Aims: To explore the impact of seroma volume reduction on dosimetry during whole breast radiation therapy (WBRT) and evaluate the significance of adaptive planning.
Presentation of Case: A 71-year-old female with left breast invasive carcinoma underwent lumpectomy and radiotherapy. An initial CT (CT1) six weeks taken post-op showed a seroma cavity, and a second CT (CT2) five weeks later documented a 65% seroma volume reduction (from 217 c.c. to 75 c.c.). Five radiotherapy techniques were evaluated: two-field conventional, three-field conventional, forward IMRT, inverse IMRT, and VMAT. Inverse IMRT and VMAT achieved better high-dose coverage and reproducibility but had larger dose variations. They also showed higher maximum doses and increased hot spot volumes, indicating potential overdosage risks. Conventional techniques provided stable lower-dose coverage but less uniform high-dose distribution compared to IMRT and VMAT.
Discussion: The significant reduction in seroma volume affected dosimetry, highlighting the importance of adaptive planning. In this case, daily KV and weekly MV imaging were used for alignment, but CBCT may better monitor seroma changes. Adaptive radiotherapy, repeated CT simulations, and CBCT are essential for effective treatment. Further research should focus on improving treatment precision through advanced imaging and radiotherapy technologies.
Conclusion: This single WBRT case highlights the dosimetric impact of seroma reduction and the importance of imaging and adaptive strategies. Advanced techniques like inverse IMRT and VMAT improve precision but need careful IGRT monitoring. These findings emphasize the need for individualized adaptive planning considerations and further research to optimize protocols for managing seroma volume changes during WBRT.
Author(s) Details:
Yen Cho Huang
Department of Radiation Oncology, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan.
Jih Hsiang Yeh
Department of Radiation Oncology, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan.
Chien Sheng Tsai
Department of Radiation Oncology, Keelung Chang Gung Memorial Hospital, Keelung, Taiwan.
Recent Global Research Developments in Advances in Whole Breast Radiation Therapy: Techniques and Outcomes
Hypo-fractionated Whole Breast Irradiation (WBI): Traditionally, WBI was delivered over 5-7 weeks following breast-conserving surgery (BCS). However, hypo-fractionated WBI has become the standard approach, reducing treatment duration to 3-4 weeks [1] . Additionally, five-fraction WBI regimens have emerged based on data from the FAST and FAST-Forward trials.
Partial Breast Irradiation (PBI): PBI is an alternative to WBI for early-stage breast cancer patients after BCS. It reduces treatment duration and the volume of irradiated breast tissue. Multiple randomized trials with over 10-year follow-ups have demonstrated the safety and efficacy of PBI approaches.
Single-Fraction Intraoperative RT: Although evaluated in two prospective trials, its utilization outside of studies is not supported by current guidelines [1] .
Lymph Node RT: Hypofractionated approaches are safe for patients undergoing BCS or mastectomy without reconstruction [1] .
Future Directions: Research is ongoing to explore even shorter regimens and evaluate the omission of RT versus endocrine therapy for favorable-risk patients. Additionally, studies are assessing shorter radiation courses in breast reconstruction patients and using tumor genomics to identify suitable candidates for radiation omission [1] .
References
- Shah, C., Al-Hilli, Z., & Vicini, F. (2021). Advances in breast cancer radiotherapy: implications for current and future practice. JCO oncology practice, 17(12), 697-706.
