A pilot study of chronomodulated infusional 5-fluorouracil chemoradiation for pancreatic cancer

Adjuvant therapy in pancreatic cancer: a critical appraisal

Adenocarcinoma of the pancreas carries a grim prognosis. Surgery is currently the only curative option, but even the few patients undergoing complete resection of early localised disease run a high risk for relapse and death. Although numerous clinical trials have been conducted during the past 20 years to find an effective adjuvant treatment, thus far no general consensus on the most appropriate regimen has been reached. In a small randomised study performed in the 1980s by the GITSG (Gastrointestinal Tumor Study Group), encouraging results were obtained with fluorouracil (5-FU)-based split-course chemoradiotherapy, but these findings were not confirmed in a randomised study initiated some years later by the EORTC (European Organisation for Research and Treatment of Cancer). More recently, the ESPAC (European Study Group for Pancreatic Cancer)-1 trial even indicated a detrimental effect of chemoradiotherapy, while chemotherapy with 5-FU was shown to have a significant positive impact on long-term survival. However, this latter finding is in contrast to earlier studies of adjuvant chemotherapy with 5-FU combinations from Norway and Japan that did not suggest a prolonged beneficial effect of 5-FU on survival. Thus, the results for adjuvant regimens based on systemic 5-FU with or without external radiotherapy are conflicting. Clinical experience with intraoperative radiotherapy or regionally targeted chemotherapy to prevent local relapse, though encouraging, is still preliminary. More recently, gemcitabine, which is the most effective single agent in advanced pancreatic cancer, has also been evaluated in the adjuvant setting. The RTOG (Radiation Therapy Oncology Group)-9704 trial demonstrated that gemcitabine is superior to 5-FU as an addition to chemoradiotherapy, but the results did not allow conclusions about the value of radiation in the combined modality approach. The Charité Onkologie CONKO-001 is a randomised trial from Germany and Austria that compared adjuvant gemcitabine with observation alone. Gemcitabine was very well tolerated and almost doubled median disease-free survival and overall survival rate at 5 years, although the advantage in overall survival failed to reach statistical significance. In summary, the available data from randomised clinical trials of adjuvant therapy suggest that (i) chemoradiotherapy has no obvious advantage compared with chemotherapy alone; and (ii) chemotherapy with gemcitabine is effective and probably offers the best benefit-risk ratio of all currently available adjuvant treatment options.

The multidisciplinary management of gastrointestinal cancer. Pancreatic cancer: from pathogenesis to cure

Pancreatic cancer is the fourth leading cause of cancer-related death in the USA. The disease has a high mortality rate and the 5-year survival rate is estimated to be 4%. Currently, surgical resection is only possible in 20% of patients; even then, the overall 5-year survival rate is only 25%. As such, surgical therapy alone is not sufficient for pancreatic carcinoma, and prospective investigation of additional modalities is crucial. Numerous negative trials have shown that chemotherapy alone is the standard of care after resection of pancreatic carcinoma. However, results remain poor and progress with new drugs is needed in this setting. For locally advanced disease, the situation is more complicated; the ideal chemoradiation schedule has not been clearly defined, and improvements could come in the near future from the use of new radiotherapy tools and targeted therapies. For advanced disease, chemotherapy alone has given very disappointing results. A multidisciplinary approach combining biological assessment of targets with clinical trials to evaluate new targeted drugs should be considered.

Emerging drugs in pancreatic cancer

Improving survival in patients with pancreatic cancer remains a formidable challenge. For the few patients with localised stages of the disease, intra-operative radiotherapy, adjuvant chemoradiotherapy and neo-adjuvant therapies remain non-validated and the survival benefit conferred by 5-fluorouracil-folinic acid adjuvant chemotherapy over radical surgery alone is still a matter of debate. Gemcitabine has recently emerged as the standard single agent in advanced stages of the disease and pharmacokinetic refinements such as the use of a fixed-dose infusion rate may further improve still rather modest result figures. At present, most efforts deal with the development of more effective doublet or triplet therapies, combining gemcitabine with either conventional cytotoxic drugs--the most promising being oxaliplatin--or more innovative, targeted therapeutic agents. Among these agents, matrix metalloprotease inhibitors and farnesyltransferase inhibitors have already undergone Phase III trials, alone or in combination with gemcitabine, with rather disappointing results. However, preclinical and Phase I and II studies of cyclooxygenase-2 or lipoxygenase inhibitors, various immunotherapeutic approaches and several tyrosine kinase inhibitors or monoclonal antibodies against growth factors or their receptors are encouraging and may provide some hope for patients with pancreatic cancer.

Clinical experience with chronomodulated infusional 5-fluorouracil chemoradiotherapy for pancreatic adenocarcinoma

PURPOSE

To evaluate retrospectively the efficacy and chronic toxicities of concurrent radiotherapy and chronomodulated infusion 5-fluorouracil (5-FU) in patients with pancreatic adenocarcinoma.

METHODS AND MATERIALS

Twenty-eight patients with pancreatic adenocarcinoma were treated between January 1997 and May 2000 with 5-FU chronomodulated chemoradiotherapy. Chronomodulated delivery of chemotherapy was chosen on the basis of a lower toxicity profile in the treatment of GI malignancies. The median age was 64 years. Of the 28 patients, 12 were men and 16 were women. Eight patients had unresectable disease and 20 were treated after pancreatic resection. The median radiation dose was 50.4 Gy given in 28 fractions. The median field length and width was 10.6 cm and 10.9 cm, respectively. Concurrent chemotherapy with 5-FU was administered 5 d/wk, with a median total dose of 8.4 g/m2 (300 mg/m2/d). Chronomodulated 5-FU delivery consisted of a low basal infusion for 16 h followed by an 8-h escalating-deescalating infusion peaking at 10 pm. Survival and recurrence data were evaluated using Kaplan-Meier actuarial analysis. Toxicities were recorded using the Radiation Therapy Oncology Group grading system.

RESULTS

The median follow-up for all patients was 26 months (range, 4-68 months). The median overall survival for the 20 patients treated postoperatively was 34 months, with a 3- and 5-year actuarial survival rate of 40% and 21%, respectively. If the 3 patients with carcinoma of the ampulla were removed from the data set, the mean overall survival in the resected patients was 34 months, with a 3-year and 5-year actuarial survival rate of 40% and 17%, respectively. The 8 unresectable patients had a median overall survival of 14 months, and none lived past 2 years. No patient experienced Grade 3 or 4 hematologic toxicity or weight loss. Five patients had nausea and dehydration requiring i.v. fluids; only one (4%) was hospitalized. Four patients required a dose reduction of 5-FU, one for nausea, one for a transient ischemic attack, one for an infection, and one because of myocardial infarction. Seven resected patients, four of whom had no evidence of disease, developed diabetes mellitus 1-2 years after radiotherapy.

CONCLUSION

Chronomodulated 5-FU administration, based on the concept of chronotolerance, has relatively low acute toxicity. Our median survival rate was greater than that after most chemoradiotherapy programs that result in more acute toxicity. Additional study is warranted to evaluate chronomodulated radiosensitizing chemotherapy schedules in prospective trials and with attention to late effects after radiotherapy, including diabetes mellitus.

Four Decades of Continuing Innovation With Fluorouracil: Current and Future Approaches to Fluorouracil Chemoradiation Therapy

Purpose

Chemoradiotherapy, the combination of external radiation therapy and concurrent chemotherapy, has been the basis for the oncologic management of many patients since its development in the 1960s. Fluorouracil (FU) chemoradiotherapy has demonstrated success in several organ sites with multiple dosing schedules that now guide the selection of oral analogs of FU to provide new chemoradiotherapy options.

Methods

This article reviews the metabolism and pharmacology of FU and the advantages of administration of FU by continuous infusion or bolus. The potential role and impact of the oral fluorouracil prodrugs UFT, S-1, BOF-A2, and capecitabine as replacements for intravenous administration are discussed. The results of recent chemoradiotherapy studies with FU from 2000 to 2003 are summarized in rectal, head and neck, esophageal, gastric, pancreatic, biliary, anal, and cervical cancers.

Results

Chemoradiotherapy with FU has the potential to widen the therapeutic window by minimizing normal tissue toxicity while maintaining effective tumor toxicity. Overall, FU chemoradiotherapy maximizes local control and, for some tumor sites (such as head and neck, pancreatic, biliary, cervical, esophageal, and gastric cancers), improves survival rates. Moreover, FU chemoradiotherapy results in improved organ preservation with excellent functional outcome in several anatomic sites including head and neck cancer, anal, and rectal cancer, with improved sphincter preservation.

Conclusion

FU chemoradiotherapy continues to play an important role in the management of many cancer sites. During the last four decades, optimal dosing schedules have produced a therapeutic gain. The introduction of oral prodrug analogs will likely further improve the results of FU therapy in several organ systems, such as the rectum, head and neck, and esophagus.

Circadian timing in cancer treatment: the biological foundation for an integrative approach

Despite the many innovations that have occurred in cancer treatment, the age-specific mortality for most adult tumors has remained stable during the past 30 years. There have been clinically significant improvements in the outcomes of young and middle-aged patients, yet the vast majority of cancer patients are more than 50 years of age, among whom we observe few improvements in clinical outcomes. Clearly, many of today's cytotoxic agents have been shown to be effective in-vitro and in animal model systems; however, few have proved efficacious in dramatically improving survival outcomes in adult cancer. There is now increasing evidence to suggest that the administration of cytotoxic agents, at the appropriate circadian phase, can significantly increase the therapeutic index of current cancer therapies.

Postoperative adjuvant therapy for pancreatic cancer

The majority of patients diagnosed with pancreatic cancer present at an advanced stage, and only a small percentage are considered technically resectable at diagnosis. The overall prognosis for the majority is dismal, with a median survival in untreated cases of only 24 weeks. Even in resected patients the overall 5-year survival rate is generally only 5% to 10%; however, some reports indicate higher 5-year survival rates in patients treated with surgery who are pathologically staged with no lymph node involvement. Even when macroscopically complete resection is achieved, local recurrence (LR) rates are unacceptably high (30% to 70%), which is usually attributed to the difficulty of obtaining microscopically free surgical margins. Microscopic clearance is difficult to achieve because these tumors frequently extend into the peripancreatic tissues (e.g., retropancreatic fat), abut or invade the adjacent large vessels (the portal vein and superior mesenteric artery), and have a propensity to invade the lymphovascular and perineural space. Other common sites of failure after attempted curative resection include metastasis to the liver and the peritoneal cavity. Patients who present with pancreatic cancer, and for whom curative surgery is deemed possible, are thus potential candidates for adjuvant therapy because of the high local failure rate following resection alone. The radiotherapy dose that can be achieved in the postoperative setting for pancreatic cancer is limited because of the proximity of critical structures (e.g., the kidney, liver, small intestines, stomach, and spinal cord). Newer techniques such as conformal radiotherapy and intensity-modulated radiotherapy have the advantage of being able (theoretically) to precisely localize the dose to the target volume while reducing the dose to critical structures. These techniques may potentially enable the tumorcidal dose to be increased; however, they are only now becoming widespread. Systemic radiation-sensitizing chemotherapy is also a promising approach to take advantage of additive or synergistic effects with radiation locally, and for the sterilization of systemic disease. This concept of concomitant chemotherapy with radiotherapy, or chemoradiotherapy, has proved effective in a number of sites, including the anal canal, rectum, lung, and pancreas. The recent trials reviewed here varied considerably in terms of the total dose and technique used, and the choice of radiation sensitizing treatment.

COX-2 inhibitors as radiation sensitizers for upper GI tract cancers: esophagus, stomach, and pancreas

Cancers of the esophagus, stomach, and pancreas have been successfully treated recently with combinations of radiosensitizing chemotherapy and irradiation. New approaches building onto 5-fluorouracil chemoradiation include capecitabine (Xeloda) and irradiation. Capecitabine is an oral 5-fluorouracil (5-FU) prodrug that is more convenient than using infusional 5-FU, appears to have a similar therapeutic profile, and can be combined with daily irradiation. The addition of a cyclooxygenase-2 (COX-2) inhibitor is being investigated in upper gastrointestinal cancer sites because there is a high degree of overexpression of COX-2 in these cancers.

Chronomodulated chemotherapy and irradiation: an idea whose time has come?

The chronomodulated delivery of systemic chemotherapy given with irradiation (chemoradiation) is driven by an understanding of: the chronobiology of normal tissue response to cytotoxic insult, chronopharmacology, and by technologic advances in vascular access and in the availability of portable programmable pumps. Since circadian variation exists in the proliferative activity of acute-reacting normal tissues like the gut and bone marrow, a potential therapeutic gain can be realized by the chronomodulated administration of S-phase chemotherapeutic agents at biological times when these normal tissues are in a different cell phase and thus relatively spared (chronotolerance). The reasons for this are complex and possibly include newly described time-keeping genes that may influence the cell cycle. Another important aspect of chronotolerance is based on chronopharmacologic behavior of S-phase chemotherapeutic radiation sensitizing agents, especially 5-fluorouracil (5-FU). In this review laboratory and clinical evidence is presented for using chronomodulated 5-FU or the topoisomerase-I inhibitor, camptothecin, when best tolerated biologically. Although the main body of this work has been accomplished with pure chemotherapy schedules, there is emerging clinical evidence this approach to treatment also applies to the application of chemoradiation. This knowledge has been exploited only recently in the clinic. These data should be viewed as a call for additional studies to investigate the precise timing of systemic chemotherapeutic radio sensitizers to ameliorate toxicity and maximize treatment effect, especially with newer and potentially more toxic chemoradiation programs.