Treatment planning of epithelial ovarian cancers using helical tomotherapy.
Whole Abdomen Radiotherapy (WAR) for epithelial ovarian cancer though effective has been used sparingly due to inadequate target coverage and poor sparing of Organ At Risk (OAR) leading to significantly higher toxicities. Newer radiation techniques have shown potential for significant improvement in the therapeutic ratio. The purpose of this study was to evaluate Helical Tomotherapy(HT) for WAR. The objective parameters were to obtain uniform and adequate target coverage with maximum OAR sparing. HT plans were generated for five patients with field-width of 5.0/2.5 cm, modulation factor of 3.5/3.0, and a pitch of 0.3. A dose of 25 Gy in 25 fractions was prescribed to the abdomen with a simultaneous boost of 45 Gy in 25 fractions to the pelvis. Dose-volume parameters and various indices were analyzed and compared. Mean volume (standard-deviation) of abdominal and pelvic PTV (planning target volume) was 6630 +/-450 cm3 and 1235 +/-98 cm3 respectively. Mean length of PTV in cranio-caudal direction was 41+/-4 cm. Volume receiving 95% and 107% of the prescription dose, (V95% and V107%) was 95.6+/-2.7% and 2.6+/-0.5% for abdominal-PTV, and 95.7+/-2.4% and 0% for pelvic-PTV respectively. Homogeneity and Conformity indices were 17.5+/-1.7, 1.2+/-0.03 for abdominal PTV, and 5.2+/-0.7, 1.1+/-0.02 for pelvic-PTV respectively. Median dose received by the kidneys, liver and bone marrow were 9.6+/-1.2 Gy, 17+/-2.7 Gy and 22+/-1.4 Gy respectively. HT achieves an excellent coverage of WAR target with simultaneous pelvic boost and better organ (kidneys and liver) sparing. HT for WAR has the potential as consolidative therapy which is being evaluated further in a phase II cohort study in epithelial ovarian cancers.
Jamema
Swamidas V
SV
Department of Medical Physics, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, India.
Mahantshetty
Umesh
U
Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, India.
Goel
Vineeta
V
Department of Radiation Oncology, Advanced Center for Training Research and Education in Cancer, Tata Memorial Center, Kharghar, Navi Mumbai, India.
Engineer
Reena
R
Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, India.
Deshpande
Deepak D
DD
Department of Medical Physics, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, India.
Sarin
Rajiv
R
Department of Radiation Oncology, Advanced Center for Training Research and Education in Cancer, Tata Memorial Center, Kharghar, Navi Mumbai, India.
Shrivastava
Shyam Kishore
SK
Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Mumbai, India.
D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D009375:Neoplasms, Glandular and Epithelial / Q000532:radiotherapy*; D010051:Ovarian Neoplasms / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D054894:Spiral Cone-Beam Computed Tomography / Q000379:methods*