Chemoradiotherapy for locally advanced pancreatic cancer: a radiotherapy dose escalation and organ motion study.
OBJECTIVE
To determine the efficacy of radiation dose escalation and to examine organ motion during conformal radiotherapy for locally advanced pancreatic cancer.


METHODS
Thirty-nine patients who were consecutively treated with chemoradiotherapy were studied. Fifteen patients, treated from 1993 to 1997, received 50 Gy in 20 fractions (group I). Twenty-four patients, treated from 1997 to 2003, received an escalated dose of 55 Gy in 25 fractions (group II). Intra-fraction pancreatic tumour motion was assessed in three patients using megavoltage movies during radiation delivery to track implanted radio-opaque markers.


RESULTS
Improved survival rates were seen in latterly treated group II patients (P=0.083), who received escalated radiotherapy to smaller treatment volumes due to advances in verification. Worse toxicity effects (World Health Organization grade 3-4) were reported by some patients (<10%), but treatment compliance was similar in both groups, indicating equivalent tolerance. Substantial intra-fraction tumour displacement due to respiratory motion was observed: this was greatest in the superior/inferior (mean=6.6 mm) and anterior/posterior (mean=4.75 mm) directions. Lateral displacements were small (<2 mm).


CONCLUSIONS
Dose escalation is feasible in pancreatic cancer, particularly when combined with a reduction in irradiated volume, and enhanced efficacy is indicated. Large, globally applied margins to compensate for pancreatic tumour motion during radiotherapy may be inappropriate. Strategies to reduce respiratory motion, and/or the application of image-guided techniques that incorporate individual patients' respiratory motion into radiotherapy planning and delivery, will probably improve pancreatic radiotherapy.
Henry
A M
AM
Academic Department of Radiation Oncology, The University of Manchester, Department of Medical Statistics, Christie Hospital NHS Trust, Manchester, UK.
Ryder
W D J
WD
Moore
C
C
Sherlock
D J
DJ
Geh
J I
JI
Dunn
P
P
Price
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use; D003131:Combined Modality Therapy; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000145:classification; D012189:Retrospective Studies
D000970:Antineoplastic Agents