Vegetarian Diets and Breast Cancer. Preliminary Results from the AHS-2 Cohort

s / Annals of Epidemiology 24 (2014) 682e702 685 P10. Vegetarian Diets and Breast Cancer. Preliminary Results from the AHS-2 Cohort Jason Alberto Penniecook MD, Gary E. Fraser MD, PhD. Loma Linda University Purpose: To determine the effect of vegetarian dietary patterns on the risk of breast cancer (BC) in women of the Adventist Health Study-2 (AHS-2), a prospective cohort of 96,469 subjects recruited between 2002 and 2007. Methods: Dietary patterns were determined according to the intake frequency of specific foods (red meat, poultry, fish, eggs and dairy products) using a previously validated food frequency questionnaire. The reported intake of specific food groups classified subjects into 5 groups: vegan, lactoovo-vegetarian, pesco-vegetarian, semi-vegetarian and non-vegetarian. Incident cases were identified through matching personal identifiers of the AHS-2 subjects with those from 49 state cancer registries. Attained age was used as the time variable for the left-censored proportional hazard regression analyses. A priori covariates were chosen based on existing literature. These include: race, physical and hormonal characteristics, physical activity, family history of cancer (breast or ovarian) and screening. Results: Preliminary analysis has identified 548 cases in 48,134 participants (462 postmenopausal cases). Using non-vegetarians as the reference we found that a vegan pattern was associated with a lower risk of BC (Hazard Ratio [HR] 0.65 95% Confidence Interval [CI95%] 0.42-0.99); lacto-ovo, pesco and semi-vegetarian (consumption of fish, poultry or red meats more than once per month but less than once per week) patterns were not associated with BC risk (HR 0.98 CI95% 0.79-1.22, HR 0.89 CI95% 0.64-1.23 and HR 1.05 CI95% 0.73-1.52 respectively). Conclusions: There is a lower risk of BC amongst womenwith vegan dietary patterns. Other vegetarian patterns were not associated to BC risk. P11. Multiple Primary Tumors Following Stage II and III Rectal Cancer in Patients Receiving Radiotherapy, 1998-2010 Julie Smith Gagen PhD, MPH, George Goodwin III MPH, Jonathan Tay MD. University of Nevada, Reno Objective: This report investigated the impact of radiation therapy among stage II/III rectal cancer patients who were resected for cure and then developed second primary cancer. Methods: The analysis included patients diagnosed with rectal cancer from 1992-2010 and who were registered in the National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) database. Standardized incidence ratios assessed the location of second primary cancers by the receipt and sequence of radiation therapy. A Cox proportional hazards model examined the predictors for patients who developed second primary cancers. Results: The hazard ratio for developing any type of second primary was 12% higher in patients receiving preoperative radiotherapy, Hazard Ratio and 95% Confidence Interval, HR 95%CI: 1.12 (1.0,1.2), and 33% lower for patients receiving post-operative radiotherapy, HR 95%CI: 0.75 (0.7,0.8), relative to patients who did not receive radiation therapy. The location of the second cancer varied by both the receipt and sequence of radiation therapy. Secondary rectal cancers were reduced 170% after post-operative radiation and 103% after pre-operative radiation, compared to the non-receipt of radiation therapy. The impact of radiation therapy on secondary colon cancers was not as marked. Rectal cancer patients undergoing radiation therapy are at a higher risk of thyroid cancers and leukemia but males have a lower risk of prostate cancer. Conclusions: While pre-operative radiation therapy is advantageous for reducing rectal cancer recurrence, this study identifies advantages of postoperative radiation for reducing second primary cancers. This research will help improve recommendations for post-diagnosis surveillance in patients with rectal cancer. P12. Cancer of Unknown Primary: Time Trends in Incidence, United States Elena Mnatsakanyan MD, Wei-Chen Tung PhD, RN, Brenna Caine CTR, Julie Smith Gagen Ph.D. MPH. University of Nevada, Reno Purpose: To describe the epidemiological features and trends of cancer of unknown primary (CUP) in the U.S. population. Methods: The Surveillance Epidemiology and End Results (SEER) registry was used to examine incidence rates, adjusted to the World Segi 1960 population, by demographic and tumor characteristics among patients diagnosed with CUP between 1973 to 2010. Annual percent changes in incidence rates were estimated using Joinpoint regression. Results: The incidence rate of pathologically investigated CUP was 4.1 per 100,000 and is consistent with reports from other countries. In the U.S., CUP incidence rates have been decreasing since the early 1980’s; 3.6 percent per year in the last two decades. The U.S. experienced decreases earlier than other countries. U.S. males and African Americans had the highest rates of CUP. The rates of non-microscopically confirmed CUP has dropped 2.6 percent per year since 1973, but 24% of CUP patients do not receive microscopic confirmation and 21% of those with microscopically investigated cancer receive a vague histology (i.e. epithelial) diagnosis. Twenty percent of patients with pathological investigation receive radiation. Patients were twice as likely to be diagnosed with a non-pathologically investigated CUP if they were living in areas with the lowest income quartile relative to areas with the highest income quartile. Conclusion: Although the incidence of CUP is decreasing, we document CUP that may be due to insufficient diagnostic inquiry. Questions raised by the findings in this data provide hypotheses for further epidemiological and biological studies in the elucidation of CUP incidence and treatment. P13. Oral Bisphosphonate Exposure and Risk of Esophageal and Gastric Cancer Emily Vogtmann PhD, MPH, Douglas A. Corley, Lucy M. Almers, Chris R. Cardwell, Liam J. Murray, Christian C. Abnet. National Cancer Institute Purpose: The association between oral bisphosphonate use and esophageal cancer has been controversial. Therefore, we examined the association within the Kaiser Permanente Northern California population. Methods: Cases of esophageal (squamous cell carcinoma and adenocarcinoma) and gastric adenocarcinoma (cardia and non-cardia) diagnosed between 1997 and 2011 were matched to controls on gender, age at index date, membership duration prior to index, race, and region of residence.1,011 esophageal and 1,923 gastric cancer cases were matched to 49,886 and 93,747 controls, respectively. Oral bisphosphonate prescription fills prior to the index date were extracted. Conditional logistic regression was used to calculated odds ratios (OR) and 95% confidence intervals (95% CI) with adjustment for potential confounders. Results: Within esophageal cancer cases, 4.7% of squamous cell carcinoma cases and 2.2% of adenocarcinoma cases had ever used oral bisphosphonates compared to 3.7% of controls. Within gastric cancer cases, 5.6% of cardia, 5.3% of non-cardia, and 6.8% of other gastric cancer cases had ever used oral bisphosphonates compared to 5.1% of controls. After adjustment for potential confounders, we observed an adverse association with gastric cardia cancer (OR 1.57; 95% CI: 1.07-2.32), but no consistent associations were found for esophageal squamous cell carcinoma (OR 0.77; 95% CI: 0.46-1.29), esophageal adenocarcinoma (OR 0.66; 95% CI: 0.37-1.15), or gastric non-cardia cancer (OR 0.80, 95% CI: 0.58-1.10). Conclusions: We observed no association between oral bisphosphonate use and esophageal cancer risk within a large community-based population. A significant association was detected with gastric cardia cancer risk which could be a spurious finding. P14. A Meta-Analysis of the Incidence of Cancers in Solid Organ Transplant Recipients Chu-Ling Yu ScD, Chiung-Yu Huang Huang PhD. Mid-Atlantic Permanente Research Institute Purpose: Cancer is an established complication after solid organ transplantation due to immunosuppression and oncogenic viral infections. It is less clear how cancer risk differs by transplanted organ. The meta-analysis compared the incidence of a broad spectrum of cancers in solid organ transplant recipients with the incidence in the general population, first for all solid organ transplant recipients combined, and separately by transplanted organ.