Gastrointestinal cancer research : GCR最新文献

The management of anal cancer is driven by randomized and nonrandomized clinical trials. However, trials may present conflicting conclusions. Furthermore, different clinical situations may not be addressed in certain trials because of eligibility inclusion criteria. Although prospective studies point to the use of definitive 5-fluorouracil and mitomycin C-based chemoradiation as a standard, some areas remain that are not well defined. In particular, management of very early stage disease, radiation dose, and the use of intensity-modulated radiation therapy remain unaddressed by phase III studies. The American College of Radiology (ACR) Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Background: The treatment of metastatic colorectal cancer (mCRC) includes drugs targeting the epidermal growth factor receptor (EGFR). Mutation in codon 12 or 13 in the Kirsten rat sarcoma viral oncogene homolog (KRAS) gene, downstream of the EGFR, evokes constitutive activation of the RAS/RAF/MAPK signaling pathway and correlates with resistance to anti-EGFR monoclonal antibody (mAb) therapies. However, a retrospective study reported that a proportion of patients with the KRAS G13D mutation may respond to cetuximab. A similar analysis for panitumumab was not as conclusive. We sought to determine the sensitivity of CRC cell lines to cetuximab or panitumumab treatment and to investigate the correlation of the KRAS mutational status of the CRC cell lines to the responsiveness to cetuximab or panitumumab.

Methods: To determine the responsiveness of CRC cell lines to cetuximab or panitumumab, cell lines were treated with an optimized concentration of each mAb, and proliferation assays were conducted.

Results: After treatment with cetuximab or panitumumab, at the optimum concentration of 8 μg/well, the KRAS G13D mutant cell lines HCT-116, LoVo, and T84 showed intermediate sensitivity to both treatments, between the resistant KRAS G12V mutant cell line SW480 and the sensitive KRAS wild-type cell line LIM1215. One of the G13D cell lines was significantly more sensitive to panitumumab than to cetuximab (P = .02).

Conclusion: The specific KRAS mutation determines the responsiveness to anti-EGFR monoclonal antibody treatment, corresponding to reported clinical observations.

Background: A standard neoadjuvant regimen has not been defined for borderline resectable (BR) pancreatic cancer. This phase II trial was designed to determine the safety of accelerated fraction radiotherapy (AFRT) with capecitabine in patients with BR pancreatic cancer.

Methods: The patients had newly diagnosed BR adenocarcinoma of the pancreas and normal organ function. Intensity-modulated (n = 11) or 3D conformal (n = 2) radiotherapy was given to a dose of 50 Gy in 2.5-Gy fractions with capecitabine 825 mg/m(2) twice on radiation days. The primary outcome was the frequency of severe treatment-related adverse events (AEs). The study was stopped before planned interim analysis because of 2 severe (grades 4 and 5) gastric ulcerations.

Results: Thirteen patients were enrolled with a median age of 66 years. All patients completed treatment. Seven (54%) experienced grade 3+ treatment-related AEs. Severe gastric ulceration occurred in 2 patients despite receipt of ≥43 Gy to only 1% (2-3 cm(3)) of the stomach. Lymphopenia (n = 7) was the only other severe AE that occurred in >1 patient. In 7 of the 13 patients, disease had progressed outside the pancreas at restaging. Five of the 13 underwent resection, and all had >10% viable tumor. Median progression-free survival (PFS) was 2.4 months (95% CI 1.9-5.9), and median survival was 9.1 months (95% CI 5.9-not reached). Among those who underwent resection, median PFS was 13.0 months (95% CI 4.4-not reached). Median survival was not reached.

Conclusions: Given the limited efficacy signal and severe gastric ulcerations, we do not recommend this regimen for pancreatic cancer. We also do not recommend the use of high doses per fraction outside a clinical trial.

Background: This study was conducted to identify the factors associated with acute gastrointestinal (GI) toxicity during pelvic chemoradiotherapy (PCRT) in patients with rectal cancer.

Methods: We analyzed 177 patients with rectal cancer treated from 2007 through 2010. Clinical information, including weekly diarrhea and proctitis toxicity grade during PCRT, was recorded. GI structures including bowel and anal canal were contoured. The associations between toxicity and clinical and dosimetric predictors were tested.

Results: The median age was 60; 76 patients were women; 98 were treated with intensity-modulated radiotherapy (IMRT) and 79 with 3D conformal RT (3DCRT). A higher rate of grade 2+ diarrhea was observed in the women, starting at week 4 (24% women vs. 11% men, P = .01; week 5: 33% vs. 12%, P = .002), as well as in all the patients treated with 3DCRT (22% vs. 12% IMRT, P = .03; week 5: 32% vs. 11%, P = .001). On multivariate analysis, the normal tissue complication probability (NTCP) model including bowel V45 (bowel volume receiving ≥45 Gy) showed that being female, and use of 3DCRT, was most predictive of grade 2+ diarrhea (area under the curve [AUC] = 0.76; R S = 0.35; P < .001). A higher rate of grade 2+ proctitis was seen in patients <60 years of age starting at week 3 (21% vs. 9%, P = .02; week 4: 35% vs. 16%, P = .003). The NTCP model including anal canal V15 and younger age was most predictive of grade 2+ proctitis (AUC = 0.67; R S = 0.25; P < .001).

Conclusions: Women and all patients who were treated with 3DCRT had higher rates of grade 2+ diarrhea, and the younger patients had a higher rate of grade 2+ proctitis during PCRT. The use of more stringent dosimetric constraints in higher risk patients is a strategy for minimizing toxicity.