ACT-Discover: identifying karyotype heterogeneity in pancreatic cancer evolution using ctDNA.

BACKGROUND: Liquid biopsies and the dynamic tracking of somatic mutations within circulating tumour DNA (ctDNA) can provide insight into the dynamics of cancer evolution and the intra-tumour heterogeneity that fuels treatment resistance. However, identifying and tracking dynamic changes in somatic copy number alterations (SCNAs), which have been associated with poor outcome and metastasis, using ctDNA is challenging. Pancreatic adenocarcinoma is a disease which has been considered to harbour early punctuated events in its evolution, leading to an early fitness peak, with minimal further subclonal evolution. METHODS: To interrogate the role of SCNAs in pancreatic adenocarcinoma cancer evolution, we applied whole-exome sequencing of 55 longitudinal cell-free DNA (cfDNA) samples taken from 24 patients (including 8 from whom a patient-derived xenograft (PDX) was derived) with metastatic disease prospectively recruited into a clinical trial. We developed a method, Aneuploidy in Circulating Tumour DNA (ACT-Discover), that leverages haplotype phasing of paired tumour biopsies or PDXs to identify SCNAs in cfDNA with greater sensitivity. RESULTS: SCNAs were observed within 28 of 47 evaluable cfDNA samples. Of these events, 30% could only be identified by harnessing the haplotype-aware approach leveraged in ACT-Discover. The exceptional purity of PDX tumours enabled near-complete phasing of genomic regions in allelic imbalance, highlighting an important auxiliary function of PDXs. Finally, although the classical model of pancreatic cancer evolution emphasises the importance of early, homogenous somatic events as a key requirement for cancer development, ACT-Discover identified substantial heterogeneity of SCNAs, including parallel focal and arm-level events, affecting different parental alleles within individual tumours. Indeed, ongoing acquisition of SCNAs was identified within tumours throughout the disease course, including within an untreated metastatic tumour. CONCLUSIONS: This work demonstrates the power of haplotype phasing to study genomic variation in cfDNA samples and reveals undiscovered intra-tumour heterogeneity with important scientific and clinical implications. Implementation of ACT-Discover could lead to important insights from existing cohorts or underpin future prospective studies seeking to characterise the landscape of tumour evolution through liquid biopsy.

Is aflibercept an optimal treatment for wt RAS mCRC patients after progression to first line containing anti-EGFR?

PURPOSE: To determine the efficacy and safety data of aflibercept + FOLFIRI in wt RAS mCRC patients after progression to standard chemotherapy + anti-EGFR treatment. METHODS: Retrospective, observational study in real life conducted in wt RAS mCRC patients treated with FOLFIRI-aflibercept after progression to standard first line chemotherapy + anti-EGFR treatment. RESULTS: A total of 120 patients from 12 Spanish hospitals were enrolled. Median age is 60 years (62.5%/37.5%male/female). Primary tumor site is 24.1%/75.9% right/left-side colon, and 40.8% of patients had a prior resection. All patients had wild-type RAS tumors including 5% of patients with BRAF mutations and received anti-EGFR treatment. At the time aflibercept was initiated, ECOG PS is 0/1 in 96% of patients. Median number of FOLFIRI-aflibercept cycles is 12. Efficacy results: Overall response rate is 33%; progression-free survival (PFS) is 6.9 months (95%CI: 6.1-7.8). Primary tumor resection was the only significant variable related to PFS in the multivariate analysis. Median overall survival (OS) is 14.5 months (95%CI: 9.7-19.3). ECOG and number of metastatic sites were related to OS in multivariate analysis. About 54.1% of patients received a third-line therapy including TAS-102 (23%), regorafenib (18.5%), and capecitabine (9.2%). TOXICITY: Grade 3-4 toxicities were observed in 37.5% of the patients (hematologic 16.6%, hypertension 7.5%, asthenia 5.9%, and perforation 2.5%). Aflibercept dose was reduced in 18.3% of patients. CONCLUSIONS: The results show that patients with wt RAS mCRC who received an anti-EGFR as part of the first-line treatment achieved similar RR, PFS, OS, and toxicities to those reported in VELOUR trial. These results suggest that FOLFIRI-aflibercept after first-line treatment with anti-EGFR is an appropriated option for RAS wt mCRC.

Erysipeloid rash: A rare adverse event induced by gemcitabine.

Some rare cases of erysipelas-like or pseudocellulitis have been reported in relation to gemcitabine. This rare adverse event is more frequent in the presence of edema. Here, we report a case of pseudocellulitis after adjuvant treatment for pancreatic cancer. Oncologists should be aware of this infrequent and non-well understood adverse event. They should be especially careful when administering gemcitabine in the presence of lymphedema.

A propósito de un caso. Linfoma T/NK nasal / About a case. Nasal T/NK lymphoma

El linfoma nasal de células NK/T es una patología rara en Occidente pero frecuente en áreas endémicas de Asia y Sudamérica. Constituye una entidad muy agresiva que se extiende localmente con destrucción de órganos vecinos y, en un alto porcentaje, con afectación sistémica que conduce a la muerte en menos de un año. Presentamos el caso de una paciente diagnosticada linfoma de células NK/T, confinado en tabique nasal, y de más de diez años de evolución, que respondió completamente a tratamiento sin presentar en ningún momento signos de agresividad clínica. (AU)