DNA Mismatch Repair-deficient Rectal Cancer Is Frequently Associated With Lynch Syndrome and With Poor Response to Neoadjuvant Therapy.

We evaluated 368 consecutively resected rectal cancers with neoadjuvant therapy for DNA mismatch repair (MMR) protein status, tumor response to neoadjuvant therapy, histopathologic features, and patient survival. Nine (2.4%) rectal cancers were mismatch repair-deficient (MMRD): 8 (89%) Lynch syndrome-associated tumors and 1 (11%) sporadic MLH1-deficient tumor. Of the 9 MMRD rectal cancers, 89% (8/9) had a tumor regression score 3 (poor response) compared with 23% (81/359) of MMR proficient rectal cancers ( P <0.001). Patients with MMRD rectal cancer less often had downstaging after neoadjuvant therapy compared with patients with MMR proficient rectal cancer (11% vs. 57%, P =0.007). In the multivariable logistic regression analysis, MMRD in rectal cancer was associated with a 25.11-fold increased risk of poor response to neoadjuvant therapy (tumor regression score 3) (95% confidence interval [CI]: 3.08-44.63, P =0.003). In the multivariable Cox regression analysis, the only variables significantly associated with disease-free survival were pathologic stage III disease (hazard ratio [HR]=2.46, 95% CI: 1.54-3.93, P <0.001), College of American Pathologists (CAP) tumor regression score 2 to 3 (HR=3.44, 95% CI: 1.76-6.73, P <0.001), and positive margins (HR=2.86, 95% CI: 1.56-5.25, P =0.001). In conclusion, we demonstrated that MMRD in rectal cancer is an independent predictor of poor response to neoadjuvant therapy and infrequently results in pathologic downstaging following neoadjuvant therapy. We also confirmed that MMRD in rectal cancer is strongly associated with a diagnosis of Lynch syndrome. Our results suggest that MMR status may help to provide a more patient-centered approach when selecting neoadjuvant treatment regimens and may help predict tumor response to neoadjuvant therapy.

Individualized Bayesian Risk Assessment for Cervical Squamous Neoplasia.

BACKGROUND: Cervical screening could potentially be improved by better stratifying individual risk for the development of cervical cancer or precancer, possibly even allowing follow-up of individual patients differently than proposed under current guidelines that focus primarily on recent screening test results. We explore the use of a Bayesian decision science model to quantitatively stratify individual risk for the development of cervical squamous neoplasia. MATERIALS AND METHODS: We previously developed a dynamic multivariate Bayesian network model that uses cervical screening and histopathologic data collected over 13 years in our system to quantitatively estimate the risk of individuals for the development of cervical precancer or invasive cervical cancer. The database includes 1,126,048 liquid-based cytology test results belonging to 389,929 women. From-the-vial, high risk human papilloma virus (HPV) test results and follow-up gynecological surgical procedures were available on 33.6% and 12% of these results (378,896 and 134,727), respectively. RESULTS: Historical data impacted 5-year cumulative risk for both histopathologic cervical intraepithelial neoplasia 3 (CIN3) and squamous cell carcinoma (SCC) diagnoses. The risk was highest in patients with prior high grade squamous intraepithelial lesion cytology results. Persistent abnormal cervical screening test results, either cytologic or HPV results, were associated with variable increasing risk for squamous neoplasia. Risk also increased with prior histopathologic diagnoses of precancer, including CIN2, CIN3, and adenocarcinoma in situ. CONCLUSIONS: Bayesian modeling allows for individualized quantitative risk assessments of system patients for histopathologic diagnoses of significant cervical squamous neoplasia, including very rare outcomes such as SCC.