10% Tumor diameter shrinkage on the first follow-up computed tomography predicts clinical outcome in patients with advanced renal cell carcinoma treated with angiogenesis inhibitors: a follow-up validation study

Optimizing the tumor shrinkage threshold for evaluating immunotherapy efficacy for advanced non-small-cell lung cancer

PURPOSE

The rise of immune checkpoint inhibitors (ICIs) in recent years has coincided with unusual clinical response patterns. Modification of the sum of longest diameters (SLD)-based threshold that reflecting dynamic change of the tumor burden and predicting response to ICIs, may markedly improve current treatment regimens.

METHODS

The baseline and post-treatment SLD of target lesion was recorded and the maximum percent change of the SLD from baseline was designated as SLD-change score. The optimal cut-off value was obtained using the X-tile program. The relationship between SLD-change score and survival outcome (PFS, OS) was evaluated.

RESULTS

10% cut-off value of SLD-change score was found to be most distinctive for PFS. Responders defined according to this cut-off value showed a significant improvement for PFS and OS. Bone metastasis and brain metastasis were also two independent prognostic factors of PFS and OS, respectively.

CONCLUSIONS

10% SLD change score could discriminate for ICIs treatment response, which holds great promise in promoting the development of precise immunotherapeutic strategy.

Optimization of the tumour response threshold in advanced gastroenteropancreatic neuroendocrine carcinomas treated with cisplatin/etoposide combined chemotherapy

OBJECTIVES

To identify early and more accurate imaging response criteria for computed tomography evaluation to define 'responders' in advanced gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC) patients treated with cisplatin/etoposide combined chemotherapy.

MATERIALS AND METHODS

Thirty-seven patients with GEP-NEC treated with first-line cisplatin/etoposide (E/P) combined chemotherapy were enrolled in this study. Computed tomography scans of the chest, abdomen, and pelvis were performed at baseline, during the treatment course, and during follow-up. Tumour size was measured, and tumour response was evaluated by Response Evaluation Criteria in Solid Tumours (RECIST) 1.1. Receiver operating characteristic (ROC) analysis was carried out among the patients who progressed during follow-up. Thresholds from -55% to + 5% were tested by Kaplan-Meier analysis to define "responders" for significantly improved progression-free survival (PFS). The overall survival rate was compared between these two groups.

RESULTS

A reduction of 45% (vs. baseline) achieved the highest sensitivity (70%) and specificity (90%) by ROC analysis. This threshold divided patients into 15 responders and 22 nonresponders. Patients who were grouped as responders by the -45% threshold had a significantly longer PFS (11.06 months) than nonresponders (7.97 months, hazard ratio, 3.636; 95% confidence interval, 1.293-10.164). No significant difference was shown in overall survival between these two groups (29.1 vs. 21.4 months, P = 0.190).

CONCLUSION

A 45% reduction in target lesions may be considered to be a more reliable predictor than the RECIST 1.1 criteria in evaluating the outcome of GEP-NEC patients treated with E/P chemotherapy.

Tumor diameter response in patients with metastatic clear cell renal cell carcinoma is associated with overall survival

OBJECTIVE

Tumor shrinkage of at least 10% after presurgical targeted molecular therapy (TMT) in renal cell carcinoma (RCC) patients has been associated with better overall survival (OS) outcomes. We characterized primary and metastatic tumor diameter response and OS in patients with metastatic clear cell RCC (ccRCC) who received preoperative TMT, immunotherapy, or both followed by deferred cytoreductive nephrectomy (dCN).

MATERIALS AND METHODS

Patients with metastatic ccRCC (n = 198) who underwent preoperative therapy and dCN from 2005 to 2019 were identified retrospectively. Longest primary and metastatic tumor diameters were calculated using cross-sectional images obtained before systemic therapy and dCN using the Response Evaluation Criteria in Solid Tumors. Patients were stratified by tumor shrinkage of at least 10% in the primary and/or metastatic tumors after systemic therapy. The Kaplan-Meier method was used to estimate OS, and Cox proportional hazards models were used to assess the association of patient characteristics with OS.

RESULTS

In total, 31.31% of patients had only metastatic tumor shrinkage (MTS) ≥ 10%, 8.08% had only primary tumor shrinkage (PTS) ≥ 10%, 32.32% had PTS and MTS ≥ 10%, and 28.28% had PTS/MTS < 10%. The median OS, number of patients with tumor shrinkage ≥ 10%, and International Metastatic Database Consortium (IMDC) scores were similar among the 3 systemic therapy groups (all P ≥ 0.80). Patients with MTS ≥ 10%, PTS ≥ 10%, and PTS/MTS ≥ 10% had significantly longer median OS compared to patients with PTS/MTS < 10% (P < 0.01). Patients with intermediate-risk IMDC scores had significantly longer median OS compared to patients in the poor-risk group. After adjusting for preoperative therapy and IMDC risk group, MTS ≥ 10%, PTS ≥ 10%, and PTS/MTS ≥ 10% were associated with better OS outcomes (HR 0.48 95% CI 0.32-0.73, P < 0.001; HR 0.48, 95% CI 0.23-0.98, P = 0.04; HR 0.44, 95% CI 0.29-0.67, P < 0.001, respectively).

CONCLUSIONS

Intermediate risk score and shrinkage of at least 10% in the primary tumor, metastases, or both were associated with better OS outcomes in patients with metastatic ccRCC who underwent dCN independent of the type of preoperative systemic therapy.

Systemic treatment of the metastatic renal cell carcinoma: usefulness of the apparent diffusion coefficient of diffusion-weighted MRI in prediction of early therapeutic response

Accurate prediction of early treatment response to systemic therapy (ST) with tyrosine kinase inhibitors (TKI) in patients with metastatic renal cell carcinoma (mRCC) could help avoid ineffective and expensive treatment with serious side effects. Neither RECIST v.1.1 nor Choi criteria successfully discriminate between patients with mRCC who received ST having a short or long time to progression (TTP). There is no biomarker, which is able to predict early therapeutic response to TKIs application in patients with mRCC. The goal of our study was to investigate the potential of apparent diffusion coefficient (ADC) of diffusion-weighted imaging (DWI) of MRI in prediction of early therapeutic response to ST with pazopanib in patients with mRCC. The retrospective study enrolled 32 adult patients with conventional mRCC who received pazopanib (mean duration-7.5 ± 3.45). The mean duration of follow-up was 11.85 ± 4.34 months. In all patients as baseline examination and 1 month after treatment, 1.5T MRI including DWI sequence was performed followed by ADC measurement of the main renal lesion. For assessment of the therapeutic response, RECIST 1.1 is used. Partial response (PR), stable disease (SD) and progressive disease (PD) were observed in 12 (37.50%), 10 (31.25%) and 10 (31.25%) cases with mean TTP of 10.33 ± 2.06 months (95% confidence interval, CI = 9.05-11.61), 7.40 ± 2.50 months (95% CI = 5.61-9.19) and 4.20 ± 1.99 months (95% CI = 2.78-5.62) accordingly (p < 0.05). There was no difference in change of main lesions' longest size 1 month after ST in patients with PR, SD and PD. Comparison of mean ADC values before and 1 month after systemic treatment showed significant decrease by 19.11 ± 10.64% (95% CI = 12.35-25.87) and by 7.66 ± 6.72% (95% CI = 2.86-12.47) in subgroups with PR and SD, respectively (p < 0.05). There was shorter TTP in patients with mRCC if ADC of the main renal lesion 1 month after the ST increased from the baseline less than 1.73% compared to patients with ADC levels above this threshold: 5.29 ± 3.45 versus 9.50 ± 2.04 months accordingly (p < 0.001). Overall, our findings highlighted the use of ADC as a predictive biomarker for early therapeutic response assessment. Use of ADC will be effective and useful for reliable prediction of responders and non-responders to systemic treatment with pazopanib.

RECIST and CHOI criteria in the evaluation of tumor response in patients with metastatic colorectal cancer treated with regorafenib, a prospective multicenter study

Background

To evaluate the objective response rate (ORR) at 2 months of treatment with regorafenib according to RECIST 1.1, Choi, and modified Choi (mChoi) criteria in patients with metastatic colorectal cancer (mCRC).

Methods

Baseline and 2-month contrast-enhanced computed-tomography (CECT) scans of 55 patients with mCRC, prospectively enrolled in phase II TEXCAN trial, were centrally assessed. The primary endpoint was 2-month ORR by RECIST 1.1, Choi, and mChoi criteria. Final outcome was overall survival (OS).

Results

Of 55 patients included in this study (Intention-to-treat [ITT1] population), 35 had CECT at 2 months (ITT2 population). According to RECIST 1.1 criteria, 20 (57%) patients were SD and 15 were PD (43%) in the ITT2 population. According to Choi criteria, 18 (51%) patients were responders and 17 (48%) were non-responders. Median OS was 5.3 months (95% CI 3.7–8.6) in the ITT1 population and 8.9 months (95% CI 5.1–12.6) in the ITT2 population. In the ITT2 population, median OS was 16 months (95% CI 6.6–17.5) in SD patients (n = 20) and 4.6 months (95% CI 3.3–5.8) in PD patients (n = 15), according to RECIST 1.1 criteria (HR = 6.48). Median OS was 7.9 months (95% CI 4.2–17.5) in responders (n = 18) and 9.9 months (95% CI 3.7-NA) in non-responders (n = 17) according to Choi criteria (HR = 1.06). All patients except one were classified as non-responders with mChoi criteria.

Conclusion

At 2 months, unlike RECIST 1.1, Choi and mChoi criteria could not identify mCRC patients with regorafenib survival benefit.

Trial registration

ClinicalTrials.gov Identifier: NCT02699073.Registered March 4, 2016, Retrospectively registered.

Modification of the tumor response threshold in patients of advanced non-small cell lung cancer treated with chemotherapy plus targeted agents: a pooled study from five clinical trials in one institution

Background

Chemotherapy with targeted therapy is a promising therapeutic option for advanced non-small cell lung cancer (NSCLC) patients. Response Evaluation Criteria in Solid Tumors (RECIST) criteria were used in tumor response evaluation. We assumed an optimal threshold for this therapeutic setting and tried to seek a new tumor shrinkage cutoff with the data from five clinical trials in one institution.

Methods

The X-tile program was used to identify the optimal cut-off value of tumor shrinkage. PFS and OS were compared in the current study. Kaplan-Meier method was used to describe PFS and OS. 95% CI was calculated for PFS and OS outcomes to assess the treatment efficacy. A P value of less than 0.05 was considered statistically significant. SPSS 23.0 was used for all statistical analysis.

Results

X-tile analysis yielded -10% in the ∆SLD of the target lesions as the optimal threshold for response/non-response. The 10% tumor shrinkage could discriminate responders from non-responders in PFS (10.1 vs. 2.50 months, P=0.0007) and OS (23.00 vs. 7.66 months, P<0.0001). Univariate and multivariable analysis showed that 10% tumor shrinkage was a valid prognostic factor for PFS (P=0.018) and OS outcome (P<0.0001).

Conclusions

A 10.0% tumor shrinkage in the SLD indicated an indicative efficacy evaluation threshold for NSCLC patients treated with chemotherapy plus targeted agents.

Comparison of computed tomography imaging analyses for evaluation after chemotherapy in patients with colorectal cancer: a retrospective pooled analysis of six phase II clinical trials

BACKGROUND

There are several methods for analyzing computed tomography (CT) images to evaluate chemotherapy efficacy in clinical studies. However, the optimal analysis method for each drug is still under debate. We conducted a pooled analysis using data from six phase II studies to evaluate four analysis methods in colorectal cancers (CRCs): morphological responses (MRs), early tumor shrinkage (ETS), depth of response (DpR), and response evaluation criteria in solid tumors (RECIST) ver.1.1.

METHODS

We included 249 patients in this analysis. Pretreatments and findings of subsequent CT imaging were analyzed based on the MR, ETS, DpR, and RECIST ver.1.1. Differences in overall survival (OS) between the responders and non-responders according to each method were evaluated using survival analysis.

RESULTS

The responders had significantly better hazard ratios (HRs) for OS, in terms of DpR (≥ median), ETS, objective response rate (ORR) [complete response (CR) + partial response (PR)], and disease control rate [CR + PR + stable disease (SD)]. Patients with right-sided colon cancers showed better HRs for DpR, but not for ETS and ORR. Contrastingly, patients with left-sided CRCs had better HRs for ETS, DpR, and ORR. MR was not associated with outcomes in this study, even in cases where bevacizumab was used. In patients with liver metastasis, ETS, DpR, and ORR showed better HRs, but not in those with lung metastasis.

CONCLUSION

Early tumor shrinkage and DpR might be predictive markers only in left-sided CRCs with liver metastasis. Each imaging analysis has a different value based on the primary and metastatic sites.

Analysis of response-related endpoints in trials of first-line medical treatment of metastatic colorectal cancer

BACKGROUND

Tumor radiologic response after systemic chemotherapy has been used as endpoint of trials of patients with metastatic colorectal cancer (mCRC), which can report the best overall response rate (ORR) and the disease control rate (DCR) by RECIST criteria as well as the early tumor shrinkage (ETS). The present study perform a trial-level analysis to verify whether such response-related endpoints are predictive of overall survival (OS).

METHODS

After a systematic search, randomized clinical trials (RCTs) were selected each time they evaluated the three response endpoints and progression-free survival (PFS). Two arms per trial were selected, and the correlation between the difference in each endpoint and the difference in OS was calculated. The analysis then evaluated the effects of treatment on ∆ORR, or ∆DCR, ∆ETS, ∆PFS, and on ∆OS, using separate linear regressions for each of them, and the proportion of variability explained (R²_trial) on OS for each of the four endpoints was calculated.

RESULTS

The systematic review of the literature led to the selection of 12 RCTs, 7 phase-3 and 5 phase-2. ETS reported a different performance in the entire sample compared to phase-3 trials (R²_trial = 0.172 vs. 0.842), differently from DCR (R²_trial = 0.541 vs. 0.816) and ORR (R²_trial = 0.349 vs. 0.740). Surprisingly, PFS predicted OS with a weak correlation, which was not significant in the subgroup of phase-3 studies (R²_trial = 0.455 vs. 0.466).

CONCLUSION

The results of the present trial-level analysis report a good performance of two response-related endpoints, DCR and ETS, and suggest that they could be differently used depending on the setting of disease and the type of medical treatment.

A Phase II, single-arm trial of neoadjuvant axitinib plus avelumab in patients with localized renal cell carcinoma who are at high risk of relapse after nephrectomy (NEOAVAX)

Surgery is the standard treatment for nonmetastatic renal cell carcinoma. Despite curative intent, patients with a high risk of relapse have a 5-year metastasis-free survival rate of only 30% and prevention of recurrence is an unmet need. In a Phase III trial (JAVELIN Renal 101), progression-free survival of axitinib + avelumab was superior to sunitinib with a favorable objective response rate and no added toxicity profiles as known for axitinib or avelumab single agent. NEOAVAX is designed as open label, single arm, Phase II trial with a Simon’s two-stage design evaluating neoadjuvant axitinib + avelumab followed by complete surgical resection in 40 patients with high-risk nonmetastatic clear-cell renal cell carcinoma. Primary end point is remission of the primary tumor (RECIST 1.1; Response Evaluation Criteria In Solid Tumors) following neoadjuvant therapy. Secondary end points include disease-free survival, overall survival, rate of metastasis and local recurrence, safety, and tolerability. Exploratory end points include investigation of effects on neoangiogenesis, immune infiltrates and myeloid-derived suppressor cell components to support a rationale for the combined use of axitinib and avelumab (NCT03341845).

Metastatic Tumor Burden and Loci as Predictors of First Line Sunitinib Treatment Efficacy in Patients with Renal Cell Carcinoma

The aim of this study was to investigate the prognostic impact of baseline tumor burden and loci on the efficacy of first line renal cancer treatment with sunitinib. Baseline and on-treatment CT scans were evaluated. Both the Kaplan-Meier and Weibull modelling survival estimators have been used to describe sunitinib treatment response. Logistic regression was used to confirm associations between tumor site, burden and survival. Additionally, analysis of the metastases co-occurrence was conducted using the Bayesian inference on treated and external validation cohorts. 100 patients with metastatic clear cell renal cell carcinoma were treated with sunitinib in this study. Presence of metastases in the abdominal region (HR = 3.93), and the number of brain metastases correlate with shorter PFS, while the presence of thoracic metastases (HR = 0.47) with longer PFS. Localization of metastases in the abdominal region significantly impacts risk of metastases development in other locations including bone and brain metastases. Biology of metastases, in particular their localization, requires further molecular and clinical investigation.

Are tumor size changes predictive of survival for checkpoint blockade based immunotherapy in metastatic melanoma?

BACKGROUND

In oncology clinical development, objective response rate, disease control rate and early tumor size changes are commonly used as efficacy metrics for early decision-making. However, for immunotherapy trials, it is unclear whether these early efficacy metrics are still predictive of long-term clinical benefit such as overall survival. The goal of this paper is to identify appropriate early efficacy metrics predictive of overall survival for immunotherapy trials.

METHODS

Based on several checkpoint blockade based immunotherapy studies in metastatic melanoma, we evaluated the predictive value of early tumor size changes and RECIST-based efficacy metrics at various time points on overall survival. The cut-off values for tumor size changes to predict survival were explored via tree based recursive partitioning and validated by external data. Sensitivity analyses were performed for the cut-offs.

RESULTS

The continuous tumor size change metric and RECIST-based trichotomized response metric at different landmark time points were found to be statistically significantly associated with overall survival. The predictive values were higher at Week 12 and 18 than those at Week 24. The percentage of tumor size changes appeared to have comparable or lower predictive values than the RECIST-based trichotomized metric, and a cut-off of approximately 10% tumor reduction appeared to be reasonable for predicting survival.

CONCLUSIONS

An approximate 10% tumor reduction may be a reasonable cut-off for early decision-making while the RECIST-based efficacy metric remains the primary tool. Early landmark analysis is especially useful for decision making when accrual is fast. Composite response rate (utilizing different weights for PR/CR and SD) may be worth further investigation.

TRIAL REGISTRATION

Clinical trials gov, NCT01295827 , Registered February 15, 2011; NCT01704287 , Registered October 11, 2012; NCT01866319 , Registered May 31, 2013.

Imaging Advances in the Management of Kidney Cancer

New developments in cross-sectional imaging, including contrast-enhanced ultrasound, dual-energy computed tomography, multiparametric magnetic resonance imaging, single-photon emission computed tomography, and positron emission tomography, together with novel application of existing and novel radiotracers, have changed the landscape of renal mass characterization (ie, virtual biopsy) as well as the detection of metastatic disease, prognostication, and response assessment in patients with advanced kidney cancer. A host of imaging response criteria have been developed to characterize the response to targeted and immune therapies and correlate with patient outcomes, each with strengths and limitations. Recent efforts to advance the field are aimed at increasing objectivity with quantitative techniques and the use of banks of imaging data to match the vast genomic data that are becoming available. The emerging field of radiogenomics has the potential to transform further the role of imaging in kidney cancer management through eventual noninvasive characterization of the tumor histology and genetic microenvironment in single renal masses and/or metastatic disease. We review of the effect of currently available imaging techniques in the management of patients with kidney cancer, including localized, locally advanced, and metastatic disease.

A risk-based approach to identifying oligometastatic disease on imaging

Recognition of <3 metastases in <2 organs, particularly in cancers with a known predisposition to oligometastatic disease (OMD) (colorectal, prostate, renal, sarcoma and lung), offers the opportunity to focally treat the lesions identified and confers a survival advantage. The reliability with which OMD is identified depends on the sensitivity of the imaging technique used for detection and may be predicted from phenotypic and genetic factors of the primary tumour, which determine metastatic risk. Whole‐body or organ‐specific imaging to identify oligometastases requires optimization to achieve maximal sensitivity. Metastatic lesions at multiple locations may require a variety of imaging modalities for best visualisation because the optimal image contrast is determined by tumour biology. Newer imaging techniques used for this purpose require validation. Additionally, rationalisation of imaging strategies is needed, particularly with regard to timing of imaging and follow‐up studies. This article reviews the current evidence for the use of imaging for recognising OMD and proposes a risk‐based roadmap for identifying patients with true OMD, or at risk of metastatic disease likely to be OM.

CT evaluation of response in advanced gastroenteropancreatic neuroendocrine tumors treated with long-acting-repeatable octreotide: what is the optimal size variation threshold?

OBJECTIVE

To identify a reliable early indicator of deriving progression-free survival (PFS) benefit in patients with advanced gastroenteropancreatic neuroendocrine tumors (GEP-NETs) treated with octreotide long-acting repeatable (LAR).

METHODS

We investigated the images of 50 patients with well-differentiated advanced GEP-NETs treated with LAR octreotide and underwent baseline and follow-up thoracic, abdominal, and pelvic computed tomography. Receiver-operating characteristic (ROC) analysis and the Kaplan-Meier method were used to identify the optimal threshold to distinguish between those with and without significant improvement of PFS.

RESULTS

The optimal threshold for determining a response to octreotide LAR was -10% ΔSLD, with a sensitivity and specificity of 85.7% and 80%, respectively. At this threshold, 19 patients were responders and 31 were non-responders; the median PFS was 20.2 and 7.6 months in responders and non-responders (hazard ratio, 2.66; 95% confidence interval, 1.32-5.36).

CONCLUSION

A 10% shrinkage in tumor size is an optimal early predictor of response to octreotide LAR in advanced GEP-NETs.

KEY POINTS

• Octreotide LAR can significantly prolong PFS among patients with well-differentiated advanced GEP-NETs. • No optimal tumor size-based response criteria are reported in GEP-NETs with octreotide. • Ten percent tumor shrinkage is a reliable indicator of the response to octreotide for advanced GEP-NETs.

Prognostic and Predictive Factors for Renal Cell Carcinoma

Metastatic renal cell carcinoma (mRCC) is an incurable malignancy, characterized by its resistance to traditional chemotherapy, radiation, and hormonal therapy. Treatment perspectives and prognosis of patients with mRCC have been significantly improved by advances in the understanding of its molecular pathogenesis, which have led to the development of targeted therapeutics. Different molecular factors derived from the tumor or the host detected in both tissue or serum could be predictive of therapeutic benefit. Some of them suggest a rational selection of patients to be treated with certain therapies, though none have been validated for routine use. This article provides an overview of both clinical and molecular factors associated with predictive or prognostic value in mRCC and emphasizes that both should be considered in parallel to provide the most appropriate, individualized treatment and achieve the best outcomes in clinical practice.

Prospective phase II trial of pazopanib plus CapeOX (capecitabine and oxaliplatin) in previously untreated patients with advanced gastric cancer

We designed a single-arm, open label phase II study to determine the efficacy and toxicity of the combination of pazopanib with CapeOx (capecitabine and oxaliplatin) in metastatic /recurrent advanced gastric cancer (AGC) patients. Previously untreated AGC patients received capecitabine (850 mg/m² bid, day 1–14) plus oxaliplatin (130 mg/m², day 1) in combination with pazopanib (800 mg, day 1–21) every three weeks. Treatment was continued until progression of the disease or intolerable toxicity was observed. In all, 66 patients were treated with pazopanib plus CapeOx. The median age of the patients was 51.5 years (range, 23.0–77), and the median ECOG performance status was 1 (0–1). Among all 66 patients, one complete response and 37 partial responses were observed (overall response rate, 62.4%; 95% confidence interval (CI), 45.7–73.5% accounting for the 2-stage design of this trial). Stable disease was observed in 23 patients (34.8%), revealing a 92.4% disease control rate. The median progression free survival and overall survival were 6.5 months (95% CI, 5.6–7.4) and 10.5 months (95% CI, 8.1–12.9), respectively. Thirty-four patients (51.5%) experienced a treatment-related toxicity of grade 3 or more. The most common toxicities of grade 3 or more were neutropenia (15.1%), anemia (10.6%), thrombocytopenia (10.6%), anorexia (7.6%), nausea (3.0%), and vomiting (3.0%). There were no treatment-related deaths. The combination of pazopanib and CapeOx showed moderate activity and an acceptable toxicity profile as a first-line treatment in metastatic / recurrent AGC patients (ClinicalTrials.gov NCT01130805).

Imaging Response of Antiangiogenic and Immune-Oncology Drugs in Metastatic Renal Cell Carcinoma (mRCC): Current Status and Future Challenges

This report aims to review criteria which have been proposed for treatment evaluation in mRCC under anti-angiogenic and immune-oncologic therapies and discuss future challenges for imagers. RECIST criteria seem to only partially reflect the clinical benefit derived from anti-angiogenic drugs in mRCC. New methods of analysis propose to better evaluate response to these drugs, including a new threshold for size criteria (-10%), attenuation (Choi and modified Choi criteria), functional imaging techniques (perfusion CT, ultrasound or MRI), and new PET radiotracers. Imaging of progression is one of the main future challenges facing imagers. It is progression and not response that will trigger changes in therapy, therefore it is tumour progression that should be identified by imaging techniques to guide the oncologist on the most appropriate time to change therapy. Yet little is known on dynamics of tumour progression, and much data still needs to be accrued to understand it. Finally, as immunotherapies develop, flare or pseudo-progression phenomena are observed. Studies need to be performed to determine whether imaging can distinguish between patients undergoing pseudo-progression for which therapy should be continued, or true progression for which the treatment must be changed.

Determination of an optimal response cut-off able to predict progression-free survival in patients with well-differentiated advanced pancreatic neuroendocrine tumours treated with sunitinib: an alternative to the current RECIST-defined response

Background:

Sunitinib prolongs progression-free survival (PFS) in patients with advanced pancreatic neuroendocrine tumours (pNET). Response Evaluation Criteria in Solid Tumors (RECIST)-defined partial responses (PR; classically defined as ⩾30% size decrease from baseline) are infrequent.

Methods:

Individual data of pNET patients from the phase II [NCT00056693] and pivotal phase III [NCT00428597] trials of sunitinib were analysed in this investigator-initiated, post hoc study. The primary objective was to determine the optimal RECIST (v.1.0) response cut-off value to identify patients who were progression-free at 11 months (median PFS in phase III trial); and the most informative time-point (highest area under the curve (AUC) by receiver operating characteristic (ROC) analysis and logistic regression) for prediction of benefit (PFS) from sunitinib.

Results:

Data for 237 patients (85 placebo; 152 sunitinib (n=66.50 mg ‘4-weeks on/2-weeks off’ schedule; n=86 ‘37.5 mg continuous daily dosing (CDD)’)) and 788 scans were analysed. The median PFS for sunitinib and placebo were 9.3 months (95% CI 7.6–12.2) and 5.4 months (95% CI 3.5–6.01), respectively (hazard ratio (HR) 0.43 (95% CI 0.29–0.62); P<0.001). A PR was seen in 19 patients (13%) on sunitinib; the median change in the sum of the lesions (vs baseline) was −12.8% (range −100 to +36.4). Month 7 was the most informative time-point (AUC 0.78 (95% CI 0.66–0.9); odds ratio 1.05 (95% CI 1.01–1.08), P=0.002). Reduction of 10% (vs baseline) achieved the highest sensitivity (50%) and specificity (82%), amongst cut-offs tested. A 10% reduction in marker lesions was associated with improved PFS in the whole sunitinib population (HR 0.55 (95 CI 0.3–0.9); P=0.04); mostly in patients on sunitinib CDD (HR 0.33 (95% CI 0.2–0.7); P=0.005). A 10% reduction in marker lesions (P=0.034) and sunitinib treatment (P=0.012) independently impacted on PFS (multivariable analysis).

Conclusions:

A 10% reduction within marker lesions identifies pNET patients benefiting from sunitinib treatment with implications for maintenance of dose intensity and future trial design.

Population Pharmacokinetic/Pharmacodynamic Modeling of Sunitinib by Dosing Schedule in Patients with Advanced Renal Cell Carcinoma or Gastrointestinal Stromal Tumor

Background

Sunitinib is a multi-targeted tyrosine kinase inhibitor used in the treatment of advanced renal cell carcinoma (RCC) and imatinib-resistant/intolerant gastrointestinal stromal tumors (GIST).

Methods

A meta-analysis of 10 prospective clinical studies in advanced RCC and GIST was performed to support the development of pharmacokinetic (PK) and PK/pharmacodynamic (PD) models that account for the effects of important covariates. These models were used to make predictions with respect to the PK, safety, and efficacy of sunitinib when administered on the traditional 4-weeks-on/2-weeks-off schedule (Schedule 4/2) versus an alternative schedule of 2 weeks on/1 week off (Schedule 2/1).

Results

The covariates found to have a significant effect on one or more of the PK or PD parameter studies included, age, sex, body weight, race, baseline Eastern Cooperative Oncology Group performance status, tumor type, and dosing schedule. The models predicted that, in both RCC and GIST patients, Schedule 2/1 would have comparable efficacy to Schedule 4/2, despite some differences in PK profiles. The models also predicted that, in both indications, sunitinib-related thrombocytopenia would be less severe when sunitinib was administered on Schedule 2/1 dosing compared with Schedule 4/2.

Conclusion

These findings support the use of sunitinib on Schedule 2/1 as a potential alternative to Schedule 4/2 because it allows for the management of toxicity without loss of efficacy.

Electronic supplementary material

The online version of this article (doi:10.1007/s40262-016-0404-5) contains supplementary material, which is available to authorized users.

Long-Term Response to Sunitinib Treatment in Metastatic Renal Cell Carcinoma: A Pooled Analysis of Clinical Trials

BACKGROUND

We characterized clinical outcomes of patients with metastatic renal cell carcinoma (mRCC) treated with sunitinib who were long-term responders (LTRs), defined as patients having progression-free survival (PFS) > 18 months.

PATIENTS AND METHODS

A retrospective analysis of data from 5714 patients with mRCC treated with sunitinib in 8 phase II/III clinical trials and the expanded access program. Duration on-study and objective response rate (ORR) were compared between LTRs and patients with PFS ≤ 18 months ("others"). PFS and overall survival (OS) were summarized using Kaplan-Meier methodology.

RESULTS

Overall, 898 (15.7%) patients achieved a long-term response and 4816 (84.3%) patients did not achieve long-term response. The median (range) duration on-study was 28.6 (16.8-70.7) months in LTRs and 5.5 (0-68.8) months in others. ORR was 51% in LTRs versus 14% in others (P < .0001). Median PFS in LTRs was 32.11 months and median OS was not reached. LTRs had higher percentage of early tumor shrinkage ≥ 10% at the first scan (67.1% vs. 51.2%; P = .0018) and greater median maximum on-study tumor shrinkage from baseline (-56.9 vs. -27.1; P < .0001) versus others. White race, Eastern Cooperative Oncology Group performance status 0, time from diagnosis to treatment ≥ 1 year, clear cell histology, no liver metastasis, lactate dehydrogenase ≤ 1.5 upper limit of normal (ULN), corrected calcium ≤ 10 mg/dL, hemoglobin greater than the lower limit of normal, platelets less than or equal to ULN, body mass index ≥ 25 kg/m2, and low neutrophil-to-lymphocyte ratio were associated with LTR.

CONCLUSION

A subset of patients with mRCC treated with sunitinib achieved long-term response. LTRs had improved ORR, PFS, and OS.

Early primary renal tumor response predicts clinical outcome in patients with primary unresectable renal cell carcinoma with synchronous distant metastasis receiving molecularly targeted therapies

The aim of the present study was to investigate the prognostic factors for patients with primary unresectable renal cell carcinoma (RCC) with synchronous distant metastasis receiving molecularly targeted therapies. A total of 26 patients with primary unresectable RCC with synchronous distant metastasis underwent molecularly targeted therapies at the Kurume University Hospital (Kurume, Japan) between March 2008 and March 2016. Early primary renal tumor response was evaluated at 8-12 weeks after the introduction of molecularly targeted therapy and a 10% decrease in the diameter of primary renal tumor was used as the cut-off value. The median overall survival from the initiation of first-line molecularly targeted therapy was 18.3 months. Univariate analyses for various factors identified early primary renal tumor response (P=0.0004) and best response to first-line treatment (P=0.0002) as prognostic variables. Multivariate analyses also identified early primary renal tumor response (P=0.0099) and best response to first-line treatment (P=0.0054) as independent prognostic factors. A comparison of clinical characteristics between the group with ≥10% shrinkage and the group with disease progression or <10% shrinkage revealed that the number of metastatic sites and pretreatment monocyte-to-lymphocyte ratio tended to be predictive factors for primary renal tumor response. These results suggest that early primary renal tumor shrinkage is highly variable for patients with primary unresectable RCC with synchronous distant metastasis receiving molecularly targeted therapies.

A Phase II Study of Intermittent Sunitinib in Previously Untreated Patients With Metastatic Renal Cell Carcinoma

Purpose

Sunitinib is a standard initial therapy in metastatic renal cell carcinoma (mRCC), but chronic dosing requires balancing toxicity with clinical benefit. The feasibility and clinical outcome with intermittent sunitinib dosing in patients with mRCC was explored.

Patients and Methods

Patients with treatment-naïve, clear cell mRCC were treated with four cycles of sunitinib (50 mg once per day, 4 weeks of receiving treatment followed by 2 weeks of no treatment). Patients with a ≥ 10% reduction in tumor burden (TB) after four cycles had sunitinib held, with restaging scans performed every two cycles. Sunitinib was reinitiated for two cycles in those patients with an increase in TB by ≥ 10%, and again held with ≥ 10% TB reduction. This intermittent sunitinib dosing continued until Response Evaluation Criteria in Solid Tumors-defined disease progression while receiving sunitinib, or unacceptable toxicity occurred. The primary objective was feasibility, defined as the proportion of eligible patients who underwent intermittent therapy.

Results

Of 37 patients enrolled, 20 were eligible for intermittent therapy and all patients (100%) entered the intermittent phase. Patients were not eligible for intermittent sunitinib because of progressive disease (n = 13), toxicity (n = 1), or consent withdrawal (n = 3) before the end of cycle 4. The objective response rate was 46% after the first four cycles of therapy. The median increase in TB during the periods off sunitinib was 1.6 cm (range, −2.9 to 3.4 cm) compared with the TB immediately before stopping sunitinib. Most patients exhibited a stable sawtooth pattern of TB reduction while receiving sunitinib and TB increase while not receiving sunitinib. Median progression-free survival to date is 22.4 months (95% CI, 5.4 to 37.6 months) and median overall survival is 34.8 months (95% CI, 14.8 months to not applicable).

Conclusion

Periodic extended sunitinib treatment breaks are feasible and clinical efficacy does not seem to be compromised.

Optimal tumor shrinkage predicts long-term outcome in advanced nonsmall cell lung cancer (NSCLC) treated with target therapy: Result from 3 clinical trials of advanced NSCLC by 1 institution

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are used as standard therapies for advanced nonsmall cell lung cancer (NSCLC) patients with EGFR mutation positive. Because these targeted therapies could cause tumor necrosis and shrinkage, the purpose of the study is to search for a value of optimal tumor shrinkage as an appropriate indicator of outcome for advanced NSCLC.A total of 88 NSCLC enrollees of 3 clinical trials (IRESSA registration clinical trial, TRUST study and ZD6474 study), who received Gefitinib (250 mg, QD), Erlotinib (150 mg, QD), and ZD6474 (100 mg, QD), respectively, during December 2003 and October 2007, were retrospectively analyzed. The response evaluation criteria in solid tumors (RECIST) were used to identify responders, who had complete response (CR) or partial responses (PR) and nonresponders who had stable disease (SD) or progressive disease (PD). Receiver operating characteristics (ROC) analysis was used to find the optimal tumor shrinkage as an indicator for tumor therapeutic outcome. Univariate and multivariate Cox regression analyses were performed to compare the progression-free survival (PFS) and overall survival (OS) between responders and nonresponders stratified based on radiologic criteria.Among the 88 NSCLC patients, 26 were responders and 62 were nonresponders based on RECIST 1.0. ROC indicated that 8.32% tumor diameter shrinkage in the sum of the longest tumor diameter (SLD) was the cutoff point of tumor shrinkage outcomes, resulting in 46 responders (≤8.32%) and 42 nonresponders (≥8.32%). Univariate and multivariate Cox regression analyses indicated that (1) the responders (≤8.32%) and nonresponders (≥ -8.32%) were significantly different in median PFS (13.40 vs 1.17 months, P < 0.001) and OS (19.80 vs 7.90 months, P < 0.001) and (2) -8.32% in SLD could be used as the optimal threshold for PFS (hazard ratio [HR], 8.11, 95% CI, 3.75 to 17.51, P < 0.001) and OS (HR, 2.36, 95% CI, 1.41 to 3.96, P = 0.001).However, 8.32% tumor diameter shrinkage is validated as a reliable outcome predictor of advanced NSCLC patients receiving EGFR-TKIs therapies and may provide a practical measure to guide therapeutic decisions.

Metastatic renal cell carcinoma imaging evaluation in the era of anti-angiogenic therapies

During the last decade, the arsenal of anti-angiogenic (AAG) agents used to treat metastatic renal cell carcinoma (RCC) has grown and revolutionized the treatment of metastatic RCC, leading to improved overall survival compared to conventional chemotherapy and traditional immunotherapy agents. AAG agents include inhibitors of vascular endothelial growth factor receptor signaling pathways and mammalian target of rapamycin inhibitors. Both of these classes of targeted agents are considered cytostatic rather than cytotoxic, inducing tumor stabilization rather than marked tumor shrinkage. As a result, decreases in tumor size alone are often minimal and/or occur late in the course of successful AAG therapy, while tumor devascularization is a distinct feature of AAG therapy. In successful AAG therapy, tumor devascularization manifests on computed tomography images as a composite of a decrease in tumor size, a decrease in tumor attenuation, and the development of tumor necrosis. In this article, we review Response Evaluation Criteria in Solid Tumors (RECIST)-the current standard of care for tumor treatment response assessment which is based merely on changes in tumor length-and its assessment of metastatic RCC tumor response in the era of AAG therapies. We then review the features of an ideal tumor imaging biomarker for predicting metastatic RCC response to a particular AAG agent and serving as a longitudinal tumor response assessment tool. Finally, a discussion of the more recently proposed imaging response criteria and new imaging trends in metastatic RCC response assessment will be reviewed.

Early Tumour Shrinkage: A Tool for the Detection of Early Clinical Activity in Metastatic Renal Cell Carcinoma

BACKGROUND

The predictive role of objective remission remains undefined for targeted agents in metastatic renal cell carcinoma (mRCC); however, early tumour shrinkage (eTS) was shown to be predictive and/or prognostic for overall survival (OS) and progression-free survival (PFS) in mRCC in several small studies.

OBJECTIVE

To evaluate the degree of eTS following systemic therapy that may predict survival in mRCC.

DESIGN, SETTING, AND PARTICIPANTS

Data from 4334 patients with mRCC in phase 2 and 3 clinical trials between 2003 and 2013 were pooled for analyses. Early tumour shrinkage was assessed based on percentage change in sum of the longest diameters of target lesions at first postbaseline scan. Patients were categorised by a more or equal versus less optimal threshold of eTS, assessed using receiver operating characteristic (ROC) analysis. OS and PFS in patients with eTS were summarised using the Kaplan-Meier method.

INTERVENTION

Axitinib, bevacizumab, interferon α, sorafenib, sunitinib, or temsirolimus.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We measured optimal thresholds of eTS and eTS as a predictor of OS or PFS.

RESULTS AND LIMITATIONS

Optimal threshold of eTS for the prediction of OS and PFS was determined to be approximately 10%. In Cox proportional hazards models, compared with patients without eTS, those with eTS had significantly longer OS (hazard ratio [HR]: 0.615; p<0.0001; median: 28.5 vs 16.0 mo) and PFS (HR: 0.628; p<0.0001; median: 10.5 vs 5.3 mo). The major limitation was the retrospective nature of our analysis, including different lines and types of therapy, although subset analyses detected a similar predictive pattern for eTS across all lines and types of therapy.

CONCLUSIONS

Early tumour shrinkage ≥10% at first postbaseline assessment could serve as a putative early end point in patients with mRCC. A prospective evaluation of eTS in clinical trials is warranted.

PATIENT SUMMARY

Early tumour shrinkage may be used to identify patients with metastatic renal cell carcinoma who would benefit from treatment with antitumour agents.

TRIAL REGISTRATION

The clinical trials are registered on ClinicalTrials.gov (NCT00267748, NCT00338884, NCT00835978, NCT00065468, NCT00083889, NCT00631371, NCT00920816, NCT00077974, NCT00137423, NCT00054886, NCT00678392, and NCT00474786).

Optimizing clinical benefit with targeted treatment in mRCC: "Tumor growth rate" as an alternative clinical endpoint

Tumor growth rate (TGR), usually defined as the ratio between the slope of tumor growth before the initiation of treatment and the slope of tumor growth during treatment, between the nadir and disease progression, is a measure of the rate at which tumor volume increases over time. In patients with metastatic renal cell carcinoma (mRCC), TGR has emerged as a reliable alternative parameter to allow a quantitative and dynamic evaluation of tumor response. This review presents evidence on the correlation between TGR and treatment outcomes and discusses the potential role of this tool within the treatment scenario of mRCC. Current evidence, albeit of retrospective nature, suggests that TGR might represent a useful tool to assess whether treatment is altering the course of the disease, and has shown to be significantly associated with progression-free survival and overall survival. Therefore, TGR may represent a valuable endpoint for clinical trials evaluating new molecularly targeted therapies. Most importantly, incorporation of TGR in the assessment of individual patients undergoing targeted therapies may help clinicians decide if a given agent is no longer able to control disease growth and whether continuing therapy beyond RECIST progression may still produce clinical benefit.

Pragmatic medicine in solid cancer: a translational alternative to precision medicine

The precision medicine (PM) initiative is a response to the dismal outlook in solid cancer. Despite heterogeneity, common mechanistic denominators may exist across the spectrum of solid cancer. A shift from conventional research and development (R&D) toward PM will require conceptual and structural change. As individuals and as a society, we welcome innovation, but question change. We ask: In solid cancer, does PM identify and address the causes of prior failures, and, if so, are the proposed solutions feasible? And, when may we expect safer, more effective and affordable drugs in the clinic? Considerations that prompt a pragmatic rethink include a failure analysis of translational R&D in solid cancer suggesting that trials and regulations need to be aligned with the natural history of the disease. In successful therapeutic interventions in chronic, complex disease, surrogate markers and endpoints should be consistent with the Prentice's criteria. In solid cancer, drug induced tumor shrinkage, is a drug effect and not a disease response; tumor shrinkage does not reflect nor predict interruption of the disease. Overall, we support a pragmatic, multidisciplinary, and collaborative R&D, and suggest that direction be set by clinical need and utility, and by questions, not answers. PM will prove worthwhile if it could improve clinical outcomes. The lag in therapeutics relative to diagnostics is a cause for confusion. Overdiagnosis adds to fear and harm, especially in the absence of effective interventions. A revised initiative that prioritizes metastasis research could replicate the successful HIV/AIDS model in solid cancer. A pragmatic approach may further translational efforts toward meaningfully effective, generally available, and affordable solutions.

Algorithms in the First-Line Treatment of Metastatic Clear Cell Renal Cell Carcinoma--Analysis Using Diagnostic Nodes

BACKGROUND

With the advent of targeted therapies, many treatment options in the first-line setting of metastatic clear cell renal cell carcinoma (mccRCC) have emerged. Guidelines and randomized trial reports usually do not elucidate the decision criteria for the different treatment options. In order to extract the decision criteria for the optimal therapy for patients, we performed an analysis of treatment algorithms from experts in the field.

MATERIALS AND METHODS

Treatment algorithms for the treatment of mccRCC from experts of 11 institutions were obtained, and decision trees were deduced. Treatment options were identified and a list of unified decision criteria determined. The final decision trees were analyzed with a methodology based on diagnostic nodes, which allows for an automated cross-comparison of decision trees. The most common treatment recommendations were determined, and areas of discordance were identified.

RESULTS

The analysis revealed heterogeneity in most clinical scenarios. The recommendations selected for first-line treatment of mccRCC included sunitinib, pazopanib, temsirolimus, interferon-α combined with bevacizumab, high-dose interleukin-2, sorafenib, axitinib, everolimus, and best supportive care. The criteria relevant for treatment decisions were performance status, Memorial Sloan Kettering Cancer Center risk group, only or mainly lung metastases, cardiac insufficiency, hepatic insufficiency, age, and "zugzwang" (composite of multiple, related criteria).

CONCLUSION

In the present study, we used diagnostic nodes to compare treatment algorithms in the first-line treatment of mccRCC. The results illustrate the heterogeneity of the decision criteria and treatment strategies for mccRCC and how available data are interpreted and implemented differently among experts.

IMPLICATIONS FOR PRACTICE

The data provided in the present report should not be considered to serve as treatment recommendations for the management of treatment-naïve patients with multiple metastases from metastatic clear cell renal cell carcinoma outside a clinical trial; however, the data highlight the different treatment options and the criteria used to select them. The diversity in decision making and how results from phase III trials can be interpreted and implemented differently in daily practice are demonstrated.

mTOR-inhibitor treatment of metastatic renal cell carcinoma: contribution of Choi and modified Choi criteria assessed in 2D or 3D to evaluate tumor response

PURPOSE

To determine whether 2D or 3D Choi and modified Choi (mChoi) criteria could assess the efficacy of everolimus against metastatic renal cell carcinoma (mRCC).

METHODS

RECIST-1.1, Choi, and mChoi criteria were applied retrospectively to analyse baseline and 2-month contrast-enhanced computed tomography (CECT) images in 48 patients with mRCC enrolled in the everolimus arm of the French randomized double-blind multicentre phase III trial comparing everolimus versus placebo (RECORD-1). The primary endpoint was centrally reviewed progression-free survival (PFS) calculated from the initial RECORD-1 analysis. Mean attenuation was determined for 2D target lesion regions of interest drawn on CECT sections whose largest diameters had been measured, and for the 3D whole target lesion.

RESULTS

The median PFS was 5.5 months. The median PFS for everolimus responders defined using 3D mChoi criteria was significantly longer than for non-responders (7.6 versus 5.4 months, respectively), corresponding to a hazard ratio for progression of 0.45 (95 % CI: 0.22-0.92), with respective 1-year survival rates of 31 % and 9 %. No other 2D or 3D imaging criteria at 2 months identified patients who would benefit from everolimus.

CONCLUSIONS

At 2 months, only 3D mChoi criteria were able to identify mRCC patients with a PFS benefit from everolimus.

KEY POINTS

Choi criteria could not identify everolimus-treated patients with significantly prolonged PFS. mCHOI enabled identification of everolimus-treated mRCC patients with a PFS benefit. 3D attenuation measurement criteria appeared to perform better than single-slice measurement.

RECIST 1.1 compared with RECIST 1.0 in patients with advanced renal cell carcinoma receiving vascular endothelial growth factor-targeted therapy

OBJECTIVE. Response Evaluation Criteria in Solid Tumors (RECIST) is the most widely accepted method to objectively assess response to therapy in renal cell carcinoma (RCC) treated with vascular endothelial growth factor (VEGF)-targeted therapy. Both RECIST 1.0 and 1.1 have been used to assess response to VEGF-targeted therapies; however, systematic comparisons are lacking. MATERIALS AND METHODS. Sixty-two patients with metastatic RCC treated with VEGF-targeted therapies were retrospectively studied. Tumor measurements and response assessment according to RECIST 1.1 and RECIST 1.0 were compared, including the number of target lesions, baseline measurements, response at each follow-up, best overall response, and time to progression (TTP). Morphologic changes and new enhancement were also assessed over the course of treatment, and TTP was evaluated using morphologic change criteria in combination with RECIST 1.1. RESULTS. The number of target lesions according to RECIST 1.1 was significantly fewer than by RECIST 1.0 (median, 2 vs 4; p < 0.0001). At first imaging follow-up, the percentage change of the sums of the diameter measurements by RECIST 1.1 and RECIST 1.0 were highly concordant (R = 0.857; mean shrinkage, 12.1% by RECIST 1.1 vs 10.8% by RECIST 1.0). Best response assessment was highly concordant between the two criteria (weighted κ = 0.819). There was no evidence of a difference in TTP by the two criteria, with a median TTP of 8.9 months (95% CI for the median, 5.5-13.9) by RECIST 1.1 and 8.9 months (95% CI for the median, 5.8-13.6) by RECIST 1.0. The median TTP by RECIST 1.1 alone was 8.9 months compared with 5.6 months for RECIST 1.1 and morphologic changes combined. CONCLUSION. RECIST 1.1 and RECIST 1.0 response assessments were overall highly concordant in patients with RCC treated with VEGF-targeted therapy, with fewer target lesions according to RECIST 1.1 but no difference in TTP.

Early tumour shrinkage as a prognostic factor and surrogate end-point in colorectal cancer: a systematic review and pooled-analysis

PURPOSE

Early tumour shrinkage (ETS), defined as a reduction of at least 20% in tumour size at first reassessment, has been recently investigated retrospectively in first-line trials of metastatic colorectal cancer (CRC), and appears to be associated with better outcomes. We have performed a systematic review and meta-analysis of published trials to evaluate the prognostic value of ETS in CRC in terms of overall survival (OS) and progression-free survival (PFS).

MATERIAL AND METHODS

An electronic search of the PubMed, SCOPUS, EMBASE, the Web of Science, and the Cochrane Central Register of Controlled Trial databases identified trials that compared outcomes of patients with or without ETS during first-line chemotherapy for metastatic CRC. The OS, reported as a hazard ratio (HR) with a 95% confidence interval (CI), was the primary outcome measure; the correlation coefficient (R) between ETS with median OS was also estimated.

RESULTS

Twenty-one trials from 10 publications were analysed. Overall, patients with ETS were associated with a better OS (HR, 0.58; 95% CI, 0.53 to 0.64; P<0.00001) and PFS (HR, 0.57; 95% CI, 0.47-0.69; P<0.00001) compared with patients who were early non-responders. However, ETS was poorly correlated with OS in terms of surrogacy (R=0.37; 95% CI - 0.31-0.78; P=0.28).

CONCLUSIONS

ETS is a good prognostic factor but an inappropriate surrogate for predicting outcome in CRC patients. These findings support ETS as prognostic tool in ascertaining earlier non-responders; however, its role as a surrogate end-point deserves further evaluation.