Download Introduction Pancreatic cancer is the fifth most frequently diagnosed

Introduction
Pancreatic cancer is the fifth most frequently diagnosed cancer worldwide and is the fourth leading
cause of cancer-related death [1]. Curative resection for pancreatic cancer provides the best
opportunity of prolonged survival, with a reported overall 5-year survival after curative resection of
15%-20%. However, only 10%-20% of patients with pancreatic cancer are eligible for curative
resection [2, 3]. The current gold standard therapy is curative resection followed by adjuvant
chemotherapy.
Recently, a number of reports have suggested the existence of a close association between the
systemic inflammatory response and the prognosis in cancer patients [4-11]. Exacerbation of
inflammation leads to the inhibition of apoptosis, promotion of angiogenesis and DNA damage, and
promotes cancer growth and metastasis [12]. Numerous studies have reported associations between
the values of several markers of the systemic inflammatory response, such as the
neutrophil/lymphocyte ratio (NLR), the platelet/lymphocyte ratio (PLR), and the Glasgow prognostic
score (GPS), and the prognosis in pancreatic cancer patients [4, 6, 7, 13, 14]. However, in most of
these reported studies, the sample sizes were rather small and both patients who received/did not
receive resection followed by adjuvant chemotherapy were enrolled. Although systemic inflammatory
markers are easily measurable, they are more likely to be affected by the presence of infection,
however, in most of these reported studies, the effect of employing biliary drainage prior to surgery
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was not investigated [6, 15, 16]. Therefore, the relationship between the prognosis of pancreatic cancer
and systemic inflammatory markers remains under debate.
The aim of this study was to determine the relationship between several systemic inflammatory
markers and the prognosis of pancreatic cancer patients who received curative resection followed by
adjuvant chemotherapy. Moreover, this study was performed to determine the relationship between
the direction of change of the NLR after one cycle of adjuvant chemotherapy and the response to
adjuvant chemotherapy.
Methods
Study Design
The data of 197 pancreatic cancer patients in our database who underwent potentially curative
resection (R0 or R1) at the National Cancer Center Hospital East between January 2009 and January
2015 were retrospectively reviewed. Of these, we excluded 57 patients for the following reasons:
neoadjuvant chemotherapy or chemoradiotherapy (26 patients), evidence of infection (3 patients),
resection with macroscopic residual tumor (R2) (2 patients), lost to follow-up (16 patients),
histological type other than tubular adenocarcinoma, papillary adenocarcinoma and poorly
differentiated adenocarcinoma (7 patients), other cause of death (3 patients). In addition, 30 patients
who did not receive adjuvant chemotherapy following tumor resection were also excluded. Finally,
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the data of the remaining 110 patients were analyzed.
The resected specimens were histopathologically classified according to the International Union
Against Cancer (UICC) TNM classification (7th edition). In regard to the adjuvant chemotherapy
administered after the curative resection, 47 patients (42.7%) received gemcitabine monotherapy, 54
(49.1%) received S-1 (mixture of tegafur, 5-chloro-2,4-dihydroxypyridine and oxonic acid)
monotherapy, and 9 (8.2%) received combined gemcitabine plus S-1 chemotherapy.
Peripheral blood samples were collected from the patients within 7 days of the tumor resection
surgery. The laboratory data, including the neutrophil, lymphocyte and platelet counts, and serum
levels of albumin (Alb), C-reactive protein (CRP) and carbohydrate antigen (CA) 19-9, were obtained
from the medical records. The NLR, PLR and GPS, well known systemic inflammatory markers, were
evaluated in this study. The NLR was calculated as the neutrophil count divided by the lymphocyte
count. The PLR was calculated as the platelet count divided by the lymphocyte count. The GPS was
calculated from the serum CRP and Alb levels, as follows: patients with both an elevated serum CRP
level (>0.3mg/dl) and hypoalbuminemia (<3.5g/ml) were allocated a score of 2, patients with only one
of these laboratory abnormalities were allocated a score of 1, and patients with neither of these
abnormalities were allocated a score of 0. The timings of collection of the blood samples for
determination of the direction of change of the NLR after adjuvant chemotherapy were within 2 days
before the start of adjuvant chemotherapy and after one cycle of adjuvant chemotherapy. The change
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in the NLR was calculated from the NLR determined after one cycle of adjuvant chemotherapy divided
by the NLR before the start of adjuvant chemotherapy: a value>1 was defined as NLR increase and a
value<1 was defined as NLR decrease.
To determine the optimal cutoff value of the NLR for prediction of the overall survival (OS), we
compared the OS rates using cutoff values of 2.0, 2.5, 3.0 and 3.5. The results of the above analysis
conducted by the Kaplan-Meier method and the log-rank test yielded an NLR of 3.0 as the optimal
cutoff value for predicting the survival rate. The cutoff value of the PLR has been reported previously
to be 150 [15].
Pancreatic fistula formation was evaluated according to the classification of the International Study
Group of Pancreatic Fistula [17]. Complications other than pancreatic fistula were classified according
to the definition proposed by Dindo et al [18]. Only complications of grade 2 severity or over were
recorded.
The primary end point was the OS. Survival time was calculated from the date of surgery to the date
of the last follow-up or death. The median follow-up period was 23 months (range, 5-70 months).
The study was conducted with the approval of the Research Ethics Committee of the National Cancer
Center Hospital.
Statistical Analysis
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The data are presented as medians and ranges. Time-to-event variables were calculated by the
Kaplan-Meier method and compared by the log-rank test. The Cox regression model was used for the
univariate analysis. Variables identified as having a significant prognostic value in the univariate
analysis were entered into the multivariate Cox proportional hazards model. The Mann-Whitney U
test was used to compare the relationship between the presence/absence of preoperative biliary
drainage or direction of change of the NLR with chemotherapy and other variables. All statistical
analyses were conducted using the JMP® 11 software (SAS Institute Inc., Cary, NC, USA).
Results
Patient characteristics
The median age of the 110 patients was 68.5 years. There were 72 (65.5%) men and 38 (34.5%)
women. The number of patients who received preoperative biliary drainage was 38 (34.5%). In regard
to the surgical procedure performed for resection of the pancreatic cancer, 76 (69.1%) patients
underwent pancreatoduodenectomy, 31 (28.2%) underwent distal pancreatectomy, and 3 (2.7%)
underwent total pancreatectomy. The median postoperative hospital stay was 13 days. Of the 110
patients, 38 (28.2%) developed postoperative complications and 18 (16.4%) pancreatic fistula
formation (≥Grade B). The demographics, tumor characteristics, and systemic inflammatory marker
levels in the study patients are shown in Table 1. A total of 101 (91.8%) patients were classified as
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having tubular adenocarcinoma. The number of patients with a positive nodal status was 77 (70%).
Because all the patients with a positive nodal status were categorized into stage IIB or more, we treated
the two synonymously. There were 101 (91.8%) patients with no residual tumor (R0) after surgery and
9 (8.2%) with microscopic residual tumor (R1) after surgery. The median interval to initiation of
adjuvant chemotherapy was 53 days.
Comparison of the clinical variables in relation to the OS
The median survival time of the patients was 40 months (interquartile range, 30-47months). The
univariate Cox regression analysis revealed an increase of the serum CA19-9 levels, except in cases
of tubular adenocarcinoma, disease stage IIB or more, and NLR increase as significant prognostic
factors for the OS (Table 2). In this study, the NLR, PLR and GPS were not identified as significant
predictors of the OS. The multivariate analysis carried out using the Cox regression model identified,
only the direction of change of the NLR as an independent risk factor for the OS (Table 2). In the
Kaplan-Meier survival analysis, NLR increase predicted a poorer prognosis as compared to NLR
decrease (median OS, 30 months vs. 47 months, respectively; p=0.005; Fig 1).
Relationships between preoperative biliary drainage and the values of the systemic inflammatory
markers
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The relationships between the presence/absence of preoperative biliary drainage and the values of
the systemic inflammatory markers, including the NLR, PLR and GPS, are shown in Table 3. Increases
of the NLR, PLR and GPS were significantly related to the preoperative use of biliary drainage.
Relationships between the direction of change of the NLR and clinicopathological variables
The clinicopathological variables in patients grouped by the direction of change of the NLR are
shown in Table 4. There were no significant differences in either the clinical variables or the tumor
characteristics between groups stratified according to the direction of change (increase or decrease) of
the NLR.
Discussion
The first causal link between inflammation and cancer was reported by Rudolf Virchow in 1863, who
described the presence of leukocytes in neoplastic tissues [12, 19]. Tumors can not only develop under
the stimulation of inflammation, but can also induce systemic and local inflammatory responses that
may provide a favorable microenvironment for tumor invasion and metastasis [4, 20]. The systemic
inflammatory response is associated with the release of pro-inflammatory cytokines such as
interleukin (IL)-6, and growth factors, resulting in tumor growth and metastasis [3, 7, 13, 20].
Kusumanto et al. [21] reported that circulating neutrophils contain and secrete the major portion of
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the circulating vascular endothelial growth factor (VEGF). VEGF is a pro-angiogenic factor that is
known to promote tumor angiogenesis, and may play an integral role in tumor growth and progression
[14, 16, 20, 22, 23]. Lymphocytopenia is an indicator of immunosuppression at both the local and
systemic levels [13, 14]. Thrombocytosis is related to the stimulation of megakaryocytes by pro-
inflammatory mediators such as IL-1 and IL-6 [7, 13]. CRP, white is an acute-phase protein produced
by the hepatocytes, is related to the systemic inflammation, and hypoalbuminemia, an indicator of
malnutrition, is known to be related to impaired host immunity [13, 20].
Thus, some studies have indicated the existence of associations between the values of several
inflammatory markers, such as the NLR, PLR and GPS, calculated from variables reflecting systemic
inflammation, and the prognosis in cancer patients, including those with pancreatic cancer [4- 11].
In this study, the NLR, PLR and GPS were not identified as significant prognostic factors in
pancreatic cancer patients treated by curative resection followed by adjuvant chemotherapy. This could
be thought to be attributable to the use of preoperative biliary drainage. Lewis et al. [6] pointed out in
their systematic review that many studies were poorly reported inclusion of patients who had
preoperative biliary drainage. Shirai et al. [7] reported that an increase of the PLR was associated with
the presence of preoperative biliary drainage. In this analysis, we excluded cases with evidence of
infection. Notwithstanding, the values of each of the systemic inflammatory markers were
significantly related to the preoperative use of biliary drainage. Thus, these systemic inflammatory
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markers were probably not identified as prognostic factors in this study as they may more strongly
reflect the potential infectious status caused by preoperative biliary drainage.
In this study, we determined the change of the NLR after one cycle of adjuvant chemotherapy as
compared to the value recorded prior to the start of the therapy, and demonstrated that a decrease of
the NLR after adjuvant chemotherapy was associated with a median OS of 47 months whereas an
increase was associated with a median OS of 30 months (P = 0.005). Thus, the direction of change of
the NLR after the start of chemotherapy was identified as an independent prognostic factor for OS in
pancreatic cancer patients treated by curative resection followed by adjuvant chemotherapy. Resection
followed by adjuvant chemotherapy represents the current gold standard therapy for resected
pancreatic cancer. Therefore, it is very important to identify the subgroup of patients who will benefit
most from adjuvant chemotherapy in the multimodality therapy [2, 8]. The direction of change of the
NLR, which can be easily measured, might be useful to predict the efficacy of adjuvant chemotherapy
in resected pancreatic cancer patients.
Luo et al. [2] reported that the postchemotherapy direction of change of the NLR could be used to
predict the response to chemotherapy in patients with advanced pancreatic cancer undergoing
chemotherapy. To the best of our knowledge, this is the first report describing the existence of a
correlation between the OS and post-treatment direction of change of the NLR in pancreatic cancer
patients treated by curative resection followed by adjuvant chemotherapy.
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Until now, most identified prognostic factors depend on the pathologic characteristics of the resected
tumor specimen determined after surgery [14, 20]. Meanwhile, some studies have reported the
existence of correlations between the values of systemic inflammatory marker, including the NLR,
and the pathological variables. For example, a correlations have been reported between the NLR and
the tumor differentiation grade, advanced disease stage, and positive nodal status [14, 16]. On the other
hand, Bhatti et al [3] reported that while the NLR showed no significant association with any of the
pathological factors, it was a significant independent prognostic factor. In this study also, the NLR
change was identified as a significant independent prognostic factor, but was not associated with any
clinicopathological variables. Therefore, the association between the direction of change of the NLR
and the prognosis cannot be solely explained by the pathological variables.
Recent studies have identified myeloid-derived suppressor cells (MDSCs), which are potent
suppressors of tumor immunity, and the negative regulatory programmed death-1/programmed death-
1 ligand (PD-1/PD-L) pathway in T-cell activation [24, 25]. Ohigashi et al. [24] reported that the PD-
L status was an independent prognostic factor in patients with esophageal cancer. The significance of
the PD-L status in other cancers and the effects of immunotherapy targeting the PD-L status have been
investigated. Some studies have suggested that the percentage of MDSCs in peripheral circulating
blood is increased in various types of cancers, including pancreatic cancer, as compared to that in
normal volunteers, and that the MDSCs contribute to chemoresistance of tumors [25, 26]. Ohki et al.
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[25] suggested that the depletion of MDSCs could be a strong tool for adjuvant therapy if
chemotherapy successfully decreases the count of MDSCs. Therapy targeted at the depletion of
MDSCs might represent a new approach for cancer immunotherapy [27, 28].
The PD-L status and MDSCs, associated with immune evasion and suppression, are closely related
to tumor growth and metastasis. A recent study reported a significant association between the count of
MDSCs and the NLR in patients with gastric and colorectal cancer [25]. Although the post-treatment
direction of change of the NLR was identified as an independent prognostic factor in this study, it was
not associated with either the clinical variables or the tumor characteristics. Thus, this study might
suggest that the direction of change of the NLR following treatment might reflect tumor immune
evasion and suppression, reflected by the PD-L status and count of MDSCs. Adjuvant chemotherapy
inhibits the PD-L pathway and activity of the MDSCs. As a result, a decrease of the NLR after adjuvant
chemotherapy was associated with a better prognosis than an increase of the NLR after adjuvant
chemotherapy
Only few reports of investigation of the prognostic significance of systemic inflammatory marker
values in the adjuvant chemotherapy setting in pancreatic cancer patients have been published [8, 29].
The direction of change of the NLR after adjuvant chemotherapy may help in predicting the effect of
chemotherapy, including immunotherapy, in pancreatic cancer patients.
The sample size in our study was relatively large as compared to that in previously reported studies.
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However, the major limitation of this study was that it was retrospective in nature and was conducted
at a single institution. Although our findings were of interest, their clinical relevance is not yet
completely understood and further research is required.
In conclusion, systemic inflammatory marker values are influenced by the use of preoperative biliary
drainage, caution should be exercised while interpreting the significance of changes in the values of
systemic inflammatory markers. On the other hand, the direction of change of the NLR after one cycle
of adjuvant chemotherapy may help in predicting the effect of chemotherapy, including
immunotherapy, in pancreatic cancer patients undergoing treatment by curative resection followed by
adjuvant chemotherapy.
Reference
1. Jemal A, Bray F, Center MM, Ferlay J, Ward E, Forman D. Global cancer statistics. CA Cancer J
Clin. 2011; 61(2):69-90.
2. Luo G, Guo M, Liu Z, Xiao Z, Jin K, Long J, et al. Blood neutrophil-lymphocyte ratio predicts
survival in patients with advanced pancreatic cancer treated with chemotherapy. Ann Surg Oncol.
2015; 22(2):670-6.
3. Bhatti I, Peacock O, Lloyd G, Larvin M, Hall RI. Preoperative hematologic markers as
independent predictors of prognosis in resected pancreatic ductal adenocarcinoma: neutrophillymphocyte versus platelet-lymphocyte ratio. Am J Surg. 2010; 200(2):197-203.
4. Cheng H, Long F, Jaiswar M, Yang L, Wang C, Zhou Z. Prognostic role of the neutrophil-tolymphocyte ration in pancreatic cancer: a meta-analysis. Sci Rep. 2015. DOI: 10.1038/srep11026.
5. Inoue D, Ozaki M, Matsuyama M, Yamada I, Takano K, Saiura A, et al. Prognostic value of
neutrophil-lymphocyte ratio and level of C-reactive protein in a large cohort of pancreatic cancer
12
patients: a retrospective study in a single institute in Japan. Jpn J Clin Oncol. 2015; 45(1):61-6.
6. Stevens L, Pathak S, Nunes QM, Pandanaboyana S, Macutkiewicz C, Smart N, et al. Prognostic
significance of pre-operative C-reactive protein and the neutrophil-lymphocyte ratio in resectable
pancreatic cancer: a systematic review. HPB. 2015; 17(4):285-91.
7. Shirai Y, Shiba H, Sakamoto T, Horiuchi T, Haruki K, Fujiwara Y, et al. Preoperative platelet to
lymphocyte ratio predicts outcome of patients with pancreatic ductal adenocarcinoma after
pancreatic resection. Surgery. 2015; 158(2):360-5.
8. Morinaga S, Murakawa M, Katayama Y, Yamaoku K, Aoyama T, Kanazawa A, et al. Glasgow
prognostic score predicts clinical outcomes in patients with pancreatic cancer undergoing adjuvant
gemcitabine monotherapy after curative surgery. Anticancer Res. 2015; 35(9):4865-70.
9. Proctor MJ, Morrison DS, Talwar D, Balmer SM, O’Reilly DSJ, Foulis AK, et al. An
inflammation-based prognostic score (mGPS) predicts cancer survival independent of tumour site:
a Glasgow inflammation outcome study. Br J Cancer. 2011; 104(4):726-34.
10. Kinoshita A, Onoda H, Imai N, Iwaku A, Oishi M, Tanaka K, et al. The C-reactive protein/albumin
ratio, a novel inflammation-based prognostic score, predicts outcomes in patients with
hepatocellular carcinoma. Ann Surg Oncol. 2015; 22(3):803-10.
11. Shimoda M, Katoh M, Kita J, Sawada T, Kubota K. The Glasgow prognostic score is a good
predictor of treatment outcome in patients with unresectable pancreatic cancer. Chemotherapy.
2010; 56(6):501-6.
12. Nakayama Y, Gotohda N, Shibasaki H, Nomura S, Kinoshita T, Hayashi R. Usefulness of the
neutrophil/lymphocyte ratio measured preoperatively as a predictor of peritoneal metastasis in
patients with advanced gastric cancer. Surg Today. 2014; 44(11):2146-52.
13. Ahmad J, Grimes N, Farid S, Morris-Stiff G. Inflammatory response related scoring systems in
assessing the prognosis of patients with pancreatic ductal adenocarcinoma: a systematic review.
Hepatobiliary Pancreat Dis Int. 2014; 13(5):474-81.
14. Yang JJ, Hu ZG, Shi WX, Deng T, He SQ, Yuan SG. Prognostic significance of neutrophil to
lymphocyte ratio in pancreatic cancer: a meta-analysis. World J Gastroenterol. 2015; 21(9):280715.
15. Stotz M, Gerger A, Eisner F, Szkandera J, Loibner H, Ress AL, et al. Increased neutrophillymphocyte ratio is a poor prognostic factor in patients with primary operable and inoperable
pancreatic cancer. Br J Cancer. 2013; 109(2):416-21.
16. Ben Q, An W, Wang L, Wang W, Yu L, Yuan Y. Validation of the pretreatment neutrophillymphocyte ratio as a predictor of overall survival in a cohort of patients with pancreatic ductal
adenocarcinoma. Pancreas. 2015; 44(3):471-7.
17. Bassi C, Dervenis C, Butturini G, Fingerhut A, Yeo C, Izbicki J, et al. Postoperative pancreatic
fistula: an international study group (ISGPF) definition. Surgery. 2005; 138(1):8-13.
13
18. Dindo D, Demartines N, Clavien PA. Classification of surgical complications: a new proposal
with evaluation in a cohort of 6336 patients and results of a survey. Ann surg. 2004; 240(2):20513.
19. Balkwill F, Mantovani A. Inflammation and cancer: back to Virchow? Lancet. 2001;
357(9255):539-45.
20. Wang DS, Luo HY, Qiu MZ, Wang ZQ, Zhang DS, Wang FH, et al. Comparison of the prognostic
values of various inflammation based factors in patients with pancreatic cancer. Med Oncol. 2012;
29(5):3092-100.
21. Kusumanto YH, Dam WA, Hospers GA, Meijer C, Mulder NH. Platelets and granulocytes, in
particular the neutrophis, form important compartments for circulating vascular endothelial
growth factor. Angiogenesis. 2003; 6(4):283-7.
22. Shamamian P, Schwartz JD, Pocock BJ, Monea S, Whiting D, Marcus SG, et al. Activation of
progelatinase A (MMP-2) by neutrophil elastase, cathepsin G, and proteinase-3: a role for
inflammatory cells in tumor invasion and angiogenesis. J Cell Physiol. 2001; 189(2):197-206.
23. Halazun KJ, Aldoori A, Malik HZ, Al-Mukhtar A, Prasad KR, Toogoog GJ, et al. Elevated
preoperative neutrophil to lymphocyte ratio predicts survival following hepatic resection for
colorectal liver metastases. Eur J Surg Oncol. 2008; 34(1):55-60.
24. Ohigashi Y, Sho M, Yamada Y, Tsurui Y, Hamada K, Ikeda N, et al. Clinical significance of
programmed death-1 ligand and programmed death-1 ligand-2 expression in human esophageal
cancer. Clin Cancer Res. 2005; 11(8):2947-53.
25. Ohki S, Shibata M, Gonda K, Machida T, Shimura T, Nakamura I, et al. Circulating myeloidderived suppressor cells are increased and correlate to immune suppression, inflammation and
hypoproteinemia in patients with cancer. Oncol Rep. 2012; 28(2):453-8.
26. Takeuchi S, Baghdadi M, Tsuchikawa T, Wada H, Nakamura T, Abe H, et al. Chemotherapyderived inflammatory responses accelerate the formation of immunosuppressive myeloid cells in
the tissue microenvironment of human pancreatic cancer. Cancer Res. 2015. DOI:10.1158/00085472.CAN-14-2921.
27. Stromnes IM, Brockenbrough JS, Izeradjene K, Carlson MA, Cuevas C, Simmons RM, et al.
Targeted depletion of an MDSC subset unmasks pancreatic ductal adenocarcinoma to adaptive
immunity. Gut. 2014; 63(11):1769-81.
28. Porembka MR, Mitchem JB, Belt BA, Hsieh CS, Lee HM, Herndon J, et al. Pancreatic
adenocarcinoma induces bone marrow mobilization of myeloid-derived suppressor cells which
promote primary tumor growth. Cancer Immunol Immunother. 2012; 61(9):1373-85.
29. Garcea G, Ladwa N, Neal CP, Metcalfe MS, Dennison AR, Berry DP. Preoperative neutrophil-tolymphocyte ratio (NLR) is associated with reduced disease-free survival following curative
resection of pancreatic adenocarcinoma. World J Surg. 2011; 35(4):868-72.
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