Early tumor shrinkage after first-line medical treatment of metastatic colorectal cancer: a meta-analysis

Impact of early tumor shrinkage and depth of response in patients with BRAF V600E-mutant metastatic colorectal cancer

BACKGROUND

Early tumor shrinkage (ETS) and depth of response (DpR) are early indicators of survival in patients with metastatic colorectal cancer (mCRC) undergoing anti-epidermal growth factor receptor monoclonal antibody treatment. However, their relevance in v-raf murine sarcoma viral oncogene homolog B1 (BRAF) V600E mutant (MT) mCRC remains unclear. In this study, we evaluate the association between ETS/DpR and clinical outcomes in BRAF V600E MT mCRC.

PATIENTS AND METHODS

Patients with mCRC who were diagnosed with BRAF V600E MT and treated with first-line chemotherapy between June 2011 and March 2023 at a single cancer institute were enrolled. The association between ETS/DpR and clinical outcomes in patients with at least one target lesion was assessed. The cutoff value for ETS and DpR was set at 20% and 25%. Multivariate analysis of factors affecting progression-free survival (PFS) and overall survival (OS) was conducted.

RESULTS

In total, 54 patients with BRAF V600E MT mCRC exhibited at least one target lesion. Patients with ETS and DpR were 24 (44.4%) and 27 (50%), respectively. Moreover, median PFS and OS were 7.5 and 17.1 months, respectively. Patients with ETS exhibited longer PFS and tended toward longer OS than those without ETS. Similarly, patients with DpR exhibited longer PFS and OS than those without DpR. Multivariate analysis confirmed a significant association between DpR and longer PFS and OS.

CONCLUSION

ETS and DpR could serve as early surrogate markers of clinical outcomes in patients with BRAF V600E MT mCRC treated with first-line chemotherapy.

Standard diametric versus volumetric early tumor shrinkage as a predictor of survival in metastatic colorectal cancer: subgroup findings of the randomized, open-label phase III trial FIRE-3 / AIO KRK-0306

OBJECTIVES

Early tumor shrinkage (ETS) quantifies the objective response at the first assessment during systemic treatment. In metastatic colorectal cancer (mCRC), ETS gains relevance as an early available surrogate for patient survival. The aim of this study was to increase the predictive accuracy of ETS by using semi-automated volumetry instead of standard diametric measurements.

METHODS

Diametric and volumetric ETS were retrospectively calculated in 253 mCRC patients who received 5-fluorouracil, leucovorin, and irinotecan (FOLFIRI) combined with either cetuximab or bevacizumab. The association of diametric and volumetric ETS with overall survival (OS) and progression-free survival (PFS) was compared.

RESULTS

Continuous diametric and volumetric ETS predicted survival similarly regarding concordance indices (p > .05). In receiver operating characteristics, a volumetric threshold of 45% optimally identified short-term survivors. For patients with volumetric ETS ≥ 45% (vs < 45%), median OS was longer (32.5 vs 19.0 months, p < .001) and the risk of death reduced for the first and second year (hazard ratio [HR] = 0.25, p < .001, and HR = 0.39, p < .001). Patients with ETS ≥ 45% had a reduced risk of progressive disease only for the first 6 months (HR = 0.26, p < .001). These survival times and risks were comparable to those of diametric ETS ≥ 20% (vs < 20%).

CONCLUSIONS

The accuracy of ETS in predicting survival was not increased by volumetric instead of diametric measurements. Continuous diametric and volumetric ETS similarly predicted survival, regardless of whether patients received cetuximab or bevacizumab. A volumetric ETS threshold of 45% and a diametric ETS threshold of 20% equally identified short-term survivors.

KEY POINTS

• ETS based on volumetric measurements did not predict survival more accurately than ETS based on standard diametric measurements. • Continuous diametric and volumetric ETS predicted survival similarly in patients receiving FOLFIRI with cetuximab or bevacizumab. • A volumetric ETS threshold of 45% and a diametric ETS threshold of 20% equally identified short-term survivors.

Impact of early tumor shrinkage on quality of life in patients treated with first-line cetuximab plus chemotherapy for unresectable metastatic colorectal cancer: results of Phase II QUACK trial

PURPOSE

Although early tumor shrinkage (ETS) is a predictor of improved overall survival (OS), the association between ETS and health-related quality of life (HRQOL) remains unclear for patients with metastatic colorectal cancer (mCRC) treated with first-line cetuximab plus chemotherapy.

METHODS

The data were collected from a prospective trial that assessed HRQOL using the EORTC QLQ-C30. The impact of ETS on HRQOL was estimated using a linear mixed-effects model for repeated measures.

RESULTS

ETS was achieved in 82 (64.1%) of 128 mCRC patients treated with first-line cetuximab plus chemotherapy, and these patients had a significantly longer OS than those without ETS (HR, 0.38; 95% CI, 0.20-0.72; P = .002). Asymptomatic patients with ETS had a favorable OS, while symptomatic patients without ETS had a worse OS (2-year OS rates, 77.8% vs. 42.5%). Symptomatic patients with ETS had similar outcomes as asymptomatic patients without ETS (2-year OS rates, 64.1% vs. 67.0%). For symptomatic patients, ETS was associated with improved HRQOL scores between baseline and 8 weeks: the mean changes for patients with and without ETS were 5.86 and -4.94 for global health status (GHS)/QOL, 26.73 and 3.79 for physical functioning, and 13.58 and -3.10 for social functioning, respectively. The improved HRQOL was comparable to that of asymptomatic patients without ETS. For asymptomatic patients, ETS showed a decreased deterioration in HRQOL.

CONCLUSION

Our findings highlight the importance of ETS for HRQOL and prognostic estimates, and assessing ETS may provide clinically useful information for physicians and patients to make more informed decisions.

Early tumor shrinkage identifies long-term disease control and survival in patients with lung cancer treated with atezolizumab

Background

Preliminary evidence indicates that early tumor shrinkage (ETS) following immune checkpoint inhibitor (ICI) initiation may be associated with survival outcomes in patients with advanced melanoma. ETS has not been explored as a biomarker of survival outcomes or patient-reported outcomes in patients with advanced non-small cell lung cancer (NSCLC) treated with ICIs.

Methods

The study pooled data from patients with NSCLC in the randomized trials OAK and POPLAR (atezolizumab vs docetaxel; n=1464), and single-arm atezolizumab trials BIRCH and FIR (n=797). The association between ETS (≥10% decrease in pretreatment sum-of-longest diameters of target-lesions at 6 weeks) and overall survival (OS), progression-free survival (PFS), time to deterioration (TDD) in health-related quality-of-life (HRQoL) and physical function (PF) was assessed using Cox proportional hazard analysis.

Results

ETS occurred in 20% of atezolizumab-treated patients with NSCLC within OAK and POPLAR and was associated with highly favorable OS (HR 0.33, p<0.001), PFS (HR 0.31, p<0.001), TDD in HRQoL (HR 0.73, p=0.01) and PF (HR 0.52, p<0.001). The results were replicated in the BIRCH and FIR data. Atezolizumab-treated patients achieving ETS had markedly improved OS compared with docetaxel-treated patients achieving ETS (24-month OS 55% vs 32%); PFS was also markedly improved (24-month PFS 31% vs 4%). In contrast, for patients not achieving ETS, atezolizumab-treatment was associated with more modest OS (24-month OS 23% vs 20%) and PFS (24-month PFS 3% vs 1%) improvement compared with docetaxel. Overall, the effect size for ETS within the atezolizumab-treated patients was significantly greater than that in the docetaxel-treated patients (P(interaction)=0.002 for OS and P(interaction)<0.001 for PFS).

Conclusions

ETS is an easily measurable biomarker, predictive of highly favorable survival and patient-reported outcomes with atezolizumab treatment for advanced NSCLC. Further, ETS identifies patients with significantly greater treatment benefit for ICI therapy.

Systemic Chemotherapy is a Promising Treatment Option for Patients with Colonic Stents: A Review

Approximately 10% of patients with colorectal cancer (CRC) develop malignant large bowel obstruction (MLBO) at diagnosis. Furthermore, for 35% of patients with MLBO, curative primary tumor resection is unfeasible because of locally advanced disease and comorbidities. The practice of placing a self-expandable metallic stent (SEMS) has dramatically increased as an effective palliative treatment. Recent advances in systemic chemotherapy for metastatic CRC have significantly contributed to prolonging patients' prognosis and expanding the indications. However, the safety and efficacy of systemic chemotherapy in patients with SEMS have not been established. This review outlines the current status of this relatively new therapeutic strategy and future perspectives. Some reports on this topic have demonstrated that 1) systemic chemotherapy and the addition of molecular targeted agents contribute to prolonged survival in patients with SEMS; 2) delayed SEMS-related complications are a major concern, and this requires strict patient monitoring; however, primary tumor control by chemotherapy might result in decreased complications, especially regarding re-obstruction; and 3) using bevacizumab could be a risk factor for SEMS-related perforation, which may be lethal. Although this relatively new approach for unresectable stage IV obstructive CRC requires a well-planned clinical trial, this therapy could be promising for patients who are unideal candidates for emergency surgery and require immediate systemic chemotherapy.

Comparison of Various Phase I Combination Therapy Designs in Oncology for Evaluation of Early Tumor Shrinkage Using Simulations

There is still a lack of efficient designs for identifying the dose response in oncology combination therapies in early clinical trials. The concentration response relationship can be identified using the early tumor shrinkage time course, which has been shown to be a good early response marker of clinical efficacy. The performance of various designs using an exposure–tumor growth inhibition model was explored using simulations. Different combination effects of new drug M and cetuximab (reference therapy) were explored first assuming no effect of M on cetuximab (to investigate the type I error (α)), and subsequently assuming additivity or synergy between cetuximab and M. One‐arm, two‐arm, and four‐arm designs were evaluated. In the one‐arm design, 60 patients received cetuximab + M. In the two‐arm design, 30 patients received cetuximab and 30 received cetuximab + M. In the four‐arm design, in addition to cetuximab and cetuximab + M as standard doses, combination arms with lower doses of cetuximab were evaluated (15 patients/arm). Model‐based predictions or “simulated observations” of early tumor shrinkage at week 8 (ETS8) were compared between the different arms. With the same number of individuals, the one‐arm design showed better statistical power than other designs but led to strong inflation of α in case of misestimated reference for ETS8 value. The two‐arm design protected against this misestimation and, with the same total number of subjects, would provide higher statistical power than a four‐arm design. However, a four‐arm design would be helpful for exploring more doses of cetuximab in combination with M to better understand the interaction.

The outcome of primary tumor resection in the unresectable stage IV colorectal cancer patients who received the bevacizumab-containing chemotherapy

Primary tumor resection (PTR) for unresectable metastatic colorectal cancer (mCRC) patients has been documented to be associated with postoperative hyper-neovascularization and enhanced growth of metastases, which may be prevented by bevacizumab. This study aimed to investigate the survival outcome of PTR in patients who received palliative bevacizumab-containing chemotherapy (BCT).From January 2006 to December 2018, medical records of 240 mCRC patients who received palliative BCT at a single tertiary colorectal cancer center were retrospectively reviewed. Patients were classified into three groups: PTR-a (PTR before BCT, n = 60), PTR-b (PTR during BCT, n = 17), and BCT-only group (n = 163). Resectable mCRCs or recurrent diseases were excluded, and the end-point was overall survival (OS) rate.Three groups had similar age, cell differentiation, location of the primary tumor, and the number of metastatic organs. More than two-thirds of patients who received PTR experienced disease-progressions (PD) during their postoperative chemotherapy-free time (PTR-a vs PTR-b; 66.7% vs 76.5%, P = .170), but OS was not inferior to the BCT-only group (PTR-a vs BCT-only; HR 0.477 [95% CI 0.302-0.754], P = .002/PTR-b vs BCT-only; HR 0.77 [95% CI 0.406-1.462], P = .425). The postoperative chemotherapy-free time was similar between PTR-a and PTR-b (median 32.0 [14-98] days vs 41.0 [18-71] days, P = .142), but non-obstructive indications (perforation, bleeding, pain) were the more frequent in the PTR-b than PTR-a. Young age, the number of BCT, and PTR-a were the independent factors for OS.The efficacy of the PTR for unresectable mCRC has been controversial, but this study demonstrated that PTR should be considered for the unresectable mCRC patients regardless before and during BCT.

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.