Background: KRAS mutation status is a candidate marker for predicting survival in patients with metastatic colorectal cancer (mCRC) treated with cetuximab (CTX). Patients and methods:We studied the KRAS mutation status of 113 patients with irinotecan refractory mCRC treated with CTX in clinical trials. A predictive model for objective response (OR), progression-free survival (PFS) and overall survival (OS) was constructed using logistic and Cox regression.Results: OR was seen in 27 of 66 KRAS wild-type (WT) patients versus 0 of 42 in KRAS mutants. Median OS was significantly better in KRAS WT versus mutants (43.0 versus 27.3 weeks; P = 0.020). Decrease in tumor sizes was significantly larger at all time points in WT patients. KRAS WT patients with an initial relative decrease of tumor size >9.66% at week 6 had a significantly better median OS compared with all other patients (74.9 versus 30.6 weeks; P = 0.0000025). Within KRAS WT patients OS was significantly better in patients with an initial decrease compared with those without [median OS: 74.9 versus 30.6 weeks (P = 0.00000012)].Conclusions: KRAS WT status is associated to survival benefit in CTX treated mCRC. This benefit is even more pronounced in those patients with early radiological response. These characteristics may be exploited for response prediction.Key words: cetuximab, colorectal cancer, EGFR, KRAS, survival introduction A recent advance in oncology is the targeting of the epidermal growth factor receptor (EGFR) in the treatment of many tumor types. Cetuximab (CTX) (ErbituxÒ, Merck KGaA, Darmstadt, Germany) is a chimeric immunoglobulin G1 monoclonal antibody which binds the EGFR with high affinity and competitively inhibits ligand binding [1]. This prevents activation of downstream signalling pathways such as the PI3K/ Akt, RAS/Erk and STAT pathways, resulting in the inhibition of cellular proliferation and in the induction of apoptosis. However, for many tumor types including metastatic colorectal cancer (mCRC), it is not clear what proportion of tumors are dependent on EGFR signalling for their survival, nor how additional molecular alterations present in the tumor may influence primary or secondary resistance to EGFR inhibitors. CTX is approved for irinotecan-resistant mCRC expressing EGFR by immunohistochemistry (IHC). Response rates in this group however only amount to 23% in combination with chemotherapy and about 10% in monotherapy [2,3]. Increased response rates in the combination arm did not translate into increased survival. As yet no clinical or molecular markers are available to identify those patients with a longer overall survival (OS). Predictive markers of response and survival benefit after CTX are urgently required to allow the rational and effective use of these drugs.In a small series, Lièvre et al. [4] have shown objective response (OR) to CTX to be excluded in KRAS-mutated CRC and most importantly, showed an increase in OS for the KRAS wild-type (WT) patients. We retrospectively studied the ability of KRAS mutations and tumo...

Mycosis fungoides (MF) is an indolent form of non-Hodgkin lymphoma and the most common type of primary cutaneous T-cell lymphoma. The overall incidence of MF is approximately 4 per 1 million. Involvement of the vulva by MF is extremely rare, with only seven reported cases in the literature. At the vulva, it is mainly a metastatic lesion and rarely a primary malignancy. We describe a case of vulvar MF and discuss the previous cases. The presentation can easily be confused with benign skin disorders. A vulvar lesion can reflect a systemic disease. When a patient consults for a vulvar lesion it is therefore important not only to look at the vulva but also to examine her in and ask general questions. In a patient with a vulvar mass and cutaneous lesions on other locations MF should be considered in the differential diagnosis.

Bilateral jaw claudication as a symptom of carotid atherosclerosis is a rare condition. It can be treated by unilateral carotid endarterectomy.

4132 Background: A recent study has shown that the presence of a KRAS mutation is associated with the absence of objective response to cetuximab (CTX) in advanced colorectal cancers (mCRC). Our hypothesis was that CTX cannot induce any tumor shrinkage in KRAS mutant mCRC. Methods: We analyzed KRAS exon 2 mutation status by Taqman, PCR and sequencing on 37 available tumor samples from patients with mCRC progressive on chemotherapy. Twenty patients received CTX combined with irinotecan (BOND) and 17 received CTX in monotherapy (7 BOND, 10 SALVAGE). We measured the change in tumor size between baseline and the consecutive evaluations. At week 12 and at week 24, we statistically tested the change from baseline between the groups with KRAS wild type (WT) and KRAS mutation (MUT) using the t-test. RECIST criteria for tumor response were used. Results: 3 patients had progressive disease (PD), 26 stable disease (SD), 8 partial response (PR) and 0 complete response. A KRAS MUT was found in 17 tumors (46%): 2 in PD (66.7%), 15 in SD (57.7%) and none in PR patients (p<0.01; responders vs. non responders). At 12 weeks there was a mean decrease in tumor size of 23.1% (SE=7.38) in the KRAS WT and an increase of 2.6% (SE=4.13) in the KRAS MUT mCRC. At 24 weeks KRAS WT and MUT mCRC had a 45.8% (SE=8.61) and a 1.3% (SE=6.67) mean decrease respectively (p= 0.0081 at 12 weeks; p=0.0015 at 24 weeks). The mean tumor size of the KRAS WT did not decrease further after 24 weeks. In the subgroup of SD tumor size regression was observed but only in WT patients. Mean time to progression was 32 (range 12–96) and 30 weeks (range 12–84) for KRAS WT (SD + PR) and MUT respectively. Conclusion: We confirmed KRAS MUT precludes objective response to CTX in mCRC. In addition we found tumor size regression in SD patients being restricted to WT patients. We observed rapid onset of these differences suggesting an important role of KRAS MUT status in early tumor shrinkage. However the onset of progression was not different according to KRAS MUT status. [Table: see text]

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