Changes of tumor and normal structures of the neck during radiation therapy for head and neck cancer requires adaptive strategy

Abstract

Radiation therapy (RT) in general requires a treatment period of 5 to 7 weeks. Tumor shrinkage in response to RT and weight loss due to radiationinduced mucositis may impact on the dose distribution in both target and organ at risk in patients Abstract : The treatment period over which radiation therapy is administered extends over several weeks. Since tumor shrinkage in response to radiation therapy and weight loss due to radiation-induced mucositis may impact on the dose distribution in both target and organ at risk in patients with head and neck cancer, the anatomical changes of tumor and neck volumes during this period should be taken into consideration. We investigated the anatomical changes that occurred in the target and normal structure of the neck during radiation therapy for pharyngeal cancer, and evaluated the necessity of an adaptive strategy. Ten patients with pharyngeal cancer who underwent radical chemoradiation therapy using 3-dimensional conformal radiation therapy RT ( ORIGINAL Changes

Head and neck adaptive radiotherapy: Predicting the time to replan

“…Replanned patients underwent a re‐CT significantly earlier than those patients who were not replanned, with intervention occurring in week four and week five, respectively. Different time points that may be optimal for adaptive intervention have been proposed (Table ) . Parotid gland volume change dominates this decision and reimaging and replanning is often suggested in the first half of treatment .…”

Identifying patients who may benefit from adaptive radiotherapy: Does the literature on anatomic and dosimetric changes in head and neck organs at risk during radiotherapy provide information to help?

“…Fifty-two potentially eligible records were found in MEDLINE and EMBASE, and forty-four additional papers were extracted from reference lists. We excluded twenty-eight records as they were conference abstracts, two studies because only the abstract was available [21,22], and two papers because their journal was not part of the Thomson Reuters journal citation reports Ò [23,24]. Furthermore, three papers were excluded as they were general reviews on image guided radiotherapy (IGRT) and ART [9,19,25].…”

Long‐term outcome of 18F‐fluorodeoxyglucose‐positron emission tomography‐guided dose painting for head and neck cancer: Matched case‐control study

“…Acute toxicity was prospectively scored on a weekly basis during treatment. Scoring of late toxicity was done prospectively at months 1,3,6,9,12,16,20, and 24, and halfyearly thereafter. From the fifth year on, patients were followed yearly.…”

“…Complexity of the tumor as a biologically heterogeneous and dynamic ecosystem challenges the current practice of fractionated radiotherapy using uniform dose distributions without treatment adaptation over several weeks. This can lead to a mismatch in relation to the nonuniform and nonstatic biological characteristics of the tumor . Applying dose painting that maps radiation dose to tumor radiobiology‐relevant abnormalities, as detected by biological imaging, presents an attractive alternative.…”

“…This can lead to a mismatch in relation to the nonuniform and nonstatic biological characteristics of the tumor. 1 Applying dose painting that maps radiation dose to tumor radiobiology-relevant abnormalities, as detected by biological imaging, 2,3 presents an attractive alternative. In 2003, a hypothesis that 18 F-fluorodeoxyglucose-positron emission tomography ( 18 F-FDG-PET) of head and neck cancer could detect intratumoral subvolumes of radioresistance and, thus, guide dose escalation 4 underlay our first dose-painting clinical trial conducted in 2003-2005.…”