Fractionated Grid Therapy in Treating Cervical Cancers: Conventional Fractionation or Hypofractionation?

Journal Article · Tue Jan 01 04:00:00 EST 2008 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2007.08.024· OSTI ID:21039730

Wang, Jian Z; Mayr, Nina; Xiang, Kong; Jiankui, Yuan; Gupta, Nilendu; Lo, Simon; Grecula, John; Montebello, Joseph; Martin, Douglas ^[1]; Yuh, William ^[2]

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1. Department of Radiation Medicine, Ohio State University, Columbus, OH (United States)
2. Department of Radiology, Ohio State University, Columbus, OH (United States)

Purpose: To evaluate the conventionally fractionated and hypofractionated grid therapy in debulking cervical cancers using the linear quadratic (LQ) model. Methods and Materials: A Monte Carlo technique was used to calculate the dose distribution of a commercially available grid in a 6-MV photon beam. The LQ model was used to evaluate the therapeutic outcome of both the conventionally fractionated (2 Gy/fraction) and hypofractionated (15 Gy/fraction) grid therapy regimens to debulk cervical cancers with different LQ parameters. The equivalent open-field dose (EOD) to the cancer cells and therapeutic ratio (TR) were defined by comparing grid therapy with the open debulking field. The clinical outcomes from 114 patients were used to verify our theoretical model. Results: The cervical cancer and normal tissue cell survival statistics for grid therapy in two regimens were calculated. The EODs and TRs were derived. The EOD was only a fraction of the prescribed dose. The TR was dependent on the prescribed dose and the LQ parameters of both the tumor and normal tissue cells. The grid therapy favors the acutely responding tumors inside radiosensitive normal tissues. Theoretical model predictions were consistent with the clinical outcomes. Conclusions: Grid therapy provided a pronounced therapeutic advantage in both the hypofractionated and conventionally fractionated regimens compared with that seen with single fraction, open debulking field regimens, but the true therapeutic advantage exists only in the hypofractionated grid therapy. The clinical outcomes and our study indicated that a course of open-field radiotherapy is necessary to control tumor growth fully after a grid therapy.

• OSTI ID: 21039730
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 70; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
FRACTIONATED IRRADIATION
MONTE CARLO METHOD
NEOPLASMS
PATIENTS
PHOTON BEAMS
RADIATION DOSE DISTRIBUTIONS
RADIATION DOSES
RADIOTHERAPY