Influence of Klebsiella pneumoniae and quinolone treatment on prognosis in patients with pancreatic cancer

BACKGROUND

An increasing body of evidence suggests that microbiota may promote progression of pancreatic ductal adenocarcinoma (PDAC). It was hypothesized that gammaproteobacteria (such as Klebsiella pneumoniae) influence survival in PDAC, and that quinolone treatment may attenuate this effect.

METHODS

This was a retrospective study of patients from the Massachusetts General Hospital (USA) and Ludwig-Maximilians-University (Germany) who underwent preoperative treatment and pancreatoduodenectomy for locally advanced or borderline resectable PDAC between January 2007 and December 2017, and for whom a bile culture was available. Associations between tumour characteristics, survival data, antibiotic use and results of intraoperative bile cultures were investigated. Survival was analysed using Kaplan-Meier curves and Cox regression analysis.

RESULTS

Analysis of a total of 211 patients revealed that an increasing number of pathogen species found in intraoperative bile cultures was associated with a decrease in progression-free survival (PFS) (-1·9 (95 per cent c.i. -3·3 to -0·5) months per species; P = 0·009). Adjuvant treatment with gemcitabine improved PFS in patients who were negative for K. pneumoniae (26·2 versus 15·3 months; P = 0·039), but not in those who tested positive (19·5 versus 13·2 months; P = 0·137). Quinolone treatment was associated with improved median overall survival (OS) independent of K. pneumoniae status (48·8 versus 26·2 months; P = 0·006) and among those who tested positive for K. pneumoniae (median not reached versus 18·8 months; P = 0·028). Patients with quinolone-resistant K. pneumoniae had shorter PFS than those with quinolone-sensitive K. pneumoniae (9·1 versus 18·8 months; P = 0·001).

CONCLUSION

K. pneumoniae may promote chemoresistance to adjuvant gemcitabine, and quinolone treatment is associated with improved survival.

Risk of malignancy in small pancreatic cysts decreases over time

BACKGROUND

Pancreatic cysts <15 mm without worrisome features have practically no risk of malignancy at the time of diagnosis but this can change over time. Optimal duration of follow-up is a matter of debate. We evaluated predictors of malignancy and attempted to identify a time to safely discontinue surveillance.

METHODS

Bi-centric study utilizing prospectively collected databases of patients with pancreatic cysts measuring <15 mm and without worrisome features who underwent surveillance at the Massachusetts General Hospital (1988-2017) and at the University of Verona Hospital Trust (2000-2016). The risk of malignant transformation was assessed using the Kaplan-Meier method and parametric survival models, and predictors of malignancy were evaluated using Cox regression.

RESULTS

806 patients were identified. Median follow-up was 58 months (6-347). Over time, 58 (7.2%) cysts were resected and of those, 11 had high grade dysplasia (HGD) or invasive cancer. Three additional patients had unresectable cancer for a total rate of malignancy of 1.7%. Predictors of development of malignancy included an increase in size ≥2.5 mm/year (HR = 29.54, 95% CI: 9.39-92.91, P < 0.001) and the development of worrisome features (HR = 9.17, 95% CI: 2.99-28.10, P = 0.001). Comparison of parametric survival models suggested that the risk of malignancy decreased after three years of surveillance and was lower than 0.2% after five years.

CONCLUSIONS

Pancreatic cysts <15  mm at the time of diagnosis have a very low risk of malignant transformation. Our findings indicate the risk decreases over time. Size increase of ≥2.5 mm/year is the strongest predictor of malignancy.

An elevated CA 19-9 is associated with invasive cancer and worse survival in IPMN

BACKGROUND

Current guidelines for IPMN include an elevated serum carbohydrate antigen (CA) 19-9 among the worrisome features. However, the correlation of CA 19-9 with histological malignant features and survival is unclear. Serum CEA is also currently used for preoperative management of IPMN, although its measurement is not evidence-based. Accordingly, we aimed to assess the role of these tumor markers as predictors of malignancy in IPMN.

METHODS

IPMN resected between 1998 and 2018 at Massachusetts General Hospital were analyzed. Clinical, pathological and survival data were collected and compared to preoperative levels of CA 19-9 and CEA. Receiver operating characteristic (ROC) and Cox regression analyses were performed considering cut-offs of 37 U/ml (CA 19-9) and 5 μg/l (CEA).

RESULTS

Analysis of 594 patients showed that preoperative CA 19-9 levels > 37 U/ml (n = 128) were associated with an increased likelihood of invasive carcinoma when compared to normal levels (45.3% vs. 18.0%, P < 0.001), while there was no difference with respect to high-grade dysplasia (32.9% vs 31.9%, P = 0.88). The proportion of concurrent pancreatic cancer was higher in patients with CA 19-9 > 37 U/ml (17.2% vs 4.9%, P < 0.001). An elevated CA 19-9 was also associated with worse overall and disease-free survival (HR = 1.943, P = 0.007 and HR = 2.484, P < 0.001 respectively). CEA levels did not correlate with malignancy.

CONCLUSION

In patients with IPMN, serum CA19-9 > 37 U/ml is associated with invasive IPMN and concurrent pancreatic cancer as well as worse survival, but not with high-grade dysplasia. Serum CEA appears to have minimal utility in the management of these patients.

Promoting effect of a high-fat/high-protein diet in DMBA-induced ductal pancreatic cancer in rats

OBJECTIVE

To investigate whether a high-fat/high-protein diet (HFPD) acts as a promoter of the natural course of cancer growth in the 7,12-dimethylbenzanthracene (DMBA)-induced ductal pancreatic cancer model in rats.

SUMMARY BACKGROUND DATA

DMBA implantation to the rat pancreas induces ductal adenocarcinoma. Information regarding the effects of diet and the presence of K-ras mutation in this model is not available.

METHODS

Rats were randomly assigned to regular rat chow or a diet with a 30% content in fat and protein (HFPD). The presentation of cancer, the histologic spectrum of neoplasia at 1 and 9 months, and the prevalence of cancer in relation to diet were assessed. Histologic specimens comprising normal ducts, hyperplasia, dysplasia/carcinoma in situ, or carcinoma were designated by a pathologist and microdissected. Genomic DNA was extracted, and K-ras and H-ras gene mutations were determined by a mutant-enriched polymerase chain reaction assay and direct sequencing.

RESULTS

Rats fed HFPD increased their weight significantly compared with controls. DMBA induced characteristic stages of neoplasia at the implant site but not elsewhere. Macroscopic cancers of the pancreatic head presented regularly with common bile duct and gastric outlet obstruction. The prevalence of K-ras mutations was proportional to the degree of epithelial abnormality. K-ras mutations were significantly more frequent in cancer than in normal and hyperplastic ducts. H-ras mutations were not found. At 1 month in the HFPD-fed rats, the prevalence of cancer (16%) and dysplasia (16%) was not significantly different from the prevalence of cancer (29%) and dysplasia (8%) in the chow-fed rats. At 9 months the prevalence of cancer in the HFPD-fed rats increased to 29%, whereas that in the chow-fed rats decreased to 17%. The combined prevalence of cancer and dysplasia at 9 months in the HFPD-fed rats (34%) significantly exceeded that in the chow-fed rats.

CONCLUSIONS

DMBA induces characteristic stages of neoplasia in the evolution of ductal pancreatic cancer in rats. K-ras mutations occur progressively in the ladder of oncogenesis, as in human pancreatic neoplasms. The addition of a diet with a high fat and protein content acts as a promoter of carcinogenesis, possibly by interfering with repair mechanisms and natural regression of early lesions.

Effect of matrix metalloproteinase inhibition on pancreatic cancer invasion and metastasis: an additive strategy for cancer control

OBJECTIVE

To investigate the effect of a matrix metalloproteinase (MMP) inhibitor, BB-94, on the viability, invasion, and metastases of pancreatic cancer.

SUMMARY BACKGROUND DATA

Inhibitors of MMPs, enzymes that degrade extracellular matrix, have been tested as single chemotherapeutic agents for pancreatic cancer.

METHODS

Capan1 and AsPC1 cell lines were studied. BB-94 cytotoxicity was evaluated by cell proliferation assays. Production of MMP2 and MMP9 in conditioned media was demonstrated by gelatin zymography. The in vitro effect of BB-94 on cell invasion was assayed using invasion chambers. Hepatic metastases from pancreatic cancer were induced by intrasplenic injections of Capan1 or AsPC1 cells in nude mice. The in vivo effect of BB-94 on liver metastases was evaluated by comparing animals receiving BB-94 treatment with controls receiving vehicle alone. Variables measured included death rate and tumor burden (liver-to-body weight ratio).

RESULTS

BB-94 was not cytotoxic between 3 and 3,000 ng/mL. Zymography demonstrated production of MMP2 and MMP9 by both cell lines, with complete inhibition of these enzymes by BB-94 at 48 ng/mL. Invasion chamber assays showed that BB-94 (48-400 ng/mL) impeded cell invasion in vitro compared with untreated controls. In vivo, BB-94 prevented death or reduced the death rate from hepatic metastases in animals injected with Capan1 or AsPC1 cells. BB-94 treatment resulted in significant reductions in hepatic tumor burden compared with untreated controls.

CONCLUSIONS

Inhibition of MMP reduces both growth of pancreatic cancer metastases and the death rate. These actions do not reflect cytotoxicity but rather result from impaired cancer cell attachment, migration, and organ invasion. MMP inhibitors may provide an additive effect to cytotoxic agents in multidimensional treatment regimens for pancreatic cancer.

Microcystic adenoma of the pancreas

Three cases of pancreatic microcystic adenoma (PMA) are presented. These tumors comprise less than 1% of all pancreatic tumors in a large series, and exhibit a benign course, in contrast to mucinous cystadenomas, which have a definite malignant potential. The cases here presented are middle and advanced aged women who complained of epigastric discomfort and mild weight loss. Two of them also had a palpable epigastric mass and one of them diabetes mellitus. They were treated surgically with total excision of the tumor. During surgery and thereafter no evidence of spreading beyond the pancreas was found. CT scan shows a characteristic image of PMA, which may then be confirmed by a percutaneous biopsy. If the patient is asymptomatic or a poor surgical risk, it is reasonable to rely on this evidence and follow the patient rather than operate.