A cautionary tale: an evaluation of the performance of treatment switching adjustment methods in a real world case study.

BACKGROUND: Treatment switching in randomised controlled trials (RCTs) is a problem for health technology assessment when substantial proportions of patients switch onto effective treatments that would not be available in standard clinical practice. Often statistical methods are used to adjust for switching: these can be applied in different ways, and performance has been assessed in simulation studies, but not in real-world case studies. We assessed the performance of adjustment methods described in National Institute for Health and Care Excellence Decision Support Unit Technical Support Document 16, applying them to an RCT comparing panitumumab to best supportive care (BSC) in colorectal cancer, in which 76% of patients randomised to BSC switched onto panitumumab. The RCT resulted in intention-to-treat hazard ratios (HR) for overall survival (OS) of 1.00 (95% confidence interval [CI] 0.82-1.22) for all patients, and 0.99 (95% CI 0.75-1.29) for patients with wild-type KRAS (Kirsten rat sarcoma virus). METHODS: We tested several applications of inverse probability of censoring weights (IPCW), rank preserving structural failure time models (RPSFTM) and simple and complex two-stage estimation (TSE) to estimate treatment effects that would have been observed if BSC patients had not switched onto panitumumab. To assess the performance of these analyses we ascertained the true effectiveness of panitumumab based on: (i) subsequent RCTs of panitumumab that disallowed treatment switching; (ii) studies of cetuximab that disallowed treatment switching, (iii) analyses demonstrating that only patients with wild-type KRAS benefit from panitumumab. These sources suggest the true OS HR for panitumumab is 0.76-0.77 (95% CI 0.60-0.98) for all patients, and 0.55-0.73 (95% CI 0.41-0.93) for patients with wild-type KRAS. RESULTS: Some applications of IPCW and TSE provided treatment effect estimates that closely matched the point-estimates and CIs of the expected truths. However, other applications produced estimates towards the boundaries of the expected truths, with some TSE applications producing estimates that lay outside the expected true confidence intervals. The RPSFTM performed relatively poorly, with all applications providing treatment effect estimates close to 1, often with extremely wide confidence intervals. CONCLUSIONS: Adjustment analyses may provide unreliable results. How each method is applied must be scrutinised to assess reliability.

Associations between AI-Assisted Tumor Amphiregulin and Epiregulin IHC and Outcomes from Anti-EGFR Therapy in the Routine Management of Metastatic Colorectal Cancer.

PURPOSE: High tumor production of the EGFR ligands, amphiregulin (AREG) and epiregulin (EREG), predicted benefit from anti-EGFR therapy for metastatic colorectal cancer (mCRC) in a retrospective analysis of clinical trial data. Here, AREG/EREG IHC was analyzed in a cohort of patients who received anti-EGFR therapy as part of routine care, including key clinical contexts not investigated in the previous analysis. EXPERIMENTAL DESIGN: Patients who received panitumumab or cetuximab ± chemotherapy for treatment of RAS wild-type mCRC at eight UK cancer centers were eligible. Archival formalin-fixed paraffin-embedded tumor tissue was analyzed for AREG and EREG IHC in six regional laboratories using previously developed artificial intelligence technologies. Primary endpoints were progression-free survival (PFS) and overall survival (OS). RESULTS: A total of 494 of 541 patients (91.3%) had adequate tissue for analysis. A total of 45 were excluded after central extended RAS testing, leaving 449 patients in the primary analysis population. After adjustment for additional prognostic factors, high AREG/EREG expression (n = 360; 80.2%) was associated with significantly prolonged PFS [median: 8.5 vs. 4.4 months; HR, 0.73; 95% confidence interval (CI), 0.56-0.95; P = 0.02] and OS [median: 16.4 vs. 8.9 months; HR, 0.66 95% CI, 0.50-0.86; P = 0.002]. The significant OS benefit was maintained among patients with right primary tumor location (PTL), those receiving cetuximab or panitumumab, those with an oxaliplatin- or irinotecan-based chemotherapy backbone, and those with tumor tissue obtained by biopsy or surgical resection. CONCLUSIONS: High tumor AREG/EREG expression was associated with superior survival outcomes from anti-EGFR therapy in mCRC, including in right PTL disease. AREG/EREG IHC assessment could aid therapeutic decisions in routine practice. See related commentary by Randon and Pietrantonio, p. 4021.

Development and validation of prognostic models for anal cancer outcomes using distributed learning: protocol for the international multi-centre atomCAT2 study.

BACKGROUND: Anal cancer is a rare cancer with rising incidence. Despite the relatively good outcomes conferred by state-of-the-art chemoradiotherapy, further improving disease control and reducing toxicity has proven challenging. Developing and validating prognostic models using routinely collected data may provide new insights for treatment development and selection. However, due to the rarity of the cancer, it can be difficult to obtain sufficient data, especially from single centres, to develop and validate robust models. Moreover, multi-centre model development is hampered by ethical barriers and data protection regulations that often limit accessibility to patient data. Distributed (or federated) learning allows models to be developed using data from multiple centres without any individual-level patient data leaving the originating centre, therefore preserving patient data privacy. This work builds on the proof-of-concept three-centre atomCAT1 study and describes the protocol for the multi-centre atomCAT2 study, which aims to develop and validate robust prognostic models for three clinically important outcomes in anal cancer following chemoradiotherapy. METHODS: This is a retrospective multi-centre cohort study, investigating overall survival, locoregional control and freedom from distant metastasis after primary chemoradiotherapy for anal squamous cell carcinoma. Patient data will be extracted and organised at each participating radiotherapy centre (n = 18). Candidate prognostic factors have been identified through literature review and expert opinion. Summary statistics will be calculated and exchanged between centres prior to modelling. The primary analysis will involve developing and validating Cox proportional hazards models across centres for each outcome through distributed learning. Outcomes at specific timepoints of interest and factor effect estimates will be reported, allowing for outcome prediction for future patients. DISCUSSION: The atomCAT2 study will analyse one of the largest available cross-institutional cohorts of patients with anal cancer treated with chemoradiotherapy. The analysis aims to provide information on current international clinical practice outcomes and may aid the personalisation and design of future anal cancer clinical trials through contributing to a better understanding of patient risk stratification.

Addressing the variation in adjuvant chemotherapy treatment for colorectal cancer: Can a regional intervention promote national change?

Analysis of routine population-based data has previously shown that patterns of surgical treatment for colorectal cancer can vary widely, but there is limited evidence available to determine if such variation is also seen in the use of chemotherapy. This study quantified variation in adjuvant chemotherapy across both England using cancer registry data and in more detail across the representative Yorkshire and Humber regions. Individuals with Stages II and III colorectal cancer who underwent major resection from 2014 to 2015 were identified. Rates of chemotherapy were calculated from the Systemic Anticancer Treatment database using multilevel logistic regression. Additionally, questionnaires addressing different clinical scenarios were sent to regional oncologists to investigate the treatment preferences of clinicians. The national adjusted chemotherapy treatment rate ranged from 2% to 46% (Stage II cancers), 19% to 81% (Stage III cancers), 24% to 75% (patients aged <70 years) and 5% to 46% (patients aged ≥70 years). Regionally, the rates of treatment and the proportions of treated patients receiving combination chemotherapy varied by stage (Stage II 4%-26% and 0%-55%, Stage III 48%-71% and 40%-84%) and by age (<70 years 35%-68% and 49%-91%; ≥70 years 15%-39% and 6%-75%). Questionnaire responses showed significant variations in opinions for high-risk Stage II patients with both deficient and proficient mismatch repair tumours and Stage IIIB patients aged ≥70 years. Following a review of the evidence, open discussion in our region has enabled a consensus agreement on an algorithm for colorectal cancer that is intended to reduce variation in practice.

Association of Bevacizumab Plus Oxaliplatin-Based Chemotherapy With Disease-Free Survival and Overall Survival in Patients With Stage II Colon Cancer: A Secondary Analysis of the AVANT Trial.

Importance: In the pivotal Bevacizumab-Avastin Adjuvant (AVANT) trial, patients with high-risk stage II colon cancer (CC) had 5-year and 10-year overall survival (OS) rates of 88% and 75%, respectively, with adjuvant fluorouracil and oxaliplatin-based chemotherapy; however, the trial did not demonstrate a disease-free survival (DFS) benefit of adding bevacizumab to oxaliplatin-based chemotherapy in stage III CC and suggested a detrimental effect on OS. The Long-term Survival AVANT (S-AVANT) study was designed to collect extended follow-up for patients in the AVANT trial. Objective: To explore the efficacy of adjuvant bevacizumab combined with oxaliplatin-based chemotherapy in patients with high-risk, stage II CC. Design, Setting, and Participants: This prespecified secondary end point analysis of the AVANT and S-AVANT studies included 573 patients with curatively resected high-risk stage II CC and at least 1 of the following criteria: stage T4, bowel obstruction or perforation, blood and/or lymphatic vascular invasion and/or perineural invasion, age younger than 50 years, or fewer than 12 nodes analyzed. The AVANT study was a multicenter randomized stage 3 clinical trial. Data were collected from December 2004 to February 2019, and data for this study were analyzed from March to September 2019. Intervention: Patients were randomly assigned to receive 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX4), FOLFOX4 with bevacizumab, or capecitabine and oxaliplatin (XELOX) with bevacizumab. Main Outcomes and Measures: The primary end points of this secondary analysis were DFS and OS in patients with high-risk stage II CC. Results: The AVANT study included 3451 patients, of whom 573 (16.6%) had high-risk stage II CC (192 [33.5%] randomized to FOLFOX4 group; 194 [33.9%] randomized to FOLFOX4 with bevacizumab group; 187 [32.6%] randomized to XELOX with bevacizumab group). With a median (interquartile range) age of 57.0 (47.2-65.7) years, the study population comprised 325 men (56.7%) and 248 women (43.3%). After a median (interquartile range) follow-up of 6.9 (6.1-11.3) years, the 3-year DFS and 5-year OS rates were 88.2% (95% CI, 83.7%-93.0%) and 89.7% (95% CI, 85.4%-94.2%) in the FOLFOX4 group, 86.6% (95% CI, 81.8%-91.6%) and 89.7% (95% CI, 85.4%-94.2%) in the FOLFOX4 with bevacizumab group, and 86.7% (95% CI, 81.8%-91.8%) and 93.2% (95% CI, 89.6%-97.0%) in the XELOX with bevacizumab group, respectively. The DFS hazard ratio was 0.94 (95% CI, 0.59-1.48; P = .78) for FOLFOX4 with bevacizumab vs FOLFOX4 and 1.07 (95% CI, 0.69-1.67; P = .76) for XELOX with bevacizumab vs FOLFOX4. The OS hazard ratio was 0.92 (95% CI, 0.55-1.55; P = .76) for FOLFOX4 with bevacizumab vs FOLFOX4 and 0.85 (95% CI, 0.50-1.44; P = .55) for XELOX with bevacizumab vs FOLFOX4. Conclusions and Relevance: In this secondary analysis of data from the AVANT trial, adding bevacizumab to oxaliplatin-based chemotherapy was not associated with longer DFS or OS in patients with high-risk stage II CC. The findings suggest that the definition of high-risk stage II CC needs to be revisited. Trial Registration: ClinicalTrial.gov Identifiers: AVANT (NCT00112918); S-AVANT (NCT02228668).

TP53 mutational status and cetuximab benefit in rectal cancer: 5-year results of the EXPERT-C trial.

In this updated analysis of the EXPERT-C trial we show that, in magnetic resonance imaging-defined, high-risk, locally advanced rectal cancer, adding cetuximab to a treatment strategy with neoadjuvant CAPOX followed by chemoradiotherapy, surgery, and adjuvant CAPOX is not associated with a statistically significant improvement in progression-free survival (PFS) and overall survival (OS) in both KRAS/BRAF wild-type and unselected patients. In a retrospective biomarker analysis, TP53 was not prognostic but emerged as an independent predictive biomarker for cetuximab benefit. After a median follow-up of 65.0 months, TP53 wild-type patients (n = 69) who received cetuximab had a statistically significant better PFS (89.3% vs 65.0% at 5 years; hazard ratio [HR] = 0.23; 95% confidence interval [CI] = 0.07 to 0.78; two-sided P = .02 by Cox regression) and OS (92.7% vs 67.5% at 5 years; HR = 0.16; 95% CI = 0.04 to 0.70; two-sided P = .02 by Cox regression) than TP53 wild-type patients who were treated in the control arm. An interaction between TP53 status and cetuximab effect was found (P < .05) and remained statistically significant after adjusting for statistically significant prognostic factors and KRAS.

Selecting patients with locally advanced rectal cancer for neoadjuvant treatment strategies.

Rectal cancer remains a significant problem worldwide. Outcomes vary significantly according to the stage of disease and prognostic factors, including the distance of the tumor from the circumferential resection margin. Accurate staging, including high-resolution magnetic resonance imaging, allows stratification of patients into low-, moderate-, and high-risk disease; this information can be used to inform multidisciplinary team decisions regarding the role of neoadjuvant therapy. Both neoadjuvant short-course radiotherapy and long-course chemoradiation reduce the risk of local recurrence compared with surgery alone, but they have little impact on survival. Although there remains a need to reduce overtreatment of those patients at moderate risk, evaluation of intensified regimens for those with high-risk disease is still required to reduce distant failure rates and improve survival in these patients with an otherwise poor prognosis.

Metastatic squamous cell carcinoma of the anus: time for a shift in the treatment paradigm?

Anal cancers are rare tumours; however, the incidence is increasing in both men and women. Changing trends in sexual behaviour, smoking, and infection with the human papillomavirus are thought to be responsible for the increase. Patients with metastatic disease have a poor prognosis, with 5-year median overall survival rates of 10% in men and 20% in women. The standard systemic treatment of metastatic disease remains cisplatin and 5-fluorouracil, and aside from several non-randomised small phase II trials there has been no real progress over the past two decades. Based on the efficacy of cetuximab in squamous cell carcinomas from other primary sites, there appears to be clinical rationale for evaluation of anti-epidermal growth factor inhibitors in anal squamous cell carcinoma. In order to facilitate research and implement more effective treatment strategies international collaboration in clinical trials incorporating tissue collection for biomarkers is essential.

Multicenter randomized phase II clinical trial comparing neoadjuvant oxaliplatin, capecitabine, and preoperative radiotherapy with or without cetuximab followed by total mesorectal excision in patients with high-risk rectal cancer (EXPERT-C).

PURPOSE: To evaluate the addition of cetuximab to neoadjuvant chemotherapy before chemoradiotherapy in high-risk rectal cancer. PATIENTS AND METHODS: Patients with operable magnetic resonance imaging-defined high-risk rectal cancer received four cycles of capecitabine/oxaliplatin (CAPOX) followed by capecitabine chemoradiotherapy, surgery, and adjuvant CAPOX (four cycles) or the same regimen plus weekly cetuximab (CAPOX+C). The primary end point was complete response (CR; pathologic CR or, in patients not undergoing surgery, radiologic CR) in patients with KRAS/BRAF wild-type tumors. Secondary end points were radiologic response (RR), progression-free survival (PFS), overall survival (OS), and safety in the wild-type and overall populations and a molecular biomarker analysis. RESULTS: One hundred sixty-five eligible patients were randomly assigned. Ninety (60%) of 149 assessable tumors were KRAS or BRAF wild type (CAPOX, n = 44; CAPOX+C, n = 46), and in these patients, the addition of cetuximab did not improve the primary end point of CR (9% v 11%, respectively; P = 1.0; odds ratio, 1.22) or PFS (hazard ratio [HR], 0.65; P = .363). Cetuximab significantly improved RR (CAPOX v CAPOX+C: after chemotherapy, 51% v 71%, respectively; P = .038; after chemoradiation, 75% v 93%, respectively; P = .028) and OS (HR, 0.27; P = .034). Skin toxicity and diarrhea were more frequent in the CAPOX+C arm. CONCLUSION: Cetuximab led to a significant increase in RR and OS in patients with KRAS/BRAF wild-type rectal cancer, but the primary end point of improved CR was not met.

Toward the non-surgical management of locally advanced rectal cancer.

Neoadjuvant short-course radiotherapy and long-course chemoradiation (CRT) reduce local recurrence rates when compared to surgery alone and remain widely accepted as standard of care for patients with locally advanced rectal cancer. However, surgery is not without complications and a non-surgical approach in carefully selected patients warrants evaluation. A pathological complete response to CRT is associated with a significant improvement in survival and it has been suggested that a longer time interval between the completion of CRT and surgery increases tumor downstaging. Intensification of neoadjuvant treatment regimens to increase tumor downstaging has been evaluated in a number of clinical trials and more recently the introduction of neoadjuvant chemotherapy prior to CRT has demonstrated high rates of radiological tumor regression. Careful selection of patients using high-resolution MRI may allow a non-surgical approach in a subgroup of patients achieving a complete response to neoadjuvant therapies after an adequate time period. Clearly this needs prospective evaluation within a clinical trial setting, incorporating modern imaging techniques, and tissue biomarkers to allow accurate prediction and assessment of response.

A 'hot' leg: a rare case of isolated long bone metastases from cervical cancer.

A 70-year-old woman with a past medical history of FIGO stage IIIA cervical cancer presented with severe pain in her right leg and after investigations was found to have isolated metastases within the right tibia, fibula and calcanuem. Bone metastases from cervical cancer are relatively rare and tend to occur in the spine and pelvis. There are only a handful of case reports of isolated long bone metastases from cervical cancer in the literature. This case highlights the importance of diagnostic imaging and the role of histological confirmation when there is diagnostic uncertainty.