Abstract 876
Background
To investigate the feasibility and benefits of target re-delineation and dose prescription for adaptive replanned radiotherapy in nasopharyngeal carcinoma (NPC) patients who underwent intensity-modulated radiotherapy (IMRT).
Methods
Fifty-four consecutive NPC patients who underwent IMRT were enrolled in this study. The replanning CT (CT-II) for each patient was generated at the 22nd fraction of the IMRT. In Plan-I, GTVnx-I was defined as all detected gross disease. The high-risk clinical target volume (CTV1-I), as subclinical disease consisting of a 1-cm margin surrounding the GTVnx-I. The low-risk clinical target volume (CTV2), as a 0.5- to 1.0-cm margin surrounding the CTV1-I. In Plan-II, the GTVnx-II, as all detected gross disease detected after 22 fractions. CTV1-II maintained the extent of the originally irradiated CTV1-I, including the area in which the tumor disappeared/dissolved after 22 fractions. The CTV2 was not delineated. The doses prescribed were as follows: Plan-I: PGTVnx/rpn/nd 53-54 Gy/25 F; PCTV1/nd 47.5-48 Gy/25 F; PCTV2 45 Gy/25 F; and Plan-II: PGTVnx/rpn/nd: 15-15.5 Gy/7 F; PCTV1/nd 13.5 Gy/7 F. The parameters were compared. Clinical outcomes and toxicities were evaluated.
Results
The median reductions in the GTVnx, GTVnd-R, bilateral parotids and bilateral submandibular glands were 25.07%, 38.17%, 23.43% (left), 21.12% (right), 23.37% (left) and 23.00% (right) (P < 0.05), respectively; bilateral RPLN and GTVnd-L exhibited median reductions of 22.50% (left), 25.00% (right), and 32.80% (P > 0.05), respectively. The average V95% of PGTVnx reached nearly 100% in the two plans. Plan-II significantly reduced the Dmean% in the optic chiasma, thyroid gland, hypopharynx, spinal cord, brain stem, pituitary, oropharynx and oral cavity compared with Plan-A (P < 0.05). Recurrence did not occur in the regression area, and the acute reactions were mild. The 3-year OS/LRFFS/DMFS rates were 93.3%/90.5%/91.4%, respectively.
Conclusions
Adaptive replanned IMRT in NPC provided a new perspective for target re-delineation and dose prescription. The results of this study showed significant dosimetric and clinical benefits without recurrence and reducing survival.
Clinical trial identification
Legal entity responsible for the study
Sun Yat-sen University Cancer Center.
Funding
Has not received any funding.
Editorial Acknowledgement
Disclosure
The author has declared no conflicts of interest.
Resources from the same session
1159 - Molecular characterization and search for founding effects in Canarian families with Hereditary Breast and Ovarian Cancer Syndrome
Presenter: Elisenda Llabres Valenti
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
3725 - Effect of the polymorphism rs2066844 of the NOD2 gene on colon cancer incidence in a high cardiovascular risk population. Modulation by gender
Presenter: Judith Begona Ramirez Sabio
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
3708 - Effect of the polymorphisms rs1476413, rs1801131, rs4846052 and rs6541003 of the MTHFR gene on prostate cancer in a high cardiovascular risk population
Presenter: Judith Begona Ramirez Sabio
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
5057 - Association of a genetic variant in cyclin-dependent kinase Inhibitor 2A gene with the increased risk of breast cancer
Presenter: Soodabeh Shahid Sales
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
5970 - Investigating the role of HAT protein TIP60 in regulating functional dynamics of nuclear receptor PXR
Presenter: KARISHMA BAKSHI
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
1360 - The role of downregulated SIRT3 expression in patients with hepatocellular carcinoma
Presenter: Hanhee Jo
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
1634 - Prediction and Intervention of Colorectal Cancer Risk with Artificial Intelligent System
Presenter: Yang Ge
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
4921 - Measuring the Efficiency of Cancer Care in Europe
Presenter: Rikard Althin
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
1235 - Circulating cell-free DNA isolated from plasma of mesenteric veins predicts prognosis in stage II colorectal cancer patients
Presenter: Chih-Yung Yang
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract
5169 - _lonality of uterine carcinosarcoma as a factor of clinical prognosis.
Presenter: Natalia Levitskaya
Session: Poster display session: Basic science, Endocrine tumours, Gastrointestinal tumours - colorectal & non-colorectal, Head and neck cancer (excluding thyroid), Melanoma and other skin tumours, Neuroendocrine tumours, Thyroid cancer, Tumour biology & pathology
Resources:
Abstract