The efficacy of immunotherapy varies widely among different gastrointestinal cancers. Response to immune checkpoint inhibitors is shown to correlate with tumor mutation load (TML), mismatch repair ...deficiency (dMMR) status, and programmed cell death-ligand 1 (PD-L1) expression. Herein, we quantify TML, dMMR, and PD-L1 expression and determine their interrelationship in gastrointestinal cancers. Here, a total of 4,125 tumors from 14 different gastrointestinal cancer sites were studied using validated assays. Next-generation sequencing was performed on genomic DNA isolated from formalin-fixed paraffin-embedded tumor specimens using the NextSeq platform. TML was calculated using only somatic nonsynonymous missense mutations sequenced with a 592-gene panel. Microsatellite instability (MSI) was assessed using direct analysis of altered known MSI loci in the target regions of the sequenced genes. PD-L1 expression was analyzed by IHC. Interestingly, right-sided colon and small-bowel adenocarcinomas had the highest prevalence of TML-high tumors (14.6% and 10.2%, respectively). Pancreatic neuroendocrine tumors and gastrointestinal stromal tumors had the lowest rates of TML-high (1.3% and 0%, respectively). TML-high was strongly associated with MSI-H (
< 0.0001). However, all TML-high anal cancers (8.3%) were microsatellite stable (MSS). Higher PD-L1 expression was more likely to be seen in MSI compared with MSS tumors (20.6% vs. 7.8%,
< 0.0001).
TML-high rate varied widely among gastrointestinal cancers. Although MSI is conceivably the main driver for TML-high, other factors may be involved. Future clinical trials are needed to evaluate whether the integration of TML, MSI, and PD-L1 could better identify potential responders to immunotherapy.
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ASCO believes that high-quality observational studies can advance evidence-based practice for cancer care and are complementary to randomized controlled trials (RCTs). Observational studies can ...generate hypotheses by evaluating novel exposures or biomarkers and by revealing patterns of care and relationships that might not otherwise be discovered. Researchers can then test these hypotheses in RCTs. Observational studies can also answer or inform questions that either have not been or cannot be answered by RCTs. In addition, observational studies can be used for postmarketing surveillance of new cancer treatments, particularly in vulnerable populations. The incorporation of observational research as part of clinical decision making is consistent with the position of many leading institutions. ASCO identified five overarching recommendations to enhance the role of observational research in clinical decision making: (1) improve the quality of electronic health data available for research, (2) improve interoperability and the exchange of electronic health information, (3) ensure the use of rigorous observational research methodologies, (4) promote transparent reporting of observational research studies, and (5) protect patient privacy.
Summary Background Intermediate or surrogate endpoints for survival can shorten time lines for drug approval. We aimed to assess circulating tumour cell (CTC) count as a prognostic factor for ...survival in patients with progressive, metastatic, castration-resistant prostate cancer receiving first-line chemotherapy. Methods We identified patients with progressive metastatic castration-resistant prostate cancer starting first-line chemotherapy in the IMMC38 trial. CTCs were isolated by immunomagnetic capture from blood samples at baseline and after treatment. Baseline variables, including CTC count, titre of prostate-specific antigen (PSA), and concentration of lactate dehydrogenase (LDH), and post-treatment variables (change in CTCs and PSA) were tested for association with survival with Cox proportional hazards models. Concordance probability estimates were used to gauge discriminatory strength of the informative factors in identifying patients at low-risk and high-risk of survival. Findings Variables associated with high risk of death were high LDH concentration (hazard ratio 6·44, 95% CI 4·24–9·79), high CTC count (1·58, 1·41–1·77), and high PSA titre (1·26, 1·10–1·45), low albumin (0·10, 0·03–0·39), and low haemoglobin (0·72, 0·64–0·81) at baseline. At 4 weeks, 8 weeks, and 12 weeks after treatment, changes in CTC number were strongly associated with risk, whereas changes in PSA titre were weakly or not associated (p>0·04). The most predictive factors for survival were LDH concentration and CTC counts (concordance probability estimate 0·72–0·75). Interpretation CTC number, analysed as a continuous variable, can be used to monitor disease status and might be useful as an intermediate endpoint of survival in clinical trials. Prospective recording of CTC number as an intermediate endpoint of survival in randomised clinical trials is warranted. Funding The Prostate Cancer Foundation, Immunicon Corporation, Memorial Sloan-Kettering Cancer Center.
The combination of gemcitabine plus cisplatin (GC) is a standard regimen in patients with locally advanced or metastatic urothelial cancer. A phase I/II study suggested that a three-drug regimen that ...included paclitaxel had greater antitumor activity and might improve survival.
We conducted a randomized phase III study to compare paclitaxel/cisplatin/gemcitabine (PCG) with GC in patients with locally advanced or metastatic urothelial carcinoma. Primary outcome was overall survival (OS). Secondary outcomes were progression-free survival (PFS), overall response rate, and toxicity.
From 2001 to 2004, 626 patients were randomly assigned; 312 patients were assigned to PCG, and 314 patients were assigned to GC. After a median follow-up of 4.6 years, the median OS was 15.8 months on PCG versus 12.7 months on GC (hazard ratio HR, 0.85; P = .075). OS in the subgroup of all eligible patients was significantly longer on PCG (3.2 months; HR, 0.82; P = .03), as was the case in patients with bladder primary tumors. PFS was not significantly longer on PCG (HR, 0.87; P = .11). Overall response rate was 55.5% on PCG and 43.6% on GC (P = .0031). Both treatments were well tolerated, with more thrombocytopenia and bleeding on GC than PCG (11.4% v 6.8%, respectively; P = .05) and more febrile neutropenia on PCG than GC (13.2% v 4.3%, respectively; P < .001).
The addition of paclitaxel to GC provides a higher response rate and a 3.1-month survival benefit that did not reach statistical significance. Novel approaches will be required to obtain major improvements in survival of incurable urothelial cancer.
A method for enumerating circulating tumor cells (CTC) has received regulatory clearance. The primary objective of this prospective study was to establish the relationship between posttreatment CTC ...count and overall survival (OS) in castration-resistant prostate cancer (CRPC). Secondary objectives included determining the prognostic utility of CTC measurement before initiating therapy, and the relationship of CTC to prostate-specific antigen (PSA) changes and OS at these and other time points.
Blood was drawn from CRPC patients with progressive disease starting a new line of chemotherapy before treatment and monthly thereafter. Patients were stratified into predetermined Favorable or Unfavorable groups (<5 and > or =5 CTC/7.5mL).
Two hundred thirty-one of 276 enrolled patients (84%) were evaluable. Patients with Unfavorable pretreatment CTC (57%) had shorter OS (median OS, 11.5 versus 21.7 months; Cox hazard ratio, 3.3; P < 0.0001). Unfavorable posttreatment CTC counts also predicted shorter OS at 2 to 5, 6 to 8, 9 to 12, and 13 to 20 weeks (median OS, 6.7-9.5 versus 19.6-20.7 months; Cox hazard ratio, 3.6-6.5; P < 0.0001). CTC counts predicted OS better than PSA decrement algorithms at all time points; area under the receiver operator curve for CTC was 81% to 87% and 58% to 68% for 30% PSA reduction (P = 0.0218). Prognosis for patients with (a) Unfavorable baseline CTC who converted to Favorable CTC improved (6.8 to 21.3 months); (b) Favorable baseline CTC who converted to Unfavorable worsened (>26 to 9.3 months).
CTC are the most accurate and independent predictor of OS in CRPC. These data led to Food and Drug Administration clearance of this assay for the evaluation of CRPC.
Retrospective studies suggest that p53 alteration is prognostic for recurrence in patients with urothelial bladder cancer and predictive for benefit from combination methotrexate, vinblastine, ...doxorubicin, and cisplatin (MVAC) adjuvant chemotherapy.
Patients with pT1/T2N0M0 disease whose tumors demonstrated ≥ 10% nuclear reactivity on centrally performed immunohistochemistry for p53 were offered random assignment to three cycles of adjuvant MVAC versus observation; p53-negative patients were observed. By using a log-rank test with one-sided α = .05 and β = .10, 190 p53-positive patients were planned to be randomly assigned to detect an absolute improvement in probability of recurring by 3 years from 0.50 to 0.30.
A total of 521 patients were registered, 499 underwent p53 assessment, 272 (55%) were positive, and 114 (42%) were randomly assigned. Accrual was halted on the basis of the data and safety monitoring board review of a futility analysis. Overall 5-year probability of recurring was 0.20 (95% CI, 0.16 to 0.24) with no difference on the basis of p53 status. Only 67% of patients randomly assigned to MVAC received all three cycles with 12 patients receiving no treatment. There was no difference in recurrence in the randomly assigned patients (hazard ratio, 0.78; 95% CI, 0.29 to 2.08; P = .62).
Neither the prognostic value of p53 nor the benefit of MVAC chemotherapy in patients with p53-positive tumors was confirmed, but the high patient refusal rate, lower than expected event rate, and failures to receive assigned therapy severely compromised study power.
Bladder cancer is a paradigm of solid tumor malignancy, and despite increased understanding of the molecular biology of this disease, cure rates have not changed greatly for 20 years. Further ...progress is being slowed by poor accrual of patients to structured clinical trials. The use of preclinical models, and in particular bladder cancer xenografts and cell lines, may allow more rational design of clinical trials, provided that the experimental questions posed are within the capability of the respective models. With the availability of targeted therapeutic drugs for treating bladder cancer, these models may be useful for the design of drug combination regimens and optimal sequencing of reagents.
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