Point/Counterpoint: Is It Time for Universal Germline Genetic Testing for All GI Cancers?

Use of germline genetic testing among patients with cancer is increasing because of (1) the availability of multigene panel tests that include multiple cancer susceptibility genes in a single test, (2) decreased costs of these tests and improvements in insurance coverage, and (3) US Food and Drug Administration-approval of genotype-directed therapies such as poly(ADP-ribose) polymerase inhibitors for individuals with certain cancers and pathogenic germline variants in BRCA1 and BRCA2 (with possible benefits with other genes in the homologous repair deficiency pathway). In addition, National Comprehensive Cancer Network guidelines have already endorsed germline genetic testing for all patients with certain cancer types (epithelial ovarian cancer, exocrine pancreatic cancer, and high-grade/metastatic prostate cancer), regardless of age or personal/family history of cancer. Herein, we debate the pros and cons of offering germline multigene panel testing to all patients diagnosed with any GI cancer. The authors agree that it may just be a matter of time before germline multigene panel testing is offered to all patients with cancer; however, this article will highlight some of the benefits, risks, and limitations of this approach so that research can help fill some of the gaps to ensure that genetic medicine continues to be implemented in ways that improve real-world patient care and outcomes.

Effect of High-Dose vs Standard-Dose Vitamin D3 Supplementation on Body Composition among Patients with Advanced or Metastatic Colorectal Cancer: A Randomized Trial.

Skeletal muscle and adipose tissue express the vitamin D receptor and may be a mechanism through which vitamin D supplementation slows cancer progression and reduces cancer death. In this exploratory analysis of a double-blind, multicenter, randomized phase II clinical trial, 105 patients with advanced or metastatic colorectal cancer who were receiving chemotherapy were randomized to either high-dose vitamin D3 (4000 IU) or standard-dose (400 IU) vitamin D3. Body composition was measured with abdominal computed tomography at enrollment (baseline) and after cycle 8 of chemotherapy (16 weeks). As compared with standard-dose vitamin D3, high-dose vitamin D3 did not significantly change body weight [-0.7 kg; (95% CI: -3.5, 2.0)], body mass index [-0.2 kg/m2; (95% CI: -1.2, 0.7)], muscle area [-1.7 cm2; (95% CI: -9.6, 6.3)], muscle attenuation [-0.4 HU; (95% CI: -4.2, 3.2)], visceral adipose tissue area [-7.5 cm2; (95% CI: -24.5, 9.6)], or subcutaneous adipose tissue area [-8.3 cm2; (95% CI: -35.5, 18.9)] over the first 8 cycles of chemotherapy. Among patients with advanced or metastatic colorectal cancer, the addition of high-dose vitamin D3, vs standard-dose vitamin D3, to standard chemotherapy did not result in any changes in body composition.

Health behaviours and beliefs in individuals with familial pancreatic cancer.

Individuals at high risk for pancreatic cancer are recommended surveillance and healthy lifestyle behaviours and patient experience with recommendations are understudied. To describe engagement and experience with surveillance, tobacco and alcohol use, health beliefs and motivation (Champion Health Belief Measure) and the relationship with personal, psychosocial (Impact of Event Scale), and familial characteristics. Interest in integrative therapies (complementary therapies) are described. A multi-site cross-sectional survey including individuals at high risk for pancreatic cancer with no diagnosis of pancreatic cancer who have been evaluated at a comprehensive cancer center. Descriptive statistics and Wilcoxon rank sum test and Fisher's exact test were used to assess univariate associations. Of the 132 respondents (72% response rate), 92 (70%) reported undergoing surveillance which was associated with older age (p = 0.001). Of which, 36% and 51% report that magnetic resonance imaging (MRI) or endoscopic ultrasound (EUS), respectively, were uncomfortable; 22% and 30% dread the next MRI or EUS, respectively. Of those who reported alcohol consumption (n = 88); 15% consumed 1 or more drinks daily and no alcohol consumption was associated with higher Impact of Event scale scores (p = 0.024). A total of six participants were currently smoking every day or some days. Participants reported high motivation to engage in heathy behaviours and 92% were interested in integrative therapies. In these select participants, most were engaging in pancreatic cancer surveillance, alcohol intake was moderate, and tobacco intake was minimal. Modifiable factors, such as experience and comfort with surveillance could be addressed. The sample is motivated to engage in behavioural health intervention.

Effect of High-Dose vs Standard-Dose Vitamin D3 Supplementation on Progression-Free Survival Among Patients With Advanced or Metastatic Colorectal Cancer: The SUNSHINE Randomized Clinical Trial.

Importance: In observational studies, higher plasma 25-hydroxyvitamin D (25[OH]D) levels have been associated with improved survival in metastatic colorectal cancer (CRC). Objective: To determine if high-dose vitamin D3 added to standard chemotherapy improves outcomes in patients with metastatic CRC. Design, Setting, and Participants: Double-blind phase 2 randomized clinical trial of 139 patients with advanced or metastatic CRC conducted at 11 US academic and community cancer centers from March 2012 through November 2016 (database lock: September 2018). Interventions: mFOLFOX6 plus bevacizumab chemotherapy every 2 weeks and either high-dose vitamin D3 (n = 69) or standard-dose vitamin D3 (n = 70) daily until disease progression, intolerable toxicity, or withdrawal of consent. Main Outcomes and Measures: The primary end point was progression-free survival (PFS) assessed by the log-rank test and a supportive Cox proportional hazards model. Testing was 1-sided. Secondary end points included tumor objective response rate (ORR), overall survival (OS), and change in plasma 25(OH)D level. Results: Among 139 patients (mean age, 56 years; 60 [43%] women) who completed or discontinued chemotherapy and vitamin D3 (median follow-up, 22.9 months), the median PFS for high-dose vitamin D3 was 13.0 months (95% CI, 10.1 to 14.7; 49 PFS events) vs 11.0 months (95% CI, 9.5 to 14.0; 62 PFS events) for standard-dose vitamin D3 (log-rank P = .07); multivariable hazard ratio for PFS or death was 0.64 (1-sided 95% CI, 0 to 0.90; P = .02). There were no significant differences between high-dose and standard-dose vitamin D3 for tumor ORR (58% vs 63%, respectively; difference, -5% [95% CI, -20% to 100%], P = .27) or OS (median, 24.3 months vs 24.3 months; log-rank P = .43). The median 25(OH)D level at baseline for high-dose vitamin D3 was 16.1 ng/mL vs 18.7 ng/mL for standard-dose vitamin D3 (difference, -2.6 ng/mL [95% CI, -6.6 to 1.4], P = .30); at first restaging, 32.0 ng/mL vs 18.7 ng/mL (difference, 12.8 ng/mL [95% CI, 9.0 to 16.6], P < .001); at second restaging, 35.2 ng/mL vs 18.5 ng/mL (difference, 16.7 ng/mL [95% CI, 10.9 to 22.5], P < .001); and at treatment discontinuation, 34.8 ng/mL vs 18.7 ng/mL (difference, 16.2 ng/mL [95% CI, 9.9 to 22.4], P < .001). The most common grade 3 and higher adverse events for chemotherapy plus high-dose vs standard-dose vitamin D3 were neutropenia (n = 24 [35%] vs n = 21 [31%], respectively) and hypertension (n = 9 [13%] vs n = 11 [16%]). Conclusions and Relevance: Among patients with metastatic CRC, addition of high-dose vitamin D3, vs standard-dose vitamin D3, to standard chemotherapy resulted in a difference in median PFS that was not statistically significant, but with a significantly improved supportive hazard ratio. These findings warrant further evaluation in a larger multicenter randomized clinical trial. Trial Registration: ClinicalTrials.gov Identifier: NCT01516216.

Identification of a Variety of Mutations in Cancer Predisposition Genes in Patients With Suspected Lynch Syndrome.

BACKGROUND & AIMS: Multigene panels are commercially available tools for hereditary cancer risk assessment that allow for next-generation sequencing of numerous genes in parallel. However, it is not clear if these panels offer advantages over traditional genetic testing. We investigated the number of cancer predisposition gene mutations identified by parallel sequencing in individuals with suspected Lynch syndrome. METHODS: We performed germline analysis with a 25-gene, next-generation sequencing panel using DNA from 1260 individuals who underwent clinical genetic testing for Lynch syndrome from 2012 through 2013. All patients had a history of Lynch syndrome-associated cancer and/or polyps. We classified all identified germline alterations for pathogenicity and calculated the frequencies of pathogenic mutations and variants of uncertain clinical significance (VUS). We also analyzed data on patients' personal and family history of cancer, including fulfillment of clinical guidelines for genetic testing. RESULTS: Of the 1260 patients, 1112 met National Comprehensive Cancer Network (NCCN) criteria for Lynch syndrome testing (88%; 95% confidence interval [CI], 86%-90%). Multigene panel testing identified 114 probands with Lynch syndrome mutations (9.0%; 95% CI, 7.6%-10.8%) and 71 with mutations in other cancer predisposition genes (5.6%; 95% CI, 4.4%-7.1%). Fifteen individuals had mutations in BRCA1 or BRCA2; 93% of these met the NCCN criteria for Lynch syndrome testing and 33% met NCCN criteria for BRCA1 and BRCA2 analysis (P = .0017). An additional 9 individuals carried mutations in other genes linked to high lifetime risks of cancer (5 had mutations in APC, 3 had bi-allelic mutations in MUTYH, and 1 had a mutation in STK11); all of these patients met NCCN criteria for Lynch syndrome testing. A total of 479 individuals had 1 or more VUS (38%; 95% CI, 35%-41%). CONCLUSIONS: In individuals with suspected Lynch syndrome, multigene panel testing identified high-penetrance mutations in cancer predisposition genes, many of which were unexpected based on patients' histories. Parallel sequencing also detected a high number of potentially uninformative germline findings, including VUS.