Circulating DNA in the neoadjuvant setting of early stage colon cancer.

BACKGROUND: While circulating tumour (ct)DNA is an indicator of minimal residual disease and negative prognostic factor in stage II-III colon cancer, no study has ever analysed the value of this biomarker in colon cancer patients treated with neoadjuvant chemotherapy. We sought to fill this gap by using prospectively collected plasma samples from 80 stage III colon cancer patients, receiving one cycle of neoadjuvant FOLFOX followed by surgery +/- adjuvant FOLFOX in the PePiTA trial. MATERIAL AND METHODS: Samples were collected at baseline, 2 weeks and surgery. NPY and WIF1 were selected as universal methylation markers for ctDNA, and analysed with ddPCR technology. ROC curves were applied for cut-off points, and outcome measures included 5-year disease-free survival (DFS) and 6-year overall survival (OS). RESULTS: After a median follow-up of 52.5 months, baseline circulating-free (cf) DNA was an independent prognostic factor for DFS (HR 3.35, 95% CI: 1.15-9.77, p = .03), and a trend towards a similar association was observed for relative cfDNA changes between baseline and surgery (HR 2.57, 95% CI: 0.94-7.05, p = .07). Among 60 ctDNA assessable patients, 25 (42%) had detectable ctDNA at baseline. While detection of ctDNA at any pre-operative timepoint was not associated with outcome, patients with ctDNA increase (change of the worst trending methylation marker ≥11%, or mean ctDNA change of NPY and WIF1 ≥ 0%) between baseline and surgery showed a trend towards worse 5-year DFS (HR 3.66, 95% CI: 0.81-16.44, p = .09). CONCLUSION: This is the first study of ctDNA in the neoadjuvant setting of early-stage colon cancer. Results are hypothesis-generating and should be confirmed in larger series.

Prognostic value of adipose tissue and muscle mass in advanced colorectal cancer: a post hoc analysis of two non-randomized phase II trials.

BACKGROUND: The prognostic value of body composition in cancer patients has been widely studied during the last decade. The main finding of these studies is that sarcopenia, or skeletal muscle depletion, assessed by CT imaging correlates with a reduced overall survival (OS). By contrast, the prognostic value of fat mass remains ill-defined. This study aims to analyze the influence of body composition including both muscle mass and adipose tissue on OS in a homogeneous population of advanced colorectal cancer (CRC) patients. METHODS: Among 235 patients with chemorefractory advanced CRC included in the SoMore and RegARd-C trials, body composition was assessed in 217 patients on baseline CT images. The relationship between body composition (sarcopenia, muscle density, subcutaneous and visceral fat index and density), body mass index (BMI) and OS were evaluated. RESULTS: Patients with a higher BMI had a better OS (≥30 versus < 30, HR: 0.50; 0.33-0.76). Those with low muscle index and muscle density had an increased mortality (HR: 2.06; 1.45-2.93 and HR: 1.54; 1.09-2.18, respectively). Likewise, low subcutaneous and visceral fat index were associated with an increased risk of dying (HR: 1.63; 1.23-2.17 and 1.48; 1.09-2.02 respectively), as were a high subcutaneous and visceral adipose tissue density (HR: 1.93; 1.44-2.57 and 2.40; 1.79-3.20 respectively). In multivariate analysis, a high visceral fat density was the main predictor of poor survival. CONCLUSIONS: Our results confirm the protective role of obesity in CRC patients at an advanced stage, as well as the negative prognostic impact of muscle depletion on survival. More importantly, our data show for the first time that visceral adipose tissue density is an important prognostic factor in metastatic CRC. TRIAL REGISTRATION: NCT01290926 , 07/02/2011 and NCT01929616 , 28/08/2013.

Unusual presentation of a hepatocellular carcinoma as a potential late side effect of radiotherapy in a patient treated for Wilms tumor in childhood.

BACKGROUND: The development of a second primary tumor is a potential late side effect of radiotherapy. Particularly, an increased risk of secondary cancers, mostly of digestive or breast origin, has been observed in patients treated with high-dose radiotherapy for Wilms tumor (WT) in childhood. However, hepatocellular carcinoma (HCC) has been very rarely described as a potentially radiotherapy-induced tumor. We describe the case of a patient with an aggressive HCC 50 years after the treatment of a WT. CASE PRESENTATION: A 49-year old man, treated at the age of 6 weeks for a right WT by a right nephrectomy and adjuvant radiotherapy, presented with a right abdominal mass. Imaging demonstrated a 100-mm tumor invading the inferior segment of the right liver, the right colon and the right psoas muscle. The patient had no previous history of liver disease, nor of alcohol consumption, and hepatitis serologies were negatives. Biopsy demonstrated a poorly differentiated tumor of unknown origin. A panel of tumor markers was negative. Explorative surgery has been performed allowing en bloc R0 tumor resection, including resection of segments VI and VII of the liver, right hemicolectomy and resection of the anterior sheet of the right psoas muscle. Pathological examination revealed a poorly differentiated HCC. No signs of cirrhosis or chronic liver disease were observed in the non-tumor liver. Twenty weeks after surgery, the patient developed a multifocal tumor recurrence that was treated with intra-arterial 90Yttrium radioembolization. CONCLUSION: In this case, the absence of risk factors for HCC, such as cirrhosis, viral hepatitis and chronic liver disease, highly suggests the development of HCC to be related to previous high-dose radiation therapy given for a right WT to a field involving the inferior part of the liver. This observation shows radiotherapy to/near the liver, particularly in childhood, to be a potential risk factor for HCC, stressing the need for a long-term specific follow-up in patients irradiated in childhood.

Randomized Phase II Study of Cabazitaxel Versus Methotrexate in Patients With Recurrent and/or Metastatic Squamous Cell Carcinoma of the Head and Neck Previously Treated With Platinum-Based Therapy.

LESSONS LEARNED: Cabazitaxel has activity in squamous cell carcinoma of the head and neck (SCCHN) and taxane-resistant cell lines. For the first time, cabazitaxel was investigated in incurable patients with recurrent SCCHN. Patients were randomly assigned to cabazitaxel every 3 weeks or weekly methotrexate.This phase II study did not meet its primary endpoint.Cabazitaxel has low activity in SCCHN.The toxicity profile in this population also was not favorable owing to the high rate of febrile neutropenia observed (17%). BACKGROUND: Cabazitaxel is a second-generation taxane that improves the survival of patients with metastatic castrate-resistant prostate cancer following docetaxel therapy. Cabazitaxel has activity in squamous cell carcinoma of the head and neck (SCCHN) and taxane-resistant cell lines. In this randomized phase II trial, we investigated cabazitaxel in patients with recurrent SCCHN. METHODS: Patients with incurable SCCHN with progression after platinum-based therapy were randomly assigned to cabazitaxel every 3 weeks (cycle 1, 20 mg/m2, increased to 25 mg/m2 for subsequent cycles in the absence of nonhematological adverse events [AEs] greater than grade 2 and hematological AEs greater than grade 3) or methotrexate (40 mg/m2/week). The patients were stratified according to their performance status and previous platinum-based chemotherapy for palliation versus curative intent. The primary endpoint was the progression-free survival rate (PFSR) at 18 weeks. RESULTS: Of the 101 patients, 53 and 48, with a median age of 58.0 years (range, 41-80), were randomly assigned to cabazitaxel or methotrexate, respectively. The PFSR at 18 weeks was 13.2% (95% confidence interval [CI], 5%-25%) for cabazitaxel and 8.3% (95% CI, 2%-20%) for methotrexate. The median progression-free survival was 1.9 months in both arms. The median overall survival was 5.0 and 3.6 months for cabazitaxel and methotrexate, respectively. More patients experienced serious adverse events with cabazitaxel than with methotrexate (54% vs. 36%). The most common drug-related grade 3-4 AE in the cabazitaxel arm was febrile neutropenia (17.3%). CONCLUSION: This study did not meet its primary endpoint. Cabazitaxel has low activity in recurrent SCCHN.

Monitoring metabolic response using FDG PET-CT during targeted therapy for metastatic colorectal cancer.

INTRODUCTION: The introduction of targeted drugs has had a significant impact on the approach to assessing tumour response. These drugs often induce a rapid cytostatic effect associated with a less pronounced and slower tumoural volume reduction, thereby impairing the correlation between the absence of tumour shrinkage and the patient's unlikelihood of benefit. The aim of the study was to assess the predictive value of early metabolic response (mR) evaluation after one cycle, and its interlesional heterogeneity to a later metabolic and morphological response assessment performed after three cycles in metastatic colorectal cancer (mCRC) patients treated with combined sorafenib and capecitabine. METHODS: This substudy was performed within the framework of a wider prospective multicenter study on the predictive value of early FDG PET-CT response assessment (SoMore study). A lesion-based response analysis was performed, including all measurable lesions identified on the baseline PET. On a per-patient basis, a descriptive 4-class response categorization was applied based upon the presence and proportion of non-responding lesions. For dichotomic response comparison, all patients with at least one resistant lesion were classified as non-responding. RESULTS: On baseline FDG PET-CT, 124 measurable "target" lesions were identified in 38 patients. Early mR assessments showed 18 patients (47 %) without treatment resistant lesions and 12 patients (32 %) with interlesional response heterogeneity. The NPV and PPV of early mR were 85 % (35/41) and 84 % (70/83), respectively, on a per-lesion basis and 95 % (19/20) and 72 % (13/18), respectively, on a dichotomized per-patient basis. CONCLUSIONS: Early mR assessment performed after one cycle of sorafenib-capecitabine in mCRC is highly predictive of non-response at a standard response assessment time. The high NPV (95 %) of early mR could be useful as the basis for early treatment discontinuation or adaptation to spare patients from exposure to non-effective drugs.

Systematic qualitative review of randomised trials conducted in nonsmall cell lung cancer with a noninferiority or equivalence design.

The use of noninferiority randomised trials for patients with advanced non-small cell lung cancer has emerged during the past 10-15 years but has raised some issues related to their justification and methodology. The present systematic review aimed to assess trial characteristics and methodological aspects. All randomised clinical trials with a hypothesis of noninferiority/equivalence, published in English, were identified. Several readers extracted a priori defined methodological information. A qualitative analysis was then performed. We identified 20 randomised clinical trials (three phase II and 17 phase III), 11 of them being conducted in strong collaboration with industry. We highlighted some deficiencies in the reports like the lack of justification for both the noninferiority assumption and the definition of the noninferiority margin, as well as inconsistencies between the results and the authors' conclusions. CONSORT guidelines were better followed for general items than for specific items (p<0.001). Improvement in the reporting of the meth"odology of noninferiority/equivalence trials is needed to avoid misleading interpretation and to allow readers to be fully aware of the assumptions underlying the trial designs. They should be restricted to limited specific situations with a strong justification why a noninferiority hypothesis is acceptable.

Antiphospholipid syndrome-induced ischemic stroke following pembrolizumab: Case report and systematic review.

Immune checkpoint inhibitors (ICI) improve the prognosis of patients with advanced non-small cell lung cancer. However, clinicians should be aware of potentially life-threatening immune-related adverse events (irAEs). We report a case of a 67-year-old man with lung adenocarcinoma who developed an acute ischemic stroke after the second administration of pembrolizumab. The patient benefited from thrombolysis and mechanical thrombectomy with improved neurological outcome. An anti-phospholipid syndrome (APS) was diagnosed. Simultaneously, he developed a grade IV autoimmune hepatitis. Bothmanifestations were considered irAEs and the ICI treatment was discontinued. Steroids were initiated resulting in irAEs resolution. Remarkably, the patient achieved a complete oncological response and persistent remission after one year follow-up despite early discontinuation of pembrolizumab. Of note, APS is rarely reported as irAE. To our knowledge, this is the first case reported in the context of lung cancer. A systematic review of the literature is provided.

Critically ill cancer patient's resuscitation: a Belgian/French societies' consensus conference.

To respond to the legitimate questions raised by the application of invasive methods of monitoring and life-support techniques in cancer patients admitted in the ICU, the European Lung Cancer Working Party and the Groupe de Recherche Respiratoire en Réanimation Onco-Hématologique, set up a consensus conference. The methodology involved a systematic literature review, experts' opinion and a final consensus conference about nine predefined questions1. Which triage criteria, in terms of complications and considering the underlying neoplastic disease and possible therapeutic limitations, should be used to guide admission of cancer patient to intensive care units?2. Which ventilatory support [High Flow Oxygenation, Non-invasive Ventilation (NIV), Invasive Mechanical Ventilation (IMV), Extra-Corporeal Membrane Oxygenation (ECMO)] should be used, for which complications and in which environment?3. Which support should be used for extra-renal purification, in which conditions and environment?4. Which haemodynamic support should be used, for which complications, and in which environment?5. Which benefit of cardiopulmonary resuscitation in cancer patients and for which complications?6. Which intensive monitoring in the context of oncologic treatment (surgery, anti-cancer treatment …)?7. What specific considerations should be taken into account in the intensive care unit?8. Based on which criteria, in terms of benefit and complications and taking into account the neoplastic disease, patients hospitalized in an intensive care unit (or equivalent) should receive cellular elements derived from the blood (red blood cells, white blood cells and platelets)?9. Which training is required for critical care doctors in charge of cancer patients?

Fortnightly or fractionated weekly docetaxel-cisplatin-5-FU as first-line treatment in advanced gastric and gastroesophageal junction adenocarcinoma: The randomized phase II DoGE study.

BACKGROUND: While docetaxel/cisplatin/5-fluorouracil (DCF) outperforms CF in first-line gastric adenocarcinoma, toxicity remains an issue. METHODS: This multicenter phase II trial randomized chemonaïve metastatic gastric adenocarcinoma patients to fractionated weekly DCF (D 40 mg/m2 , C 35 mg/m², F 1800 mg/m² over 24 h, on days 1 and 8 every 3 weeks, arm (1) or fortnightly DCF (D 50 mg/m2 , C 50 mg/m², F 2000 mg/m² over 48 h every 2 weeks, arm (2). Prophylactic granulocyte colony-stimulating factor (G-CSF) was not allowed. The primary endpoint was the rate of febrile neutropenia within the first six treatment weeks (early FN). RESULTS: A total of 106 eligible patients were recruited. The early and overall FN rates were 9.5% and 17% in arm 1, respectively, and 5.9% and 8% in arm 2, respectively. Grade ≥3 toxicities occurred in 81% of patients in arm 1 and 90% of patients in arm 2, the most common being neutropenia (33% vs. 61%), fatigue (27% vs. 25%), vomiting (21% vs. 12%), anorexia (19% vs. 18%), and diarrhea (17% vs. 10%). Median progression-free survival and overall survival were 5.1 (95% CI, 3.2-6.5) and 8.2 months (95% CI, 6.0-14.5), respectively, in arm 1 and 5.2 (95% CI, 3.0-6.9) and 11.9 months (95% CI, 7.4-15.9), respectively, in arm 2. CONCLUSIONS: Fractionated weekly and fortnightly DCF regimens are associated with a low risk of early FN, and a better hematological toxicity profile as compared to historical DCF without compromising efficacy. Both regimens offer greater convenience removing the need for systematic use of prophylactic G-CSF.

Sex and Regorafenib Toxicity in Refractory Colorectal Cancer: Safety Analysis of the RegARd-C Trial.

BACKGROUND: Regorafenib is a standard treatment for refractory metastatic colorectal cancer (mCRC). In view of the toxicity burden, significant research efforts have been made to increase the therapeutic ratio of this multikinase inhibitor. Predictive factors for treatment-related adverse events (TRAEs), however, are still lacking. MATERIALS AND METHODS: We assessed the association between a number of baseline clinical, laboratory and imaging parameters and the occurrence of TRAEs in 136 patients who had received regorafenib (160 mg/day, 3-weeks-on/1-week-off) in a prospective phase II clinical trial. RESULTS: Grade ≥ 2 TRAEs during the first cycle of treatment (84% vs. 60%, P = .002) and grade ≥ 3 TRAEs throughout the whole treatment (71% vs. 53%, P = .035) occurred more frequently in females, with sex being the only independent predictive factor of early and any-time toxicity (OR 3.4; 95% CI: 1.2-11.1, P = .02 and OR 2.1; 95% CI: 1.0-4.4, P = .045, respectively). Fatigue, anorexia, hypertension, and rash were reported significantly more frequently by females than males (P < .04). Females were also more likely to suffer early (19% vs. 5%, P = .014) and any-time serious AEs (28% vs. 9%, P = .005), and to require early dose modifications (55% vs. 37%, P = .055). CONCLUSION: This is the first study showing an association between sex and TRAEs during regorafenib treatment for mCRC. If confirmed in larger, independent series, these results could pave the way for the implementation of personalized regorafenib dosing strategies with the potential to optimize oncological outcomes while reducing toxicity and preserving quality of life.

Acute appendicitis as an unusual cause of invasive ductal breast carcinoma metastasis.

Acute appendicitis is one of the most common causes of abdominal pain at the emergency room. In rare cases, it can be caused by malignancy, even metastatic lesions from extra-abdominal neoplasia. Herein, we report a case of a 64-year-old female with a history of invasive ductal carcinoma of the breast treated by chemotherapy, surgery, radiotherapy and hormonotherapy, relapsing several years later as a bone and a pleura metastasis successfully cured by locoregional therapy and hormonal treatment. She presented with acute abdominal pain without signs of peritonitis. Abdominal computed tomodensitometry showed sign of appendicitis. Therefore, laparoscopic exploration and appendicectomy was performed. During surgery, multiple peritoneal nodules were found and harvested. Pathology showed metastatic nodules of invasive ductal breast carcinoma, including in the appendicular wall, concluding to peritoneal carcinomatosis. The postoperative course was uneventful, but the patient died 1 year later after refusing anticancer treatment.

Real life safety and effectiveness of nivolumab in older patients with non-small cell lung cancer: Results from the Belgian compassionate use program.

OBJECTIVES: To compare real life effectiveness and safety of nivolumab in patients with non-small cell lung cancer (NSCLC), according to age and Eastern Cooperative Group performance status (ECOG-PS). METHODS: We performed a retrospective analysis of patients treated with nivolumab for NSCLC within a Belgian compassionate use program from July 2015 until December 2016. Safety and effectiveness were compared between patients aged ≥70 years and < 70 years and between ECOG-PS 0/1 and ≥ 2. RESULTS: A total of 324 patients with NSCLC were included. There was no significant difference between older (≥70) and younger (<70 years) patients with regards to progression free survival (PFS) (4 months (95%CI 2.6;4.8) versus 3.7 months (95%CI 1;7), p = 0.483) and overall survival (OS) (9.3 months (95% CI 5.5;13.1 months) versus 8.4 months (95%CI 6.3; 10.5), p = 0,638). Patients with an ECOG-PS ≥2 had a significant lower median PFS and OS compared to patients with an ECOG-PS 0-1 (2.2 (95%CI 1.4; 2.9) versus 5.6 months (95%CI 4.1; 7.1), p = 0.001 and 3.4 (95%CI 2.3; 4.5) versus 11.1 months (95%CI 8.9; 13.2), p < 0.001 respectively). No significant difference in all grades or grade 3/4 adverse events (AEs) were observed between the different age groups (p = 0.526 and p = 0.603 respectively). Patients with an ECOG-PS 0/1 had significantly more all grades AEs (p = 0.009) but no difference in grade 3/4 AEs was observed (p = 0.406) compared to ECOG-PS ≥2. CONCLUSION: This real life retrospective study confirms that safety and effectiveness of nivolumab is similar between different age groups, but that effectiveness is driven by performance status.

Systemic treatments for thymoma and thymic carcinoma: A systematic review.

Thymic tumours are rare diseases that for most of the cases are cured with surgery and eventually adjuvant radiotherapy. However, about 30% of patients present with advanced stage or relapsing tumours, which require administration of chemotherapy. While cisplatin-adriamycin-cyclophosphamide combination is regularly prescribed, other drugs have been assessed in the literature. Our aim is to evaluate the effectiveness (response rate) of systemic treatments, whatever the therapeutic line, including chemotherapy, targeted therapies and immunotherapies, in thymoma and thymic carcinoma, using the principles of evidence-based medicine. A systematic review was designed using the PICO system, by an experienced librarian and clinicians' experts in thoracic oncology, through the Ovid Medline system. Only phase II-IV trials and retrospective studies including at least 14 patients treated with the same regimen were considered. Articles were independently selected by at least two investigators. Fifty-five eligible articles were retrieved. Sixty% were dealing with platinum-based regimens, mainly cisplatin, and showed overall similar activity (mostly response rate above 50%) independently of the line of treatment or histological type (thymoma versus thymic carcinoma). Non-platinum based regimens included octreotide-prednisone and capecitabine-gemcitabine. Promising data of immunotherapy with antiPDL1 antibody (pembrolizumab) requires confirmation. Based on available data, the most popular and active regimens are cisplatin-anthracycline (CAP or ADOC) or cisplatin-etoposide combinations that should be recommended when considering first-line chemotherapy in thymoma or thymic carcinoma.

Autoimmune paraneoplastic syndromes associated to lung cancer: A systematic review of the literature: Part 2: Hematologic, cutaneous and vascular syndromes.

The development of new immune treatment in oncology and particularly for lung cancer may induce new complications, particularly activation or reactivation of auto-immune diseases. In this context, a systematic review on the auto-immune paraneoplastic syndromes associated with lung cancer appears useful. This article is the second of a series of five and deals with hematologic, cutaneous and vascular syndromes.

Autoimmune paraneoplastic syndromes associated to lung cancer: A systematic review of the literature Part 4: Neurological paraneoplastic syndromes, involving the peripheral nervous system and the neuromuscular junction and muscles.

The development of new immune treatment in oncology and particularly for lung cancer may induce new complications, particularly activation or reactivation of auto-immune diseases. In this context, a systematic review on the auto-immune paraneoplastic syndromes that can complicate lung cancer appears useful. This article is the fourth of a series of five and deals mainly with neurological paraneoplastic syndromes involving the peripheral nervous system and the neuromuscular junction and muscles.

Autoimmune paraneoplastic syndromes associated to lung cancer: A systematic review of the literature: Part 5: Neurological auto-antibodies, discussion, flow chart, conclusions.

The development of new immune treatment in oncology and particularly for lung cancer may induce new complications, particularly activation or reactivation of auto-immune diseases. In this context, a systematic review on the auto-immune paraneoplastic syndromes that can complicate lung cancer appears useful. This article is the last of a series of five and deals mainly with onconeural antibodies involved in neurological paraneoplastic syndromes and provides the final discussion.

Long-acting octreotide as secondary prevention of chemotherapy-induced diarrhea: proof of concept.

BACKGROUND: The aim of this study is to investigate the role of Octreotide LAR in secondary prevention in patients with chemotherapy-induced diarrhea. METHODS: In this study, patients experiencing CID ≥ grade 2 received 30 mg long-acting octreotide as a monthly injection and the next chemotherapy dose was administrated with a 25% dose decrease. If no CID ≥ grade 2 occurred, subsequent chemotherapy doses were increased to the initial 100% values. The primary endpoint of the study was the diarrhea control rate (< grade 2) for patients receiving the optimal dose of chemotherapy for a minimum of 2 cycles. RESULTS: Twenty-nine patients were included. Ten patients experienced no improvement or ended the study very early after the first injection of octreotide LAR. Nineteen patients had a reduction in the grade of diarrhea after the first administration of Octreotide LAR and a reduced chemotherapy dose. Seven of them (24%) did not reach the end of the study because of disease progression (6) or lost in follow-up (1). Ultimately 12 patients (41%) continued the study till the end. In ten of these twelve patients, there was a significant and persisting reduction of diarrhea while receiving full dose chemotherapy. CONCLUSION: This study suggests that monthly injections with long-acting octreotide might be used as a secondary prevention of chemotherapy-induced diarrhea. Its usefulness and optimal dosage in secondary prevention in combination with antidiarrheal agents needs further research.

The Prognostic Significance of Metabolic Response Heterogeneity in Metastatic Colorectal Cancer.

BACKGROUND: Tumoral heterogeneity is a major determinant of resistance in solid tumors. FDG-PET/CT can identify early during chemotherapy non-responsive lesions within the whole body tumor load. This prospective multicentric proof-of-concept study explores intra-individual metabolic response (mR) heterogeneity as a treatment efficacy biomarker in chemorefractory metastatic colorectal cancer (mCRC). METHODS: Standardized FDG-PET/CT was performed at baseline and after the first cycle of combined sorafenib (600mg/day for 21 days, then 800mg/day) and capecitabine (1700 mg/m²/day administered D1-14 every 21 days). MR assessment was categorized according to the proportion of metabolically non-responding (non-mR) lesions (stable FDG uptake with SUVmax decrease <15%) among all measurable lesions. RESULTS: Ninety-two patients were included. The median overall survival (OS) and progression-free survival (PFS) were 8.2 months (95% CI: 6.8-10.5) and 4.2 months (95% CI: 3.4-4.8) respectively. In the 79 assessable patients, early PET-CT showed no metabolically refractory lesion in 47%, a heterogeneous mR with at least one non-mR lesion in 32%, and a consistent non-mR or early disease progression in 21%. On exploratory analysis, patients without any non-mR lesion showed a significantly longer PFS (HR 0.34; 95% CI: 0.21-0.56, P-value <0.001) and OS (HR 0.58; 95% CI: 0.36-0.92, P-value 0.02) compared to the other patients. The proportion of non-mR lesions within the tumor load did not impact PFS/OS. CONCLUSION: The presence of at least one metabolically refractory lesion is associated with a poorer outcome in advanced mCRC patients treated with combined sorafenib-capecitabine. Early detection of treatment-induced mR heterogeneity may represent an important predictive efficacy biomarker in mCRC. TRIAL REGISTRATION: ClinicalTrials.gov NCT01290926.