Machine Learning Predicts Oxaliplatin Benefit in Early Colon Cancer.

PURPOSE: A combination of fluorouracil, leucovorin, and oxaliplatin (FOLFOX) is the standard for adjuvant therapy of resected early-stage colon cancer (CC). Oxaliplatin leads to lasting and disabling neurotoxicity. Reserving the regimen for patients who benefit from oxaliplatin would maximize efficacy and minimize unnecessary adverse side effects. METHODS: We trained a new machine learning model, referred to as the colon oxaliplatin signature (COLOXIS) model, for predicting response to oxaliplatin-containing regimens. We examined whether COLOXIS was predictive of oxaliplatin benefits in the CC adjuvant setting among 1,065 patients treated with 5-fluorouracil plus leucovorin (FULV; n = 421) or FULV + oxaliplatin (FOLFOX; n = 644) from NSABP C-07 and C-08 phase III trials. The COLOXIS model dichotomizes patients into COLOXIS+ (oxaliplatin responder) and COLOXIS- (nonresponder) groups. Eight-year recurrence-free survival was used to evaluate oxaliplatin benefits within each of the groups, and the predictive value of the COLOXIS model was assessed using the P value associated with the interaction term (int P) between the model prediction and the treatment effect. RESULTS: Among 1,065 patients, 526 were predicted as COLOXIS+ and 539 as COLOXIS-. The COLOXIS+ prediction was associated with prognosis for FULV-treated patients (hazard ratio [HR], 1.52 [95% CI, 1.07 to 2.15]; P = .017). The model was predictive of oxaliplatin benefits: COLOXIS+ patients benefited from oxaliplatin (HR, 0.65 [95% CI, 0.48 to 0.89]; P = .0065; int P = .03), but COLOXIS- patients did not (COLOXIS- HR, 1.08 [95% CI, 0.77 to 1.52]; P = .65). CONCLUSION: The COLOXIS model is predictive of oxaliplatin benefits in the CC adjuvant setting. The results provide evidence supporting a change in CC adjuvant therapy: reserve oxaliplatin only for COLOXIS+ patients, but further investigation is warranted.

A cost analysis of sorafenib for desmoid tumors.

INTRODUCTION: A recent randomized trial demonstrated that sorafenib improved progression free survival (PFS) in patients with desmoid tumors despite many patients experiencing stable disease or spontaneous regression without treatment. Utilizing these trial data, we performed a cost analysis of sorafenib efficacy through two years of treatment. METHODS: Current Medicare Part D rates for sorafenib were utilized (dose 400 mg/day, cost $309/day). Annual costs per progression and objective response were calculated. Radiologic progression and response were defined using RECIST criteria. Patients with disease progression were separately analyzed in two groups: both clinical and radiologic (CAR), and radiologic alone. RESULTS: 84 previously randomized patients were analyzed (placebo: 35, sorafenib: 49). At one year, sorafenib was associated with a 43% absolute risk reduction (ARR) of CAR progression and number-needed-to-treat (NNT) of 2.3 patients/year, costing $259,406. At two years, ARR was 48% and NNT of 2.1 patients/year, costing $473,697. When evaluating only patients with RECIST defined radiologic progression, sorafenib patients experienced ARR of 13.9% with NNT 7.2 and estimated costs of $812,052 at one year. Two-year ARR was 17.5% with NNT 5.7 and estimated costs $1,285,052. Sorafenib patients experienced improved RECIST partial response rates at 1 and 2 years of 14.7% and 14.3%, with NNT 6.8 and 6.9, and costs of $766,938 and $1,556,433; respectively. CONCLUSION: For the treatment of desmoid tumors, Sorafenib led to improved PFS, but at a significant cost per patient. Favorable RECIST outcomes were less likely and costlier. Patients should be informed of possible benefits of treatment versus potential financial burden.

NSABP FC-6: Surgical conversion rate in colorectal cancer patients with unresectable, KRAS wild-type liver metastases receiving mFOLFOX7 plus cetuximab.

PURPOSE: This study sought to determine the R0 resection rate in KRAS wild-type (WT), liver-only metastatic colorectal cancer (CRC) patients initially identified as having unresectable disease who were treated with FOLFOX7 plus cetuximab. Exploratory molecular analyses were undertaken before and after treatment. METHODS: Twenty patients were enrolled. None had prior adjuvant chemotherapy. Cetuximab was added to a FOLFOX7 backbone and administered at 500 mg/m2 every 14 days with dose reductions to 400 and 300 mg/m2 in the event of toxicity. In the absence of toxicity, dose-escalations to 600, 700, and 800 mg/m2 were allowed. The mean dose of cetuximab (mg/m2 /week) throughout the study was 289 mg/m2 . Paired samples were collected for correlative studies, where feasible. RESULTS: We assessed the conversion rates from unresectable to resectable in hepatic-only, KRAS exon 2 WT mCRC. Seventeen of 20 patients undergoing chemotherapy were considered resectable by imaging criteria; R0 resection was achieved in 15/20 patients. Molecular profiling revealed heterogeneity between patients at the gene-expression, pathway signaling, and immune-profile levels. CONCLUSIONS: Although 15/20 (75%) converted to R0 resection, by 2 years, 10/15 R0 resections had recurred. Therefore, chemotherapy plus cetuximab is of limited long-term benefit in this setting. ctDNA analysis may guide additional therapy including immunotherapy.

Pancreatic resections: 30 and 90-day outcomes in octogenarians.

BACKGROUND: Pancreatic tumors are frequently found in a geriatric population. Given that the median age of patients with pancreatic cancer is 70 years at diagnosis and the ubiquity of CT and MRI imaging has increased the detection of pancreas masses, pancreatic surgeons often find themselves operating on patients of advanced age. This study sought to evaluate the outcomes of pancreatic resection in an octogenarian population at a single institution with a dedicated surgical oncology team. STUDY DESIGN: A retrospective chart review was performed for all patients undergoing pancreatic resection over a 13-year period at an academic community cancer center. Patient characteristics and operative outcomes were compared between patients aged 80 and older, and those younger than 80. Student t-tests, Fisher's exact test, and Kruskal-Wallis tests were used for univariate analyses. RESULTS: Over the 13-year period, a total of 48 patients of 403 undergoing pancreatic resections were aged 80 or older. Of these 48 patients, 35 underwent pancreaticoduodenectomy (Whipple) and 13 underwent distal pancreatectomy. Patient characteristics including ASA classification were similar among the two age groups. The procedures themselves were equally complicated with similar operative times, transfusion requirements, estimated blood losses, and portal vein resections. The number and severity of complications such as delayed gastric emptying and pancreatic leak were not statistically different between the two groups. Additionally, the 30-day reoperation, readmission, and mortality rates were not statistically different. Outcomes at 90-days revealed an increased rate of readmission amongst octogenarians who underwent Whipple without an increase in rates of major complications. The total number of deaths in the octogenarian group was 3 (6.2%) vs. 6 (1.7%) in the non-octogenarian group (p = 0.080). The median length of stay was similar amongst the two age groups. CONCLUSIONS: At a large-volume academic community cancer center with a dedicated surgical oncology team, highly selected octogenarians can undergo pancreatic resection safely with outcomes that do not differ significantly from their younger counterparts.

Characteristics of Gastrointestinal Stromal Tumors incidentally discovered during abdominal surgery.

BACKGROUND: Gastrointestinal Stromal Tumors (GISTs) are rare sarcomas with 5000 new cases arising in the United States each year. Despite their low incidence, general surgeons should be familiar with GISTs since a quarter of these neoplasms are encountered incidentally. METHODS: A retrospective medical records review was conducted to create a database of all GISTs resected from January 2005 to May 2019. We isolated patients who had incidental discovery of GISTs intraoperatively or within final pathology. Characteristics of patient (Age, gender), index procedure (malignant vs. benign, elective vs. emergent) and tumor (location, size and mitotic rate) were analyzed. RESULTS: A total 48 patients were incidentally discovered to have a GIST excised during index operation. The mean age of these patients was 62 years, with 27 females and 21 males. The primary location of tumors in descending frequency was stomach (30), small bowel (15), colon/rectum (2) and esophagus (1). The average size of all tumors was 1.2 cm, with the average size of the stomach, small bowel, colon/rectum and esophagus at 0.9 cm, 1.7 cm, 0.9 cm and 0.3 cm respectively. Mitotic rate was less than 5 mitosis per 50 HPF in 96% of patients. Incidental tumors were identified during both bariatric (13) and non-bariatric stomach surgery (8), colorectal surgery (14), hernia repair (4), ampullary/pancreatic surgery (5), esophageal surgery (2) liver surgery (1) and uterine surgery (1). Most incidental-GISTs were identified during elective surgery (81%, 39). Finally, 15 of the tumors were identified during surgery for other malignancies. CONCLUSIONS: One quarter (25%) of the GISTs encountered at our academic community cancer center over a 15-year period were discovered incidentally. These tumors had less malignant characteristics overall and were likely cured with surgical resection.

Microbiome and colorectal cancer: A review of the past, present, and future.

The gastrointestinal tract is home to diverse and abundant microorganisms, collectively referred to as the microbiome. This ecosystem typically contains trillions of microbial cells that play an important role in regulation of human health. The microbiome has been implicated in host immunity, nutrient absorption, digestion, and metabolism. In recent years, researchers have shown that alteration of the microbiome is associated with disease development, such as obesity, inflammatory bowel disease, and cancer. This review discusses the five decades of research into the human microbiome and the development of colorectal cancer - the historical context including experiments that sparked interest, the explosion of research that has occurred in the last decade, and finally the future of testing and treatment.

Meta-Analysis on the Effect of Pasireotide for Prevention of Postoperative Pancreatic Fistula.

BACKGROUND: A randomized controlled trial of routine administration of pasireotide demonstrated decreased incidence of clinically significant postoperative pancreatic fistula (POPF). Recent studies have not replicated these results. A meta-analysis was performed to evaluate its efficacy in this setting. METHODS: Prospective trials utilizing pasireotide prophylactically after pancreatectomy were reviewed. The primary outcome was clinically significant POPF. Secondary outcomes included length of stay (LOS), readmission rates, and mortality. Study heterogeneity was assessed. RESULTS: Five studies totaling 1571 patients were identified. There was no difference in age, sex, or cancer rates. Pasireotide patients had smaller pancreatic ducts (P < .001) and softer glands (P = .04). For all pancreatectomies, there was no difference in POPF rates (odds ratio [OR] 0.84; 95% CI 0.60-1.16, P = .29). Patients undergoing distal pancreatectomy (OR 0.70; 95% CI 0.30-1.63, P = .41) had similar rates of POPF versus pancreaticoduodenectomy (PD) patients who experienced a lower incidence of POPF (OR 0.60; 95% CI 0.42-0.86, P = .006).Mortality rates and LOS were similar. Readmission rates were decreased with pasireotide (OR 0.61; 95% CI 0.44-0.85). CONCLUSIONS: Routine administration of pasireotide did not decrease POPF rates for all pancreatectomies, but was associated with lower rates for PD, and decreased readmission rates. Further prospective, randomized studies are warranted.

Meta-analysis on the Effect of Pasireotide for Prevention of Postoperative Pancreatic Fistula.

BACKGROUND: A randomized controlled trial (RCT) of routine administration of pasireotide demonstrated decreased incidence of clinically significant postoperative pancreatic fistula (POPF). Recent studies have not replicated these results. A meta-analysis was performed to evaluate its efficacy in this setting. METHODS: Prospective trials utilizing pasireotide prophylactically after pancreatectomy were reviewed. The primary outcome was clinically significant POPF. Secondary outcomes included length of stay (LOS), readmission rates, and mortality. Study heterogeneity was assessed. RESULTS: Five studies totaling 1571 patients were identified. There was no difference in age, sex, or cancer rates. Pasireotide patients had smaller pancreatic ducts (P ≤.001) and softer glands (P = .04). For all pancreatectomies, there was no difference in POPF rates (OR 0.84; 95% CI 0.60-1.16, P = .29). Patients undergoing distal pancreatectomy (OR 0.70; 95% CI 0.30-1.63, P = .41) had similar rates of POPF versus pancreaticoduodenectomy (PD) patients that experienced a lower incidence of POPF (OR 0.60; 95% CI 0.42-0.86, P = .006). Mortality rates and LOS were similar. Readmission rates were decreased with pasireotide (OR 0.61; 95% CI 0.44-0.85). CONCLUSIONS: Routine administration of pasireotide did not decrease POPF rates for all pancreatectomies, but was associated with lower rates for PD and decreased readmission rates. Further prospective, randomized studies are warranted.

Intergroup Randomized Phase III Study of Postoperative Oxaliplatin, 5-Fluorouracil, and Leucovorin Versus Oxaliplatin, 5-Fluorouracil, Leucovorin, and Bevacizumab for Patients with Stage II or III Rectal Cancer Receiving Preoperative Chemoradiation: A Trial of the ECOG-ACRIN Research Group (E5204).

BACKGROUND: The addition of bevacizumab to chemotherapy improved outcomes for patients with metastatic colon cancer. E5204 was designed to test whether the addition of bevacizumab to mFOLFOX6, following neoadjuvant chemoradiation and definitive surgery, could improve overall survival (OS) in patients with stage II/III adenocarcinoma of the rectum. SUBJECTS, MATERIALS, AND METHODS: Patients with stage II/III rectal cancer who had completed neoadjuvant 5-fluorouracil-based chemoradiation and had undergone complete resection were enrolled. Patients were randomized to mFOLFOX6 (Arm A) or mFOLFOX6 with bevacizumab (Arm B) administered every 2 weeks for 12 cycles. RESULTS: E5204 registered only 355 patients (17% of planned accrual goal) as it was terminated prematurely owing to poor accrual. At a median follow-up of 72 months, there was no difference in 5-year overall survival (88.3% vs. 83.7%) or 5-year disease-free survival (71.2% vs. 76.5%) between the two arms. The rate of treatment-related grade ≥ 3 adverse events (AEs) was 68.8% on Arm A and 70.7% on Arm B. Arm B had a higher proportion of patients who discontinued therapy early as a result of AEs and patient withdrawal than did Arm A (32.4% vs. 21.5%, p = .029).The most common grade 3-4 treatment-related AEs were neutropenia, leukopenia, neuropathy, diarrhea (without prior colostomy), and fatigue. CONCLUSION: At 17% of its planned accrual, E5204 did not meet its primary endpoint. The addition of bevacizumab to FOLFOX6 in the adjuvant setting did not significantly improve OS in patients with stage II/III rectal cancer. IMPLICATIONS FOR PRACTICE: At 17% of its planned accrual, E5204 was terminated early owing to poor accrual. At a median follow-up of 72 months, there was no significant difference in 5-year overall survival (88.3% vs. 83.7%) or in 5-year disease-free survival (71.2% vs. 76.5%) between the two arms. Despite significant advances in the treatment of rectal cancer, especially in improving local control rates, the risk of distant metastases and the need to further improve quality of life remain a challenge. Strategies combining novel agents with chemoradiation to improve both distant and local control are needed.

Precision Medicine in Colorectal Surgery.

This article reviews advances in precision medicine for colorectal carcinoma that have influenced screening and treatment, and potentially prevention. Advances in molecular techniques have made it possible for better patient selection for therapies; therefore, mutational analysis should be performed at diagnosis to guide treatment. Future efforts should focus on validating these treatments in specific subgroups and on understanding the mechanisms of resistance to therapies to enable treatment optimization, promote efficacy, and reduce treatment costs and toxicities.

High volume pancreaticoduodenectomy performed at an academic community cancer center.

BACKGROUND: We sought to evaluate the post-operative outcomes of patients undergoing pancreaticoduodenectomy at a high volume academic community cancer center. METHODS: A retrospective review was performed of patients undergoing pancreaticoduodenectomy over a 10-year period. RESULTS: Over 10 years, 213 patients underwent pancreaticoduodenectomy. Median age was 66y. Most patients had significant comorbidities (median ASA = 3) and were overweight (median BMI = 27). Median operative time and blood loss were 253 min and 500 ml, respectively. 160 (75%) out of 213 patients had a malignant lesion on final pathology. 121 (76%) out of 160 had R0 resection. Median lymph nodes harvested was 13. Overall incidence of DGE was 31% (67/213), with clinically significant DGE in 15% (32/213). Pancreatic leak rate was 18% (37/213), with clinically significant leaks in 10% (21/213). Median length of stay was 8 days. Grade 3/4 morbidity rate was 21% (44/206), and 30-day mortality was 2% (5/213). CONCLUSIONS: At a high volume academic community cancer center, pancreaticoduodenectomy can be performed with excellent outcomes on par with any academic center or university hospital.

Genetic and Genomic Characterization of 462 Melanoma Patient-Derived Xenografts, Tumor Biopsies, and Cell Lines.

Tumor-sequencing studies have revealed the widespread genetic diversity of melanoma. Sequencing of 108 genes previously implicated in melanomagenesis was performed on 462 patient-derived xenografts (PDXs), cell lines, and tumors to identify mutational and copy number aberrations. Samples came from 371 unique individuals: 263 were naive to treatment, and 108 were previously treated with targeted therapy (34), immunotherapy (54), or both (20). Models of all previously reported major melanoma subtypes (BRAF, NRAS, NF1, KIT, and WT/WT/WT) were identified. Multiple minor melanoma subtypes were also recapitulated, including melanomas with multiple activating mutations in the MAPK-signaling pathway and chromatin-remodeling gene mutations. These well-characterized melanoma PDXs and cell lines can be used not only as reagents for a large array of biological studies but also as pre-clinical models to facilitate drug development.