Survival improvement for patients with metastatic colorectal cancer over twenty years

Over the past two decades of successive clinical trials in metastatic colorectal cancer (CRC), the median overall survival of both control and experimental arms has steadily improved. However, the incremental change in survival for metastatic CRC patients not treated on trial has not yet been quantified. We performed a retrospective review of 1420 patients with de novo metastatic CRC who received their primary treatment at the University of Texas M.D. Anderson Cancer Center (UTMDACC) from 2004 through 2019. Median OS was roughly stable for patients diagnosed between 2004 and 2012 (22.6 months) but since has steadily improved for those diagnosed in 2013 to 2015 (28.8 months), and 2016 to 2019 (32.4 months). Likewise, 5-year survival rate has increased from 15.7% for patients diagnosed from 2004 to 2006 to 26% for those diagnosed from 2013 to 2015. Notably, survival improved for patients with BRAFV600E mutant as well as microsatellite unstable (MSI-H) tumors. Multivariate regression analysis identified surgical resection of liver metastasis (HR = 0.26, 95% CI, 0.19-0.37), use of immunotherapy (HR = 0.44, 95% CI, 0.29-0.67) and use of third line chemotherapy (regorafenib or trifluridine/tipiracil, HR = 0.74, 95% CI, 0.58-0.95), but not year of diagnosis (HR = 0.99, 95% CI, 0.98-1), as associated with better survival, suggesting that increased use of these therapies are the drivers of the observed improvement in survival.

Efficacy of Systemic Chemotherapy in Patients With Low-grade Mucinous Appendiceal Adenocarcinoma: A Randomized Crossover Trial

Importance

Appendiceal adenocarcinoma is a rare tumor, and given the inherent difficulties in performing prospective trials in such a rare disease, there are currently minimal high-quality data to guide treatment decisions, highlighting the need for more preclinical and clinical investigation for this disease.

Objective

To prospectively evaluate the effectiveness of fluoropyrimidine-based systemic chemotherapy in patients with inoperable low-grade mucinous appendiceal adenocarcinoma.

Design, Setting, and Participants

This open-label randomized crossover trial recruited patients at a single tertiary care comprehensive cancer center from September 2013 to January 2021. The data collection cutoff was May 2022. Enrollment of up to 30 patients was planned. Eligible patients had histological evidence of a metastatic low-grade mucinous appendiceal adenocarcinoma, with radiographic imaging demonstrating the presence of mucinous peritoneal carcinomatosis and were not considered candidates for complete cytoreductive surgery. Key exclusion criteria were concurrent or recent investigational therapy, evidence of bowel obstruction, and use of total parenteral nutrition. Data were analyzed from November 2021 to May 2022.

Interventions

Patients were randomized to either 6 months observation followed by 6 months of chemotherapy, or initial chemotherapy followed by observation.

Main Outcomes and Measures

The primary end point was the percentage difference in tumor growth in treatment and observation groups. Key secondary end points included patient-reported outcomes in the chemotherapy and observation periods, objective response rate, rate of bowel complications, and differences in overall survival (OS).

Results

A total of 24 patients were enrolled, with median (range) age of 63 (38 to 82) years, and equal proportion of men and women (eg, 12 men [50%]); all patients had ECOG performance status of 0 or 1. A total of 11 patients were randomized to receive chemotherapy first, and 13 patients were randomized to receive observation first. Most patients (15 patients [63%]) were treated with either fluorouracil or capecitabine as single agent; 3 patients (13%) received doublet chemotherapy (leucovorin calcium [folinic acid], fluorouracil, and oxaliplatin or folinic acid, fluorouracil, and irinotecan hydrochloride), and bevacizumab was added to cytotoxic chemotherapy for 5 patients (21%). Fifteen patients were available to evaluate the primary end point of difference in tumor growth during treatment and observation periods. Tumor growth while receiving chemotherapy increased 8.4% (95% CI, 1.5% to 15.3%) from baseline but was not significantly different than tumor growth during observation (4.0%; 95% CI, -0.1% to 8.0%; P = .26). Of 18 patients who received any chemotherapy, none had an objective response (14 patients [77.8%] had stable disease; 4 patients [22.2%] had progressive disease). Median (range) OS was 53.2 (8.1 to 95.5) months, and there was no significant difference in OS between the observation-first group (76.0 [8.6 to 95.5] months) and the treatment-first group (53.2 [8.1 to 64.1] months; hazard ratio, 0.64; 95% CI, 0.16-2.55; P = .48). Patient-reported quality-of-life metrics identified that during treatment, patients experienced significantly worse fatigue (mean [SD] score, 18.5 [18.6] vs 28.9 [21.3]; P = .02), peripheral neuropathy (mean [SD] score, 6.67 [12.28] vs 38.89 [34.88]; P = .01), and financial difficulty (mean [SD] score, 8.9 [15.2] vs 28.9 [33.0]; P = .001) compared with during observation.

Conclusions and Relevance

In this prospective randomized crossover trial of systemic chemotherapy in patients with low-grade mucinous appendiceal adenocarcinoma, patients did not derive clinical benefit from fluorouracil-based chemotherapy, given there were no objective responses, no difference in OS when treatment was delayed 6 months, and no difference in the rate of tumor growth while receiving chemotherapy.

Trial Registration

ClinicalTrials.gov Identifier: NCT01946854.

Utility of circulating tumor DNA (ctDNA) in the management of appendiceal adenocarcinoma (AA)

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Background: Appendiceal adenocarcinoma (AA) is a rare and heterogenous cancer with marked differences in clinical course between high- and low-grade tumors. Unlike colorectal cancer (CRC) and other gastrointestinal malignancies, AA virtually never has hematogenous metastases, rather, metastasis is limited to the peritoneum. Here we present a retrospective, single institution study of AA to identify the prevalence of detectable ctDNA, evaluate the clinical predictive value of positive ctDNA, and assess what clinical, pathologic, or molecular features predict positive ctDNA. Methods: 160 blood samples from 147 patients with AA metastatic to the peritoneum were profiled with a CLIA approved 73 gene mutational panel as part of routine clinical practice. Paired tumor sequencing was available for 73 patients. Survival was measured starting from day ctDNA was drawn. Mutations that most likely represented clonal hematopoiesis were removed from analysis. Results: Out of 160 ctDNA samples, 120 were taken in the setting of radiographically apparent metastatic disease. Of these, 46 (38.3%) had any detectable mutation. 40 ctDNA tests were performed when patients had no radiographic evidence of disease (NED); 15 (37.5%) of which had any detectable mutation. High-grade tumors were more likely to have detectable ctDNA with detection rates of 10/46 (21.7%), 18/46 (39.1%), and 33/68 (48.5%) for well, moderately, and poorly-differentiated tumors, respectively. Restricting analysis to the 73 patients with paired tissue and blood samples and 73 genes sequenced in both, of 81 mutations detected in tumor only, 21 were detected in blood (sensitivity of 26%). Sensitivity was highest for mutation in TP53 (53.8%) suggesting these tumors may have a greater propensity to shed DNA into circulation. Overall, the sensitivity of ctDNA detection in metastatic AA was markedly less than what was observed in a cohort of 274 metastatic CRC patients from the same institution (288/581 = 49.6%). For AA patients with detectable ctDNA, variant allele frequency (VAF) in AA was significantly lower compared to CRC (median VAF 0.04% vs. 6%, p = <0.0001). Detectable ctDNA was associated with shorter overall survival (46.2 mo for positive ctDNA vs. not-yet-reached for negative ctDNA, HR = 2.5, p = 0.016) and shorter disease free survival (DFS) (60 mo vs. not-yet-reached, HR = 3.4, p = 0.05). As expected, patients with radiographic evidence of disease did worse than patients with NED (HR = 2.1. p = 0.08), but of note this hazard ratio was less than that for positive ctDNA. Conclusions: In patients with AA, the presence of detectable ctDNA is associated with shorter overall and disease-free survival. Sensitivity of ctDNA detection in metastatic AA is overall markedly lower than CRC, with detection more likely in high-grade tumors and higher sensitivity in tumors containing TP53 mutation.

Identification of Colorectal Cancer Cell Stemness from Single-Cell RNA Sequencing

Cancer stem cells (CSC) play a critical role in metastasis, relapse, and therapy resistance in colorectal cancer. While characterization of the normal lineage of cell development in the intestine has led to the identification of many genes involved in the induction and maintenance of pluripotency, recent studies suggest significant heterogeneity in CSC populations. Moreover, while many canonical colorectal cancer CSC marker genes have been identified, the ability to use these classical markers to annotate stemness at the single-cell level is limited. In this study, we performed single-cell RNA sequencing on a cohort of 6 primary colon, 9 liver metastatic tumors, and 11 normal (nontumor) controls to identify colorectal CSCs at the single-cell level. Finding poor alignment of the 11 genes most used to identify colorectal CSC, we instead extracted a single-cell stemness signature (SCS_sig) that robustly identified "gold-standard" colorectal CSCs that expressed all marker genes. Using this SCS_sig to quantify stemness, we found that while normal epithelial cells show a bimodal distribution, indicating distinct stem and differentiated states, in tumor epithelial cells stemness is a continuum, suggesting greater plasticity in these cells. The SCS_sig score was quite variable between different tumors, reflective of the known transcriptomic heterogeneity of CRC. Notably, patients with higher SCS_sig scores had significantly shorter disease-free survival time after curative intent surgical resection, suggesting stemness is associated with relapse.

IMPLICATIONS

This study reveals significant heterogeneity of expression of genes commonly used to identify colorectal CSCs, and identifies a novel stemness signature to identify these cells from scRNA-seq data.

Serum Tumor Markers and Outcomes in Patients With Appendiceal Adenocarcinoma

Importance

Serum tumor markers carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and cancer antigen 125 (CA125) have been useful in the management of gastrointestinal and gynecological cancers; however, there is limited information regarding their utility in patients with appendiceal adenocarcinoma.

Objective

To assess the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes and pathologic and molecular features in patients with appendiceal adenocarcinoma.

Design, Setting, and Participants

This is a retrospective cohort study at a single tertiary care comprehensive cancer center. The median (IQR) follow-up time was 52 (21-101) months. Software was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least 1 tumor marker measured at MD Anderson between March 2016 and May 2023. Data were analyzed from January to December 2023.

Main Outcomes and Measures

Association of serum tumor markers with survival in patients with appendiceal adenocarcinoma. Cox proportional hazards regression analyses were also performed to assess associations between clinical factors (serum tumor marker levels, demographics, and patient and disease characteristics) and patient outcomes (overall survival).

Results

A total of 1338 patients with appendiceal adenocarcinoma were included, with a median (range) age at diagnosis of 56.5 (22.3-89.6) years. The majority of the patients had metastatic disease (1080 patients [80.7%]). CEA was elevated in 742 of the patients tested (56%), while CA19-9 and CA125 were elevated in 381 patients (34%) and 312 patients (27%), respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; elevated vs normal was 81% vs 95% for CEA (hazard ratio [HR], 4.0; 95% CI, 2.9-5.6), 84% vs 92% for CA19-9 (HR, 2.2; 95% CI, 1.4-3.4), and 69% vs 93% for CA125 (HR, 4.6; 95% CI, 2.7-7.8) (P < .001 for all). Quantitative evaluation of tumor markers was associated with outcomes. Patients with highly elevated (top 10th percentile) CEA, CA19-9, or CA125 had markedly worse survival, with 5-year survival rates of 59% for CEA (HR, 9.8; 95% CI, 5.3-18.0), 64% for CA19-9 (HR, 6.0; 95% CI, 3.0-11.7), and 57% for CA125 (HR, 7.6; 95% CI, 3.5-16.5) (P < .001 for all). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease, elevated CEA, CA19-9, or CA125 were all still associated worse survival (HR for CEA, 3.4; 95% CI, 2.5-4.8; P < .001; HR for CA19-9, 1.8; 95% CI, 1.2-2.7; P = .002; and HR for CA125, 3.9; 95% CI, 2.4-6.4; P < .001). Interestingly, tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high-grade tumors relative to low-grade tumors (mean value, 18.3 vs 15.0; difference, 3.3; 95% CI, 0.9-3.7; P < .001). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with an 11-fold increased risk of death in patients with all 3 tumor markers elevated relative to those with none elevated. Somatic mutations in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9.

Conclusions and Relevance

In this retrospective study of serum tumor markers in patients with appendiceal adenocarcinoma, CEA, CA19-9, and CA125 were associated with overall survival in appendiceal adenocarcinoma. Given their value, all 3 biomarkers should be included in the initial workup of patients with a diagnosis of appendiceal adenocarcinoma.

The Landscape of ctDNA in Appendiceal Adenocarcinoma

PURPOSE

Appendiceal adenocarcinoma is a rare malignancy with distinct histopathologic subtypes and a natural history with metastasis primarily limited to the peritoneum. Little is known about the molecular pathogenesis of appendiceal adenocarcinoma relative to common tumors.

EXPERIMENTAL DESIGN

We analyzed molecular data for patients within the Guardant Health database with appendix cancer (n = 718). We then identified patients with appendiceal adenocarcinoma at our institution (from October 2004-September 2022) for whom ctDNA mutation profiling (liquid biopsy) was performed (n = 168) and extracted clinicopathologic and outcomes data. Of these 168 patients, 57 also had tissue-based tumor mutational profiling, allowing for evaluation of concordance between liquid and tissue assays.

RESULTS

The mutational landscape of ctDNA in appendiceal adenocarcinoma is distinct from tissue-based sequencing, with TP53 being the most frequently mutated (46%). Relative to other tumors, appendiceal adenocarcinoma seems less likely to shed ctDNA, with only 38% of patients with metastatic appendiceal adenocarcinoma having detectable ctDNA (OR = 0.26; P < 0.0001 relative to colorectal cancer). When detectable, the median variant allele frequency was significantly lower in appendiceal adenocarcinoma (0.4% vs. 1.3% for colorectal cancer; P ≤ 0.001). High-grade, signet ring, or colonic-type histology, metastatic spread beyond the peritoneum, and TP53 mutation were associated with detectable ctDNA. With respect to clinical translation, patients with detectable ctDNA had worse overall survival (HR = 2.32; P = 0.048). In the Guardant Health cohort, actionable mutations were found in 93 patients (13.0%).

CONCLUSIONS

Although metastatic appendiceal adenocarcinoma tumors are less likely to shed tumor DNA into the blood relative to colorectal cancer, ctDNA profiling in appendiceal adenocarcinoma has clinical utility.

Automated, High-Throughput Platform to Generate a High-Reliability, Comprehensive Rectal Cancer Database

PURPOSE

Dynamic operations platforms allow for cross-platform data extraction, integration, and analysis, although application of these platforms to large-scale oncology enterprises has not been described. This study presents a pipeline for automated, high-fidelity extraction, integration, and validation of cross-platform oncology data in patients undergoing treatment for rectal cancer at a single, high-volume institution.

METHODS

A dynamic operations platform was used to identify patients with rectal cancer treated at MD Anderson Cancer Center between 2016 and 2022 who had magnetic resonance imaging (MRI) imaging and preoperative treatment details available in the electronic health record (EHR). Demographic, clinicopathologic, tumor mutation, radiographic, and treatment data were extracted from the EHR using a methodology adaptable to any disease site. Data accuracy was assessed by manual review. Accuracy before and after implementation of synoptic reporting was determined for MRI data.

RESULTS

A total of 516 patients with localized rectal cancer were included. In the era after institutional adoption of synoptic reports, the dynamic operations platform extracted T (tumor) category data from the EHR with 95% accuracy compared with 87% before the use of synoptic reports, and N (lymph node) category with 88% compared with 58%. Correct extraction of pelvic sidewall adenopathy was 94% compared with 78%, and extramural vascular invasion accuracy was 99% compared with 89%. Neoadjuvant chemotherapy and radiation data were 99% accurate for patients who had synoptic data sources.

CONCLUSION

Using dynamic operations platforms enables automated cross-platform integration of multiparameter oncology data with high fidelity in patients undergoing multimodality treatment for rectal cancer. These pipelines can be adapted to other solid tumors and, together with standardized reporting, can increase efficiency in clinical research and the translation of actionable findings toward optimizing patient outcomes.

A prospective randomized crossover trial of systemic chemotherapy in patients with low-grade mucinous appendiceal adenocarcinoma

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Background: Appendiceal adenocarcinoma is both a rare and heterogenous tumor, with marked contrast in the natural history of low-grade and high-grade tumors (5-year OS 68% for low-grade vs. 7% for high-grade). While low-grade appendiceal adenocarcinoma is primarily treated with surgical resection sometimes followed by hyperthermic intraperitoneal chemotherapy (HIPEC), many inoperable candidates are treated with systemic chemotherapy although there is no prospective data supporting this practice. The purpose of our study was to objectively evaluate the effectiveness of systemic chemotherapy in low-grade mucinous appendiceal adenocarcinoma. Methods: A randomized crossover trial of surgically unresectable low-grade (well differentiated) mucinous appendiceal adenocarcinoma was performed with patients randomized to either 6 months observation followed by 6 months of chemotherapy (physician’s choice), or initial chemotherapy followed by observation. In this way each patient would serve as their own control. Enrollment of 30 patients was planned to have complete 6- and 12-month tumor measurements for 24 patients, providing 80% power at 0.05 significance level to detect a 5.0% difference in change in tumor size as measured by peritoneal RECIST in observation vs. treatment periods. Results: The trial closed early due to slow accrual. A total of 24 patients were enrolled. The majority of patients were treated with either 5FU or capecitabine (n = 15, 63%), bevacizumab was added for 3 (13%), and 3 were treated with doublet chemotherapy (FOLFOX/FOLFIRI). 15 patients who completed both treatment and observation periods were available for the primary analysis, the mean difference in tumor size was -4.5% (95% CI: -12.6, 3.7), indicating a slight trend towards faster growth on treatment than observation. This difference was not statistically or clinically significant (8.4% growth on treatment vs. 4.0% observation, p=0.26). Of the 18 patients who received any chemotherapy during the study period, zero achieved an objective response, 14 (77.8%) had stable disease during the entire year of follow up, and 4 (12.2%) had progression on study. Patient reported quality of life metrics identified that fatigue (p=0.02), peripheral neuropathy (p=0.014), and financial difficulty (p=0.0013) were all significantly worse while on treatment. There was not a significant difference in rate of bowel obstruction between the treatment first vs. observation first arms (12.5%, (n=3) vs 8.3%, (n=2)). Conclusions: These data from a prospective, randomized crossover trial indicate that patients with low-grade mucinous appendiceal adenocarcinoma do not derive benefit from 5FU based chemotherapy but do incur toxicity. These data further highlight the unique biology of low-grade appendiceal cancer and demonstrates the need to identify novel systemic therapies for this patient population. Clinical trial information: NCT01946854 .

Outcomes of IBD-associated colorectal cancer and implications in early-onset colorectal cancer

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Background: Inflammatory bowel disease (IBD) increases the risk of developing colorectal cancer (CRC), and colitis-associated CRC (CA-CRC) mortality is on the rise. It has been postulated that CA-CRC may be contributing to the increasing prevalence of early-onset CRC (EOCRC) but supportive studies are currently lacking. Molecular and clinical differences between CA-CRC and sporadic-CRC (S-CRC) have been reported, however outcomes for CA-CRC remains unclear. Signet ring cell carcinoma (SRC) is a rare subtype of CRC which is seen at higher frequencies, along with mucinous histology, in both CA-CRC and EOCRC. In this study, we validate the association of SRC and mucinous (SRC/M) histology with CA-CRC and EOCRC, and utilize it to estimate the amount of EOCRC attributable to undiagnosed or subclinical IBD. Methods: A retrospective study was conducted using three independent mCRC patient datasets from MDACC. The mATTACC discovery cohort consisted of 32 IBD- and 425 S-mCRC patients enrolled in a prospective biomarker trial. Validation of tumor histology was completed with a tumor registry (n=1696), excluding the MSI-High samples, and a real-world evidence (RWE) cohort from MDACC containing 269 CA-mCRC and 29,596 S-mCRC patients, was used as our validation cohort. Results: In the mATTACC cohort SRC/M histology was found in 37.5% of CA-mCRC and 11.7% of S-mCRC, showing a strong association between SRC/M and CA-mCRC (OR = 4.54, 95% CI: 2.19-9.43). The RWE cohort confirmed the correlation of SRC/M with CA-mCRC (28.6%) relative to S-mCRC (11.4%) patients (OR = 3.13, 95%CI: 2.39-4.09). An association was found between SRC/M and EOCRC (OR = 1.35; 95% CI: 1.24-1.47). By comparing the prevalence of SRC/M in EOCRC and late-onset CRC and correcting by the proportion of CA-CRC cases with SRC/M histology, we estimate that between 8.28% to 10.15% of EOCRC may attributable to undiagnosed/subclinical IBD. Using the RWE cohort, median overall survival was determined to be lower for CA-mCRC (31m) relative to S-mCRC (39m; p=0.007), yielding a HR of 1.26 (95% CI: 1.06-1.48). CA-mCRC patients with EOCRC (25m) were also found to have significantly worse outcomes than S-mCRC patients (40m) with EOCRC (p=0.0005; HR = 1.61, 95%CI: 1.23-2.11). Within CA-mCRC, patients with SRC or SRC/M histology (21m) had decreased OS compared to mucinous histology (51m), indicating the poor prognosis of SRC in CA-mCRC (p=0.028; HR=0.53, 95% CI: 0.3-0.94). Conclusions: Tumor biology consistent with CA-CRC, including SRC/M histology, may be present in 8.3% – 10.2% of patients with EOCRC without a clinical diagnosis of IBD, and harbors worse outcomes. Although other confounding biology may be underlying this association, recognition of undiagnosed IBD in CRC patients, especially those with metastatic disease, is important as it may impact prognosis and treatment strategies for this high-risk patient population.

Tumor mutations associated with outcomes in colorectal peritoneal metastases

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Background: The association between tumor mutations beyond KRAS and BRAF for patients with peritoneal metastases (PM) from colorectal cancer (CRC) are poorly understood. Here we describe these associations with survival after diagnosis of PM. Methods: CRC patients with PM with or without synchronous liver or lung metastases treated at a single institution from 2016 to 2020 were retrospectively studied. Standard of care next-generation sequencing was performed on tissue specimens with a targeted panel of genes frequently mutated in cancer. Clinical data, including survival and last contact, were obtained from medical records. Multivariate Cox regression was used to identify associations between overall survival after diagnosis of PM (OS) with clinical, histopathologic and somatic mutation data. Results: Of 526 PM patients, 179 (34.2%) also had synchronous liver metastases, and these patients had worse OS compared to PM alone (HR 1.67, [1.26-2.22], p=0.0003). Lung metastases were identified in 57 (10.8%) and were not associated with worse OS (HR 1.34, [0.90-1.97], p=0.15). Poorly differentiated grade (HR 2.08, [1.42-3.04], p=0.0002), mucinous histology (HR 1.44, [1.07-1.94], p=0.016), male gender (HR 1.37, [1.05-1.78), p=0.019), and age (HR 1.02, [1.01-1.04], p=0.004) were independently associated with OS. Tumor sequencing data was available for 442 (87%) patients. TP53 was the most common mutation (61.5% of patients) and was associated with decreased OS (HR=1.51 [1.12-2.02], p=0.005). BRAF mutation (85% of which were V600E) was identified in 9.7% of patients and was also associated with decreased OS (HR=1.88 [1.23-2.86], p=0.003). In contrast, PTEN mutation (4.3%) was associated with improved OS (0.41 (0.17-0.99), p=0.049), while both KRAS (51.4%) and SMAD4 mutations (16%) were not (KRAS: HR 0.94, [0.72-1.24], p=0.68; SMAD4: HR 0.78, [0.53-1.16], p=0.21). Conclusions: Mutational data for PM patients has a distinct profile and unique associations with OS when compared to other sites of metastatic disease. TP53 and BRAF mutations were associated with worse survival, while PTEN mutation was associated with improved OS. KRAS mutation was more prevalent than expected in an unselected cohort, and not associated with OS. A better understanding of PM-specific associations with survival may influence treatment strategies for this difficult disease site.