Chronic lymphocytic leukaemia and Richter's transformation: multimodal review and new imaging paradigms

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia in adults. It is a malignancy of CD5 B-cells characterised by small, mature-appearing lymphocytes accumulating in the blood, bone marrow, and lymphoid tissues. Richer transformation (RT) is an important adverse complication. Detection of RT is critical to allow initiation of appropriate therapy. CLL staging and response evaluation is complicated and nuanced. From our extensive tertiary centre experience of several hundred CLL cases over the last decade, we detail key computed tomography (CT) and positron-emission tomography (PET) imaging features of the natural history of CLL. The authors present an original imaging-based patient-management paradigm for the investigation of potential RT, which will inform global practice. Potential applications of whole-body diffusion weighted imaging, novel PET radiotracers, minimal residual disease, and ct-DNA are addressed.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

A seven-Gene Signature assay improves prognostic risk stratification of perioperative chemotherapy treated gastroesophageal cancer patients from the MAGIC trial

Background

Following neoadjuvant chemotherapy for operable gastroesophageal cancer, lymph node metastasis is the only validated prognostic variable; however, within lymph node groups there is still heterogeneity with risk of relapse. We hypothesized that gene profiles from neoadjuvant chemotherapy treated resection specimens from gastroesophageal cancer patients can be used to define prognostic risk groups to identify patients at risk for relapse.

Patients and methods

The Medical Research Council Adjuvant Gastric Infusional Chemotherapy (MAGIC) trial (n = 202 with high quality RNA) samples treated with perioperative chemotherapy were profiled for a custom gastric cancer gene panel using the NanoString platform. Genes associated with overall survival (OS) were identified using penalized and standard Cox regression, followed by generation of risk scores and development of a NanoString biomarker assay to stratify patients into risk groups associated with OS. An independent dataset served as a validation cohort.

Results

Regression and clustering analysis of MAGIC patients defined a seven-Gene Signature and two risk groups with different OS [hazard ratio (HR) 5.1; P < 0.0001]. The median OS of high- and low-risk groups were 10.2 [95% confidence interval (CI) of 6.5 and 13.2 months] and 80.9 months (CI: 43.0 months and not assessable), respectively. Risk groups were independently prognostic of lymph node metastasis by multivariate analysis (HR 3.6 in node positive group, P = 0.02; HR 3.6 in high-risk group, P = 0.0002), and not prognostic in surgery only patients (n = 118; log rank P = 0.2). A validation cohort independently confirmed these findings.

Conclusions

These results suggest that gene-based risk groups can independently predict prognosis in gastroesophageal cancer patients treated with neoadjuvant chemotherapy. This signature and associated assay may help risk stratify these patients for post-surgery chemotherapy in future perioperative chemotherapy-based clinical trials.

Investigating the feasibility of tumour molecular profiling in gastrointestinal malignancies in routine clinical practice

Background

Targeted capture sequencing can potentially facilitate precision medicine, but the feasibility of this approach in gastrointestinal (GI) malignancies is unknown.

Patients and methods

The FOrMAT (Feasibility of a Molecular Characterisation Approach to Treatment) study was a feasibility study enrolling patients with advanced GI malignancies from February 2014 to November 2015. Targeted capture sequencing (mainly using archival formalin-fixed paraffin-embedded diagnostic/resection samples) was carried out to detect mutations, copy number variations and translocations in up to 46 genes which had prognostic/predictive significance or were targets in current/upcoming clinical trials.

Results

Of the 222 patients recruited, 215 patients (96.8%) had available tissue samples, 125 patients (56.3%) had ≥16 genes successfully sequenced and 136 patients (61.2%) had ≥1 genes successfully sequenced. Sample characteristics influenced the proportion of successfully sequenced samples, e.g. tumour type (colorectal 70.9%, biliary 52.6%, oesophagogastric 50.7%, pancreas 27.3%, P = 0.002), tumour cellularity (high versus low: 78.3% versus 13.3%, P ≤ 0.001), tumour content (high versus low: 78.6% versus 27.3%, P = 0.001) and type of sample (resection versus biopsy: 82.4% versus 47.6%, P ≤ 0.001). Currently, actionable alterations were detected in 90 (40.5%) of the 222 patients recruited (66% of the 136 patients sequenced) and 2 patients subsequently received a targeted therapy. The most frequently detected currently actionable alterations were mutations in KRAS, BRAF, TP53 and PIK3CA. For the 205 patients with archival samples, the median time to obtain sequencing results was 18.9 weeks, including a median of 4.9 weeks for sample retrieval and 5.1 weeks for sequencing.

Conclusions

Targeted sequencing detected actionable alterations in formalin-fixed paraffin-embedded samples, but tissue characteristics are of critical importance in determining sequencing success. Routine molecular profiling of GI tumours outside of clinical trials is not an effective use of healthcare resources unless more targeted drugs become available.

ClinicalTrials.gov identifier

NCT02112357.

The results of local excision with or without postoperative adjuvant chemoradiotherapy for early rectal cancer among patients choosing to avoid radical surgery

AIM

The study aimed to establish the oncological outcome of patients who opted for close surveillance with or without adjuvant chemoradiotherapy rather than radical surgery after local excision (LE) of early rectal cancer.

METHOD

The Royal Marsden Hospital Rectal Cancer database was used to identify rectal cancer patients treated by primary LE from 2006 to 2015. All patients were entered in an intensive surveillance programme.

RESULTS

Twenty-eight of 34 analysed patients had a high or very high risk of residual disease predicted by adverse histopathological features for which the recommendation had been radical surgery. Eighteen (52%) of the 34 had received radiotherapy following LE. Three-year disease-free survival for the 34 patients was 85% (95% CI 78.8%-91.2%) and overall survival was 100%. Twenty-two of 24 patients with a low tumour which would have required total rectal excision have so far avoided radical surgery and remain disease free at a median follow-up of 3.2 years.

CONCLUSION

The findings suggest that with modern MRI and clinical surveillance radical surgery can be avoided in patients following initial LE of a histopathologically defined high risk early rectal cancer. These findings are comparable with those obtained after major radical resection and warrant further prospective investigation as a treatment arm in larger prospective trials.

PAN-EX: a pooled analysis of two trials of neoadjuvant chemotherapy followed by chemoradiotherapy in MRI-defined, locally advanced rectal cancer

BACKGROUND

EXPERT and EXPERT-C were phase II clinical trials of neoadjuvant chemotherapy (NACT) followed by chemoradiotherapy (CRT) in high-risk, locally advanced rectal cancer (LARC).

DESIGN

We pooled individual patient data from these trials. The primary objective was overall survival (OS) in the intention-to-treat (ITT) population. Prognostic factors were also analysed.

RESULTS

A total of 269 patients were included. Of these, 91.1% completed NACT, 88.1% completed CRT and 240 (89.2%) underwent curative surgery (R0/R1). After a median follow-up of 71.9 months, 5-year progression-free survival (PFS) and OS were 66.4% and 73.3%, respectively. In the group of R0/R1 resection patients, 5-year relapse-free survival (RFS) and OS were 71.6% and 77.2%, respectively, with local recurrence occurring in 5.5% and distant metastases in 20.6% of cases. Significant prognostic factors after multivariate analyses included age, tumour grade and MRI extramural venous invasion (mrEMVI) at baseline, MRI tumour regression grade (mrTRG) after CRT, ypT stage after surgery and adherence to study treatment. mrTRG after NACT was associated with PFS (P = 0.002) and OS (P = 0.018) and appeared to stratify patients based on the incremental benefit from sequential CRT. Among the outcome measures considered, in the subgroup of R0/R1 resection patients, ypT and ypStage had the highest predictive accuracy for RFS (concordance index: 0.6238 and 0.6252, respectively) and OS (concordance index: 0.6094 and 0.6132, respectively).

CONCLUSIONS

Administering NACT before CRT could be a potential strategy for high-risk LARC. In this setting, mrTRG after CRT is an independent prognostic factor, while mrTRG after NACT should be tested as a parameter for treatment selection in trials of NACT ± CRT. ypT stage may be a valuable surrogate end point for future phase II trials investigating intensified neoadjuvant treatments in similar patient populations.

Prognostic role of the LCS6 KRAS variant in locally advanced rectal cancer: results of the EXPERT-C trial

BACKGROUND

Lethal-7 (let-7) is a tumour suppressor miRNA which acts by down-regulating several oncogenes including KRAS. A single-nucleotide polymorphism (rs61764370, T > G base substitution) in the let-7 complementary site 6 (LCS-6) of KRAS mRNA has been shown to predict prognosis in early-stage colorectal cancer (CRC) and benefit from anti-epidermal growth factor receptor monoclonal antibodies in metastatic CRC.

PATIENTS AND METHODS

We analysed rs61764370 in EXPERT-C, a randomised phase II trial of neoadjuvant CAPOX followed by chemoradiotherapy, surgery and adjuvant CAPOX plus or minus cetuximab in locally advanced rectal cancer. DNA was isolated from formalin-fixed paraffin-embedded tumour tissue and genotyped using a PCR-based commercially available assay. Kaplan-Meier method and Cox regression analysis were used to calculate survival estimates and compare treatment arms.

RESULTS

A total of 155/164 (94.5%) patients were successfully analysed, of whom 123 (79.4%) and 32 (20.6%) had the LCS-6 TT and LCS-6 TG genotype, respectively. Carriers of the G allele were found to have a statistically significantly higher rate of complete response (CR) after neoadjuvant therapy (28.1% versus 10.6%; P = 0.020) and a trend for better 5-year progression-free survival (PFS) [77.4% versus 64.5%: hazard ratio (HR) 0.56; P = 0.152] and overall survival (OS) rates (80.3% versus 71.9%: HR 0.59; P = 0.234). Both CR and survival outcomes were independent of the use of cetuximab. The negative prognostic effect associated with KRAS mutation appeared to be stronger in patients with the LCS-6 TT genotype (HR PFS 1.70, P = 0.078; HR OS 1.79, P = 0.082) compared with those with the LCS-6 TG genotype (HR PFS 1.33, P = 0.713; HR OS 1.01, P = 0.995).

CONCLUSION

This analysis suggests that rs61764370 may be a biomarker of response to neoadjuvant treatment and an indicator of favourable outcome in locally advanced rectal cancer possibly by mitigating the poor prognosis of KRAS mutation. In this setting, however, this polymorphism does not appear to predict cetuximab benefit.

Patterns of relapse in extrapulmonary small cell carcinoma: retrospective analysis of outcomes from two cancer centres

OBJECTIVES

We conducted a retrospective review of patients with extrapulmonary small cell carcinomas (EPSCCs) to explore the distribution, treatments, patterns of relapse and outcomes by primary site.

SETTING

We have reviewed the outcomes of one of the largest data sets of consecutive patients with EPSCC identified from two major cancer centres.

PARTICIPANTS

Consecutive patients with a histopathological diagnosis of EPSCC from the two institutions were retrospectively identified.

PRIMARY AND SECONDARY OUTCOME MEASURES

Outcomes were evaluated including stage at presentation, treatments given, sites of relapse, time to distant relapse, progression-free survival and overall survival (OS).

RESULTS

From a total 159 patients, 114 received first-line chemotherapy, 80.5% being platinum-based. Response rate was 48%. Commonest primary sites were genitourinary and gynaecological. 44% of patients presented with metastatic disease. 55.9% relapsed with liver the commonest site, whereas only 2.5% developed brain metastases. Median OS was 13.4 months for all patients, 7.6 months and 19.5 months for those with metastatic and non-metastatic disease, respectively. Gynaecological and head and neck patients had significantly better OS compared to gastrointestinal patients.

CONCLUSIONS

EPSCCs demonstrate high response rates to chemotherapy and high rates of distant metastases. Primary sites may influence prognosis, and survival is optimal with a radical strategy. Brain metastases are rare and we therefore do not recommend prophylactic cranial irradiation.

RAS mutations and cetuximab in locally advanced rectal cancer: results of the EXPERT-C trial

BACKGROUND

RAS mutations predict resistance to anti-epidermal growthfactor receptor (EGFR) monoclonal antibodies in metastatic colorectal cancer. We analysed RAS mutations in 30 non-metastatic rectal cancer patients treated with or without cetuximab within the 31 EXPERT-C trial.

METHODS

Ninety of 149 patients with tumours available for analysis were KRAS/BRAF wild-type, and randomly assigned to capecitabine plus oxaliplatin (CAPOX) followed by chemoradiotherapy, surgery and adjuvant CAPOX or the same regimen plus cetuximab (CAPOX-C). Of these, four had a mutation of NRAS exon 3, and 84 were retrospectively analysed for additional KRAS (exon 4) and NRAS (exons 2/4) mutations by using bi-directional Sanger sequencing. The effect of cetuximab on study end-points in the RAS wild-type population was analysed.

RESULTS

Eleven (13%) of 84 patients initially classified as KRAS/BRAF wild-type were found to have a mutation in KRAS exon 4 (11%) or NRAS exons 2/4 (2%). Overall, 78/149 (52%) assessable patients were RAS wild-type (CAPOX, n=40; CAPOX-C, n=38). In this population, after a median follow-up of 63.8months, in line with the initial analysis, the addition of cetuximab was associated with numerically higher, but not statistically significant, rates of complete response (15.8% versus 7.5%, p=0.31), 5-year progression-free survival (75.5% versus 67.5%, hazard ratio (HR) 0.61, p=0.25) and 5-year overall survival (83.8% versus 70%, HR 0.54, p=0.20).

CONCLUSIONS

RAS mutations beyond KRAS exon 2 and 3 were identified in 17% of locally advanced rectal cancer patients. Given the small sample size, no definitive conclusions on the effect of additional RAS mutations on cetuximab treatment in this setting can be drawn and further investigation of RAS in larger studies is warranted.

EMVI-positive stage II rectal cancer has similar clinical outcomes as stage III disease following pre-operative chemoradiotherapy

BACKGROUND

Stage II rectal cancers comprise a heterogeneous group, and there is significant variability in practise with regards to adjuvant chemotherapy; the survival benefit of chemotherapy is perceived to be <4% in these patients. However, in recent years, the emergence of additional prognostic factors such as extramural venous invasion (EMVI) suggests that there may be sub-stratification of stage II tumours and, further, we may be under-estimating the benefit adjuvant chemotherapy provides in high-risk patients. This study examined the outcomes of patients with stage II and III rectal cancer to determine whether EMVI status influences disease-free survival (DFS).

PATIENTS AND METHODS

An analysis of a prospectively maintained database was conducted of patients presenting with rectal cancer between 2006 and 2012. All patients underwent curative surgery and had no evidence of metastases at presentation. Clinicopathological factors were compared between stage II and III disease. The primary end point was 3-year DFS; univariate and multivariate analysis was carried out using Cox proportional hazards regression models; hazard ratios (HR) with 95% confidence intervals (CIs) were calculated.

RESULTS

Four hundred and seventy-eight patients were included: 233 stage II; 245 stage III. The prevalence of EMVI was 34.9%; 57 stage II patients (24.5%) and 110 stage III patients (44.9%). On multivariate analysis, only EMVI status was a significant factor for DFS. The adjusted HR for EMVI either alone or in combination with nodal involvement was 2.08 (95% CI 1.10-2.95) and 2.74 (95% CI 1.66-4.52), respectively.

CONCLUSION

EMVI is an independently poor prognostic factor for DFS for both stage II and stage III rectal cancer. These results demonstrate that there is risk-stratification within stage II tumours which affects prognosis. When discussing the use of adjuvant chemotherapy with patients that have EMVI-positive stage II tumours, these results provide evidence for a similarly increased risk of distant failure as stage III disease without venous invasion.

HER2 in high-risk rectal cancer patients treated in EXPERT-C, a randomized phase II trial of neoadjuvant capecitabine and oxaliplatin (CAPOX) and chemoradiotherapy (CRT) with or without cetuximab

BACKGROUND

HER2 is an established therapeutic target in breast and gastric cancers. The role of HER2 in rectal cancer is unclear, as conflicting data on the prevalence of HER2 expression in this disease have been reported. We evaluated the prevalence of HER2 and its impact on the outcome of high-risk rectal cancer patients treated with neoadjuvant CAPOX and CRT±cetuximab in the EXPERT-C trial.

PATIENTS AND METHODS

Eligible patients with available tumour tissue for HER2 analysis were included. HER2 expression was determined by immunohistochemistry (IHC) in pre-treatment biopsies and/or surgical specimens (score 0-3+). Immunostaining was scored according to the consensus panel recommendations on HER2 scoring for gastric cancer. Tumours with equivocal IHC result (2+) were tested for HER2 amplification by D-ISH. Tumours with IHC 3+ or D-ISH ratio ≥2.0 were classified as HER2+. The impact of HER2 on primary and secondary end points of the study was analysed.

RESULTS

Of 164 eligible study patients, 104 (63%) biopsy and 114 (69%) surgical specimens were available for analysis. Only 3 of 104 (2.9%) and 3 of 114 (2.6%) were HER2+, respectively. In 77 patients with paired specimens, concordance for HER2 status was found in 74 (96%). Overall, 141 patients were assessable for HER2 and 6 out of 141 (4.3%) had HER2 overexpression and/or amplification. The median follow-up was 58.6 months. HER2 was not associated with a difference in the outcome for any of the study end points, including in the subset of 90 KRAS/BRAF wild-type patients treated±cetuximab.

CONCLUSIONS

Based on the low prevalence of expression as recorded in the EXPERT-C trial, HER2 does not appear to represent a useful therapeutic target in high-risk rectal cancer. However, the role of HER2 as a potential predictive biomarker of resistance to anti-EGFR-based treatments and a therapeutic target in anti-EGFR refractory metastatic colorectal cancer (CRC) warrants further investigation.

TRIAL REGISTRATION

ISRCTN Register: 99828560.

ESMO Consensus conferences: guidelines on malignant lymphoma. part 2: marginal zone lymphoma, mantle cell lymphoma, peripheral T-cell lymphoma

To complement the existing treatment guidelines for all tumour types, ESMO organizes consensus conferences to focus on specific issues in each type of tumour. In this setting, a consensus conference on the management of lymphoma was held on 18 June 2011 in Lugano, next to the 11th International Conference on Malignant Lymphoma. The conference convened ∼30 experts from all around Europe, and selected six lymphoma entities to be addressed; for each of them, three to five open questions were to be addressed by the experts. For each question, a recommendation should be given by the panel, referring to the strength of the recommendation based on the level of evidence. This consensus report focuses on the three less common lymphoproliferative malignancies: marginal zone lymphoma, mantle cell lymphoma, and peripheral T-cell lymphomas. A first report had focused on diffuse large B-cell lymphoma, follicular lymphoma, and chronic lymphocytic leukaemia.

Transformation to "high grade" neuroendocrine carcinoma as an acquired drug resistance mechanism in EGFR-mutant lung adenocarcinoma

Several different acquired resistance mechanisms of EGFR mutant lung adenocarcinoma to EGFR-tyrosine kinase inhibitor (TKI) therapy have been described, most recently transformation to small cell lung carcinoma (SCLC). We describe the case of a 46-year-old female with relapsed EGFR exon 19 deletion lung adenocarcinoma treated with erlotinib, and on resistance, cisplatin-pemetrexed. Liver rebiopsy identified an afatinib-resistant combined SCLC and non-small cell carcinoma with neuroendocrine morphology, retaining the EGFR exon 19 deletion. This case highlights acquired EGFR-TKI resistance through transformation to the high-grade neuroendocrine carcinoma spectrum and that that such transformation may not be evident at time of progression on TKI therapy.

A phase II study of ¹⁸F-fluorodeoxyglucose PET-CT in non-small cell lung cancer patients receiving erlotinib (Tarceva); objective and symptomatic responses at 6 and 12 weeks

BACKGROUND

The aim of this study was to assess if (18)F-fluorodeoxyglucose (FDG) Positron Emission Tomography (PET)-CT scanning could minimise the time non-responding patients were exposed to erlotinib (Tarceva).

METHODS

Patients were selected for clinical factors that would predict response to erlotinib. A FDG PET-CT and diagnostic contrast-enhanced (traditional) CT scan were carried out at baseline, and then a FDG PET-CT at 6 weeks and a traditional CT at 12 weeks were repeated. The primary end-point was rate of early progression in patients after 6 weeks, of which a minimum 12 out of 35 were required to make the study worthwhile. The responses at 6 (PET-CT) and 12 weeks (traditional CT) were compared and correlated with symptomatic response at both these time points.

RESULTS

Forty seven patients were recruited with 38 and 33 patients assessable by FDG PET-CT at 6 weeks and traditional CT at 12weeks, respectively. There was good correlation between Partial response (PR) at both time points and all 10 patients who had a PR at 12 weeks had a PR at 6 weeks. Of the 13 patients with progressive disease (PD) at 12 weeks, seven had PD at 6 weeks and could have had their treatment stopped early. No evaluable patient with stable disease (SD) (8/38) or PD (9/38) on FDG PET-CT at 6 weeks went on to have a later response. Symptomatic response at 6 or 12 weeks did not correlate well with objective response on scanning at either time point.

CONCLUSIONS

The primary end-point of this study was met as >12 (15/38) patients could have stopped treatment early on the basis of the FDG PET-CT scan result. A FDG PET-CT evaluable response of SD or PD at 6 weeks does predict future lack of response. No correlation was found between response and symptomatic response at either 6 or 12 weeks.

EGILS consensus report. Gastric extranodal marginal zone B-cell lymphoma of MALT

This consensus report of the EGILS (European Gastro-Intestinal Lymphoma Study) group includes recommendations on the management of gastric extranodal marginal zone B-cell lymphoma of MALT. They are based on data from the literature and on intensive discussions and votings of the experts during their annual meetings.

A multicentre study of capecitabine, oxaliplatin plus bevacizumab as perioperative treatment of patients with poor-risk colorectal liver-only metastases not selected for upfront resection

BACKGROUND

Perioperative chemotherapy improves outcome in resectable colorectal liver-only metastasis (CLM). This study aimed to evaluate perioperative CAPOX (capecitabine-oxaliplatin) plus bevacizumab in patients with poor-risk CLM not selected for upfront resection.

PATIENTS AND METHODS

Poor-risk CLM was defined as follows: more than four metastases, diameter >5 cm, R0 resection unlikely, inadequate viable liver function if undergoing upfront resection, inability to retain liver vascular supply, or synchronous colorectal primary presentation. Patients underwent baseline computed tomography, magnetic resonance imaging, and/or positron emission tomography (PET) for staging and received neoadjuvant CAPOX plus bevacizumab, with resectability assessed every four cycles. Primary end point was radiological objective response rate (ORR).

RESULTS

Forty-six patients were recruited, of which 91% underwent PET to ensure metastases confined to liver. Following neoadjuvant CAPOX plus bevacizumab, the ORR was 78% (95% confidence interval 63% to 89%). This allowed 12 of 30 (40%) patients with initial nonsynchronous unresectable CLM to be converted to resectability. In addition, 10 of 15 (67%) patients with synchronous resectable CLM underwent liver resection, with four additional patients being observed alone due to excellent response to neoadjuvant therapy. No grade 3-4 perioperative complications were seen.

CONCLUSION

Neoadjuvant CAPOX plus bevacizumab resulted in a high response rate for patients with CLMs with poor-risk features not selected for upfront resection and converted 40% of patients to resectability.

EXPERT-C: A randomized phase II European multicenter trial of neoadjuvant chemotherapy (capecitabine/oxaliplatin) and chemoradiation (CRT) with or without cetuximab followed by total mesorectal excision (TME) in patients with MRI-defined high-risk rectal cancer

360

Background: We previously demonstrated the feasibility of administering neoadjuvant chemotherapy before CRT and TME in patients with MRI selected poor prognosis rectal cancer (Chua Y J et al Lancet Oncol 2010). This trial evaluates the addition of the anti-EGFR antibody cetuximab to this treatment strategy. KRAS and BRAF mutations have been established as predictive for lack of response to anti-EGFR therapy in metastatic colorectal cancer.

Methods: Patients with newly diagnosed, histologically confirmed, MRI defined high risk rectal adenocarcinoma were randomised to receive 4 cycles of capecitabine 1,700mg/m2 with oxaliplatin 130mg/m2 (CAPOX) followed by CRT, 45Gy/25# + 5.4Gy/3# boost with concurrent continuous capecitabine 1,650mg/m2/day, TME and 4 cycles of adjuvant CAPOX (EXPERT) or the same regimen with the addition of cetuximab (400mg/m2 loading dose week 1, followed by 250mg/m2/week) (EXPERT-C). The primary endpoint is complete response (CR) (defined as pathological complete response or radiological complete response in patients who decline surgery) in KRAS and BRAF wild type tumours. Secondary endpoints include radiological response to CRT, CR in both KRAS wild type and mutant patients, R0 resection rates, progression free and overall survival and safety.

Results: Between 2005-2008, 165 eligible patients were recruited from 15 centres (EXPERT n=81, EXPERT-C n=84). 99% of patients had performance status 0-1, 98% had ≥ T3 disease, 56% had an involved or threatened circumferential resection margin and 72% had evidence of extramural venous invasion determined by MRI. The current median follow up is 30 months. 72/81 (89%) and 79/84 (94%) of patients completed neoadjuvant CRT and 72/81 (89%) and 77/84 (92%) patients underwent curative-intent surgery on the EXPERT and EXPERT-C arms respectively. Two patients declined surgery.

Conclusions: The primary and secondary endpoints will be analyzed in October 2010 and will be presented at the meeting.

[Table: see text]

Deferral of rectal surgery following a continued response to preoperative chemoradiotherapy (Watch and Wait) study: A phase II multicenter study in the United Kingdom

489

Background: Neoadjuvant chemoradiotherapy (CRT) and surgical resection are standard components of therapy for patients locally advanced rectal cancer (T3,T4 or N+) in UK. In 15%-30% of patients treated pre-operatively with CRT will develop pathological complete response (CR). The time from completion of CRT to maximal tumour response is as yet unknown. This study is the first prospective study to attempt to identify the percentage of patients who can safely omit surgery and the safety of deferred surgery in patients who achieve clinical complete response post CRT. Of the 59 patients required for the study, this provides an update on 19 patients entered.

Methods: Patients with locally advanced rectal cancer requiring neoadjuvant treatment are identified in the multidisciplinary meet (MDT). Patients undergo CRT using a minimum of 50.4Gy in 28 # daily conformal CT planned CRT with concomitant Capecitabine at 825mg/m2 BD. MRI pelvis and body CT are repeated 4 weeks post CRT and rediscussed at MDT. If there is a good partial response or CR, patients are considered for Deferral of Surgery Study. Based on the pre treatment clinical staging, patients are considered for adjuvant chemotherapy as per NICE guidance. At any point of the study, if there is histology proven tumour regrowth or progression, patient undergo surgery.

Results: 10 (53%) patients remain in CR. 6 (32%) patients underwent surgical resection with clear margin after detection of tumour regrowth at from 2-23 months post CRT. 5 out of 6 of the patients with tumour regrowth underwent PET CT as per protocol, and all tumour regrowth in those 5 patients were detected by PET CT, i.e. FDG avid disease. The pathological stages on these 6 patients were ypT2N0 CRM negative in 5 and ypT3N0 CRM negative in 1. 3 (15%) patients with tumour regrowth refused surgery.

Conclusions: In the 19 recruited patients, all the patients with tumour regrowth underwent surgical resection with clear margins. PET CT appears a useful tool for detecting tumour regrowth. The median time for tumour regrowth is 17.5 months post CRT. The trial will be successful if at least 11/59 patients are able to safely omit surgery. Accrual of patients continues.

No significant financial relationships to disclose.