TITLE:
How Safe Are Reduced Doses per Fraction in Target Volumes of 2nd to 4th Order in the Simultaneous Integrated Boost Irradiation Technique in Head and Neck Carcinoma Patients?
AUTHORS:
A. Buchali, C. Schroeder, C. Boerrnert, I. Maekelburg, W. Huhnt, A. Franzen
KEYWORDS:
Head and Neck Carcinoma, Simultaneous Integrated Boost Technique, Dose Painting, Dose per Fraction, Recurrence Risk
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.6 No.2,
February
12,
2015
ABSTRACT: Aim: The simultaneous irradiation of
target volumes of different total dose levels using intensity modulated
radiotherapy leads to reduced doses per fraction and longer treatment times in
target volumes of 2ndto
4thorder. Does the
thereby caused reduced biological effectiveness induce an increased recurrence
risk? The current work deals with the problem of recurrences of patients with
head and neck carcinomas treated either with an intensitiy (IMRT) or with a
volumetric modulated (VMAT) irradiation technique. Methods: From October 2002
to September 2014, 699 patients with carcinomas of the head and neck were
irradiated using IMRT or VMAT. The median follow up of the patients was 21.9
months (2 to 145 months). Primary tumor regions (1storder target volume) of 565 patients
were treated with doses per fraction of 2 Gy. Accordingly, further 133 target
volumes of the primary tumor received reduced doses per fraction. In 1 patient,
the lymphatic drainage was treated solely without irradiation of the primary
region. For the lympatic drainage, 854 1storder target volumes were treated with
a dose per fraction of 2 Gy. Reduced doses per fraction were applied to further
1780 target volumes. Results: 54 of 699 patients developed a recurrence in the
primary tumor region after radio-(chemo) therapy, 4 patients developed a
recurrence of the primary tumor and a unilateral recurrence of the lymphatic
drainage, 2 patients a recurrence of the primary tumor and a bilateral lymph
node recurrence. 18 patients showed an isolated unilateral recurrence and
additionally 2 patients a bilateral recurrence of the lymphatic drainage. 619
patients stayed recurrence free. In primary tumor regions, receiving a dose per
fraction of 2 Gy 55 patients (9.7%) developed a recurrence, whereas in target
volumes receiving a reduced dose per fraction 5 patients (3.8%) developed a
recurrence (p ndto 4thorder was not increased due to reduced
doses per fraction deposited by means of a simultaneous integrated boost
technique. Therefore, the simultaneous irradiation of target volumes with
different dose levels is safely applicable within one treatment plan.