A phase I study of radiation therapy and twice-weekly gemcitabine and cisplatin in patients with locally advanced pancreatic cancer

Does pre-operative chemoradiation for initially unresectable or borderline resectable pancreatic adenocarcinoma increase post-operative morbidity? A case-matched analysis

BACKGROUND

Neoadjuvant chemoradiation therapy for locally unresectable and borderline resectable pancreatic cancer may allow some patients to a undergo a resection, but whether or not this increases post-operative morbidity remains unclear.

METHODS

The post-operative morbidity of 29 patients with initially locally unresectable/borderline pancreatic cancer who underwent a resection were compared with 29 patients with initially resectable tumours matched for age, gender, the presence of comorbidities (yes/no), American Society of Anesthesiology (ASA) score, tumour location (head/body-tail), procedure (pancreaticoduodenectomy/distal pancreatectomy) and vascular resection (yes /no). Wilcoxon's signed ranks test was used for continuous variables and McNemar's chi-square test for categorical variables.

RESULTS

Compared with patients with initially resectable tumours, patients who underwent a resection after pre-operative chemoradiation therapy had similar rates of overall post-operative complications (55% versus 41%, P = 0.42), major complications (21% versus 21%, P = 1), pancreatic leaks and fistulae (7% versus 10%, P = 1) and mortality (0% versus 1.7%, P = 1).

CONCLUSION

Although some previous studies have suggested differences in post-operative morbidity after chemoradiation, our case-matched analysis did not find statistical differences in surgical morbidity and mortality associated with pre-operative chemoradiation therapy.

Unfavorable clinical implications of circulating CD44+ lymphocytes in patients with nasopharyngeal carcinoma undergoing radiochemotherapy

BACKGROUND

To evaluate the use of cellular immunity parameters as predictors of therapy response.

METHODS

Circulating lymphocytes were measued by flow cytometry in 94 nasopharyngeal carcinoma (NPC) patients following radiochemotherapy.

RESULTS

Significantly decreased percentage of CD3(+), CD4(+), and CD8(+) lymphocytes, significantly increased proportion of CD44(+), CD25(+), NK lymphocytes, and an increased CD4(+)/CD8(+) ratio were indicated in NPC patients as compared with healthy controls. Circulating CD44(+) lymphocytes in both the N2/N3 and III/IV groups were significantly increased as compared to the N0/N1 and I/II groups, respectively (P<0.05). A significant decrease in CD19(+) lymphocytes was observed in the III/IV group as compared with the I/II group (P<0.05). After radiochemotherapy, NPC patients had significantly (P<0.05) decreased percentages of CD4(+), CD44(+), and CD19(+) lymphocytes and a decreased CD4(+)/CD8(+) ratio, whereas the mean percentages of CD8(+) and NK lymphocytes were significantly (P<0.05) increased. However, compared with the pre-radiochemotherapy values, no significant (P>0.05) changes in CD3(+) or CD25(+) lymphocytes were observed in the NPC-treated group. Follow-up analysis indicated significantly lower DFS for patients with high CD44(+) lymphocytes compared to those with low CD44(+) lymphocytes after radiochemotherapy.

CONCLUSION

Circulating CD44(+) lymphocytes seems to be a promising criterion to predict survival in NPC patients undergoing radiochemotherapy.

Gemcitabine in the chemoradiotherapy for locally advanced pancreatic cancer: a meta-analysis

AIMS

Whether gemcitabine based chemoradiotherapy (GEM-based CRT) is superior to 5-fluorouracil based chemoradiotherapy (5-FU-based CRT) for locally advanced pancreatic cancer (LAPC) remains uncertain. The aim of the present study was to evaluate the effect of GEM-based CRT compared with 5-FU-based CRT.

METHODS

Electronic database including Medline, Embase, Cochrane controlled trials register, PubMed (update to December 2010) and manual bibliography searches were carried out. A meta-analysis of all randomized clinical trials (RCTs) or other comparative studies comparing GEM-based CRT and 5-FU-based CRT were performed.

RESULTS

Three RCTs and one retrospective comparative study including 229 patients were assessed. Meta-analysis showed survival advantage of GEM-based CRT compared with 5-FU-based CRT for 12-month (12-mo) survival rates (SRs) (RR=1.54, 95% CI 1.05-2.26, p=0.03). Moreover, there were also trends of benefit for SR after 6-months (RR 1.13, 95% CI 0.98-1.30, p=0.09) and 24-months (24-mo: RR 2.41, 95% CI 0.90-6.48, p=0.08), though the trends did not reach statistical significance. More frequent severe acute hematologic toxicities were found in the GEM-based CRT group.

CONCLUSIONS

The meta-analysis found that GEM-based CRT was better than 5-FU-based CRT in the treatment of LAPC, especially for 12-mo SRs. However, the acute toxicity should be carefully regarded.

The integration of chemoradiation in the care of patient with localized pancreatic cancer

The use of chemoradiation for patients with localized pancreatic cancer is controversial. Although some randomized trials have indicated that chemoradiation improves the median survival of patients with locally advanced as well as resected pancreatic cancer, other more recent trials have called into question the role of chemoradiation and have supported the use of chemotherapy. In the adjuvant setting, the high local tumor recurrence/persistence rate in all trials probably reflects the inclusion of patients with incompletely resected tumors, whose prognosis is similar to the prognosis of patients with locally advanced who do not undergo resection, making these trials difficult to interpret. More precise clinical staging and selection of patients appropriate for surgical resection is an important goal. The keys to the successful integration of radiotherapy in the care of patients with localized pancreatic cancer are selection, sequencing and smaller treatment volumes. A strategy of initial chemotherapy followed by consolidation with a well-tolerated chemoradiation regimen both in the adjuvant and locally advanced settings maximizes benefits of both treatment options, which are in fact complementary. Herein, we discuss the rationale for this approach as well as the ongoing investigation of novel radiation approaches designed to enhance outcome through the molecular and physical targeting of disease as well as the investigation of neoadjuvant chemoradiation in radiographically resectable and borderline resectable pancreatic cancer.

Surgical resection versus palliative chemoradiotherapy for the management of pancreatic cancer with local venous invasion: a decision analysis

BACKGROUND

Benefit from pancreaticoduodenectomy (PD) combined with superior mesenteric-portal vein (SMV-PV) resection in the management of pancreatic adenocarcinoma with local venous invasion remains controversial.

METHODS

Using formal decision analysis, we compared survival associated with PD plus SMV-PV resection when applied to patients with pancreatic adenocarcinoma with isolated local venous invasion (Group 1) versus that achieved with palliative chemoradiotherapy when applied to patients with locally advanced pancreatic cancer (Group 2). Individual studies were identified using Medline. A total of 1,324 and 709 patients were analyzed for Groups 1 and 2, respectively. Patients with distant metastases were excluded.

RESULTS

Overall decision analysis favored surgical resection (Group 1) over palliative chemoradiotherapy (Group 2). Sensitivity analyses indicated that this decision is sensitive to the perioperative mortality rate and the percentage of surgical resections with microscopic (R1) or macroscopic (R2) residual tumor at the resection margin. In contrast, sensitivity analysis revealed that the decision is not sensitive to the percentage of cases in which true venous invasion by cancer is documented histologically.

CONCLUSIONS

Surgical resection may confer a survival advantage over palliative chemoradiotherapy in select patients with pancreatic cancers with presumed local venous invasion.

A phase I trial of Capecitabine+Gemcitabine with radical radiation for locally advanced pancreatic cancer

Standard chemoradiotherapy with infusional 5FU for locally advanced pancreatic cancer (LAPC) has limited efficacy in this disease. The combination of Capecitabine (Cap) and Gemcitabine (Gem) are synergistic and are potent radiosensitisers. The aim of this phase I trial was thus to determine the highest administered dose of the Cap plus Gem combination with radical radiotherapy (RT) for LAPC. Patients had LAPC, adequate organ function, ECOG PS 0–1. During RT, Gem was escalated from 20–50 mg m⁻² day⁻¹ (twice per week), and Cap 800–2000 mg m⁻² day⁻¹ (b.i.d, days 1–5 of each week). Radiotherapy 50.4 Gy/28 fractions/5.5 weeks, using 3D-conformal techniques. Three patients were entered to each dose level (DL). Dose-limiting toxicity(s) (DLTs) were based on treatment-related toxicities. Twenty patients were accrued. Dose level (DL) 1: Cap/Gem; 800/20 mg m⁻² day⁻¹ (3 patients), DL2: 1000/20 (12 patients), DL3: 1300/30 (5 patients). Dose-limiting toxicities were observed in DL3; grade 3 dehydration (1 patient) and grade 3 diarrhoea and dehydration (1 patient). Dose level 2 was the recommend phase 2 dose. Disease control rate was 75%: PR=15%, SD=60%. Median overall survival was 11.2 months. The addition of Cap and Gem to radical RT was feasible and active and achieved at relatively low doses.

Primary advanced unresectable pancreatic cancer

Median as well as overall survival of pancreatic cancer patients in the advanced stage is extremely low despite advances in cancer therapy regarding tumor cell biology, therapy resistance, and diagnosis. In matters of chemoradiation therapy (CRT) in locally advanced pancreatic cancer, favorable positive effect has been reached with different radiotherapy proceedings such as intraoperative radiation therapy with or without external chemo-/radiation therapy or with CRT alone with regard to local tumor pain, local tumor remission, or local control of disease and overall survival. Primary (chemo-) radiation therapy only rarely leads to local remission. Intraoperative radiation therapy (IORT) merely reaches pain palliation in most cases. By administering up-to-date primary CRT, especially with gemcitabine-associated CRT, local remission in up to 50% of patients can be observed. By applying neoadjuvant CRT, better resectability and the reduction of postoperative positive lymph node metastasis has been seen in patients with resectable or possibly resectable pancreatic cancer. With primary CRT, resectability can also be achieved in patients with primary unresectable pancreatic cancer. It has been shown at the evaluation of patients' progression samples--either treated with neoadjuvant or primarily with radiotherapy (with conventional radiation technique)--that the rate of local recurrence or local progression can be reduced in comparison with historical cohorts. By contrast, the rate on distant metastases was not affected. Whereas concurrent CRT leads to favorable local tumor control, this procedure has a minor effect as to the survival in most of the studies. Because metastases occur mostly out of the irradiation field and because of partly advanced local tumor progression, the concept of combined CRT with continuing chemotherapy was developed. Median survival of pancreatic patients in the advanced stage is approx. 3-5 months, with a 12-month survival probability of 10% despite advances in cancer therapy. On the other hand, the 5-year survival probability is 0.4%-3.0%. The causes of such a dismal prognosis can be understood first of all in the commonly late diagnosis, second in the aggressive tumor cell biology with continuing therapy resistance, and finally because an acceptable resection rate can be achieved only in specialized centers. Only 10%-15% of patients can be resected after the diagnosis of pancreatic cancer. Resection is considered a potential curative therapy. However, median survival of these patients amounts to only 13-18 months, with a 5-year survival of 10%-20%. The survival rate did not improve with a radical resection and extended lymphadenectomy. Furthermore, 15%-30% of primary nonmetastatic pancreatic cancer is unresectable due to extended vessel infiltration at time of diagnosis. The prognosis for these patients is very dismal due to lack of specific therapy; moreover, median overall survival is a maximum of 6-8 months.

Gemcitabine, cisplatin, and radiotherapy for patients with locally advanced pancreatic adenocarcinoma: results of the North Central Cancer Treatment Group Phase II Study N9942

PURPOSE

A phase II study was conducted to determine the efficacy and toxicity of radiotherapy with concomitant gemcitabine and cisplatin for patients with locally advanced pancreatic adenocarcinoma.

PATIENTS AND METHODS

Forty-eight patients with locally advanced pancreatic adenocarcinoma received gemcitabine (30 mg/m2) and cisplatin (10 mg/m2) twice weekly during the first 3 weeks of radiotherapy. The radiation dose to the primary tumor and regional nodes was 45 Gy in 25 fractions, and the gross tumor volume received an additional 5.4 Gy in three fractions. Four weeks after radiotherapy, patients received gemcitabine (1,000 mg/m2) once weekly every 3 of 4 weeks for a 12-week period. The primary end point was survival at 12 months. Secondary end points were time to progression, toxicity, and quality of life.

RESULTS

Survival at 1 year was 40% for 47 eligible patients. The median survival was 10.2 months. Confirmed responses were observed for 8.5% (two partial, two complete), and median time to progression was 7.3 months. Grade 4 or higher toxicity was observed for 31% and consisted primarily of hematologic and GI toxicity. There was a trend toward improved overall quality of life, measured by the Symptom Distress Scale (P = .06), with significant improvements in domains of insomnia, pain, and outlook.

CONCLUSION

The combination of radiotherapy, gemcitabine, and cisplatin was well tolerated. Survival results were similar to those achieved with other treatment regimens for patients with locally advanced pancreatic cancer but did not meet our predefined criteria for additional evaluation of this regimen.

Locally advanced pancreatic cancer: current therapeutic approach

Even though pancreatic cancer accounts for only 2% of all cancer diagnoses in the U.S., it is the fourth-leading cause of cancer death and one of the most difficult malignancies to manage. Because of the usually late onset of symptoms, only 10%-15% of patients present with resectable disease, whereas the remaining 85%-90% present with locally advanced unresectable or metastatic disease. Despite a lack of consistent evidence from previous clinical trials, chemotherapy in addition to radiation therapy is the most commonly used approach in treating locally advanced pancreatic cancer. The most appropriate chemotherapy in combination with radiation is still debatable between 5-fluorouracil and gemcitabine, and novel trends to prevent resistance and enhance efficacy incorporate biologically targeted agents. This paper reviews the current management options, controversies, and ongoing and future directions for the treatment of locally advanced adenocarcinoma of the pancreas.

Adjuvant gemcitabine and concurrent radiation for patients with resected pancreatic cancer: a phase II study

The safety and efficacy of gemcitabine and concurrent radiation to the upper abdomen followed by weekly gemcitabine in patients with resected pancreatic cancer was determined. Patients with resected adenocarcinoma of the pancreas were treated with intravenous gemcitabine administered twice-weekly (40 mg m(-2)) for 5 weeks concurrent with upper abdominal radiation (50.4 Gy in 5(1/2) weeks). At the completion of the chemoradiation, patients without disease progression were given gemcitabine (1000 mg m(-2)) weekly for two cycles. Each cycle consisted of 3 weeks of treatment followed by 1 week without treatment. Forty-seven patients were entered, 46 of whom are included in this analysis. Characteristics: median age 61 years (range 35-79); 24 females (58%); 73% stage T3/T4; and 70% lymph node positive. Grade III/IV gastrointestinal or haematologic toxicities were infrequent. The median survival was 18.3 months, while the median time to disease recurrence was 10.3 months. Twenty-four percent of patients were alive at 3 years. Only six of 34 patients with progression experienced local regional relapse as a component of the first site of failure. These results confirm the feasibility of delivering adjuvant concurrent gemcitabine and radiation to the upper abdomen. This strategy produced good local regional tumour control.

Weekly gemcitabine and cisplatin in combination with pelvic radiation in the primary therapy of cervical cancer: A phase I trial of the Puget Sound Oncology Consortium

OBJECTIVE

Define the maximum tolerated dose of weekly gemcitabine given concomitantly with standard weekly cisplatin and pelvic radiotherapy for primary treatment of cervical cancer.

METHODS

Gemcitabine at specified dose levels was given concomitantly with weekly cisplatin at 40 mg/m2 for six cycles with concurrent radiotherapy in primary therapy of stage IB-IVA cervix cancer. Radiation consisted of 4500-5000 cGy in 25 daily fractions combined with brachytherapy to take point A to > or = 8500 cGy.

RESULTS

At gemcitabine 100 mg/m2, three of six patients demonstrated a dose limiting toxicity (DLT). At gemcitabine 50 mg/m2, two of two had DLTs. DLTs consisted of severe fatigue, lymphopenia, diarrhea, and tinnitus. All patients had a clinical complete response; four pathologically confirmed. Two patients recurred outside the radiated field and seven are disease-free (median follow-up 30 months). Following the second DLT at gemcitabine 50 mg/m2, the trial was stopped according to predetermined criteria.

CONCLUSIONS

Adding low dose weekly gemcitabine to cisplatin and pelvic radiotherapy resulted in an excellent response but unacceptable toxicities. Addition of gemcitabine prior to weekly cisplatin with radiation for cervical cancer will likely require reduction of cisplatin doses.

Is adjuvant 5-FU-based chemoradiotherapy for resectable pancreatic adenocarcinoma beneficial? A meta-analysis of an unanswered question

The objective of this study was to determine the effect, if any, on survival of adjuvant 5-FU-based chemoradiotherapy following pancreaticoduodenectomy for pancreatic carcinoma. A systematic review of the published literature was undertaken. Survival estimates were derived from published reports. Five prospective studies (4 level I, 1 level II) with a total of 607 (229 surgery only; 378 surgery-adjuvant) patients followed for survival met selection criteria. Two-year survival ranged from 15%-37% in the surgery only group and 37%-43% in the surgery and adjuvant groups. The survival advantage (absolute difference) ranged from 3%-27% and no individual study achieved statistical significance (5%). Although clinical heterogeneity existed in surgery-alone control groups with regard to trial date, no statistical heterogeneity was detected (P = 0.459, chi2 test), allowing pooling of survival data. Using a fixed effects model, the summary estimate showed an absolute 2-year survival benefit with adjuvant therapy of 12% (95% CI, 3%-21%, P = 0.011). Trials after 1997 (n = 3) indicated a survival benefit of 8% to patients receiving adjuvant therapy (95% CI, -3-18%, P = 0.145). The result was not statistically significant, and there was no evidence of heterogeneity (P = 0.626, chi2 test). Summary estimates were unchanged when the analysis was performed with a random effects model. 5-FU based chemotherapy with radiotherapy given after resection imparts a small overall survival benefit of 2 years. The benefit of 5-FU-based adjuvant therapy, however, has declined in recent years, and its significance remains unproven in the context of current diagnostic and surgical practice.

A phase I study of concurrent 9-nitro-20(s)-camptothecin (9NC/Orathecin) and radiation therapy in the treatment of locally advanced adenocarcinoma of the pancreas

BACKGROUND AND PURPOSE

In vitro studies have suggested that 9-nitro-20(s)-Camptothecin (9NC/Orathecin/Rubitecan) can enhance the effects of radiation. We conducted a phase I study to assess the toxicity and determine the maximum tolerated dose of 9NC when combined with radiation in patients with locally advanced adenocarcinoma of the pancreas.

PATIENTS AND METHODS

Eleven patients with locally advanced adenocarcinoma of the pancreas received 9NC, orally during radiation. Radiation therapy consisted of 45 Gy in 25 fractions given over 5 weeks. The starting dose of 9NC was 1 mg/m2/day.

RESULTS

Eight patients received 9NC at a dose of 1 mg/m2/day and three patients received a dose of 1.25 mg/m2/day. Dose-limiting toxicity (DLT) was defined as >or=grade 3 non-hematologic toxicity and >or=grade 4 hematologic toxicity. Dose-limiting toxicity of grade 3 nausea/vomiting developed in one patient at the first dose level. At dose level 2, two of three patients developed DLT. Both developed grade 3 nausea, fatigue, and anorexia. Additionally, one of these patients had grade 3 dehydration and the other had grade 4 leukopenia, grade 3 vomiting, and grade 3 weakness.

CONCLUSIONS

9NC, 1 mg/m2/day, can be given concurrently with radiation with acceptable toxicity.

Chemoradiotherapy in patients with pancreatic carcinoma: phase-I study with a fixed radiation dose and escalating doses of weekly gemcitabine

AIM

The aim of this phase-I study is to determine the maximum tolerated dose (MTD) of weekly gemcitabine in concurrent combination with a total radiation dose of 54 Gy in patients with pancreatic cancer.

METHODS

In all patients, a total dose of 54 Gy was delivered in 30 fractions of 1.8 Gy/day. Gross tumor volume and regional lymph nodes were included in the irradiated volume with a 1- to 1.5-cm margin. The doses of weekly gemcitabine were escalated from 100 mg/m2 by increments of 50 mg/m2. Dose-limiting toxicity (DLT) was defined as hematologic toxicity, prolonged grade-3 non-hematologic toxicity, and incompletion of the planned treatment.

RESULTS

Twenty-six patients entered the trial. From level 1 (100 mg/m2) to level 4 (250 mg/m2), no patient experienced DLT except for 1 patient at level 1. At level 5 (300 mg/m2), 3 of the 5 patients met the DLT criteria. One patient developed severe pulmonary abscess, and the other 2 patients had hematologic DLT. The overall partial response rate was 29%, and the median survival time was 13.7 months. The first relapse occurred at the in-field primary site in 6 patients and at distant organs in 13 patients.

CONCLUSION

The MTD of weekly gemcitabine was 250 mg/m2 in the present chemoradiotherapy setting. The efficacy of this chemoradiotherapy regimen is currently being evaluated in the phase-II setting.

Phase II trial of induction gemcitabine/CPT-11 followed by a twice-weekly infusion of gemcitabine and concurrent external beam radiation for the treatment of locally advanced pancreatic cancer

PURPOSE

This phase II trial of induction irinotecan/gemcitabine followed by twice-weekly gemcitabine and upper abdominal radiation was initiated to determine the activity of this regimen in patients with unresectable pancreatic cancer.

METHODS

Patients with locally advanced, nonmetastatic adenocarcinoma of the pancreas received 2 cycles of induction irinotecan (100 mg/m2 IV) and gemcitabine (1000 mg/2 IV) on days 1 and 8 of each 3-week cycle. Following the induction, patients without disease progression received gemcitabine administered twice weekly (40 mg/m2/day) for 5 weeks concurrent with upper abdominal radiation (50.4 Gy over 5.5 weeks).

RESULTS

From April 2000 to August 2003, 20 patients were entered into this study, 17 of whom were evaluable for treatment response. Characteristics included a median age of 67 years (range, 44-87 years) and 14 men (70%). Grades III and IV hematologic toxicity occurred in 25% and 5% of patients respectively and was primarily thrombocytopenia. No grade IV gastrointestinal toxicities or deaths due to therapy were observed. All therapy was completed in 8 patients, 7 patients were removed due to progression, 2 due to toxicity, 2 refused further treatment, and 1 was removed per the treating physician. The median time to progression and median survival was 5.1 months (95% CI, 3.2-6.7) and 8.8 months (95% CI, 6.4-10.1) respectively. Four patients (20%) were alive at 12 and 18 months.

CONCLUSION

Induction irinotecan/gemcitabine followed by twice-weekly gemcitabine and upper abdominal radiation is feasible in patients with locally advanced pancreatic cancer. This regimen, however, has only modest activity and should not be explored further.

Docetaxel/Gemcitabine Followed by Gemcitabine and External Beam Radiotherapy in Patients With Pancreatic Adenocarcinoma

BACKGROUND

Pancreatic cancer remains highly lethal. Previous attempts with neoadjuvant therapy in this disease have been inconclusive, but a potential for benefit exists. We conducted a phase II trial of dose-intense docetaxel and gemcitabine followed by twice-weekly gemcitabine and external beam radiotherapy in patients with pancreatic adenocarcinoma.

METHODS

Patients with stage I to III disease were eligible. Docetaxel 65 mg/m(2) intravenously over 1 hour and gemcitabine 4000 mg/m(2) given intravenously over 30 minutes were given on days 1, 15, and 29. On day 43, radiotherapy was begun at 50.4 Gy with gemcitabine 50 mg/m(2) intravenously over 30 minutes twice weekly for 12 doses. After treatment, patients were considered for resection.

RESULTS

Twenty-four assessable patients were recruited onto the trial. All but one patient completed a full 12 weeks of therapy. Grade 3 and 4 hematological and nonhematological toxicities were common but manageable, and neutropenic fever did not occur. No patient had local tumor progression. Twelve patients (50%) responded by Response Evaluation Criteria in Solid Tumors Group (RECIST) criteria, including one radiographic complete response. Seventeen patients underwent resection after therapy. Margin-negative resections were performed in 13 patients, including 9 patients whose disease was borderline or unresectable before treatment. A treatment effect was seen in all resection specimens. There have been no local recurrences of tumor, and several patients remain alive without evidence of disease.

CONCLUSIONS

Docetaxel/gemcitabine followed by gemcitabine/radiotherapy is active in the treatment of pancreatic adenocarcinoma, with manageable toxicity. Tumor downstaging occurs in some patients to allow complete resection. Further investigation of this regimen is warranted.

Cisplatin sensitizes cancer cells to ionizing radiation via inhibition of nonhomologous end joining

The combination of cisplatin and ionizing radiation (IR) treatment represents a common modality for treating a variety of cancers. These two agents provide considerable synergy during treatment, although the mechanism of this synergy remains largely undefined. We have investigated the mechanism of cisplatin sensitization to IR using a combination of in vitro and in vivo experiments. A clear synergistic interaction between cisplatin and IR is observed in cells proficient in nonhomologous end joining (NHEJ) catalyzed repair of DNA double-strand breaks (DSB). In contrast, no interaction between cisplatin and IR is observed in NHEJ-deficient cells. Reconstituted in vitro NHEJ assays revealed that a site-specific cisplatin-DNA lesion near the terminus results in complete abrogation of NHEJ catalyzed repair of the DSB. These data show that the cisplatin-IR synergistic interaction requires the DNA-dependent protein kinase-dependent NHEJ pathway for joining of DNA DSBs, and the presence of a cisplatin lesion on the DNA blocks this pathway. In the absence of a functional NHEJ pathway, although the cells are hypersensitive to IR, there is no synergistic interaction with cisplatin.

Phase I study of concomitant chemoradiotherapy with paclitaxel, fluorouracil, gemcitabine, and twice-daily radiation in patients with poor-prognosis cancer of the head and neck

PURPOSE

We previously demonstrated high locoregional control, in patients with poor-prognosis head and neck cancer (HNC), using paclitaxel, 5-fluorouracil, hydroxyurea, and concomitant hyperfractionated radiotherapy. In the present phase I trial, gemcitabine, a novel antimetabolite with strong radiation-enhancing activity, replaces hydroxyurea. We sought to determine the recommended phase II dose and clinical efficacy in poor-prognosis HNC patients.

EXPERIMENTAL DESIGN

Seventy-two patients enrolled. Eligibility criteria included recurrent or second primary HNC, metastases or expected 2-year survival <20%. Chemoradiotherapy consisted of 5-fluorouracil, 600 mg/m(2)/d, for 5 days; paclitaxel, 100 mg/m(2) on Day 1; and concurrent 1.5 Gy twice-daily radiation for 5 days. Gemcitabine was dose escalated, 50-300 mg/m(2) on day 1. Cycles repeated every 14 days until the completion of chemoradiation. Dose-limiting toxicities (DLTs) included: neutropenic fever; grade > or =4 neutropenia or thrombocytopenia for >4 days; grade > or =4 mucositis or dermatitis for >7 days; or grade 3 toxicity necessitating chemotherapy dose reductions. Non-DLT dose reductions in 5-fluorouracil and/or paclitaxel were allowed.

RESULTS

Seventy-nine percent of assessable patients experienced a clinical response. Five-year actuarial survival is 33.0%, and locoregional control is 61.4%. The recommended phase II dose of gemcitabine in this regimen is 100 mg/m(2) during cycles 1-5 (1 of 7 patients with DLT) or 200 mg/m(2) delivered only during cycles 3-5 (3 of 19 with DLT). Grades 3 and 4 mucositis (56 and 21%, respectively) and dermatitis (25 and 21%, respectively) were common.

CONCLUSIONS

Gemcitabine, 5-fluorouracil, paclitaxel, and twice-daily radiation, delivered on alternating weeks, is active in patients with poor-prognosis HNC, although severe mucositis limits the clinical applicability of this regimen. Refinements in radiotherapy, including intensity-modulated radiation therapy, may improve the tolerance for this regimen.

Combined Modality Therapy of Gemcitabine and Radiation

The combination of gemcitabine and radiotherapy is a promising combined modality therapy. However, the clinical application of this combination has to be implemented carefully because of an increased toxicity to normal tissues. A body of experimental evidence shows that gemcitabine is a potent radiosensitizer in vitro and in vivo. The observations so far indicate that various mechanisms are responsible for the radiosensitizing effect. Although it is often difficult to transfer experimental data to the clinic, these studies offer the possibility to develop an improved schedule of administration for patient treatment, based on rational evidence in tumor biology. In the current review, the preclinical data that support the use of gemcitabine as a radiosensitizing agent and the clinical trials that have been conducted to date are summarized.