Comparison of two different IMRT planning techniques in the treatment of nasopharyngeal carcinoma

Abstract

Normal tissues--particularly the parotid glands--are better spared with the arc technique in patients with NPC. MU and treatment times are considerably reduced in arc IMRT plans.

Concurrent chemoradiotherapy by simultaneously integrated boost volumetric‐modulated arc therapy for nasopharyngeal carcinoma‐toxicity/quality of life and survival

“…With a primary focus on sparing the parotids, many clinical studies have proved the significant reduction of xerostomia after IMRT relative to the conventional technique . Further mean dose reduction of the parotids by SIB‐VMAT compared to SIB‐IMRT has been achieved in NPC planning . Although xerostomia remains the most common late toxicity for NPC survivors in our patients or other studies, the severity has remarkably reduced.…”

“…Different from other anatomic sites of head and neck cancer, NPC survivors presented some specific late toxicities related to the irradiation field, such as ototoxicity, temporal lobe necrosis, or cranial nerve palsy. In addition to parotid sparing, SIB‐VMAT also provides dosimetric benefits in the critical structures of skull base, temporal lobe, and ear structure for NPC planning . Cisplatin and irradiation are known to be toxic to hearing and ototoxicity remains one the most commonly encountered late toxicities for NPC patients treated by CCRT .…”

“…VMAT was made with an attempt to further increment the therapeutic window of IMRT in cancer treatment. Dual arc VMAT has been reported to have a dosimetric advantage regarding the target coverage or sparing of some organs at risk (OARs) compared to 7‐field fixed beam IMRT in NPC patients …”

Slug inhibition increases radiosensitivity of nasopharyngeal carcinoma cell line C666‑1

“…Radiotherapy was the mainstay treatment for NPC due to its relatively high radiosensitivity and deep-seated anatomical position, which made surgical resection challenging (6). In addition, great technological advances have been made in radiotherapy, including three-dimensional conformal radiotherapy and intension-modulated radiotherapy (7,8). However, due to irradiation resistance, some patients with NPC present with metastases following radiotherapy (5).…”

Beam path toxicity in candidate organs-at-risk: Assessment of radiation emetogenesis for patients receiving head and neck intensity modulated radiotherapy

“…While 3D-conformal planning is used in many cases internationally[3], the dosimetric superiority of step-and-shoot IMRT[4,5], as well as potential further conformality gains in arc-based variants[6-8], offers the advantage of improved tumor target coverage and critical normal tissue sparing[1], compared to 3D-conformal planning[9-11]. However, IMRT beam paths traverse normal tissues that may not have been directly irradiated in previous 2D and 3D techniques[2,12,13], resulting in distinct toxicity profiles from those seen in the pre-conformal radiotherapy era.…”