Phase I trial of neoadjuvant chemoradiotherapy (CRT) with capecitabine and weekly irinotecan followed by laparoscopic total mesorectal excision (LTME) in rectal cancer patients. Invest New Drugs. 2009;27:262-268. [PMID: 18923810 DOI: 10.1007/s10637-008-9192-6]

Acute small-bowel toxicity during neoadjuvant combined radiochemotherapy in locally advanced rectal cancer: determination of optimal dose-volume cut-off value predicting grade 2-3 diarrhoea

Background

Current therapeutic standard for locally advanced rectal cancer is the neoadjuvant radiochemotherapy with total mesorectal excision. Diarrhoea is the main acute side effect, induced by the dose to the small-bowel, frequently leading to a treatment modification. Aim of this study was to analyse the differences between the irradiated small-bowel volumes and the occurrence of acute diarrhea during combined radiochemotherapy for rectal cancer.

Methods

45 patients treated with a neoadjuvant radiochemotherapy (three-field box 50.4 Gy; Cetuximab, Capecitabine, Irinotecan) for locally advanced rectal cancer within a prospective phase I/II study were evaluated. Based on the dose-volume histograms, the small-bowel volumes receiving doses of 5, 10 … 45 Gy (V5, V10 …V45) were calculated and compared with the prospectively documented small- bowel toxicities.

Results

There was a statistically significant difference between irradiated small-bowel volumes and the severity of therapy related diarrhoea. The strongest validity concerning the risk of developing a grade 2–3 diarrhoea was seen at a dose level of 5 Gy (V 5) with a small-bowel volume of 291.94 cc. Patients with V 5 > 291.94 cc had significantly more often grade 2–3 diarrhoea, than patients with V5 below this cut-off value (82% vs. 29%; p < 0.0001).

Conclusions

In the inverse treatment planning of rectal caner patients the small-bowel volume receiving 5 Gy should be limited to about 300 cc.

Adjuvant therapy sparing in rectal cancer achieving complete response after chemoradiation

AIM: To evaluate the long-term results of conventional chemoradiotherapy and laparoscopic mesorectal excision in rectal adenocarcinoma patients without adjuvant therapy.

METHODS: Patients with biopsy-proven adenocarcinoma of the rectum staged cT3-T4 by endoscopic ultrasound or magnetic resonance imaging received neoadjuvant continuous infusion of 5-fluorouracil for five weeks and concomitant radiotherapy. Laparoscopic surgery was planned after 5-8 wk. Patients diagnosed with ypT0N0 stage cancer were not treated with adjuvant therapy according to the protocol. Patients with ypT1-2N0 or ypT3-4 or N+ were offered 5-fluorouracil-based adjuvant treatment on an individual basis. An external cohort was used as a reference for the findings.

RESULTS: One hundred and seventy six patients were treated with induction chemoradiotherapy and 170 underwent total mesorectal excision. Cancer staging of ypT0N0 was achieved in 26/170 (15.3%) patients. After a median follow-up of 58.3 mo, patients with ypT0N0 had five-year disease-free and overall survival rates of 96% (95%CI: 77-99) and 100%, respectively. We provide evidence about the natural history of patients with localized rectal cancer achieving a complete response after preoperative chemoradiation. The inherent good prognosis of these patients will have implications for clinical trial design and care of patients.

CONCLUSION: Withholding adjuvant chemotherapy after complete response following standard neoadjuvant chemoradiotherapy and laparoscopic mesorectal excision might be safe within an experienced multidisciplinary team.

The role of capecitabine in locally advanced rectal cancer treatment: an update

Preoperative infusional 5-fluorouracil (5-FU) and concurrent radiation therapy (RT) followed by total mesorectal surgery is the current standard of care for locally advanced rectal cancer (LAR). When compared with postoperative 5-FU-based chemoradiation, this strategy is associated with significantly lower rates of local relapse, lower toxicity and better compliance. Capecitabine is a rationally designed oral prodrug that is converted into 5-FU by intracellular thymidine phosphorylase. Substitution of infusional 5-FU with capecitabine is an attractive option that provides a more convenient administration schedule and, possibly, increased efficacy. Indeed, incorporation of capecitabine in combined modality neoadjuvant therapy for LAR has been under intense investigation during the last 10 years. Phase I and II clinical trials showed that a regimen consisting of capecitabine 825mg/m(2) twice daily for 7 days/week continuous oral administration in combination with RT is an active and well tolerated regimen, thereby being the preferred concurrent regimen. The definitive demonstration that efficacy of capecitabine/RT is similar to 5-FU/RT has been provided by the NSABP-R-04 and the German Margit trials. One approach to improve outcomes in rectal cancer is to deliver a second RT-sensitizing drug with effective systemic activity. Oxaliplatin and irinotecan are therefore good candidates. However, two phase III trials demonstrated that incorporation of oxaliplatin to capecitabine with RT did not improve early outcomes and, by contrast, increased toxicity. Capecitabine has also been combined with irinotecan. This regimen showed encouraging results in phase I and II clinical trials, which led to an ongoing phase III clinical trial. New strategies with induction chemotherapy with or without chemoradiation prior to surgery are currently under investigation. Whether or not capecitabine has a role in this setting is being investigated in ongoing trials. Incorporation of agents directed towards new targets, such as anti-epidermal growth factor receptor (EGFR) antibodies or antiangiogenic agents, in combination preoperative regimens, is being hampered by results of early trials in which efficacy outcomes with cetuximab were poor and an excessive rate of surgical complications with bevacizumab was observed. The lack of improvements in efficacy with the addition of cetuximab or bevacizumab in the adjuvant treatment of colon cancer led to concerns about further development of these agents in rectal cancer. The role of capecitabine in the postoperative adjuvant setting is the aim of the ongoing Dutch SCRIPT trial. The prediction of response associated with capecitabine has been based on expression of thymidylate synthase and dihydropyrimidine dehydrogenase, as well as on gene expression arrays. All these procedures require further validation and should be considered as investigational. In conclusion, capecitabine can safely and effectively replace intravenous continuous infusion of 5-FU in the preoperative chemoradiation setting for rectal cancer management. The addition of other new antineoplastic agents to a fluoropyrimidine-based regimen remains investigational.

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.

Preoperative chemoradiation with irinotecan and capecitabine in patients with locally advanced resectable rectal cancer: long-term results of a Phase II study

PURPOSE

Preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer has shown benefit over postoperative CRT; however, a standard CRT regimen has yet to be defined. We performed a prospective concurrent CRT Phase II study with irinotecan and capecitabine in patients with locally advanced rectal cancer to investigate the efficacy and safety of this regimen.

METHODS AND MATERIALS

Patients with locally advanced, nonmetastatic, and mid-to-lower rectal cancer were enrolled. Radiotherapy was delivered in 1.8-Gy daily fractions for a total of 45 Gy in 25 fractions, followed by a coned-down boost of 5.4 Gy in 3 fractions. Concurrent chemotherapy consisted of 40 mg/m(2) of irinotecan per week for 5 consecutive weeks and 1,650 mg/m(2) of capecitabine per day for 5 days per week (weekdays only) from the first day of radiotherapy. Total mesorectal excision was performed within 6 ± 2 weeks. The pathologic responses and survival outcomes were included for the study endpoints.

RESULTS

In total, 48 patients were enrolled; 33 (68.7%) were men and 15 (31.3%) were women, and the median age was 59 years (range, 32-72 years). The pathologic complete response rate was 25.0% (11 of 44; 95% confidence interval, 12.2-37.8) and 8 patients (18.2% [8 of 44]) showed near-total tumor regression. The 5-year disease-free and overall survival rates were 75.0% and 93.6%, respectively. Grade 3 toxicities included leukopenia (3 [6.3%]), neutropenia (1 [2.1%]), infection (1 [2.1%]), alanine aminotransferase elevation (1 [2.1%]), and diarrhea (1 [2.1%]). There was no Grade 4 toxicity or treatment-related death.

CONCLUSIONS

Preoperative CRT with irinotecan and capecitabine with treatment-free weekends showed very mild toxicity profiles and promising results in terms of survival.

Pharmacogenetic analysis in neoadjuvant chemoradiation for rectal cancer: high incidence of somatic mutations and their relation with response

Aims: The identification of predictive markers of response to chemoradiotherapy treatment remains a promising approach for patient management in order to obtain the best response with minor side effects. Initially, we investigated whether the analysis of several markers previously studied and others not yet evaluated could predict response to 5-fluorouracil- and capecitabine-based neoadjuvant treatment in locally advanced rectal cancer. Methods & materials: We studied germline and tumoral samples of 65 stage II/III rectal patients. A panel of pharmacogenetic markers was genotyped in paired peripheral blood samples and rectal cancer tumors. Results: Our results seem to confirm the previously described association of thymidylate synthase and the prediction of chemoradiotherapy response in rectal cancer. However, it failed to confirm the clinical utility proposed for XRCC1, ERCC1, ERCC2, MTHFR and EGFR polymorphisms in blood/germline samples. Subsequently, with the aim of improving prediction of individual response and assessing the role of studied polymorphisms in response to treatment, we determined if changes in tumor response to these markers could predict clinical outcome. We found a high degree of changes between germline and tumor samples, mainly somatic mutations without microsatellite instability, and a minor frequency of loss-of-heterozygosity events. In tumoral samples, XRCC1 appeared to be significantly associated (p = 0.006) with downstaging of the tumor (odds ratio: 7.93; 95% CI: 1.03–60.83), but the increasing of TYMS low-expression alleles contradict the previous results observed in germline samples. Conclusion: The detection of somatic mutations in rectal cancer tumors led us to re-evaluate the utility of the tests performed in blood samples for these polymorphisms in rectal cancer. Furthermore, studies aimed at assessing the influence of pharmacogenetic markers in treatment response performed in blood samples should take into account the particular pattern of hypermutability present in each tumor type. We hypothesize that different patterns of hypermutability present in each tumor type would be related to the different results in association studies related to response to the treatment.