Chemoradiation with novel agents for rectal cancer

Radiotherapy and Oral Capecitabine in the Preoperative Treatment of Patients with Rectal Cancer: Rationale, Preliminary Results and Perspectives

Preoperative radiotherapy alone or combined with chemotherapy increases the chances of tumor downstaging and down-sizing and facilitates sphincter-sparing surgical procedures, thereby improving survival and quality of life. Though several innovative agents are being investigated in combination with radiotherapy, 5-fluorouracil in continuous infusion remains the common schedule used in the preoperative chemoradiation setting. However, the protracted venous infusion of 5-fluorouracil requires specialized pumps and long-term venous access, which makes patients susceptible to infections or thrombosis. To overcome the 5-fluorouracil infusion-related problems, oral 5-fluorouracil precursors and inhibitors of 5-fluorouracil degradation have been developed and explored. These include oral fluoropyrimidines such as tegafur (ftora-fur), uracil plus tegafur (UFT), S-1, eniluracil and the oral carbamate capecitabine. Phase I trials have demonstrated the feasibility of the capecitabine-radiotherapy combination with respect to the bolus or infusion 5-fluorouracil-radiation approach and have defined the optimal dose of capecitabine during radiotherapy (825 mg/m2/day through a bid administration). Severe hand-foot syndrome occurred in 7-15% of patients, representing the most commonly observed toxicity. It is noteworthy that severe diarrhea with capecitabine during radiotherapy was not common. Leukopenia frequently occurred but was mild and reversible. Phase II trials, although limited in number, have evidenced a high probability of pathological complete response (up to 31%) with capecitabine and radiation, with an increased probability of sphincter-sparing surgical procedures. Although it is too early to assess whether oral capecitabine will be able to replace iv 5-fluorouracil in combination with preoperative radiotherapy, the NSABP will address this question in a large randomized trial. Finally, phase I-II trials evaluating escalating doses of capecitabine associated with oxaliplatin or irinotecan with radiotherapy are being carried out to assess the maximum-dose tolerance and efficacy in the preoperative setting. It is likely that these new chemoradiation associations might increase rectal cancer clearance, hopefully without increasing toxicity.

Genetic polymorphisms in 5-Fluorouracil-related enzymes predict pathologic response after neoadjuvant chemoradiation for rectal cancer

BACKGROUND

Many patients with rectal cancer undergo preoperative neoadjuvant chemoradiation, with approximately 70% exhibiting pathologic downstaging in response to treatment. Currently, there is no accurate test to predict patients who are likely to be complete responders to therapy. 5-Fluorouracil is used regularly in the neoadjuvant treatment of rectal cancer. Genetic polymorphisms affect the activity of thymidylate synthase, an enzyme involved in 5-Fluorouracil metabolism, which may account for observed differences in response to neoadjuvant treatment between patients. Detection of genetic polymorphisms might identify patients who are likely to have a complete response to neoadjuvant therapy and perhaps allow them to avoid operation.

METHODS

DNA was isolated from whole blood taken from patients with newly diagnosed rectal cancer who received neoadjuvant therapy (n = 50). Response to therapy was calculated with a tumor regression score based on histology from the time of operation. Polymerase chain reaction was performed targeting the promoter region of thymidylate synthase. Polymerase chain reaction products were separated using electrophoresis to determine whether patients were homozygous for a double-tandem repeat (2R), a triple-tandem repeat (3R), or were heterozygous (2R/3R). A single nucleotide polymorphism, 3G or 3C, also may be present in the second repeat unit of the triple-tandem repeat allele. Restriction fragment length polymorphism assays were performed in patients with at least one 3R allele using HaeIII.

RESULTS

Patients with at least 1 thymidylate synthase 3G allele were more likely to have a complete or partial pathologic response to 5-Fluorouracil neoadjuvant therapy (odds ratio 10.4; 95% confidence interval, 1.3-81.6; P = .01) than those without at least one 3G allele.

CONCLUSION

Identification of rectal cancer patients with specific genetic polymorphisms in enzymes involved in 5-Fluorouracil metabolism seems to predict the likelihood of complete or partial pathologic response to preoperative neoadjuvant therapy.

Neoadjuvant continuous infusion of weekly 5-fluorouracil and escalating doses of oxaliplatin plus concurrent radiation in locally advanced oesophageal squamous cell carcinoma: results of a phase I/II trial

Oxaliplatin and 5-fluorouracil have a significant activity in locally advanced oesophageal squamous cell cancer (OSCC). However, their optimal dosage and efficacy when combined with concurrent radiotherapy as neoadjuvant treatment are unknown. This non-randomised, phase I/II study aimed to define the maximum tolerated dose (MTD) and assessed the histopathological tumour response rate to neoadjuvant oxaliplatin in weekly escalating doses (40, 45, 50 mg m⁻²) and continuous infusional 5-fluorouracil (CI-5FU; 225 mg m⁻²) plus concurrent radiotherapy. Patients had resectable OSCC. Resection was scheduled for 4–6 weeks after chemoradiotherapy. During phase I (dose escalation; n=19), weekly oxaliplatin 45 mg m⁻² plus CI-5FU 225 mg m⁻² was established as the MTD and was the recommended dosage for phase II. Oesophageal mucositis was the dose-limiting toxicity at higher doses. During phase II, histopathological responses (<10% residual tumour cells within the specimen) were observed in 10 of 16 patients (63%; 95% confidence interval: 39–82%). Overall, 16 of the 25 patients (64%) who underwent resection had a histopathological response; tumour-free resection (R0) was achieved in 80%. Neoadjuvant weekly oxaliplatin 45 mg m⁻² plus CI-5FU 225 mg m⁻² with concurrent radiotherapy provides promising histological response rates and R0 resection rates in locally advanced OSCC.

Tegafur and 5-fluorouracil pelvic tissue concentrations in rectal cancer patients receiving preoperative chemoradiation

BACKGROUND AND PURPOSE

To investigate the presence of 5-Fluorouracil (5-FU) in pelvic tissue after oral administration of tegafur. To measure tegafur and 5-FU concentrations in normal rectal mucosa, perirectal fat and residual tumor in rectal cancer patients receiving preoperative chemoradiation. To correlate drug concentrations with cancer downstaging effects.

PATIENTS AND METHODS

Three tissue samples taken from 16 surgical specimens after recto-sigmoid resection were analyzed. Tegafur and 5-FU concentrations were measured using high-performance liquid chromatography. 16 patients with locally advanced rectal cancer were treated with preoperative pelvic irradiation (45-50 Gy) sensitized with oral tegafur (400 mg for every 8 hours daily). Seven patients received a precharge dose of tegafur (400 mg oral every 8 hours) 24 hours before surgery.

RESULTS

In 8 of the 9 patients who did not receive a precharge dose, detectable levels of tegafur were observed in fat tissue, normal mucosa and tumor, but detectable 5-FU levels were only observed in one patient. Mean concentrations (ranges) for tegafur in fat, normal mucosa and tumor in patients without the precharge dose were 72.19 (12.1-205.6), 179.53 (11.30-727.7) and 252.35 (27.9-874.6) ng/g, respectively; mean concentrations for 5-FU in the same samples were 0.95, 1.92 and 2.68 ng/g (1 patient), respectively. In patients receiving a tegafur precharge, both tegafur and 5-FU were present in all tissue samples with the exception of 2 fat samples, in which drug concentrations were undetectable. 5-FU levels were higher in tumor than other sites, with a median value of 68.24 ng/g (range 3.8-283.05 ng/g). Tegafur levels were also higher in tumor samples than other sites (mean 3446.53 ng/g, range 1044.5-7847.0 ng/g), except in 2 patients who had higher levels of tegafur in normal mucosa.

CONCLUSIONS

Tegafur and 5-FU are not always present in pelvic tissues 5 to 6 weeks after oral administration of tegafur. Both drugs were present in the tissues analyzed, in relevant concentrations, 24 hours after oral administration of tegafur. The data obtained suggest a tendency (not significant) toward a correlation between levels of 5-FU present in the residual tumor and cancer downstaging.

Phase III Study Comparing Standard Radiotherapy With or Without Weekly Oxaliplatin in Treatment of Locoregionally Advanced Nasopharyngeal Carcinoma: Preliminary Results

Purpose

A prospective, randomized, phase III study was performed to evaluate the feasibility and efficacy of concurrent weekly oxaliplatin with radiotherapy in patients with locoregionally advanced nasopharyngeal carcinoma (NPC).

Patients and Methods

From January 2001 to January 2003, 115 patients with locoregionally advanced NPC were randomly assigned to either radiotherapy (RT) alone (56 patients) or concurrent chemoradiotherapy (CCRT; 59 patients). All patient characteristics were well balanced in both arms. CCRT with oxaliplatin 70 mg/m2 weekly was administered for six doses from the first day of RT.

Results

All patients were eligible for toxicity and response analysis. Compliance with the protocol treatment was excellent, with 97% of patients completing all planned doses of oxaliplatin, and a lack of high-grade toxicity was observed. After a median follow-up time of 24 months, there was a significant difference in overall survival (OS), relapse-free survival (RFS), and metastasis-free survival (MFS) in favor of the CCRT arm. The 2-year OS rates were 100% for the CCRT arm and 77% for the RT arm (P = .01). The 2-year MFS rates were 92% for the CCRT arm and 80% for the RT arm (P = .02). The 2-year RFS rates were 96% for the CCRT arm and 83% for the RT arm (P = .02).

Conclusion

CCRT with weekly oxaliplatin is feasible and improves OS, MFS, and RFS rates in patients with locoregionally advanced NPC. Therefore, further randomized trials including oxaliplatin are warranted.

Neoadjuvant treatment for locally advanced rectal carcinoma

Rectal cancer is one of the most common neoplasms of Western Countries. Overall mortality at 5 years is about 40%. This cancer is commonly diagnosed at a precocious stage, but because of local relapse and/or metastatic disease, only half of radically resected patients can be considered disease free. The value of adding radiotherapy to surgery in the treatment of patients with resectable rectal cancer has been assessed in trials using either preoperative or postoperative irradiation. Preoperative irradiation is more "dose-effective" than postoperative radiotherapy; that is, a higher dose is needed postoperatively to reduce rates of local recurrence to the same extent as preoperative radiation. Nevertheless, preoperative treatment has not been routinely recommended, mainly because it has not been shown to improve overall survival and because in some trials it has been associated with increased postoperative mortality. This paper critically reviews clinical trials of chemoradiotherapy on whether an optimal combination exists for locally advanced rectal cancer. Even if in the latest years, recent advances in surgery have improved the local control of disease, the next steps in rectal cancer care should aim at the improvement of local cure rates and the enhancement of systemic control. New approaches to CT treatment are necessary. Patient enrollment into rigorous and well-conducted clinical trials will generate new information regarding investigational therapies and it will offer improved therapies for patients with this disease.

Chemoradiation with raltitrexed and oxaliplatin in preoperative treatment of stage II-III resectable rectal cancer: Phase I and II studies

PURPOSE

Two separate studies were conducted, the first to evaluate the maximal tolerated dose and the second the efficacy of raltitrexed plus oxaliplatin in conjunction with preoperative chemoradiation in patients with resectable T3 rectal carcinoma.

METHODS AND MATERIALS

A total of 48 patients received radiotherapy (50 Gy) administered to the posterior pelvis 5 d/wk for 5 weeks. Combination raltitrexed (3 mg/m(2)) and oxaliplatin (60 to 130 mg/m(2)) was administered on Days 1, 19, and 38.

RESULTS

The recommended dose of oxaliplatin is 130 mg/m(2) (maximal tolerated dose not reached). No patients developed Grade 4 acute toxicity. Grade 3 acute toxicity occurred in 9 patients (18.7%). It was hematologic in 1 patient and GI in 1 patient; 7 patients had an asymptomatic increase of transaminase. Surgery was performed in 47 (98%) of 48 patients. Of the 47 patients, 42 underwent sphincter-saving surgery; in 19, the tumor at diagnosis was located <30 mm from the anorectal ring. Chemoradiation in combination with raltitrexed and oxaliplatin produced high rates of tumor response. The overall tumor downstaging rate was 73% for T and N stages. A complete pathologic tumor response (pT0) or microscopic tumor foci (pTmic) was observed in 28 patients. The tumor regression grade (TRG), using the Mandard scoring system, was TRG1 in 16 patients (43.2%), TRG2 in 12 (32.4%), TRG3 in 12 (32.4%), TRG4 in 6 (16.2%), and TRG5 in 1 patient (2.7%).

CONCLUSION

Raltitrexed plus oxaliplatin combined with pelvic radiotherapy was effective and well tolerated in patients with resectable T3 rectal carcinoma.

18F-FDG positron emission tomography staging and restaging in rectal cancer treated with preoperative chemoradiation

PURPOSE

To assess the information supplied by FDG-PET in patients with locally advanced rectal cancer both in the initial staging and in the evaluation of tumor changes induced by preoperative chemoradiation (restaging).

METHODS AND MATERIALS

Twenty-five consecutive patients with rectal cancer were included, with tumor stages (c)T(2-4)N(x)M(0), during the period 1997-1999. We prospectively performed two FDG-PET scans in all patients to assess disease stage (1) at initial diagnosis and (2) presurgically, 4 to 5 weeks after protracted chemoradiation. Protracted chemoradiation was carried out during 5-6 weeks with 45-50 Gy, plus concurrent oral tegafur 1200 mg/day or 5-fluorouracil 500-1000 mg/m(2) administered as a 24-h continuous i.v. infusion on Days 1-4 and 21-25 of the radiotherapy treatment. Tumors were staged with CT in 95% of patients, whereas endorectal ultrasound was used in 90% of patients. Maximum standardized uptake value (SUVmax) was used as the quantitative parameter to estimate the tumor:tissue metabolic ratio.

RESULTS

Preoperative chemoradiation significantly decreased the SUVMAX: 5.9 (mean SUVmax at initial staging) vs. 2.4 (mean SUVmax after chemoradiation) with p < 0.001. Unknown liver metastases were detected by FDG-PET in 2 patients, in 1 of them with the initial staging FDG-PET scan, and with the restaging FDG-PET scan in the other. After an average follow-up of 39 months, the value of SUVmax > or =6 allowed us to discriminate for survival at 3 years: 92% vs. 60% (p = 0.04). T downstaging (total 62%) was significantly correlated with SUVmax changes: 1.9 vs. 3.3 (p = 0.03). The degree of rectal cancer response to chemoradiation, established as mic vs. mac categories, was not associated with SUVmax differences (mean values of 2.0 vs. 2.7).

CONCLUSION

Preliminary results observed suggest the potential utility of FDG-PET as a complementary diagnostic procedure in the initial clinical evaluation (8% of unsuspected liver metastases) as well as in the assessment of chemoradiation response (any T downstaged event) of locally advanced rectal cancer. Initial SUVmax might be of prognostic value related to long-term patient outcome.

Histone deacetylase inhibitors FK228,N-(2-aminophenyl)-4-[N-(pyridin-3-yl-methoxycarbonyl)amino- methyl]benzamide andm-carboxycinnamic acid bis-hydroxamide augment radiation-induced cell death in gastrointestinal adenocarcinoma cells

HDAC inhibitors induce histone hyperacetylation by a relative increase of histone acetyltransferase activity. Histone hyperacetylation may affect chromatin structure and susceptibility to DNA-damaging stress, such as IR. We here investigate whether these inhibitors can radiosensitize human gastric MKN45 and colorectal DLD1 adenocarcinoma cells. In both cells, FK228 pretreatment at minimally toxic concentrations clearly augmented IR-induced cell death, DNA fragmentation and caspase-3/-8 activation. In contrast, 5-FU did not clearly augment IR-induced cell death and caspase-3 activation. FK228 increased expression of proapoptotic BH3-only Bim proteins, and gene transfer-mediated overexpression of Bimalpha radiosensitized DLD1 cells. These data suggest that the FK228-mediated increase of Bim expression may at least partially contribute to its augmentation of radiation-induced apoptosis. However, FK228 did not distinctly affect IR-induced phosphorylation of H2AX, which is an initial event followed by DNA damage. FK228 strongly augmented IR-induced growth suppression of MKN45 tumor xenografts. In addition, other HDAC inhibitors, MS275 and CBHA, similarly augmented IR-induced cell death in both cell types. Our results suggest that these HDAC inhibitors may enhance the efficacy of radiation therapy in gastrointestinal cancer cells.