Molecular targeted treatment and radiation therapy for rectal cancer. Strahlenther Onkol. 2009;185:371-378. [PMID: 19506820 DOI: 10.1007/s00066-009-1936-5]

Intensified preoperative chemoradiation by adding oxaliplatin in locally advanced, primary operable (cT3NxM0) rectal cancer : Impact on long-term outcome. Results of the phase II TAKO 05/ABCSG R‑02 trial

Purpose

The major goals of preoperative treatment for locally advanced rectal cancers (LARCs) are improvement of local tumor control, tumor downsizing, and downstaging. Modifications with respect to standardized chemoradiation protocol, e. g., integrating oxaliplatin, are realized with the aim of improving primary tumor response and patient outcome.

Patients and methods

In this phase II multicenter study, patients with LARC of the mid- or lower rectum, cT3cNxcM0 as staged by MRI, were included and treated preoperatively with a combination of capecitabine and oxaliplatin following a standardized protocol during radiation. The focus of this long-term analysis was overall (OS) and disease-free survival (DFS).

Results

A total of 60 patients (19 women, 41 men, median age 60.5 years) were initially enrolled, 1 patient was excluded (violation of study protocol), and 1 was patient lost of follow-up, leading to a total of 58 patients for long-term analysis. The 3‑year OS was 85.5%; 3‑year DFS 71.2%. Over time, 15 patients (25.9%) developed tumor recurrence (1 locoregional, 6.7%; 11 distant, 73.3%; 3 locoregional+distant, 20%). Recurrence-specific therapy was planned in the majority of patients, in 9 of 15 patients (60%) with a radical surgical approach. Of these, 4 patients (44.4%) are again tumor-free at the end of investigation. While tumor downsizing (T level) or pathologically complete response did not influence patient survival, lymph node negativity (LNneg) after preoperative chemoradiation showed significant influence.

Conclusion

LNneg after preoperative treatment for LARC significantly influences patient survival. A radical surgical approach for recurrent LARC (locoregional, distant) should be contemplated when possible as we were able to clearly demonstrate its importance and efficacy.

The changes of tumour vascular endothelial growth factor expression after neoadjuvant chemoradiation in patients with rectal adenocarcinoma

AIM OF THE STUDY

The aim was to examine the effects of neoadjuvant chemoradiotherapy on VEGF expression in patients with locally advanced rectal cancer.

MATERIALS AND METHODS

A total of 53 patients with locally advanced rectal cancer were retrospectively studied. Neoadjuvant treatment comprised external beam radiation (50.4 Gy/28 fractions) with continuous infusion of 5-fluorouracil. Four to 6 weeks after the chemoradiotherapy, the patients underwent surgical resection. Immunohistochemistry was performed to assess VEGF expression in the pretreatment biopsies and in resected specimens.

RESULTS

Resection with microscopic residual tumour (R1) was performed in two patients while in the remaining 51 patients radical resection with microscopically negative margins (R0) was possible. Downstaging after preoperative chemoradiotherapy was observed in 34 patients (64%). After chemoradiotherapy 24 patients (45%) had decreased VEGF expression, in 20 patients (38%) there was no change, and in two patients it was not possible to assess the dynamics of VEGF expression due to pathologic complete response after chemoradiotherapy. The five-year overall survival (OS) rate was 56% (95% CI: 43-70%). Although the median OS was 2.5 times shorter in patients who experienced decreased VEGF expression during therapy, this difference did not reach statistical significance. VEGF expression was not significant in Cox regression analysis or log-rank test. VEGF expression decreased after neoadjuvant chemoradiotherapy in most patients with rectal adenocarcinoma examined. This decrease was associated with a trend of inferior prognosis.

CONCLUSIONS

VEGF expression decreased after neoadjuvant chemoradiotherapy in most patients examined. This decrease was associated with a trend of inferior prognosis.

Lapatinib-capecitabine versus capecitabine alone as radiosensitizers in RAS wild-type resectable rectal cancer, an adaptive randomized phase II trial (LaRRC trial): study protocol for a randomized controlled trial

BACKGROUND

Preoperative radiochemotherapy followed by surgical removal of the rectum with total mesorectum excision is the preferred treatment option for stages II and III rectal cancer. However, development of metastatic disease is the main cause of death for these patients with 5-year disease-free survival rates of 56 %. Anti-epidermal growth factor receptor (EGFR) targeted therapy is effective in metastatic rectal cancer, and human epidermal growth factor receptor 2 (HER-2) signaling may mediate resistance to EGFR inhibitors. Moreover, preclinical data support a synergistic effect of EGFR inhibition with radiation therapy.

METHODS/DESIGN

This Bayesian phase II trial with adaptive randomization was designed to assess the efficacy of adding lapatinib, a dual inhibitor of EGFR and HER-2, to standard radiochemotherapy with capecitabine in stages II and III rectal cancer.

DISCUSSION

The results of this trial will provide evidence of the feasibility and efficacy of the combination of lapatinib-capecitabine as radiosensitizers and explore potential predictive biomarkers for response to this novel neoadjuvant approach to resectable rectal cancer.

TRIAL REGISTRATION

EudraCT 2013-001203-36 . Registered on 13 December 2013.

Rectal cancer: Neoadjuvant chemoradiotherapy

The monolithic approach to apply the same schedule of preoperative 5-fluorouracil (5-FU)- or capecitabine-based chemoradiotherapy (CRT) to all patients with clinically staged TNM stage II/III rectal cancer need to be questioned. Five randomized trials have been completed to determine if the addition of oxaliplatin to preoperative 5-FU/capecitabine-based CRT offers an advantage compared with single-agent CRT. In contrast to the German CAO/ARO/AIO-04 trial, results from the ACCORD 12, STAR-01, PETACC-6 and NSAPB R-04 trials failed to demonstrate a significant improvement of early or late efficacy endpoints with the addition of oxaliplatin. Most of the phase II trials incorporating cetuximab into CRT reported disappointingly low rates of pCR; the combination of CRT with VEGF inhibition showed encouraging pCR rates but at the cost of increased surgical complications. Novel clinical trials currently address (1) the role of induction and consolidation chemotherapy before or after CRT, (2) minimal or omitted surgery following complete response to CRT, or (3) the omission of radiotherapy for selected patients with response to neoadjuvant chemotherapy. The notion of different multimodal treatment concepts according to tumor stage, location, mesorectal fascia margin status, molecular profiles, tumor response, and patients' preferences becomes increasingly popular and will render the multimodal treatment approach of rectal cancer more risk-adapted.

Prediction of the preoperative chemoradiotherapy response for rectal cancer by peripheral blood lymphocyte subsets

BACKGROUND

Although neoadjuvant chemoradiotherapy (CRT) has become a standard procedure to downstage locally advanced rectal cancer prior to surgery, markers to predict the response to CRT have not been fully identified. The aim of this study was to identify predictive factors of response to CRT, especially focusing on peripheral blood leukocyte subsets.

METHODS

A total of 45 consecutive patients diagnosed with primary rectal cancer were prospectively enrolled and received CRT followed by curative resection. The numbers of each lymphocyte subset in peripheral blood pre- and post-CRT were analyzed using flow cytometry. According to the pathological response to CRT, patients were classified into high (Hi-R) and low (Lo-R) response groups.

RESULTS

Hi-R cases had significantly higher numbers of pre-CRT lymphocytes (p = 0.018), T lymphocytes (p = 0.009) and helper T lymphocytes (Th lymphocytes, p = 0.015) compared to the Lo-R cases. With the receiver-operating characteristic curve for numbers of pre-CRT T lymphocytes, the area under the curve (AUC) was 0.733, and the optimal cutoff value was 1196/μl, with 76.5% sensitivity, 67.8% specificity, 59.1% positive and 82.6% negative predictive values. The numbers of pre-CRT Th lymphocytes and cytotoxic lymphocytes were both independent predictors of the high CRT response in the multivariate analysis.

CONCLUSIONS

In addition to the direct cytotoxicity of CRT, recent studies have demonstrated the induction of an immunological host response, which also contributed to the tumor regression induced by CRT. Our result suggested the potential role of circulating T lymphocytes in predicting the response to CRT in colorectal cancer patients.

Early and late toxicity of radiotherapy for rectal cancer

With the implementation of total mesorectal excision surgery and neoadjuvant (chemo) radiotherapy, the outcome of rectal cancer patients has improved and a substantial proportion of them have become long-term survivors. These advances come at the expense of radiation- and chemotherapy-related toxicity which remains an underestimated problem. Radiation-induced early toxicity in rectal cancer treatment mainly includes diarrhea, cystitis, and perineal dermatitis, while bowel dysfunction, fecal incontinence, bleeding, and perforation, genitourinary dysfunction, and pelvic fractures constitute the majority of late toxicity. It is now generally accepted that short-course radiotherapy (SCRT) and immediate surgery is associated with less early toxicity compared to conventionally fractionated chemoradiotherapy with delayed surgery. There are no significant differences in late toxicity between both treatment regimens. While there is hardly an increase in early toxicity after preoperative SCRT with immediate surgery, late toxicity is substantial compared to surgery alone. Early toxicity is more frequent when a longer interval between SCRT and surgery is used and is comparable to the toxicity observed with conventionally fractionated radiotherapy except that it occurs after the end of the radiotherapy. So far, randomized phase III trials failed to demonstrate a substantial gain in tumoural response when oxaliplatin or molecular agents are added to the multimodality treatment. Moreover, the addition of these drugs increases toxicity and remains therefore experimental.

Tumor Regression Grading After Preoperative Chemoradiotherapy for Locally Advanced Rectal Carcinoma Revisited: Updated Results of the CAO/ARO/AIO-94 Trial

Purpose

We previously described the prognostic impact of tumor regression grading (TRG) on the outcome of patients with rectal carcinoma treated with preoperative chemoradiotherapy (CRT) in the CAO/ARO/AIO-94 trial. Here we report long-term results after a median follow-up of 132 months.

Patients and Methods

TRG after preoperative CRT was determined in 386 surgical specimens by the amount of viable tumor cells versus fibrosis, ranging from TRG 4 (no viable tumor cells) to TRG 0 (no signs of regression). Clinicopathologic parameters and TRG were correlated to the cumulative incidence of local recurrence, distant metastasis, and disease-free survival (DFS).

Results

Ten-year cumulative incidence of distant metastasis and DFS were 10.5% and 89.5% for patients with TRG 4 (complete regression), 29.3% and 73.6% for TRG 2 and 3 (intermediate regression), and 39.6% and 63% for TRG 0 and 1 (poor regression), respectively (P = .005 and P = .008, respectively). On multivariable analysis, residual lymph node metastasis (ypN+) and TRG were the only independent prognostic factors for cumulative incidence of distant metastasis (P < .001 and P = .035, respectively) and DFS (P < .001 and P = .039, respectively), whereas local recurrence was significantly affected by ypN status (P < .001) and lymphatic invasion (P = .026).

Conclusion

Complete and intermediate tumor regressions were associated with improved long-term outcome in patients with rectal carcinoma after preoperative CRT independent of clinicopathologic parameters. This classification system needs to be prospectively tested in multiple data sets to validate its reproducibility in a wider setting.

Double targeting of Survivin and XIAP radiosensitizes 3D grown human colorectal tumor cells and decreases migration

BACKGROUND AND PURPOSE

In the present study, we aimed to investigate the effect of single and double knockdown of the inhibitor of apoptosis proteins (IAP) Survivin and X-linked IAP (XIAP) on three-dimensional (3D) clonogenic survival, migration capacity and underlying signaling pathways.

MATERIALS AND METHODS

Colorectal cancer cell lines (HCT-15, SW48, SW480, SW620) were subjected to siRNA-mediated single or Survivin/XIAP double knockdown followed by 3D colony forming assays, cell cycle analysis, Caspase activity assays, migration assays, matrigel transmigration assays and Western blotting (Survivin, XIAP, Focal adhesion kinase (FAK), p-FAK Y397, Akt1, p-Akt1 S473, Extracellular signal-regulated kinase (ERK1/2), p-ERK1/2 T202/Y204, Glycogen synthase kinase (GSK)3β, p-GSK3β S9, nuclear factor (NF)-κB p65).

RESULTS

While basal cell survival was altered cell line-dependently, Survivin or XIAP single and Survivin/XIAP double knockdown enhanced cellular radiosensitivity of all tested cancer cell lines grown in 3D. Particularly double knockdown conditions revealed accumulation of cells in G2/M, increased subG1 fraction, elevated Caspase 3/7 activity, and reduced migration. Intracellular signaling showed dephosphorylation of FAK and Akt1 upon Survivin and/or Survivin/XIAP silencing.

CONCLUSIONS

Our results strengthen the notion of Survivin and XIAP to act as radiation resistance factors and further indicate that these apoptosis-regulating proteins are also functioning in cell cycling and cell migration.

Thrombocytosis before pre-operative chemoradiotherapy predicts poor response and shorter local recurrence-free survival in rectal cancer

PURPOSE

Although thrombocytosis has been reported in patients with various cancers including the colorectal one, the impact of elevated platelet counts on the response to chemoradiotherapy (CRT) for rectal cancer has not been fully investigated. We investigated the clinical significance of pre- and post-CRT platelet counts in patients with rectal cancer.

METHODS

The medical records of 101 patients with rectal cancer, who had received CRT followed by surgical resection, were retrospectively reviewed. The correlations between the clinicopathological variables and the pre- or post-CRT platelet counts were analyzed. The correlations between tumor regression rate induced by CRT, as evaluated by barium enema and pathological examination, and the pre- or post-CRT platelet counts were also evaluated. Finally, the impact of pre-CRT thrombocytosis on the prognosis of these patients was assessed.

RESULTS

The pre-CRT platelet count correlated with venous invasion and tumor size, and it strongly correlated with the response rate evaluated by barium enema and the grade of pathological tumor regression. Furthermore, patients with pre-CRT thrombocytosis had significantly shorter local recurrence-free survival.

CONCLUSION

Platelet count before CRT should be a promising biomarker for predicting the efficacy of CRT and the risk of local recurrence in rectal cancer patients after CRT.

Neoadjuvant short- or long-term radio(chemo)therapy for rectal cancer: how and who should be treated?

There are two general approaches to preoperative radiotherapy (RT) in rectal cancer: short-course (25 Gy in 5 fractions) radiation with immediate surgery and long-course 5-fluorouracil (5-FU)-based chemoradiotherapy (CRT; 50.4 Gy in 28 fractions) with surgery scheduled 6-8 weeks thereafter. While it is clear that downsizing and downstaging effects are more pronounced with long-course CRT and delayed surgery, a Polish randomized trial and, more recently, an Australian phase III trial demonstrated no significant differences in long-term oncologic outcomes and late toxicity rates between either preoperative concept. Ongoing studies currently address short-course preoperative RT with a longer interval to surgery (Stockholm III trial), and short-course RT with sequential combination chemotherapy in patients with synchronous distant metastasis. With respect to the long-course CRT approach, newer-generation chemotherapeutics as well as molecularly targeted agents have been tested within phase I-III studies, both as induction/adjuvant chemotherapy as well as during concomitant CRT. Evidently, the monolithic approaches to either apply the same schedule of preoperative 5-FU-based CRT to all patients with TNM stage II/III rectal cancer or to give preoperative short-course RT for all patients with resectable rectal cancer irrespective of tumor stage and location need to be questioned. The inclusion of different multimodal treatments into the surgical oncological concept, adapted to tumor location, stage, and individual patient risk factors and preferences is upcoming. Clearly, future developments will aim at identifying and selecting patients for ideal treatment alternatives.

Radiosensitization by the histone deacetylase inhibitor vorinostat under hypoxia and with capecitabine in experimental colorectal carcinoma

Background

The histone deacetylase inhibitor vorinostat is a candidate radiosensitizer in locally advanced rectal cancer (LARC). Radiosensitivity is critically influenced by hypoxia; hence, it is important to evaluate the efficacy of potential radiosensitizers under variable tissue oxygenation. Since fluoropyrimidine-based chemoradiotherapy (CRT) is the only clinically validated regimen in LARC, efficacy in combination with this established regimen should be assessed in preclinical models before a candidate drug enters clinical trials.

Methods

Radiosensitization by vorinostat under hypoxia was studied in four colorectal carcinoma cell lines and in one colorectal carcinoma xenograft model by analysis of clonogenic survival and tumor growth delay, respectively. Radiosensitizing effects of vorinostat in combination with capecitabine were assessed by evaluation of tumor growth delay in two colorectal carcinoma xenografts models.

Results

Under hypoxia, radiosensitization by vorinostat was demonstrated in vitro in terms of decreased clonogenicity and in vivo as inhibition of tumor growth. Adding vorinostat to capecitabine-based CRT increased radiosensitivity of xenografts in terms of inhibited tumor growth.

Conclusions

Vorinostat sensitized colorectal carcinoma cells to radiation under hypoxia in vitro and in vivo and improved therapeutic efficacy in combination with capecitabine-based CRT in vivo. The results encourage implementation of vorinostat into CRT in LARC trials.

Rectal cancer: state of the art in 2012

PURPOSE OF REVIEW

To discuss the recent developments of multimodal treatment for patients with local advanced rectal cancer, including incorporation of new chemotherapeutic and targeted agents, and the optimal sequence and timing of treatment components.

RECENT FINDINGS

Five randomized trials have been completed to determine whether the addition of oxaliplatin to preoperative, fluorouracil-based chemoradiotherapy (CRT) offers an advantage compared to single-agent fluorouracil CRT. Early results from the ACCORD 12, STAR-01, and NSAPB R-04 trials did not confirm a significant improvement of early efficacy endpoints with the addition of oxaliplatin, whereas the German CAO/ARO/AIO-04 did. Most of the phase II trials incorporating cetuximab into CRT reported disappointingly low rates of pathologic complete response (pCR); the combination of CRT with VEGF inhibition showed encouraging pCR rates; however, it was associated with increased surgical complications. Novel clinical trials address the role of induction chemotherapy, of delayed, minimal or omitted surgery following CRT, or the omission of radiotherapy for selected patients.

SUMMARY

At this time, the use of oxaliplatin or targeted agents as component of multimodality treatment for rectal cancer outside of a clinical trial is not recommended. The inclusion of different treatment options, according to tumor stage, location, imaging features, and response, will render the multimodal treatment approach of rectal cancer more risk-adapted.

[Prognostic significance of changes of tumor epidermal growth factor receptor expression after neoadjuvant chemoradiation in patients with rectal adenocarcinoma]

PURPOSE

The aim of the present study was to examine the effect of neoadjuvant chemoradiation on tumor epidermal growth factor receptor (EGFR) expression in patients with locally advanced rectal adenocarcinoma.

PATIENTS AND METHODS

A total of 53 patients with rectal adenocarcinoma (clinical stages II and III) were studied. Neoadjuvant treatment consisted of 50.4 Gy/28 fractions external radiation with concomitant continuous 5-fluorouracil. Surgical resection was performed 4-6 weeks after the chemoradiation. EGFR expression in the pretreatment biopsies and in the resected specimens was assessed with immunohistochemistry.

RESULTS

Patients with an increase of EGFR expression during chemoradiation had significantly shorter disease-free survival (DFS; p = 0.003) and overall survival (OS; p = 0.005) compared to patients with either no change or decrease in EGFR expression. The 5-year DFS in patients with increased EGFR expression was only 29% compared to 61% in patients without an increase of EGFR expression. Similarly, the 5-year OS of the patients with increased EGFR expression was 29% compared to 66% in patients without an increase of EGFR expression. All recurrences in patients who had an increase of EGFR expression occurred within the first 2 years after the treatment. The increase in EGFR expression was the only significant predictor of DFS (p = 0.007) and OS (p = 0.04) using multivariate Cox regression analysis.

CONCLUSION

An increase of EGFR expression during chemoradiation may be associated with significantly shorter DFS and OS. The increase of EGFR could identify a population of patients in whom the effect of the treatment with anti-EGFR therapy should be studied.

The current state of targeted agents in rectal cancer

Targeted biologic agents have an established role in treating metastatic colorectal cancer (CRC), and the integration of targeted therapies into the treatment of CRC has resulted in significant improvements in outcomes. Rapidly growing insight into the molecular biology of CRC, as well as recent developments in gene sequencing and molecular diagnostics, has led to high expectations for the identification of molecular markers to be used in personalized treatment regimens. The mechanisms of action and toxicities of targeted therapies differ from those of traditional cytotoxic chemotherapy. Targeted therapy has raised new insight about the possibility of tailoring treatment to an individual's disease, the assessment of drug effectiveness and toxicity, and the economics of cancer care. This paper covers the last decade of clinical trials that have explored the toxicity and efficacy of targeted agents in locally advanced and metastatic CRC and how their role may benefit patients with rectal cancer. Future efforts should include prospective studies of these agents in biomarker-defined subpopulations, as well as studies of novel agents that target angiogenesis, tumor-stromal interaction, and the cell signaling pathways implicated in rectal cancer.

Simultaneous neoadjuvant radiochemotherapy with capecitabine and oxaliplatin for locally advanced rectal cancer. Treatment outcome outside clinical trials

BACKGROUND

Phase II trials of neoadjuvant treatment in UICC-TNM stage II and III rectal cancer with capecitabine and oxaliplatin demonstrated favourable rates on tumour regression with acceptable toxicity.

PATIENTS AND METHODS

Retrospective evaluation of 34 patients treated from 2005-2008 outside clinical trials (CTR) with neoadjuvant irradiation (45-50.4 Gy) and simultaneous capecitabine 825 mg/m(2) b.i.d. on days 1-14 and 22-35 and oxaliplatin 50 mg/m(2) on days 1, 8, 22 and 29 (CAPOX). Twenty-six (77%) patients received one or two courses of capecitabine 1,000 mg/m(2) b.i.d. on days 1-14 and oxaliplatin 130 mg/m(2) on day 1 (XELOX) prior to simultaneous chemoradiotherapy.

RESULTS

UICC-TNM stage regression was observed in 60% (n = 20). Dworak's regression grades 3 and 4 were achieved in 18.2% (n = 6) and 15.1% (n = 5) of the patients. Sphincter-preserving surgery was performed in 53% (n = 8) of patients with a tumour of the lower rectum. Within the mean observation of 24 months, none of the patients relapsed locally, 1 patient had progressive disease and 5 patients (15%) relapsed distantly. Toxicity of grade 3 and 4 was mainly diarrhoea 18% (n = 6) and perianal pain 9% (n = 3). Nevertheless, severe cardiac events (n = 2), severe electrolyte disturbances (n = 2), and syncopes (n = 2) were observed as well.

CONCLUSION

Treatment efficacy and common toxicity are similar to the reports of phase I/II trials. However, several severe adverse events were observed in our cohort study. The predisposing factors for these events have yet to be studied and may have implications for the selection of patients outside CTR.

Radiotherapy in elderly patients with inoperable esophageal cancer. Is there a benefit?

BACKGROUND

Radiation oncologists increasingly face elderly cancer patients impaired by comorbidities and reduced performance status. As less data are available for this particular group of patients, the aim of the study was to assess the prognosis of inoperable esophageal cancer patients ≥ 70 years undergoing definitive radiotherapy or radiochemotherapy. PATIENTS AND TREATMENT PROTOCOL: Patients aged ≥ 70 with inoperable carcinoma of the esophagus undergoing definitive radio(chemo)therapy between 1995 and 2006 at the University of Cologne were included retrospectively. Maximal total dose of radiotherapy administered was 63 Gy (5 × 1.8 Gy/week). Chemotherapy consisted of cisplatin (20 mg/m(2) on days 1-5 and days 29-33) and 5-fluorouracil (650-1,000 mg/m(2) on days 1-5 and days 29-33). Efficacy was compared with a cohort of 152 patients < 70 years treated with the same protocol during the same time period.

RESULTS

A total of 51 patients aged  ≥ 70 with inoperable cancer of the esophagus undergoing definitive therapy were identified (stage I/II 23.5%, stage III 56.9%, stage IV 9.8%; squamous cell carcinoma 74.5%, adenocarcinoma 25.5%). While 15 patients (29.4%) received combined radiochemotherapy (RCT), 40 patients (70.6%) were treated with radiotherapy alone (RT). Median progression-free survival (PFS) was 9.5 months; median overall survival (OS) was 13.9 months. Patients treated with RCT had a 2-year OS rate of 53.3% compared with 16.7% for RT patients (p = 0.039). The 2-year OS for clinically lymph node negative patients was 38.5% compared with 21.2% for lymph node positive patients (p = 0.072). Median OS was not significantly different between patients ≥ 70 years versus the patient cohort (n = 152) aged < 70 years (13.9 vs. 7.2 months, p = 0.072) but PFS showed a significant difference (4.9 vs. 9.5 months, p = 0.026) in favor of the > 70 years group.

CONCLUSION

Prognosis in elderly patients with inoperable esophageal cancer undergoing definitive radiotherapy/radiochemotherapy is limited, although it is not inferior to patients < 70 years.

Apoptotic proteins as prognostic markers and indicators of radiochemosensitivity in stage II/III rectal cancers

AIM

The expression of pro-apoptotic (Bax) and anti-apoptotic (mutated p53, Bcl-2, Bclxl) proteins was determined retrospectively using immunohistochemistry in pre-treatment biopsy samples from patients with rectal cancer treated with or without preoperative chemoradiation to investigate their role as prognostic markers and indicators of radiochemosensitivity.

METHOD

Biopsy samples from 67 patients operated for stage II/III rectal cancer and enrolled in an active follow-up programme were examined 8-10 years after surgery. Thirty-three had been treated with immediate surgery followed, in selected cases, by adjuvant postoperative chemoradiation. Thirty-four had preoperative chemoradiation. Immunohistochemical staining was carried out using an automated immunostainer on sections of paraffin-embedded tissue.

RESULTS

Independent prognostic factors for rectal cancer death were pN status (hazard ratio 3.82; 95% CI 1.67-8.73) and a high level of Bclxl positivity (hazard ratio 4.75; 95% CI 2.10-10.72) according to multivariate regression analysis by stepwise selection. Bax expression was associated with downstaging and higher survival in irradiated patients (P = 0.0004).

CONCLUSION

Pretreatment evaluation of apoptotic Bax and anti-apoptotic Bclxl factors in biopsy samples of stage II/III rectal cancers may be helpful in selecting tumours that will respond to chemoradiation or in identifying patients who will have limited benefit from chemoradiation and should therefore be selected for a more aggressive systemic regimen.

Expression of Transketolase like gene 1 (TKTL1) predicts disease-free survival in patients with locally advanced rectal cancer receiving neoadjuvant chemoradiotherapy

Background

For patients with locally advanced rectal cancer (LARC) neoadjuvant chemoradiotherapy is recommended as standard therapy. So far, no predictive or prognostic molecular factors for patients undergoing multimodal treatment are established. Increased angiogenesis and altered tumour metabolism as adaption to hypoxic conditions in cancers play an important role in tumour progression and metastasis. Enhanced expression of Vascular-endothelial-growth-factor-receptor (VEGF-R) and Transketolase-like-1 (TKTL1) are related to hypoxic conditions in tumours. In search for potential prognostic molecular markers we investigated the expression of VEGFR-1, VEGFR-2 and TKTL1 in patients with LARC treated with neoadjuvant chemoradiotherapy and cetuximab.

Methods

Tumour and corresponding normal tissue from pre-therapeutic biopsies of 33 patients (m: 23, f: 10; median age: 61 years) with LARC treated in phase-I and II trials with neoadjuvant chemoradiotherapy (cetuximab, irinotecan, capecitabine in combination with radiotherapy) were analysed by quantitative PCR.

Results

Significantly higher expression of VEGFR-1/2 was found in tumour tissue in pre-treatment biopsies as well as in resected specimen after neoadjuvant chemoradiotherapy compared to corresponding normal tissue. High TKTL1 expression significantly correlated with disease free survival. None of the markers had influence on early response parameters such as tumour regression grading. There was no correlation of gene expression between the investigated markers.

Conclusion

High TKTL-1 expression correlates with poor prognosis in terms of 3 year disease-free survival in patients with LARC treated with intensified neoadjuvant chemoradiotherapy and may therefore serve as a molecular prognostic marker which should be further evaluated in randomised clinical trials.

Circulating lymphocyte is an important determinant of the effectiveness of preoperative radiotherapy in advanced rectal cancer

Background

Although preoperative radiotherapy (RT) is widely used as the initial treatment for locally advanced rectal cancer (RC) in the neoadjuvant setting, factors determining clinical response have not been adequately defined. In order to find other factors possibly related with radiosensitivity, we evaluated the relationships between circulating blood cell counts and RT effects.

Methods

In 179 cases with advanced RC, we retrospectively examined hemoglobin (Hb) levels and counts of white blood cells (WBC), platelets and WBC subsets before and after RT and investigated their associations with the complete response (CR) rate together with other clinicopathological factors.

Results

The ratio of lymphocytes in WBC taken before RT was significantly greater in 15 CR cases as compared with those in non-CR cases. Patients with high lymphocyte percentages (25.7%) showed better outcome than the counterparts. Conversely, the ratio of neutrophiles was reduced in CR cases. The lymphocyte ratio showed an independent association with CR with multivariate analysis, and tended to be maintained at relatively high levels in CR cases.

Conclusions

In RC patients, peripheral blood lymphocytes have a significant impact on the CR rate in response to RT. Lymphocyte-mediated immune reactions are supposed to have positive roles on clinical response in radiotherapy for RC.

Novel Carcinoembryonic-Antigen-(CEA)-Specific Pretargeting System to Assess Tumor Cell Viability after Irradiation of Colorectal Cancer Cells

PURPOSE

To date, no valid imaging modality exists for early response prediction to neoadjuvant radiochemotherapy in carcinoembryonic-antigen-(CEA)-expressing rectal cancers (UICC stages II and III). It is hypothesized that the uptake of an anti-CEA antibody is directly related to the number of viable tumor cells and may be quantified by immuno-positron emission tomography (immuno-PET). Therefore, we evaluated a novel pretargeting system using TF2, a humanized bispecific trivalent monoclonal antibody (mAb), directed against CEA and the IMP-288-peptide, a hapten for binding radiometals for imaging. Uptake and kinetics of the pretargeting system were investigated in vitro prior to and after irradiation.

METHODS

TF2 was labeled with ¹³¹I and IMP-288 with ¹¹¹InCl₃. The colorectal cancer cell lines HT29, SW480, and T84 with known varying CEA expression were incubated (≤ 72 hours) with ¹³¹I-TF2 or the TF2-¹¹¹In-IMP-288 pretargeting system. Parallel cultures were irradiated with 2-10 Gy high-energy photons. Tracer uptake, proliferation, apoptosis, and CEA-RNA expression of cancer cells were investigated.

RESULTS

The uptake of tracers was dependent on CEA expression and cell count of the cell lines (uptake/10⁶ cells: 0.3% in HT29, 1.5% in SW480, and 14% in T84, p < 0.001). The TF2-¹¹¹In-IMP-288 pretargeting system showed a higher uptake after 4 and 72 hours compared to (131)I-TF2 in parallel cultures. Only in one cell line (SW480) an increased apoptosis after irradiation could be detected. Irradiation increased dose dependently both the specific uptake of ¹³¹I-TF2 and of the TF2-¹¹¹In-IMP-288 system (4-fold in HT29 and T84 after 10 Gy (72 hours), p < 0.001). These results were CEA-mRNA independent.

CONCLUSION

This novel pretargeting system allows the quantitative analysis of CEA-expressing colorectal cancer cells and represents a promising tool for evaluation of tumor cell viability after irradiation.

Preoperative oxaliplatin, capecitabine, and external beam radiotherapy in patients with newly diagnosed, primary operable, cT₃NxM0, low rectal cancer: a phase II study

PURPOSE

In patients with locally advanced rectal cancer (LARC), preoperative chemoradiation is known to improve local control, and down-staging of the tumor serves as a surrogate for survival. Intensification of the systemic therapy may lead to higher downstaging rates and, thus, enhance survival. This phase II study investigated the efficacy and safety of preoperative capecitabine and oxaliplatin in combination with radiotherapy.

PATIENTS AND METHODS

Patients with LARC of the mid and lower rectum, T₃NxM0 staged by MRI received radiotherapy (total dose 45 Gy) in combination with oral capecitabine (825 mg/m² twice a day on radiotherapy days; weeks 1-4) and oxaliplatin 50 mg/m² intravenously (days 1, 8, 15, and 22). Efficacy was evaluated as rate of tumor down-categorization at the T level.

RESULTS

A total of 59 patients were enrolled (19 women, 40 men; median age of 61 years) and all were evaluable for efficacy and toxicity. Down-categorization at the T level was observed in 53% with pathological complete response in 6 patients (10%). Actual total radiotherapy, oxaliplatin and capecitabine doses received were 97%, 90%, and 93% of the protocol-specified preplanned doses, respectively. Grade 3/4 toxicity was observed in 15 patients (25%). The most frequent was diarrhea (12%).

CONCLUSIONS

Preoperative chemoradiation with capecitabine and oxaliplatin is feasible in patients with MRI-proven cT₃ LARC. The only clinically relevant toxicity was diarrhea. Overall, efficacy of the multimodality treatment was good, but not markedly exceeding that of 5-FU- or capecitabine-based chemoradiation approaches.

Hyperfibrinogenemia after preoperative chemoradiotherapy predicts poor response and poor prognosis in rectal cancer

PURPOSE

Although hyperfibrinogenemia has been reported in patients with colorectal cancer, neither its clinical implications nor the effect of chemoradiotherapy (CRT) on the fibrinogen levels have been fully investigated. We investigated the clinical significance of pre- and post-CRT fibrinogen levels in patients with rectal cancer.

METHODS

The medical records of 82 patients with rectal cancer, who had received CRT followed by surgical resection, were retrospectively reviewed. The correlation between the clinicopathological variables and the pre- and post-CRT plasma fibrinogen levels, and that between the changes of fibrinogen, C-reactive protein (CRP), or carcinoembryonic antigen (CEA) levels after CRT and the pathological tumor regression grading was analyzed. Furthermore, the impact of post-CRT fibrinogen levels on the prognosis of these patients was assessed.

RESULTS

Plasma fibrinogen markedly decreased after CRT. The post-CRT fibrinogen level significantly correlated with lymphatic invasion, venous invasion, tumor size, depth of invasion, and the pathological tumor regression grading. The CRT-induced pathological tumor regression grading well correlated with the decrease of fibrinogen level, but not with that of CRP or CEA. Furthermore, patients with high post-CRT fibrinogen had significantly shorter disease-free survival.

CONCLUSIONS

Reduction of plasma fibrinogen induced by CRT should be a promising biomarker for evaluating the efficacy of CRT in rectal cancer patients.

Comparison of the micronucleus and chromosome aberration techniques for the documentation of cytogenetic damage in radiochemotherapy-treated patients with rectal cancer

PURPOSE

The goal of the interdisciplinary Clinical Research Unit KFO179 (Biological Basis of Individual Tumor Response in Patients with Rectal Cancer) is to develop an individual Response and Toxicity Score for patients with locally advanced rectal cancer treated with neoadjuvant radiochemotherapy. The aim of the present study was to find a reliable and sensitive method with easy scoring criteria and high numbers of cell counts in a short period of time in order to analyze DNA damage in peripheral blood lymphocytes. Thus, the cytokinesis-block micronucleus (CBMN) assay and the chromosome aberration technique (CAT) were tested.

MATERIALS AND METHODS

Peripheral blood lymphocytes obtained from 22 patients with rectal cancer before (0 Gy), during (21.6 Gy), and after (50.4 Gy) radiochemotherapy were stimulated in vitro by phytohemagglutinin (PHA); the cultures were then processed for the CBMN assay and the CAT to compare the two methods.

RESULTS

A significant increase of chromosomal damage was observed in the course of radiochemotherapy parallel to increasing radiation doses, but independent of the chemotherapy applied. The equivalence of both methods was shown by Westlake's equivalence test.

CONCLUSION

The results show that the CBMN assay and the CAT are equivalent. For further investigations, we prefer the CBMN assay, because it is simpler through easy scoring criteria, allows high numbers of cell counts in less time, is reliable, sensitive, and has higher statistical power. In the future, we plan to integrate cytogenetic damage during radiochemotherapy into the planned Response and Toxicity Score within our interdisciplinary Clinical Research Unit.

Celecoxib enhances radiation response of secondary bone tumors of a human non-small cell lung cancer via antiangiogenesis in vivo

PURPOSE

Cyclooxygenase-2 (COX-2) inhibitors mediate a systemic antitumor activity via antiangiogenesis and seem to enhance the response of primary tumors to radiation. Radiosensitizing effects of COX-2 inhibition have not been reported for bone metastases. Therefore, the aim of this study was the investigation of the radiosensitizing effects of the selective COX-2 inhibitor celecoxib in secondary bone tumors of a non-small cell lung carcinoma in vivo.

MATERIALS AND METHODS

Human A549 lung carcinomas were implanted into a cranial window preparation in male SCID mice (n = 24). Animals were treated with either celecoxib or radiation (7 Gy single photon dose) alone or a combination of celecoxib and radiation, respectively. Untreated animals served as controls. The impact of radiation and COX-2 inhibition on angiogenesis, microcirculation, and tumor growth was analyzed over 28 days by means of intravital microscopy and histological methods.

RESULTS

Monotherapies with radiation as well as celecoxib had significant antitumor effects compared to untreated controls. Both therapies reduced tumor growth and vascularization to a similar extent. The simultaneous administration of celecoxib and radiation further enhanced the antitumor and antiangiogenic effects of single-beam radiation. With the combined treatment approach, tumor vascularization and tumor size were decreased by 57% and 51%, respectively, as compared to monotherapy with radiation.

CONCLUSION

The combined application of radiation therapy and COX-2 inhibition showed synergistic effects concerning the inhibition of tumor growth and tumor angiogenesis. Therefore, the combination of radiation with COX-2 inhibitor therapy represents a promising approach to improve the therapeutic efficacy of radiotherapy of bone metastases.

Sorafenib and radiation: a promising combination in colorectal cancer

PURPOSE

To examine the combination of radiation and the multikinase inhibitor sorafenib in human colorectal cancer cell lines and xenografts.

METHODS AND MATERIALS

HT29 and SW48 colorectal cancer cells were studied in vitro using MTT assays to establish the optimal timing of radiation and sorafenib. This optimal timing was then investigated in clonogenic survival assays. Xenografts were established, and the effect of a 3-week schedule of daily radiation and sorafenib was studied by growth delay.

RESULTS

Sorafenib predominantly had minimal effects on cell growth or radiation response in MTT growth assays, though growth inhibition was significantly enhanced in HT29 cells when sorafenib was administered after radiation. The highest dose of sorafenib altered the alpha component of the cell survival curve in clonogenic assays. The combination of radiation and sorafenib was synergistic in SW48 xenografts, with a mean time to threshold tumor size of 11.4 +/- 1.0 days, 37.0 +/- 9.5 days, 15.5 +/- 3.2 days, and 98.0 +/- 11.7 days in the control, radiation, sorafenib, and combined treatment group, respectively. The effect on HT29 tumors was additive, with mean time to threshold volume of 12.6 +/- 1.1 days, 61.0 +/- 4.3 days, 42.6 +/- 11.7 days, and 100.2 +/- 12.4 days.

CONCLUSIONS

Sorafenib had little effect on radiation response in vitro but was highly effective when combined with radiation in vivo, suggesting that inhibition of proliferation and interference with angiogenesis may be the basis for the interaction.

Assay-based response evaluation in head and neck oncology: requirements for better decision making

This article gives an overview on different current strategies of assay-based response evaluation in head and neck squamous cell carcinomas (HNSCC) and critically summarizes their role and needs for future clinical evaluation. Due to a growing amount of data of phase III clinical trials of multimodality treatment options for HNSCC, treatment planning in regard to optimal outcome is becoming an interdisciplinary challenge. New concepts such as induction chemotherapy with bi- or ternary combinations of chemotherapeutics, integration of targeted therapies, concurrent and sequential chemoradiation concepts, and multimodality-based organ preservation strategies strongly compete with traditional definitive surgical procedures. Moreover, the outcome is difficult to predict due to heterogeneity of a tumor's response, impaired late functional outcome, and increased late toxicity if simultaneously applied to radiation. Retrospectively looking at non-responders with tumors classified as resectable, primary surgery is very likely to have achieved better results, since chemoradiation causes a high degree of early and late toxicities leading to extremely complicated terms and conditions in surgery following current multimodal therapeutic strategies. Unfortunately, predictive information on response characteristics of a given tumor before starting the therapy is not available in daily routine, although heterogeneity in response of a given tumor entity to treatments has been known for decades. Therefore, current therapy strategies for HNSCC still have to ignore this fact, creating an urgent need for the development of proper predictive assays. There are interesting clinical observations showing that response on induction chemotherapy may predict the outcome after radiotherapy. Some trials use this empiric phenomenon to pre-select non-responders for primary surgical treatment avoiding severe salvage complications after failure of complete chemoradiation treatment. Moving one step further, recent literature and our own investigations implicate that response evaluation of the individual patient's HNSCC in a suitable ex vivo assay just before starting the treatment is mature for clinical research. To this end, essential needs and hints are addressed and discussed.

Nuclear EGFR as novel therapeutic target: insights into nuclear translocation and function

Emerging evidence suggests the existence of a new mode of epidermal growth factor receptor (EGFR) signaling in which activated EGFR undergoes nuclear translocation following treatment with ionizing radiation. The authors provide evidence that the nuclear EGFR transport is a stress-specific cellular reaction, which is linked to src-dependent EGFR internalization into caveolae. These flask-shaped pits can fuse with endoplasmic reticulum and the EGFR is sorted into a perinuclear localization. This compartment may serve as a reservoir for nuclear EGFR transport which is regulated by PKCepsilon (protein kinase Cepsilon). Nuclear EGFR is able to induce transcription of genes essential for cell proliferation and cell-cycle regulation. Moreover, nuclear EGFR has physical contact with compounds of the DNA repair machinery and is involved in removal of DNA damage. Anti-EGFR strategies target radiation-associated EGFR nuclear translocation in different manners. EGFR-inhibitory antibodies, i.e., cetuximab (Erbitux((R))), can block nuclear translocation by EGFR immobilization within the cytosol in responder cell lines, whereas tyrosine kinase inhibitors rather target nuclear kinase activity of EGFR linked with cytosolic or nuclear functions. However, both strategies can inhibit DNA repair following irradiation.

Small interfering RNA targeting decoy receptor 3 sensitizes colon cancer cells (SW480) to radiation treatment

AIM: To investigate whether small interfering RNA (siRNA) targeting decoy receptor 3 (DcR3) can sensitize colon cancer cells (SW480) to radiation treatment and analyze the significance of DcR3 expression in the prediction of radiation resistance in colon cancer before radiotherapy.

METHODS: After SW480 cells were irradiated with different doses of ¹³⁷Cs gamma rays for different durations, the expression levels of DcR3 were determined by enzyme-linked immunosorbent assay (ELISA). An expression vector expressing siRNA targeting DcR3 was then constructed. After the expression vector was transfected into irradiated and unirradiated SW480 cells, the colony formation ability of these cells was determined by colony formation assay, and cell apoptosis was analyzed by flow cytometry.

RESULTS: Compared with unirradiated SW480 cells, the expression level of DcR3 increased in SW480 cells irradiated with different doses of ¹³⁷Cs gamma rays for different durations, especially remarkable in cells irradiated with 10 Gy ¹³⁷Cs gamma rays (P < 0.05). Compared with irradiated untransfected SW480 cells and unirradiated transfected SW480 cells, the colony formation was enhanced, the M1 peak in cell cycle was elevated and the number of apoptotic bodies increased in irradiated transfected SW480 cells.

CONCLUSION: siRNA targeting DcR3 can sensitize colon cancer cells (SW480) to radiation treatment. High DcR3 expression may predict the development of radiation resistance in colon cancer.