Molecular and Sociodemographic Colorectal Cancer Disparities in Latinos Living in Puerto Rico.

BACKGROUND: The incidence of sporadic colorectal cancer (CRC) among individuals <50 years (early-onset CRC) has been increasing in the United States (U.S.) and Puerto Rico. CRC is currently the leading cause of cancer death among Hispanic men and women living in Puerto Rico (PRH). The objective of this study was to characterize the molecular markers and clinicopathologic features of colorectal tumors from PRH to better understand the molecular pathways leading to CRC in this Hispanic subpopulation. METHODS: Microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and KRAS and BRAF mutation status were analyzed. Sociodemographic and clinicopathological characteristics were evaluated using Chi-squared and Fisher's exact tests. RESULTS: Of the 718 tumors analyzed, 34.2% (n = 245) were early-onset CRC, and 51.7% were males. Among the tumors with molecular data available (n = 192), 3.2% had MSI, 9.7% had BRAF, and 31.9% had KRAS mutations. The most common KRAS mutations observed were G12D (26.6%) and G13D (20.0%); G12C was present in 4.4% of tumors. A higher percentage of Amerindian admixture was significantly associated with early-onset CRC. CONCLUSIONS: The differences observed in the prevalence of the molecular markers among PRH tumors compared to other racial/ethnic groups suggest a distinct molecular carcinogenic pathway among Hispanics. Additional studies are warranted.

Implementation of Universal Colorectal Cancer Screening for Lynch Syndrome in Hispanics Living in Puerto Rico.

OBJECTIVE: Colorectal cancer is the leading cause of cancer death in Puerto Rico and third among Hispanics in the USA. Up to 2-4% of colorectal cancer cases are a result of Lynch syndrome (LS), a hereditary cancer syndrome caused by a germline mutation in at least one of the DNA mismatch repair genes. The objective of this study was to determine the prevalence of LS in colorectal tumors during the first 15-months after the implementation of universal tumor-based screening for LS in Puerto Rico. METHODS: A total of 317 colorectal tumors were evaluated in a large private pathology laboratory from September 2014 to December 2015. Clinical characteristics were obtained from the pathology reports. Unadjusted and adjusted logistic regression models were used to estimate the magnitude of association (odds ratio [OR] with 95% confidence intervals [CI]) between absent MMR protein expression and patient characteristics. RESULTS: Most cases (93.4%) were analyzed by immunohistochemistry; 11.8% (35 of 296) had deficient mismatch repair protein expression. While 29 of the 317 cases were subjected to PCR-based microsatellite instability analysis of which 10.3% (3 of 317) had microsatellite instability. In total, 11.0% of the tumors were reported MMR deficient. These tumors were more likely from females and more likely localized in the proximal colon compared to those with proficient MMR expression. CONCLUSIONS: Our data is consistent with the results from other studies including US Hispanics, where approximately 10% of Hispanic individuals with colorectal cancer have microsatellite instability. Our results support universal tumor-based screening for LS among Hispanics in accordance with National Comprehensive Cancer Network guidelines.

True NOTES TME resection with splenic flexure release, high ligation of IMA, and side-to-end hand-sewn coloanal anastomosis.

INTRODUCTION: Natural orifice transluminal endoscopic surgery (NOTES) represents the ultimate expression of minimally invasive surgery. We have developed and present here an initial feasibility and safety study of transanal total mesorectal excision (TME) with splenic flexure release, high ligation of the IMA and IMV, and side-to-end coloanal anastomosis with temporary diverting ileostomy for rectal cancer. METHODS: A program of full NOTES TME resection with release of the splenic flexure, high ligation of the IMA/IMV, with side-to-end coloanal anastomosis was performed transanally from December 2013 to July 2014. Demographics, preoperative, perioperative, and postoperative data were prospectively obtained. Operative components were broken into TME, colonic mobilization, splenic flexure release, IMA/IMV transection, transanal extraction of specimen, and coloanal anastomosis for analysis of performance completion. RESULTS: There were 3 women and 1 man on whom we operated. Mean age was 56 (46-65). Mean BMI was 26 (23.8-30.2). The operation was completed entirely transanally in 2 patients. Transanal component completion of the operation was as follows: TME in 3/4; colonic mobilization in 4/4; splenic flexure release in 3/4; IMA/IMV transection in 3/4; transanal specimen extraction in 4/4; coloanal anastomosis in 4/4. Abdominal time for completion of component parts was: splenic flexure release 4:53 (min:s), IMA/IMV 19:43, completion of TME 13:41. Mean EBL was 194 cc (25-500). Aside from stoma site, there were no abdominal incisions. There were no mortalities. Mesorectum was intact in all 4 patients and with negative circumferential and distal margins. CONCLUSION: This experience supports the feasibility and safety of a true NOTES TME. The critical anatomic views demonstrated on video affirm the potential of this approach for distal rectal cancer. Colorectal surgery represents the most logical application for NOTES. While highly promising, a great deal of work remains to develop the technique and applicability of NOTES colorectal surgery.