Mehta A, Kumar P, Navitha S, Silambarasan N. Incidental dose to internal mammary nodes in adjuvant radiation of post mastectomy patients. Int J Radiat Res 2025; 23 (3) :823-827
URL:
http://ijrr.com/article-1-6685-en.html
Department of Radiation Oncology, Shri Ram Murti Institute of Medical Sciences Bareilly, India , rtbareilly@gmail.com
Abstract: (28 Views)
Background: The elective irradiation of internal mammary nodes (IMN) has not been preferred, attributable to the low incidental doses delivered and the effect of systemic therapies. This study analyzed the incidental dose delivered to IMN using routine planning techniques. Materials and Methods: Twenty post-MRM patients who received adjuvant radiotherapy were selected. The CTV included the chest wall with axillary/supraclavicular lymph nodes if indicated, and a 5mm expansion was taken (PTV-planning). For study purposes, IMRT and 3DCRT plans were generated for each patient. Retrospectively, IMN was delineated, and a margin of 5 mm was taken (PTV-IMN). The dosimetry of the two techniques was compared. Results: An average of 65.03% (SD - 12.45) volume of the PTV-IMN was overlapping with PTV_planning. No significant difference between 3DCRT and IMRT was found in any of the dose parameters of PTV-IMN. The volume of PTV-IMN included inside the PTV_planning had a significant correlation with the mean dose of PTV-IMN for both 3DCRT (r=0.46, p=0.04) and IMRT (r=0.62, p=0.004). A weak positive correlation was observed between the Dmean of PTV-IMN and PTV-planning (r=0.025) and the Dmean of PTV-IMN and heart (r=0.33). The IMRT technique led to improved coverage of PTV-planning, while the heart dose favoured the 3DCRT technique. Conclusion: The treatment technique did not impact the incidental IMN doses. The IMRT led to better coverage of target volume, as reflected by a few of the dose parameters, but this did not impact the IMN doses.
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