Evolving trends in combined modality therapy for pancreatic cancer

Orthovoltage intraoperative radiation therapy for pancreatic adenocarcinoma

Purpose

To analyze the outcomes of patients from a single institution treated with surgery and orthovoltage intraoperative radiotherapy (IORT) for pancreatic adenocarcinoma.

Methods

We retrospectively reviewed 23 consecutive patients from 1990-2001 treated with IORT to 23 discrete sites with median and mean follow up of 6.5 and 21 months, respectively. Most tumors were located in the head of the pancreas (83%) and sites irradiated included: tumor bed (57%), vessels (26%), both the tumor bed/vessels (13%) and other (4%). The majority of patients (83%) had IORT at the time of their definitive surgery. Three patients had preoperative chemoradiation (13%). Orthovoltage X-rays (200-250 kVp) were employed via individually sized and beveled cone applicators. Additional mean clinical characteristics include: age 64 (range 41-81); tumor size 4 cm (range 1.4-11); and IORT dose 1106 cGy (range 600-1500). Post-operative external beam radiation (EBRT) or chemotherapy was given to 65% and 76% of the assessable patients, respectively. Outcomes measured were infield control (IFC), loco-regional control (LRC), distant metastasis free survival (DMFS), overall survival (OS) and treatment-related complications.

Results

Kaplan-Meier (KM) 2-year IFC, LRC, DMFS and OS probabilities for the whole group were 83%, 61%, 26%, and 27%, respectively. Our cohort had three grade 3-5 complications associated with treatment (surgery and IORT).

Conclusions

Orthovoltage IORT following tumor reductive surgery is reasonably well tolerated and seems to confer in-field control in carefully selected patients. However, distant metastases remain the major problem for patients with pancreatic adenocarcinoma.

Current state of adjuvant therapy in resected pancreatic adenocarcinoma

Pancreatic carcinoma cannot generally be cured by surgery alone. This review summarizes the development of adjuvant therapy over the past two decades. Four randomized controlled trials compare long-term survival of different treatments. The small GITSG-study supports combined chemoradiation, but the EORTC-study found no significant effect. A Norwegian study of adjuvant chemotherapy found an increased median survival, but no effect beyond two years. The large ESPAC-1 study shows a benefit for 5-FU based chemotherapy, while chemoradiation had a negative effect. Thus, evidence favours adjuvant therapy, but 5-FU may not be the ultimate drug. Support for gemcitabine is given by preliminary data from a German randomized trial, and further American and European studies are upcoming. However, postoperative therapy is problematic, as 20-30% of resected patients never undergo treatment because of slow recovery or other reasons. Preoperative therapy has some theoretical advantages, and moreover, patients with rapidly progressive disease may be spared surgery. Randomized controlled trials are lacking, but published results compare well with postoperative, adjuvant therapy. The value of locally targeted therapy is difficult to assess. Reasonable results have been obtained with regional chemotherapy, whereas intraoperative radiotherapy does not seem to increase survival despite reducing reducing local recurrences.

Intraoperative radiation therapy in resected pancreatic carcinoma: long-term analysis

PURPOSE

The combination of external radiotherapy (RT) plus intraoperative radiotherapy (IORT) in patients with pancreatic cancer is still debated. This study presents long-term results (minimum follow-up, 102 months) for 26 patients undergoing integrated adjuvant RT (external RT+IORT).

METHODS AND MATERIALS

From 1990 to 1995, a total of 17 patients with pancreatic cancer underwent IORT (10 Gy) and postoperative external RT (50.4 Gy). Preoperative "flash" RT was included for the last 9 patients. The liver and pancreatic head received 5 Gy (two 2.5-Gy fractions) the day before surgery. In the subsequent period (1996-1998), 9 patients underwent preoperative concomitant chemoradiation (39.6 Gy) with 5-fluorouracil, IORT (10 Gy), and adjuvant chemotherapy.

RESULTS

Preoperative chemoradiation was completed in all patients, whereas postoperative therapy was completed in 13 of 17 patients. All 26 patients underwent pancreatectomy (25 R0 and one R1 resections). One patient died of postoperative complications (3.8%) not related to IORT. The 9 patients undergoing concomitant chemoradiation were candidates for adjuvant chemotherapy; however, only 4 of 9 underwent adjuvant chemotherapy. At last follow-up, 4 patients (15.4%) were alive and disease free. Disease recurrence was documented in 20 patients (76.9%). Sixteen patients (61.5%) showed distant metastasis, and 5 patients (19.2%) showed local recurrence. The incidence of local recurrence in R0 patients was 4 of 25 (16.0%). The overall 5-year survival rate was 15.4%. There was significant correlation with overall survival of tumor diameter (p=0.019).

CONCLUSIONS

The incidence of local recurrence in this long follow-up series (19.2%) was definitely less than that reported in other studies of adjuvant RT (approximately 50%), suggesting a positive impact on local control of integrated adjuvant RT (IORT+external RT).

The role of oxaliplatin in the management of upper gastrointestinal tract malignancies

Following the successful introduction of oxaliplatin into the management of advanced colorectal cancer, its clinical utility is currently being investigated in a variety of other malignancies, including cancers of the upper gastrointestinal tract. In advanced pancreatic cancer, oxaliplatin has been found to be clinically effective in phase II trials in which it was combined with either 5-fluorouracil (5-FU) or gemcitabine, the current standard chemotherapy for this disease. In a phase II trial involving 67 patients, the combination of oxaliplatin and 5-FU in a high dose infusional regimen (n = 31) achieved an objective response rate of 9.7%, stable disease for at least three cycles in 48.4% of patients, tumour growth control in 58% of patients, a median time to progression of 4.9 months and median overall survival reaching 9.2 months. In combination with gemcitabine in a phase II trial involving 64 patients with metastatic (n = 34) or locally advanced (n = 30) pancreatic cancer, there was an objective response rate of 30.6%, treatment benefit in 39.7%, a median progression-free survival of 5.3 months and again a median overall survival of 9.2 months. Response rates and survival times did not differ between locally advanced and metastatic disease. On the basis of these encouraging results, phase III studies of oxaliplatin in advanced pancreatic cancer are now in progress in Europe and the United States. In metastatic gastric cancer, a phase II study investigated the combined use of oxaliplatin and 5-FU using the FOLFOX6 regimen in 53 patients, of whom 49 were evaluable for efficacy. The objective response rate was 44.9% and the median duration of response was 7.9 months. Large phase III trials of oxaliplatin-based treatment for advanced gastric cancer are now in progress. Oxaliplatin is also being investigated in oesophageal cancer and several other gastrointestinal tumours. In summary, oxaliplatin is emerging as an effective and highly promising chemotherapeutic agent for the treatment of upper gastrointestinal malignancies.