Results of the baseline positron emission tomography can customize therapy of localized esophageal adenocarcinoma patients who achieve a clinical complete response after chemoradiation

BACKGROUND

Patients with localized esophageal adenocarcinoma (EAC) who achieve a clinical complete response (clinCR) after preoperative chemoradiation (trimodality therapy; TMT) or definitive chemoradiation (bimodality therapy; BMT) live longer than those who achieve a <clinCR (Suzuki A, Xiao LC, Hayashi Y et al. Prognostic significance of baseline positron emission tomography and importance of clinical complete response in patients with esophageal or gastroesophageal junction cancer treated with definitive chemoradiotherapy. Cancer 2011; 117: 4823-4833; Cheedella NK, Suzuki A, Xiao L et al. Association between clinical complete response and pathological complete response after preoperative chemoradiation in patients with gastroesophageal cancer: analysis in a large cohort. Ann Oncol 2013; 24: 1262-1266; Ajani JA, Correa AM, Hofstetter WL et al. Clinical parameters model for predicting pathologic complete response following preoperative chemoradiation in patients with esophageal cancer. Ann Oncol 2012; 23: 2638-2642). We hypothesized that the initial standardized uptake value (iSUV) of positron emission tomography will define novel subsets of clinCR patients.

METHODS

We analyzed 323 EAC patients, from our prospective database, who achieved a clinCR. Various statistical methods were used to assess the influence of iSUV on patient outcome.

RESULTS

The median follow-up of 323 patients was 40.8 months [95% confidence interval (CI) 35.6-47.3 months]. Two hundred six (63.8%) patients had TMT and 117 (36.2%) had BMT. If iSUV was ≥6, TMT patients had a longer median OS (94.8 months; 95% CI 66.07-NA) than BMT patients (31.4 months; 95% CI 21.7-42.1; P ≤ 0.001). However, if iSUV was <6, the median OS of TMT and BMT patients was similar (P = 0.62). iSVU did not influence the pathologic complete response rate in TMT patients (P = 0.85).

CONCLUSION

clinCR patients with iSUV of <6 are identified as a new subset that fared equally well when treated with TMT or BMT. Future esophageal preservation strategy may be best suited for this newly identified subset of EAC patients.

Association between clinical complete response and pathological complete response after preoperative chemoradiation in patients with gastroesophageal cancer: analysis in a large cohort

BACKGROUND

Chemoradiation followed by surgery is the preferred treatment of localized gastroesophageal cancer (GEC). Surgery causes considerable life-altering consequences and achievement of clinical complete response (clinCR; defined as postchemoradiation [but presurgery] endoscopic biopsy negative for cancer and positron emission tomographic (PET) scan showing physiologic uptake) is an enticement to avoid/delay surgery. We examined the association between clinCR and pathologic complete response (pathCR).

PATIENTS AND METHODS

Two hundred eighty-four patients with GEC underwent chemoradiation and esophagectomy. The chi-square test, Fisher exact test, t-test, Kaplan-Meier method, and log-rank test were used.

RESULTS

Of 284 patients, 218 (77%) achieved clinCR. However, only 67 (31%) of the 218 achieved pathCR. The sensitivity of clinCR for pathCR was 97.1% (67/69), but the specificity was low (29.8%; 64/215). Of the 66 patients who had less than a clinCR, only 2 (3%) had a pathCR. Thus, the rate of pathCR was significantly different in patients with clinCR than in those with less than a clinCR (P < 0.001).

CONCLUSIONS

clinCR is not highly associated with pathCR; the specificity of clinCR for pathCR is too low to be used for clinical decision making on delaying/avoiding surgery. Surgery-eligible GEC patients should be encouraged to undergo surgery following chemoradiation despite achieving a clinCR.

Clinical parameters model for predicting pathologic complete response following preoperative chemoradiation in patients with esophageal cancer

BACKGROUND

Approximately 25% of patients with esophageal cancer (EC) who undergo preoperative chemoradiation, achieve a pathologic complete response (pathCR). We hypothesized that a model based on clinical parameters could predict pathCR with a high (≥60%) probability.

PATIENTS AND METHODS

We analyzed 322 patients with EC who underwent preoperative chemoradiation. All the patients had baseline and postchemoradiation positron emission tomography (PET) and pre- and postchemoradiation endoscopic biopsy. Logistic regression models were used for analysis, and cross-validation via the bootstrap method was carried out to test the model.

RESULTS

The 70 (21.7%) patients who achieved a pathCR lived longer (median overall survival [OS], 79.76 months) than the 252 patients who did not achieve a pathCR (median OS, 39.73 months; OS, P = 0.004; disease-free survival, P = 0.003). In a logistic regression analysis, the following parameters contributed to the prediction model: postchemoradiation PET, postchemoradiation biopsy, sex, histologic tumor grade, and baseline (EUS)T stage. The area under the receiver-operating characteristic curve was 0.72 (95% confidence interval [CI] 0.662-0.787); after the bootstrap validation with 200 repetitions, the bias-corrected AU-ROC was 0.70 (95% CI 0.643-0.728).

CONCLUSION

Our data suggest that the logistic regression model can predict pathCR with a high probability. This clinical model could complement others (biomarkers) to predict pathCR.

Interferon regulatory factor 3 is required for viral induction of beta interferon in primary cardiac myocyte cultures

Viral myocarditis affects an estimated 5 to 20% of the human population. The antiviral cytokine beta interferon (IFN-beta) is critical for protection against viral myocarditis in mice. That is, nonmyocarditic reoviruses induce myocarditis in mice that lack IFN-alpha/beta, and nonmyocarditic reoviruses both induce more IFN-beta and are more sensitive to the antiviral effects of IFN-beta than myocarditic reoviruses in primary cardiac myocyte cultures. Induction of IFN-beta in certain cell types involves viral activation of the transcription factor interferon regulatory factor 3 (IRF-3). To address whether IRF-3 can induce IFN-beta in cardiac myocytes, primary cardiac myocyte cultures and control L929 cells were transfected with a plasmid constitutively expressing IRF-3. Overexpression of IRF-3 resulted in induction of IFN-beta in the absence of viral infection in both cell types. To address whether IRF-3 is required for viral induction of IFN-beta, cell cultures were transfected with a plasmid constitutively expressing a dominant negative IRF-3 protein. The dominant negative IRF-3 reduced reovirus induction of IFN-beta in control L929 cells and completely eliminated induction in primary cardiac myocyte cultures. This provides the first identification of a cardiac cellular factor required for viral induction of IFN-beta and the first report of any cell type requiring IRF-3 for this response.

Reovirus induction of and sensitivity to beta interferon in cardiac myocyte cultures correlate with induction of myocarditis and are determined by viral core proteins

Reovirus-induced acute myocarditis in mice serves as a model to investigate non-immune-mediated mechanisms of viral myocarditis. We have used primary cardiac myocyte cultures infected with a large panel of myocarditic and nonmyocarditic reassortant reoviruses to identify determinants of viral myocarditic potential. Here, we report that while both myocarditic and nonmyocarditic reoviruses kill cardiac myocytes, viral myocarditic potential correlates with viral spread through cardiac myocyte cultures and with cumulative cell death. To address the role of secreted interferon (IFN), we added anti-IFN-alpha/beta antibody to infected cardiac myocyte cultures. Antibody benefited nonmyocarditic more than myocarditic virus spread (P < 0.001), and this benefit was associated with the reovirus M1 and L2 genes. There was no benefit for a differentiated skeletal muscle cell line culture (C2C12 cells), suggesting cell type specificity. IFN-beta induction in reovirus-infected cardiac myocyte cultures correlated with viral myocarditic potential (P = 0.006) and was associated with the reovirus M1, S2, and L2 genes. Sensitivity to the antiviral effects of IFN-alpha/beta added to cardiac myocyte cultures also correlated with viral myocarditic potential (P = 0.004) and was associated with the same reovirus genes. Several reoviruses induced IFN-beta levels discordant with their myocarditic phenotypes, and for those tested, sensitivity to IFN-alpha/beta compensated for the anomalous induction levels. Thus, the combination of induction of and sensitivity to IFN-alpha/beta is a determinant of reovirus myocarditic potential. Finally, a nonmyocarditic reovirus induced cardiac lesions in mice depleted of IFN-alpha/beta, demonstrating that IFN-alpha/beta is a determinant of reovirus-induced myocarditis. This provides the first identification of reovirus genes associated with IFN induction and sensitivity and provides the first evidence that IFN-beta can be a determinant of viral myocarditis and reovirus disease.

Reovirus-induced acute myocarditis in mice correlates with viral RNA synthesis rather than generation of infectious virus in cardiac myocytes

The capacity for different reovirus reassortant viruses to induce acute myocarditis in mice correlates with cytopathogenic effect in primary cultures of murine cardiac myocytes. Multiple viral genes encoding proteins involved in viral RNA synthesis are determinants of this disease. We therefore evaluated the role of viral RNA synthesis in induction of acute myocarditis by infecting primary cultures of cardiac myocytes with a panel of myocarditic and nonmyocarditic viruses and quantitating RNA synthesis. RNA synthesis correlated with induction of myocarditis and with the S1 and M1 reovirus genes. Since one consequence of viral RNA synthesis is generation of infectious virus, we looked next at viral yield from cardiac myocyte cultures. Yield of infectious virus at an early time postinfection or as a final yield from primary infections did not correlate with myocarditis, but instead both correlated with the S1 gene. The S1 gene also determined the fraction of cells infected during primary infections in the culture, which varied dramatically between viruses. Viral yields per infected cell were similar for most myocarditic and nonmyocarditic reoviruses and did not correlate with induction of myocarditis or any reovirus gene. Together, the data provide two insights into reovirus-induced acute myocarditis in mice. First, while the S1 gene. which encodes the viral attachment protein sigma1 (as well as a nonstructural protein, sigma1s, of unknown function) does not determine the myocarditic potential of these viruses, it does determine the efficiency with which they infect cardiac myocytes. Second, while viral RNA synthesis is a determinant of acute myocarditis, this is not due to generation of infectious virus. This finding suggests that some other consequence of viral RNA synthesis, for example, induction of interferon, may determine reovirus-induced acute myocarditis.

Multiple viral core proteins are determinants of reovirus-induced acute myocarditis

Previously, we showed that the M1 gene (encoding a viral core protein, mu 2, whose function is unknown) was associated with the efficiently myocarditic phenotype of a reovirus variant, 8B. Here, we have extended our genetic analysis of 8B and conducted genetic analyses of two other reovirus strains (T1L [serotype 1 strain Lang] and Abney). Our results demonstrate that multiple viral core proteins are determinants of reovirus-induced myocarditis. In contrast to our previous association of mu 2 with induction of myocarditis, this provides strong evidence that a core function achieved through the interaction of multiple core proteins is responsible for induction of the disease.

Immediate and long-term pathophysiologic mechanisms underlying the genesis of sudden cardiac death in patients with congestive heart failure

Congestive heart failure is the most important predisposing factor to the occurrence of sudden death in patients with cardiovascular disease. As left ventricular dysfunction deteriorates and symptoms of heart failure become evident, ambulatory ventricular arrhythmias become increasingly frequent and complex, and sudden cardiac death becomes an increasingly common occurrence. When the left ventricular ejection fraction has declined to less than 30 percent and symptoms of heart failure become refractory to treatment with digitalis and diuretics, 35 to 50 percent of patients will die of a lethal cardiac arrhythmia within three years. A number of factors interact to determine the occurrence of malignant ventricular arrhythmias in patients with congestive heart failure. Myocardial fibrosis and enhanced left ventricular wall stress may alter the electrophysiologic properties of the myocardium, but these factors may not be sufficient to explain the development of lethal rhythm disturbances. Neurohormonal activation may exacerbate the frequency and complexity of ambulatory arrhythmias in these patients, but such activation can persist for long periods without fatal electrophysiologic sequelae. Recent investigations suggest that electrolyte depletion may provide an important immediate precipitating cause for the occurrence of fatal ventricular tachyarrhythmias in the patient with severe left ventricular dysfunction whose susceptibility is markedly heightened by preexisting structural, hemodynamic, or neurohormonal factors. Further work is needed to determine if prophylactic therapy directed at preventing electrolyte depletion can favorably modify the long-term outcome of these severely ill patients.