2005 with follow-up through 2007 using data from the California Cancer Registry. Survival estimates were generated using the Kaplan Meier method. Multivariate cancer-specific and overall mortality analyses were performed using Cox proportional-hazard ratios with adjustment for age, gender, race/ethnicity, tumor grade, T stage, N stage, socioeconomic status, and time period (1994–7, 1998–2001, 2002–5). Results Overall survival was higher among lymph node positive patients receiving postoperative chemoradiation compared to lymph node positive patients receiving preoperative chemoradiation (median overall survival= 87 versus 62 months, P=0.0002). In adjusted analyses, patients with persistent lymph node positive disease after preoperative chemoradiation treatment had increased overall (HR =1.69, 95% CI, 1.42–2.01) and CRC-specific (HR=1.78, 95% CI, 1.44–2.19) mortality risk compared to lymph node positive disease after postoperative chemoradiation treatment. Conclusions Stage III rectal cancer patients with persistent pathologic lymph nodes after preoperative chemoradiation represent a high-risk group, with higher mortality than those treated with postoperative chemoradiation.