Early response evaluation and prediction in neoadjuvant-treated patients with esophageal cancer

Degree of tumor shrinkage following neoadjuvant chemoradiotherapy: a potential predictor for complete pathological response in esophageal cancer?

Neoadjuvant chemoradiotherapy (CRT) before surgery results in a pathological complete response (pCR) rate in about 1/3 of the patients, which is correlated with survival. It was hypothesized that volumetric tumor response to CRT would correlate with outcomes. Patients who completed trimodality therapy, where planning, pre-, and post-CRT computed tomography scans were available, and pathology was reviewed by a central pathologist, were eligible for analysis. Absolute and relative tumor volume change pretreatment and post-treatment were correlated with pCR, locoregional recurrence (LRR), disease-free survival, and overall survival. Fifty-six patients were analyzed. pCR was observed in 30% of patients. Median follow up was 20.3 (range 4-89) months. The 2- and 4-year overall survival was 61.3% (95% confidence interval [CI]: 45-74) and 25.0% (95%CI: 11-41); proportion disease free was 32.1% (95% CI: 19-46) and 20.6% (9-36) at 2 and 4 years, respectively. The median relative volume reduction was 17% (95% CI: -24, -3%). Using 20% as the criteria, the proportion of patients with pCR of ≥20% versus <20% was 13/25 (52%) versus 4/31 (13%) for those who did not (odds ratio 7.3; 95% CI: 2-27). The LRR at 2 and 4 years were 29.5% (95% CI: 16-43) and 36.2% (95% CI: 23-50). The relative tumor reduction ≥20% was significantly correlated with LRR (hazard ratio 0.24; 95% CI: 0.07-0.8; p 0.02) at 2 and 4 years, respectively. Relative tumor volume reduction following CRT is correlated with pCR and LRR. Further investigations are warranted to examine the effect of volume change, alone or in conjunction with other factors as potential predictors for pathological response.

Oesophageal cancer--an overview

Oesophageal carcinoma is one of the most virulent malignant diseases and a major cause of cancer-related deaths worldwide. Diagnosis and accuracy of pretreatment staging have substantially improved throughout the past three decades. Therapy is challenging and the optimal approach is still debated. Oesophagectomy is considered to be the procedure of choice in patients with operable oesophageal cancer. Endoscopic measures and limited surgical procedures provide an alternative in patients with early carcinomas confined to the oesophageal mucosa. Chemotherapy and radiotherapy or concurrent chemoradiotherapy are also frequently applied, either as definitive treatment or as neoadjuvant therapy within multimodal approaches. The question of whether multimodal treatment offers improved results has been the focus of many studies since the 1990s. Although results are discordant and even some meta-analyses remain inconclusive, it is now widely accepted that multimodal therapy leads to a modest survival benefit. The role of minimally invasive oesophagectomy is not yet defined. Endoscopic stent insertion, radiotherapy and other palliative measures provide relief of tumour-related symptoms in advanced, unresectable tumour stages.

Radiation sensitivity of esophageal adenocarcinoma: the contribution of the RNA-binding protein RNPC1 and p21-mediated cell cycle arrest to radioresistance

Radiation combined with chemotherapy (neo-CRT) is increasingly the standard of care for the treatment of esophageal cancer, either as neoadjuvant therapy in multimodal protocols or as primary therapy. Unfortunately, ~60% of patients demonstrate little or no response to neo-CRT. Accordingly, understanding the molecular mechanisms of resistance to therapy may underpin significant advances through the identification of nonresponders either before or early in treatment. We previously identified the RNPC1 gene, which is important in stabilizing p21, as being upregulated in the tumors of esophageal cancer patients who had a poor response to neo-CRT. We hypothesize that RNPC1 contributes to resistance to radiation therapy through a p21-mediated cell cycle accumulation/arrest mechanism. Analysis revealed that p53 and RNPC1 expression were highest in the JH-EsoAd1 cell line and lowest in OE19 cells. This was associated with accumulation of cells in G₀/G₁. p21 expression, which was highest in OE19 cells and lowest in OE33 cells, was associated with relative intrinsic sensitivity to radiation. OE33 cells were transfected with a plasmid (pCMV6-AC-GFP) encoding a C-terminal GFP-tagged RNPC1, and overexpression was confirmed by qPCR and fluorescence microscopy. Overexpression of RNPC1-GFP resulted in significantly increased levels of the p21 transcript and protein through a direct physical interaction between the RNPC1 protein and the p21 transcript. Furthermore, RNPC1 overexpression led to significant G₀/G₁ cell cycle accumulation and significantly enhanced cellular resistance to radiation. We conclude that RNPC1 contributes to tumor resistance to radiotherapy, which likely occurs through a p21-mediated G₀/G₁ accumulation mechanism. Therefore, RNPC1 may represent a potential therapeutic target for enhancing tumor sensitivity to radiation.

Early evaluation of the apoptotic index ratio is useful in predicting the efficacy of chemoradiotherapy in esophageal squamous cell carcinoma

Chemoradiotherapy for advanced esophageal cancer is a standard treatment alongside surgical treatment. Although numerous investigators have attempted to identify the predictive markers for chemoradiosensitivity, there appear to be few candidates that can be applied in clinical use. Using biopsy specimens, we investigated the apoptotic index (AI) prior to treatment and following a radiation dose of 10 Gy to detect the early response to chemoradiotherapy in 28 patients with esophageal squamous cell carcinoma. Molecular markers, including p53, p21, bax, bcl-2, HSP27, HSP70, HSP90, Ku70, Ku86 and HIF-1α, were also examined by immunohistochemical staining. The patients were divided into two groups depending on the response to chemoradiotherapy: a responder group (RG) (n=19) that included the patients with complete or partial response, and a non-responder group (NRG) (n=9), that included patients with stable or progressive disease. In the RG and NRG, the AI of pretreatment was 4.7±5.3 (mean ± SD, cells/1,000 cells) and 5.9±3.7, respectively. The apoptotic index ratio (AIR), which was determined by dividing the AI following 10 Gy radiation by the pretreatment AI, was higher in the RG compared to the NRG (4.7±4.5 versus 1.9±1.4, p=0.03). When the cut-off value of AIR was set at 2.4, the sensitivity, specificity and accuracy were 74, 78 and 76%, respectively. Among the molecular markers we examined immunohistochemically, a positive p53 expression in the pretreatment evaluation was associated with the efficacy of chemoradiotherapy (p=0.08). Regarding the expression of other molecular markers, no significant correlations were found in RG and NRG. In the present study, the results indicated that AIR is useful for the prediction of chemoradiosensitivity in esophageal squamous cell carcinoma.