Orthovoltage intraoperative radiation therapy for pancreatic adenocarcinoma

Intraoperative Radiotherapy for Resectable Pancreatic Cancer Using a Low-Energy X-Ray Source: Postoperative Complications and Early Outcomes

PURPOSE

We evaluated the safety, feasibility, and early treatment outcomes of intraoperative radiotherapy (IORT) using a low-energy X-ray source.

MATERIALS AND METHODS

Patients with resectable pancreatic cancer were enrolled in this single-institution, prospective, single-arm, phase II trial. Patients underwent surgery and IORT with 10 Gy prescribed at a 5-mm depth from the tumor bed using a 50 kV X-ray source (Intrabeam, Carl Zeiss). Six cycles of adjuvant gemcitabine-based chemotherapy were administered 8-12 weeks after surgery.

RESULTS

A total of 41 patients were included. Thirty-one patients (75.6%) underwent wide R0 resection, while 5 (12.2%) underwent R1 resection and 5 (12.2%) underwent narrow R0 resection (retroperitoneal margin <1 mm). Grade 3 postoperative complications were reported in only one patient (4.9%) who needed additional surgery due to ulcer perforation. At a median follow-up of 9 months, four patients showed local-only recurrence, nine had distant metastases, and two showed both local and distant recurrence. The 1-year local control rate was 76.4%.

CONCLUSION

Our preliminary report suggests that IORT is well-tolerated and feasible in patients with resectable pancreatic cancer. Further follow-up is needed to confirm the clinical benefits of IORT in terms of local control and overall survival.

TRIAL REGISTRATION

Trial Registration: Clinical trial registration No. (NCT03273374).

ESTRO IORT Task Force/ACROP recommendations for intraoperative radiation therapy in borderline-resected pancreatic cancer

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Radiation dose-escalation with intraoperative electron beam radiation therapy to the posterior resection margin and/or to residual disease is feasible with limited toxicity.

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Preoperative therapy prolongs the interval to surgery and IOERT, allowing an improved selection of patients who are candidates for local treatment intensification.

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Primary systemic therapy combined with chemoradiation allows to boost with IOERT in over 70% of patients with R0 surgical tumour beds.

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Median survival time ranges from 19 to 35 months in electron boosted patients.

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Overall survival at 5 years of over 30% is reported by contemporary expert IOERT institutions.

Radiation therapy (RT) is a valuable component of multimodal treatment for localized pancreatic cancer. Intraoperative radiation therapy (IORT) is a very precise RT modality to intensify the irradiation effect for cancer involving upper abdominal structures and organs, generally delivered with electrons (IOERT). Unresectable, borderline and resectable disease categories benefit from dose-escalated chemoradiation strategies in the context of active systemic therapy and potential radical surgery. Prolonged preoperative treatment may act as a filter for selecting patients with occult resistant metastatic disease. Encouraging survival rates have been documented in patients treated with preoperative chemoradiation followed by radical surgery and IOERT (>20 months median survival, >35% survival at 3 years). Intensive preoperative treatment, including induction chemotherapy followed by chemoradiation and an IOERT boost, appears to prolong long-term survival within the subset of patients who remain relapse-free for>2 years (>30 months median survival; >40% survival at 3 years). Improvement of local control through higher RT doses has an impact on the survival of patients with a lower tendency towards disease spread. IOERT is a well-accepted approach in the clinical scenario (maturity and reproducibility of results), and extremely accurate in terms of dose-deposition characteristics and normal tissue sparing. The technique can be adapted to systemic therapy and surgical progress. International guidelines (National Comprehensive Cancer Network or NCCN guidelines) currently recommend use of IOERT in cases of close surgical margins and residual disease. We hereby report the ESTRO/ACROP recommendations for performing IOERT in borderline-resectable pancreatic cancer.

The past, present, and future status of multimodality treatment for resectable/borderline resectable pancreatic ductal adenocarcinoma

A multimodal approach to treating pancreatic ductal adenocarcinoma (PDAC) is now widely accepted. Improvements in radiological assessment have enabled us to define resectability in detail. Multimodality treatment is essential for patients, especially for those with PDAC in the borderline resectable (BR) stage. Even for disease in a resectable (R) stage, adjuvant and neoadjuvant therapies have demonstrated beneficial outcomes in several trials and analyses. Thus, there is growing interest in optimization of the perioperative therapeutic strategy. We discuss the transition of resectability criteria and the global standard of adjuvant and neoadjuvant treatments for patients with R/BR-PDAC.

Orthovoltage intraoperative radiotherapy for locally advanced and recurrent colorectal cancer

BACKGROUND

Locally advanced and recurrent colorectal cancers pose a significant therapeutic challenge. Orthovoltage intraoperative radiotherapy provides one potential means of improving disease control at the time of surgery.

OBJECTIVE

This study sought to analyze outcomes and identify prognostic factors of patients treated with orthovoltage intraoperative radiotherapy for locally advanced or recurrent colorectal cancer.

DESIGN AND SETTING

This study is a retrospective chart review conducted at a tertiary medical center.

PATIENTS

Between January 1990 and July 2009, 55 patients underwent intraoperative radiotherapy to a total of 61 sites for locally advanced (n = 14) or recurrent (n = 41) cancers of colon (n = 18) or rectum/rectosigmoid junction (n = 37).

INTERVENTIONS

Median dose was 12 Gy (range, 7.5-20 Gy). Among locally advanced rectal/rectosigmoid cases, surgery included abdominoperineal resection (n = 3) or low anterior resection (n = 9). Seven treated sites had gross residual (R2) disease, 28 had pathologic or clinical microscopic residual disease (R1), and 15 were complete resections (R0). Treated sites included sacrum (n = 22), anterior pelvis/pelvic sidewall (19), sacrum and sidewall (n = 1), aortic bifurcation (n = 2), vaginal cuff (n = 2), psoas (n = 3), perivesicular region (n = 2), and other (n = 10).

MAIN OUTCOMES MEASURES

Outcomes measures included in-field local control, locoregional control, overall survival, and grade ≥3 toxicity.

RESULTS

At a median follow-up of 27 months (range, 4-237) among living patients, 2-year Kaplan-Meier estimates of in-field local control, locoregional control, and overall survival were 69%, 51%, and 59%. Margin status predicted for improved locoregional control (p = 0.01) and overall survival (p = 0.01). Seventeen patients (31%) developed a grade 3 to 5 toxicity following surgery with intraoperative radiotherapy.

LIMITATIONS

This study was limited by its retrospective nature and relatively small sample size.

CONCLUSIONS

Local control with intraoperative radiotherapy for locally advanced and recurrent colorectal cancers is good despite the high risk of residual disease. Among carefully selected patients, multimodality regimens including intraoperative radiotherapy may permit long-term survival.