mFOLFOX6 versus mFOLFOX6 + aflibercept as neoadjuvant treatment in MRI-defined T3-rectal cancer: a randomized phase-II-trial of the German Rectal Cancer Study Group (CAO/ARO/AIO 0214).

BACKGROUND: Neoadjuvant chemotherapy is an option for patients with locally advanced rectal cancer at low risk for local recurrence. This randomized phase II trial investigated whether the addition of aflibercept to modified FOLFOX6 (mFOLFOX6) could improve the rates of centrally confirmed pathological complete remissions (pCR) and (disease-free) survival in magnetic resonance imaging (MRI)-staged cT3 rectal cancer. PATIENTS AND METHODS: Patients with rectal cancer fulfilling the following criteria were included: lower border of tumor >5 cm and <16 cm from anal verge; circumferential resection margin >2 mm and T3-tumor with a maximum infiltration of 10 mm, as determined by MRI. Patients were randomized 1 : 2 to six cycles mFOLFOX6 ± aflibercept. Surgery was scheduled 4 weeks after chemotherapy. Primary endpoint was the rate of centrally confirmed pCR. The study was designed to detect an improvement of pCR from 10% to 27% (power 80%, type I error 20%). RESULTS: A total of 119 randomized patients started treatment (39 patients mFOLFOX6, arm A, and 80 mFOLFOX + aflibercept, arm B). The incidence of all grade adverse events was similar in both arms, however, adverse events grade ≥3 were more than twice as high in the experimental arm due to hypertension. Surgical complications were comparable. Aflibercept did not improve the pCR rate (arm A 26% versus arm B 19%, P = 0.47) and more patients in arm B had node positivity. With a median follow-up of 40.1 months, the 4-year disease-free survival was 83% in arm A and 85% in arm B (P = 0.82). Only two patients in arm A and one patient in arm B developed local recurrence. CONCLUSIONS: In patients with locally advanced rectal cancer and MRI-defined low risk of local recurrence, neoadjuvant mFOLFOX6 + aflibercept was feasible and did not compromise surgery. Survival data were favorable in both arms, but pCR rates were not increased by the addition of aflibercept.

Inflammatory pathways confer resistance to chemoradiotherapy in anal squamous cell carcinoma.

Anal squamous cell carcinoma (ASCC) is associated with immunosuppression and infection with human papillomavirus (HPV). Response to standard chemoradiotherapy (CRT) varies considerably. A comprehensive molecular characterization of CRT resistance is lacking, and little is known about the interplay between tumor immune contexture, host immunity, and immunosuppressive and/or immune activating effects of CRT. Patients with localized ASCC, treated with CRT at three different sites of the German Cancer Consortium (DKTK) were included. Patient cohorts for molecular analysis included baseline formalin fixed paraffin embedded biopsies for immunohistochemistry (n = 130), baseline RNA sequencing (n = 98), peripheral blood immune profiling (n = 47), and serum cytokine measurement (n = 35). Gene set enrichment analysis showed that pathways for IFNγ, IFNα, inflammatory response, TNFα signaling via NF-κB, and EMT were significantly enriched in poor responders (all p < 0.001). Expression of interferon-induced transmembrane protein 1 (IFITM1), both on mRNA and protein levels, was associated with reduced Freedom from locoregional failure (FFLF, p = 0.037) and freedom from distant metastasis (FFDM, p = 0.014). An increase of PD-L1 expression on CD4+ T-cells (p < 0.001) and an increase in HLA-DR expression on T-cells (p < 0.001) was observed in the peripheral blood after CRT. Elevated levels of regulatory T-cells and CXCL2 were associated with reduced FFLF (p = 0.0044 and p = 0.004, respectively). Inflammatory pathways in tissue in line with elevated levels of regulatory T-cells and CXCL2 in peripheral blood are associated with resistance to CRT. To counteract this resistance mechanism, the RADIANCE randomized phase-2 trial currently tests the addition of the immune checkpoint inhibitor durvalumab to standard CRT in locally advanced ASCC.

Evaluation of prognostic factors after primary chemoradiotherapy of anal cancer: A multicenter study of the German Cancer Consortium-Radiation Oncology Group (DKTK-ROG).

BACKGROUND AND PURPOSE: Prognosis after chemoradiotherapy (CRT) for anal squamous cell carcinoma (ASCC) shows marked differences among patients according to TNM subgroups, however individualized risk assessment tools to better stratify patients for treatment (de-) escalation or intensified follow-up are lacking in ASCC. MATERIALS AND METHODS: Patients' data from eight sites of the German Cancer Consortium - Radiation Oncology Group (DKTK-ROG), comprising a total of 605 patients with ASCC, treated with standard definitive CRT with 5-FU/Mitomycin C or Capecitabine/Mitomycin C between 2004-2018, were used to evaluate prognostic factors based on Cox regression models for disease-free survival (DFS). Evaluated variables included age, gender, Karnofsky performance score (KPS), HIV-status, T-category, lymph node status and laboratory parameters. Multivariate cox models were separately constructed for the whole cohort and the subset of patients with early-stage (cT1-2 N0M0) tumors. RESULTS: After a median follow-up of 46 months, 3-year DFS for patients with early-stage ASCC was 84.9%, and 67.1% for patients with locally-advanced disease (HR 2.4, p < 0.001). T-category (HR vs. T1: T2 2.02; T3 2.11; T4 3.03), N-category (HR versus N0: 1.8 for N1-3), age (HR 1.02 per year), and KPS (HR 0.8 per step) were significant predictors for DFS in multivariate analysis in the entire cohort. The model performed with a C-index of 0.68. In cT1-2N0 patients, T-category (HR 2.14), HIV status (HR 2.57), age (1.026 per year), KPS (HR 0.7 per step) and elevated platelets (HR 1.3 per 100/nl) were associated with worse DFS (C-index of 0.7). CONCLUSION: Classical clinicopathologic parameters like T-category, N-category, age and KPS remain to be significant prognostic factors for DFS in patients treated with contemporary CRT for ASCC. HIV and platelets were significantly associated with worse DFS in patients with early stage ASCC.

Circulating miRNAs as non-invasive biomarkers to predict aggressive prostate cancer after radical prostatectomy.

BACKGROUND: Prostate cancer is an extremely heterogeneous disease. Despite being clinically similar, some tumours are more likely to recur after surgery compared to others. Distinguishing those that need adjuvant or salvage radiotherapy will improve patient outcomes. The goal of this study was to identify circulating microRNA that could independently predict prostate cancer patient risk stratification after radical prostatectomy. METHODS: Seventy-eight prostate cancer patients were recruited at the Odette Cancer Centre in Sunnybrook Health Sciences Centre. All patients had previously undergone radical prostatectomy. Blood samples were collected simultaneously for PSA testing and miRNA analysis using NanoString nCounter technology. Of the 78 samples, 75 had acceptable miRNA quantity and quality. Patients were stratified into high- and low-risk categories based on Gleason score, pathological T stage, surgical margin status, and diagnostic PSA: patients with Gleason ≥ 8; pT3a and positive margin; pT3b and any margin; or diagnostic PSA > 20 µg/mL were classified as high-risk (n = 44) and all other patients were classified as low-risk (n = 31). RESULTS: Using our patient dataset, we identified a four-miRNA signature (miR-17, miR-20a, miR-20b, miR-106a) that can distinguish high- and low-risk patients, in addition to their pathological tumour stage. High expression of these miRNAs is associated with shorter time to biochemical recurrence in the TCGA dataset. These miRNAs confer an aggressive phenotype upon overexpression in vitro. CONCLUSIONS: This proof-of-principle report highlights the potential of circulating miRNAs to independently predict risk stratification of prostate cancer patients after radical prostatectomy.

Chemoradiotherapy for anal cancer: are we as good as we think?

Definitive chemoradiotherapy (CRT) is the standard treatment for anal squamous cell carcinoma (ASCC). Data regarding treatment outcome according to TNM classification is scarce. Here, we review data of randomized trials and retrospective cohorts suggesting a poor 3­year disease-free survival (DFS; or progression-free survival, PFS) of approximately 60%, or even lower, in patients with locally advanced T3-4 and/or N+ disease, while patients with T1-2N0 ASCC have 3­year DFS/PFS rates exceeding 80%. These results are in line with our data in a cohort of 210 patients with ASCC treated with definitive 5­fluorouracil/mitomycin C­based CRT to a total dose of 50.4 Gy plus a boost of 3.6-10.8 Gy. The implications of these findings and the current trials testing radiotherapy dose escalation/de-escalation strategies are reported. Finally, we will discuss the strong rationale for testing immune checkpoint blockade (ICB) with CRT in clinical trials to improve results, especially in patients with advanced ASCC.

Impact of age on the efficacy of oxaliplatin in the preoperative chemoradiotherapy and adjuvant chemotherapy of rectal cancer: a post hoc analysis of the CAO/ARO/AIO-04 phase III trial.

Background: The German rectal cancer trial CAO/ARO/AIO-04 has shown a significant benefit in 3-year disease-free survival (DFS) of adding oxaliplatin to a standard preoperative 5-fluorouracil (5-FU)-based chemoradiotherapy (CRT) and adjuvant chemotherapy in patients with locally advanced rectal cancer. The use of oxaliplatin as adjuvant treatment in elderly patients with colon cancer is controversial. We therefore investigated the impact of age on clinical outcome in the CAO/ARO/AIO-04 phase III trial. Patients and methods: We carried out a post hoc analysis of the CAO/ARO/AIO-04 phase III trial evaluating primary and secondary end points according to age. Patient and tumor characteristics, NCI CTC adverse events grades 3-4 (version 3.0), dose intensities as well as survival and recurrence data were analyzed in three specified age groups (<60, 60-70, and ≥70 years). The influence of age as a continuous variable on DFS was modeled using a subpopulation treatment effect pattern plot (STEPP) analysis. Results: A total of 1232 patients were assessable. With the exception of Eastern Cooperative Oncology Group status (P < 0.001), no differences in patient and tumor characteristics were noticed between age groups. Likewise, toxicity pattern, dose intensities of CRT and surgical results were similar in all age groups. After a median follow-up of 50 months, in patients aged <60 years a significant benefit of adding oxaliplatin to 5-FU-based CRT and adjuvant chemotherapy was observed for local (P = 0.013) and systemic recurrences (P = 0.023), DFS (P = 0.011), and even overall survival (OS; P = 0.044). The STEPP analysis revealed improved hazard ratios for DFS in patients aged 40-70 years compared with elderly patients treated with oxaliplatin. Conclusion: The addition of oxaliplatin significantly improved DFS and OS in younger patients aged <60 years with advanced rectal cancer. Patients aged ≥70 years had no benefit. Clinical Trials Number: NCT00349076.

Neoadjuvant rectal score as individual-level surrogate for disease-free survival in rectal cancer in the CAO/ARO/AIO-04 randomized phase III trial.

Background: Surrogate end points in rectal cancer after preoperative chemoradiation are lacking as their statistical validation poses major challenges, including confirmation based on large phase III trials. We examined the prognostic role and individual-level surrogacy of neoadjuvant rectal (NAR) score that incorporates weighted cT, ypT and ypN categories for disease-free survival (DFS) in 1191 patients with rectal carcinoma treated within the CAO/ARO/AIO-04 phase III trial. Patients and methods: Cox regression models adjusted for treatment arm, resection status, and NAR score were used in multivariable analysis. The four Prentice criteria (PC1-4) were used to assess individual-level surrogacy of NAR for DFS. Results: After a median follow-up of 50 months, the addition of oxaliplatin to fluorouracil-based chemoradiotherapy (CRT) significantly improved 3-year DFS [75.9% (95% confidence interval [CI] 72.30% to 79.50%) versus 71.3% (95% CI 67.60% to 74.90%); P = 0.034; PC 1) and resulted in a shift toward lower NAR groups (P = 0.034, PC 2) compared with fluorouracil-only CRT. The 3-year DFS was 91.7% (95% CI 88.2% to 95.2%), 81.8% (95% CI 78.4% to 85.1%), and 58.1% (95% CI 52.4% to 63.9%) for low, intermediate, and high NAR score, respectively (P < 0.001; PC 3). NAR score remained an independent prognostic factor for DFS [low versus high NAR: hazard ratio (HR) 4.670; 95% CI 3.106-7.020; P < 0.001; low versus intermediate NAR: HR 1.971; 95% CI 1.303-2.98; P = 0.001] in multivariable analysis. Notwithstanding the inherent methodological difficulty in interpretation of PC 4 to establish surrogacy, the treatment effect on DFS was captured by NAR, supporting satisfaction of individual-level PC 4. Conclusion: Our study validates the prognostic role and individual-level surrogacy of NAR score for DFS within a large randomized phase III trial. NAR score could help oncologists to speed up response-adapted therapeutic decision, and further large phase III trial data sets should aim to confirm trial-level surrogacy.

The Development of Technology for Effective Respiratory-Gated Irradiation Using an Image-Guided Small Animal Irradiator.

The development of image-guided small animal irradiators represents a significant improvement over standard irradiators by enabling preclinical studies to mimic radiotherapy in humans. The ability to deliver tightly collimated targeted beams, in conjunction with gantry or animal couch rotation, has the potential to maximize tumor dose while sparing normal tissues. However, the current commercial platforms do not incorporate respiratory gating, which is required for accurate and precise targeting in organs subject to respiration related motions that may be up to the order of 5 mm in mice. Therefore, a new treatment head assembly for the Xstrahl Small Animal Radiation Research Platform (SARRP) has been designed. This includes a fast X-ray shutter subsystem, a motorized beam hardening filter assembly, an integrated transmission ionization chamber to monitor beam delivery, a kinematically positioned removable beam collimator and a targeting laser exiting the center of the beam collimator. The X-ray shutter not only minimizes timing errors but also allows beam gating during imaging and treatment, with irradiation only taking place during the breathing cycle when tissue movement is minimal. The breathing related movement is monitored by measuring, using a synchronous detector/lock-in amplifier that processes diffuse reflectance light from a modulated light source. After thresholding of the resulting signal, delays are added around the inhalation/exhalation phases, enabling the "no movement" period to be isolated and to open the X-ray shutter. Irradiation can either be performed for a predetermined time of X-ray exposure, or through integration of a current from the transmission monitor ionization chamber (corrected locally for air density variations). The ability to successfully deliver respiratory-gated X-ray irradiations has been demonstrated by comparing movies obtained using planar X-ray imaging with and without respiratory gating, in addition to comparing dose profiles observed from a collimated beam on EBT3 radiochromic film mounted on the animal's chest. Altogether, the development of respiratory-gated irradiation facilitates improved dose delivery during animal movement and constitutes an important new tool for preclinical radiation studies. This approach is particularly well suited for irradiation of orthotopic tumors or other targets within the chest and abdomen where breathing related movement is significant.

Are there HIV-specific Differences for Anal Cancer Patients Treated with Standard Chemoradiotherapy in the Era of Combined Antiretroviral Therapy?

AIMS: Contradicting evidence exists regarding the safety and clinical outcome of standard treatment in HIV-positive patients with anal cancer. We report on our large, single-centre experience in HIV-positive versus HIV-negative patients treated in the era of combined antiretroviral therapy (CART). MATERIALS AND METHODS: Between 1997 and 2015, 142 patients (42 HIV-positive versus 100 HIV-negative) with anal cancer were treated with standard chemoradiotherapy. Patients received a median dose of 50.4 Gy to the planning target volume; 91 (64%) patients received an external boost to the primary tumour and/or enlarged lymph nodes of 5.4-10.8 Gy. Concurrent chemotherapy was scheduled in the first and fifth weeks of radiotherapy using 5-fluorouracil and mitomycin C. The median follow-up was 51 (range 0-325) months. RESULTS: HIV-positive patients were predominantly male (P<0.001), younger (P<0.001) and had more advanced nodal disease (P=0.042). A dose reduction of chemotherapy was necessary in 38% of HIV-positive patients and in 24% of HIV-negative patients (P=0.39). There was no significant difference in total dose or duration of radiotherapy (median 43 versus 44 days, P=0.59). Complete response (81% versus 87%, P=0.088), 5 year rates of local failure (26.2% versus 14.9%, P=0.176), 5 year rates of distant failure (14.3% versus 8.4%, P=0.371) and 5 year overall survival (70.7% versus 78.4%, P=0.491) were not significantly different. HIV-positive patients had worse 5 year cancer-specific survival (80.5% versus 93.8%, P=0.029) in univariate but not in multivariate analysis (P=0.276). CONCLUSIONS: In the CART era, tolerance and clinical outcome are similar between HIV-positive and HIV-negative patients with anal cancer after standard chemoradiotherapy.

Head and neck cancer relapse after chemoradiotherapy correlates with CD163+ macrophages in primary tumour and CD11b+ myeloid cells in recurrences.

BACKGROUND: We investigated the prognostic role of tumour-associated macrophages (TAMs) in patients with head and neck squamous cell carcinoma (HNSCC) treated with definitive chemoradiotherapy (CRT). METHODS: The expression of CD68+, CD163+ and CD11b+ cells was assessed using immunohistochemistry in n=106 pre-treatment tumour biopsy samples and was correlated with clinicopathological characteristics, including T-stage, N-stage, grading, tumour localisation, age and sex as well as local failure-free survival (LFFS), distant metastases-free survival (DMFS), progression-free (PFS), and overall survival (OS). Finally, TAMs expression and vessel density (CD31) were examined in n=12 available early local recurrence samples and compared with their matched primary tumours . The diagnostic images and radiotherapy plans of these 12 patients were also analysed. All local recurrences occurred in the high radiation dose region (⩾70 Gy). RESULTS: With a median follow-up of 40 months, OS at 2 years was 60.5%. High CD163 expression in primary tumours was associated with decreased OS (P=0.010), PFS (P=0.033), LFFS (P=0.036) and DMFS (P=0.038) in multivariate analysis. CD163 demonstrated a strong prognostic value only in human papillomavirus (p16(INK4))-negative patients. Early local recurrence specimens demonstrated a significantly increased infiltration of CD11b+ myeloid cells (P=0.0097) but decreased CD31-positive vessel density (P=0.0004) compared with their matched primary samples. CONCLUSIONS: Altogether, baseline CD163 expression predicts for an unfavourable clinical outcome in HNSCC after definitive CRT. Early local recurrences showed increased infiltration by CD11b+ cells. These data provide important insight on the role of TAMs in mediating response to CRT in patients with HNSCC.

Concomitant chemoradiotherapy versus induction chemotherapy followed by chemoradiotherapy as definitive, first line treatment of squamous cell carcinoma of the head and neck. A retrospective single center analysis.

PURPOSE: Despite the lack of evidence to support its implementation in the clinical practice, induction chemotherapy (IC) before chemoradiotherapy (CRT) is often used in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN). We retrospectively examined the tolerability, feasibility, and clinical outcome of both concepts in a single center analysis. PATIENTS AND METHODS: In all, 83 patients were treated between 2007 and 2010 with IC + CRT (n = 42) or CRT alone (n = 41). IC consisted of docetaxel, cisplatin and 5-fluorouracil (TPF), or cisplatin and 5-fluorouracil (PF). All patients were scheduled to receive 2 cycles of PF during concurrent CRT. Adverse events were assessed according to the common toxicity criteria of adverse events (CTCAE v. 3.0). Associations were tested using the χ² test, and survival estimates were calculated according to Kaplan-Meier. RESULTS: The median follow-up was 30.35 months (range 2.66-61.25 months). At 2 years, the overall survival rate was significantly higher for primary CRT compared to IC + CRT group (74.8 % vs. 54 %, respectively; p = 0.041). Significantly more treatment-related overall grade 4 toxicities were documented in the IC + CRT group compared to the CRT group (42.9% vs. 9.8%; p = 0.001). Renal toxicity ≥ grade 2 occurred in 52.4 % vs. 7.3 % (p < 0.001), respectively. In all, 93 % of the patients with primary CRT compared to 71 % with IC + CRT received the planned full radiotherapy dose (p = 0.012). CONCLUSION: This is, to our knowledge, the largest retrospective study to compare IC + CRT with primary CRT. IC showed high acute toxicity, compromised the feasibility of concurrent CRT, and was associated with reduced overall survival rates compared to primary CRT. The lack of clinical benefit in conjunction with the increased toxicity does not support implementation of IC.

Tumour-infiltrating lymphocytes predict response to definitive chemoradiotherapy in head and neck cancer.

BACKGROUND: We aimed to investigate the prognostic value of tumour-infiltrating lymphocytes' (TILs) expression in pretreatment specimens from patients with head and neck squamous cell carcinoma (HNSCC) treated with definitive chemoradiotherapy (CRT). METHODS: The prevalence of CD3+, CD8+, CD4+ and FOXP3+ TILs was assessed using immunohistochemistry in tumour tissue obtained from 101 patients before CRT and was correlated with clinicopathological characteristics as well as local failure-free- (LFFS), distant metastases free- (DMFS), progression-free (PFS) and overall survival (OS). Survival curves were measured using the Kaplan-Meier method, and differences in survival between the groups were estimated using the log-rank test. Prognostic effects of TIL subset density were determined using the Cox regression analysis. RESULTS: With a mean follow-up of 25 months (range, 2.3-63 months), OS at 2 years was 57.4% for the entire cohort. Patients with high immunohistochemical CD3 and CD8 expression had significantly increased OS (P=0.024 and P=0.028), PFS (P=0.044 and P=0.047) and DMFS (P=0.021 and P=0.026) but not LFFS (P=0.90 and P=0.104) in multivariate analysis that included predictive clinicopathologic factors, such as age, sex, T-stage, N-stage, tumour grading and localisation. Neither CD4 nor FOXP3 expression showed significance for the clinical outcome. The lower N-stage was associated with improved OS in the multivariate analysis (P=0.049). CONCLUSION: The positive correlation between a high number of infiltrating CD3+ and CD8+ cells and clinical outcome indicates that TILs may have a beneficial role in HNSCC patients and may serve as a biomarker to identify patients likely to benefit from definitive CRT.

Comparison of four target volume definitions for pancreatic cancer. Guidelines for treatment of the lymphatics and the primary tumor.

BACKGROUND AND PURPOSE: Target volume definitions for radiotherapy in pancreatic ductal adenocarcinoma (PDAC) vary substantially. Some groups aim to treat the primary tumor only, whereas others include elective lymph nodes (eLNs). eLNs close to the primary tumor are often included unintentionally within the treatment volume, depending on the respective treatment philosophies. We aimed to measure the percentages of anatomical coverage of eLNs by comparing four different contouring guidelines. PATIENTS AND METHODS: Planning target volumes (PTVs) were contoured using planning computed tomography (CT) scans of 11 patients with PDAC based on the Oxford, RTOG (Radiation Therapy Oncology Group), Michigan, and SCALOP (Selective Chemoradiation in Advanced Localised Pancreatic Cancer trial) guidelines. Clinical target volumes (CTVs) included the peripancreatic, para-aortic, paracaval, celiac trunk, superior mesenteric, and portal vein lymph node areas. Volumetric comparisons of the coverage of all eLN regions were conducted to illustrate the differences between the four contouring strategies. RESULTS: The PTV sizes of the RTOG and Oxford guidelines were comparable. The SCALOP and Michigan PTV sizes were similar to each other and significantly smaller than the RTOG and Oxford PTVs. A large variability of eLN coverage was found for the various subregions according to the respective contouring strategies. CONCLUSION: This is the first study to directly compare the percentage of anatomical coverage of eLNs according to four PTVs in the same patient cohort. Potential practical consequences are discussed in detail.

Targeting ATR in vivo using the novel inhibitor VE-822 results in selective sensitization of pancreatic tumors to radiation.

Combined radiochemotherapy is the currently used therapy for locally advanced pancreatic ductal adenocarcinoma (PDAC), but normal tissue toxicity limits its application. Here we test the hypothesis that inhibition of ATR (ATM-Rad3-related) could increase the sensitivity of the cancer cells to radiation or chemotherapy without affecting normal cells. We tested VE-822, an ATR inhibitor, for in vitro and in vivo radiosensitization. Chk1 phosphorylation was used to indicate ATR activity, γH2AX and 53BP1 foci as evidence of DNA damage and Rad51 foci for homologous recombination activity. Sensitivity to radiation (XRT) and gemcitabine was measured with clonogenic assays in vitro and tumor growth delay in vivo. Murine intestinal damage was evaluated after abdominal XRT. VE-822 inhibited ATR in vitro and in vivo. VE-822 decreased maintenance of cell-cycle checkpoints, increased persistent DNA damage and decreased homologous recombination in irradiated cancer cells. VE-822 decreased survival of pancreatic cancer cells but not normal cells in response to XRT or gemcitabine. VE-822 markedly prolonged growth delay of pancreatic cancer xenografts after XRT and gemcitabine-based chemoradiation without augmenting normal cell or tissue toxicity. These findings support ATR inhibition as a promising new approach to improve the therapeutic ration of radiochemotherapy for patients with PDAC.