Initial outcomes with image‐guided partial breast irradiation delivered with intensity‐modulated radiation therapy

Abstract

Patients were treated at a single institution to a dose of 30 Gy in five fractions delivered every other day using image‐guided intensity modulated radiation therapy (IMRT) partial breast irradiation. A total of 34 patients were treated with a median follow‐up of 4.6 months. The rate of acute Grade 1 dermatitis was 23.5% (n = 8), and Grade 1 fatigue was 17.6% (n = 6), with no Grade 2 or higher acute toxicities. The rate of chronic Grade 1 dermatitis was 25.0% (n = 6), Grade 1 fat necrosis 4.2% (n=1), with no patients demonstrating other chronic toxicities. Image‐guided APBI delivered with IMRT is associated with low rates of acute and chronic toxicity though additional follow‐up is warranted.

Five Fraction External Beam Partial Breast Irradiation

“…Given the long-term outcomes, patient convenience, and ease of administration, we recommend daily fractionation over BID for external beam PBI. The most extensive evidence is for 30 Gy in 5 fractions for PBI 1,28,29. The FAST-Forward WBI fractionation of 26 Gy in 5 fractions is increasingly used in Europe for PBI, although there is no direct clinical evidence for its use in PBI 5,30.…”

“…PBI trials utilized free breathing treatment and this remains an acceptable option, however in an effort to decrease organ-at-risk (OAR) dose, patients can be treated with respiratory control. Options range from the simplest form of deep-inspiration breath hold to more complex forms utilizing tracking-and-trailing or breath hold devices 29…”

“…At the heart of PBI is the ability to accurately delineate the tumor bed, often described as the surgical cavity and representative clips on simulation CT. There should be a 0.5 to 1.0 cm CTV expansion 29. In addition to the simulation CT, physicians should also utilize pre-operative physical exam, imaging, operative report, and pathology report to guide detailed contouring.…”

“…Options range from the simplest form of deep-inspiration breath hold to more complex forms utilizing tracking-and-trailing or breath hold devices. 29 If a patient is found to have a large seroma, > 5 cm in size or > 1/3 of the breast, one should consider seroma aspiration. If the seroma is aspirated, repeat simulation should take place a minimum of 1 to 2 days later to allow for the expected re-accumulation of fluid.…”

Accelerated Partial Breast Irradiation

“…Data from the Cleveland Clinic incorporated deep inspiratory breath hold in conjunction with daily cone-beam computed tomography; incorporating advanced planning and treatment delivery allowed for reductions in target margins from 2 to 1 cm. 47 The transition to conformal, highly accurate delivery of external beam PBI that delivers high doses in as few as 5 fractions requires complex planning and delivery which can be considered consistent with stereotactic body RT (SBRT), which the American Association of Physicists in Medicine defines as, "the delivery of large doses in a few fractions, which results in a high biological effective dose (BED). In order to minimize the normal tissue toxicity, conformation of high doses to the target and rapid fall-off doses away from the target is critical.…”