Intensity-modulated radiation therapy for early-stage breast cancer: is it ready for prime time?

Abstract

Whole breast external beam radiotherapy (WBEBRT) is commonly used as an essential arm in the treatment management of women with early-stage breast cancer. Dosimetry planning for conventional WBEBRT typically involves a pair of tangential fields. Advancement in radiation technology and techniques has the potential to improve treatment outcomes with clinically meaningful long-term benefits. However, this advancement must be balanced with safety and improved efficacy. Intensity-modulated radiation therapy (IMRT) is an advanced technique that shows promise in improving the planning process and radiation delivery. Early data on utilizing IMRT for WBEBRT demonstrate more homogenous dose distribution with reduction in organs at risk doses. This translates to toxicities reduction. The two common descriptors for IMRT are forward-planning “fields in field” and inverse planning. Unlike IMRT for other organs, the aim of IMRT for breast planning is to achieve dose homogeneity and not organ conformality. The aim of this paper was to evaluate whether IMRT is ready for prime time based on these three points: 1) workload impact, 2) the clinical impact on the patient’s quality of life, and 3) the appropriateness and applicability to clinical practice.

Impact of patient and treatment characteristics on heart and lung dose in adjuvant radiotherapy for left-sided breast cancer

“…This may be explained by patient selection, since IMRT/VMAT was often used in challenging cases for which tangential fields were deemed unsuitable, such as large breasts or patients with a sunken chest (pectus excavatum). Still, when considering use of intensity-modulated RT techniques, a presumed benefit in dose homogeneity, conformity and target coverage needs to be weighed against potentially increased low-dose exposure, as well as workload and costs, on an individual basis [21, 22]. Similarly, factors affecting cosmesis and quality of life, such as lymphedema, as well as the more short-term risk of radiation pneumonitis, may outweigh the risk of late effects in RT planning, depending on patient age and comorbidities [21, 23].…”

“…Still, when considering use of intensity-modulated RT techniques, a presumed benefit in dose homogeneity, conformity and target coverage needs to be weighed against potentially increased low-dose exposure, as well as workload and costs, on an individual basis [21, 22]. Similarly, factors affecting cosmesis and quality of life, such as lymphedema, as well as the more short-term risk of radiation pneumonitis, may outweigh the risk of late effects in RT planning, depending on patient age and comorbidities [21, 23]. Future studies will therefore need to systematically address long-term outcomes to assess the true benefits of different delivery techniques used for breast RT.…”

Dosimetric evaluation and systematic review of radiation therapy techniques for early stage node-negative breast cancer treatment

“…IMRT is the utility of multileaf collimator (MLC) technology to shape and create non-uniform intensity of radiation beams as it transverse through the patient’s body. 46 , 47 By varying the speeds at which the MLC leaves travel or the shape of the beam, the radiation beam is effectively shaped to vary the dose distribution to the target volume. 47 …”

“… 46 , 47 By varying the speeds at which the MLC leaves travel or the shape of the beam, the radiation beam is effectively shaped to vary the dose distribution to the target volume. 47 …”

Two-Level Factorial Pre-TomoBreast Pilot Study of Tomotherapy and Conventional Radiotherapy in Breast Cancer: Post Hoc Utility of a Mean Absolute Dose Deviation Penalty Score

“… 26 “Conventional” RT at the UZ Brussel implemented the earliest inception of breast IMRT as later described by others. 27 , 28 Tomotherapy was barely starting, and few had much or any experience with its use in breast cancer as shown in a correspondence that highlighted and corrected dosimetric shortcomings. 9 Both breast “conventional” RT and IP-IMRT performed in the pre-TomoBreast experiment were in their infancy; therefore, one should be cautious against transposing today.…”