Linked Life Data

15922178

Source:http://linkedlifedata.com/resource/pubmed/id/15922178

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2005-5-30
pubmed:abstractText
Three recently published randomized trials have shown a survival benefit to postoperative radiation therapy when the internal mammary chain (IMC), supraclavicular (SCV), and axillary lymphatics are treated. When treating the IMC, techniques that minimize dose to the heart and lungs may be utilized to prevent excess morbidity and mortality and achieve the survival benefit reported. The purpose of this study was to dosimetrically compare forward-planned intensity-modulated radiation therapy (fIMRT) with conventional techniques for comprehensive irradiation of the chest wall and regional lymphatics. For irradiation of the chest wall and IMC, 3 treatment plans, (1) fIMRT, (2) partially-wide tangent (PWT) fields, and (3) a photon-electron (PE) technique, were compared for 12 patients previously treated at our institution with fIMRT to the left chest wall and regional lymphatics. Additionally, the SCV and infraclavicular lymphatics were irradiated and 4 methods were compared: 2 with anterior fields only (dose prescribed to 3 and 5 cm [SC3cm, SC5cm]) and 2 with anterior and posterior fields (fIMRT, 3DCRT). Each patient was planned to receive 50 Gy in 25 fractions. Regions of interest (ROIs) created for each patient included chest wall (CW) planning target volume (PTV), IMC PTV, and SCV PTV. Additionally, the following organs at risk (OAR) volumes were created: contralateral breast, heart, and lungs. For each plan and ROI, target volume coverage (V(95-107)) and dose homogeneity (D(95-5)) were evaluated. Additionally, the mean OAR dose and normal tissue complication probability (NTCP) were computed. For irradiation of the CW, target volume coverage and dose homogeneity were improved for the fIMRT technique as compared to PE (p < 0.001, p = 0.023, respectively). Similar improvements were seen with respect to IMC PTV (p = 0.012, p = 0.064). These dosimetric parameters were also improved as compared to PWT, but not to the same extent (p = 0.011, p = 0.095 for CW PTV, and p = 0.164, p > 0.2 for IMC PTV). The PE technique resulted in the lowest heart V30, although this difference was not significant (p > 0.2). The NTCP values for excess cardiac mortality for fIMRT and PE were equivalent (1.9%) and lower than with PWT (2.8%, p > 0.2). The fIMRT technique was able to reduce heart dose and NTCP for each patient as compared to PWT. When comparing the anterior field techniques of treating SCV PTV, prescribing dose to 5 cm resulted in a improved V50 (p = 0.089). However, when compared to fIMRT, the SC3cm and SC5cm had inferior target volume coverage (p = 0.055, p = 0.014) and significantly greater dose heterogeneity (p = 0.031, p = 0.043). The addition of a posterior field increased the volume of lung receiving 40 and 50 Gy, but not significantly (p > 0.2). For complex breast treatments that irradiate the chest wall, IMC, and SCV, fIMRT resulted in improved dose homogeneity and target volume coverage as compared to conventional techniques. Furthermore, the dosimetric gains in target volume coverage with fIMRT came at no significant increase in dose to OAR. The fIMRT technique demonstrated the ability to maintain the advantage of each of the other 2 techniques: reducing the dose to OARs, as with PE, and providing superior target volume coverage, as with PWT.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:issn
0958-3947
pubmed:author
pubmed:issnType
Print
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
107-16
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Dosimetric comparison of conventional and forward-planned intensity-modulated techniques for comprehensive locoregional irradiation of post-mastectomy left breast cancers.
pubmed:affiliation
Department of Radiation Oncology, University of Texas Medical Branch, Galveston, TX 77555-0711, USA. mlcavey@utmb.edu
pubmed:publicationType
Journal Article, Comparative Study