Long-term outcomes in breast cancer patients with ten or more positive axillary nodes treated with combined-modality therapy: the importance of radiation field selection

PURPOSE: To determine the long-term outcome of a consistent treatment approach with electron beam postmastectomy radiation therapy (PMRT) in breast cancer patients with > or =10 positive nodes treated with combined-modality therapy. METHODS AND MATERIALS: TSixty-three breast cancer patients with > or =10 positive lymph nodes were treated with combined-modality therapy using an electron beam en face technique for PMRT at the University of Florida. Patterns of recurrence were studied for correlation with radiation fields. Potential clinical and treatment variables were tested for possible association with local-regional control (LRC), disease-free survival (DFS), and overall survival (OS). RESULTS: TAt 5, 10, and 15 years, OS rates were 57%, 36%, and 27%, respectively; DFS rates were 46%, 37%, and 34%; and LRC rates were 87%, 87%, and 87%. No clinical or treatment variables were associated with OS or DFS. The use of supplemental axillary radiation (SART) (p = 0.012) and pathologic N stage (p = 0.053) were associated with improved LRC. Patients who received SART had a higher rate of LRC than those who did not. Moderate to severe arm edema developed in 17% of patients receiving SART compared with 7% in patients not treated with SART (p = 0.28). CONCLUSIONS: TA substantial percentage of patients with > or =10 positive lymph nodes survive breast cancer. The 10-year overall survival in these patients was 36%. The addition of SART was associated with better LRC.     

Caractérisation des rechutes locorégionales chez des patientes atteintes d’un cancer du sein traité par irradiation pariétale par électrons : expérience monocentrique de l’institut Curie

Purpose

The purpose of this study was to evaluate locoregional control and describe the patterns of locoregional failure in women with breast cancer irradiated by a previously described post-mastectomy highly conformal electron beam radiotherapy technique.

Comparison of modulated electron radiotherapy to conventional electron boost irradiation and volumetric modulated photon arc therapy for treatment of tumour bed boost in breast cancer

Background and purpose

To compare few leaf electron collimator (FLEC)-based modulated electron radiotherapy (MERT) to conventional direct electron (DE) and volumetric modulated photon arc therapy (VMAT) for the treatment of tumour bed boost in breast cancer.

Materials and methods

Fourteen patients with breast cancer treated by lumpectomy and requiring post-operative whole breast radiotherapy with tumour bed boost were planned retrospectively using conventional DE, VMAT and FLEC-based MERT. The planning goal was to deliver 10 Gy to at least 95% of the tumour bed volume. Dosimetry parameters for all techniques were compared.

Results

Dose evaluation volume (DEV) coverage and homogeneity were best for MERT (D₉₈ = 9.77 Gy, D₂ = 11.03 Gy) followed by VMAT (D₉₈ = 9.56 Gy, D₂ = 11.07 Gy) and DE (D₉₈ = 9.81 Gy, D₂ = 11.52 Gy). Relative to the DE plans, the MERT plans predicted a reduction of 35% in mean breast dose (p < 0.05), 54% in mean lung dose (p < 0.05) and 46% in mean body dose (p < 0.05). Relative to the VMAT plans, the MERT plans predicted a reduction of 24%, 36% and 39% in mean breast dose, heart dose and body dose, respectively (p < 0.05).

Conclusions

MERT plans were a considerable improvement in dosimetry over DE boost plans. There was a dosimetric advantage in using MERT over VMAT for increased DEV conformity and low-dose sparing of healthy tissue including the integral dose; however, the cost is often an increase in the ipsilateral lung high-dose volume.     

Distinguishing B and T Lymphocytes by Scanning Electron Microscopy

This work demonstrates differences between B lymphocytes and T lymphocytes as seen in the scanning electron microscope (SEM). Slides of routinely prepared benign and malignant lymphoid tissues were viewed in the SEM. The location of prominent populations of T lymphocytes and B lymphocytes was verified by immunocytochemical staining respectively with CD3 and CD20 antisera. Benign tissues, including infant thymus and adult hyperplastic lymph node, were compared with malignant lymphomas of T-cell and B-cell types. The SEM appearance of benign B and T lymphocytes is compared utilizing the backscattered electron (BSE) mode and secondary electron (SE) mode in adult hyperplastic lymph node and infant thymus, respectively. The BSE and SE modes reveal that the sectioned T-lymphocyte nucleus has a more complex configuration than that of the B lymphocyte. T lymphocytes appear more discrete and separated one from another, while B lymphocytes exhibit close cellular association to form a syncytial array. These features are noted also in malignant lymphomas of B-lymphocyte and T-lymphocyte types, respectively. The SEM can distinguish between B and T lymphocytes by studying the differences in nuclear and chiefly the cell to cell appearances. The syncytial configuration of B lymphocytes may reflect prominent expression of cell adhesion molecules, e.g., ICAM-1, as noted in the literature.     

Treatment of extensive scalp lesions with segmental intensity-modulated photon therapy

PURPOSE: To compare static electron therapy, electron arc therapy, and photon intensity-modulated radiation therapy (IMRT) for treatment of extensive scalp lesions and to examine the dosimetric accuracy of the techniques. METHODS AND MATERIALS: A retrospective treatment-planning study was performed to evaluate the relative merits of static electron fields, arcing electron fields, and five-field photon IMRT. Thermoluminescent dosimeters (TLD) were used to verify the accuracy of the techniques. The required thickness of bolus was investigated, and an anthropomorphic phantom was also used to examine the effects of air gaps between the wax bolus used for the IMRT technique and the patient's scalp. RESULTS: Neither static nor arcing electron techniques were able to provide a reliable coverage of the planning target volume (PTV), owing to obliquity of the fields in relation to the scalp. The IMRT technique considerably improved PTV dose uniformity, though it irradiated a larger volume of brain. Either 0.5 cm or 1.0 cm of wax bolus was found to be suitable. Air gaps of up to 1 cm between the bolus and the patient's scalp were correctly handled by the treatment-planning system and had negligible influence on the dose to the scalp. CONCLUSIONS: Photon IMRT provides a feasible alternative to electron techniques for treatment of large scalp lesions, resulting in improved homogeneity of dose to the PTV but with a moderate increase in dose to the brain.     

Squamous cell carcinoma of the lip: The role of electron treatment

After skin cancer, squamous cell carcinoma (SCC) of the lip is the most common cancer of the head and neck. It can be treated in a variety of ways, including both surgery and radiotherapy. Many centres have reported excellent cure and local control rates for their chosen treatment method. Electron beam treatment is recognized as a method of treatment and has theoretical advantages related to its depth-dose characteristics. We report a retrospective study of the treatment with electrons of 26 patients with Stage T_1–2 SCCs of the lip. With a median follow-up period of 31 months (range 1.5–60) 100% local control was obtained, although two patients required surgical salvage, one for a geographical miss. One patient presented with metastatic neck nodes, and one relapsed in the neck, but both were treated with a combination of surgery and radiotherapy and were free of disease at follow-up.Patients tolerated the acute radiation reaction well and the long term cosmetic and functional results were good. Two patients experienced minor soft tissue necrosis, one of whom required surgical treatment.Electron treatment for T_1–2 SCC of the lip is an effective, well tolerated treatment for these patients, many of whom are elderly and frail.     

Semiconductor diode characterization for total skin electron irradiation

In this paper, a semiconductor diode characterization was performed. The diode characterization was completed using an electron beam with 4 MeV of energy. The semiconductor diode calibration used irradiation with an electron beam in an ion chamber. “In vivo” dosimetry was also conducted. The dosimetry results revealed that the semiconductor diode was a good candidate for use in the total skin electron therapy (TSET) treatment control.     

Comparison of Electron and X-Ray Beams for Tumor Bed Boost Irradiation in Breast-Conserving Treatment

Purpose

This study aimed to compare the dosimetric profiles of electron beams (EB) and X-ray beams (XB) for boosting irradiation in breast cancer patients who underwent breast-conserving surgery and postoperative radiotherapy.

Methods

For 131 breast cancer patients who underwent breast-conserving surgery, we compared plans for EB and XB boost irradiation after whole-breast irradiation. The organs at risk (OAR) included the cardiac chambers, coronary arteries, ipsilateral lung, and skin. The conformity index (CI), inhomogeneity index (IHI), and dose-volume parameters for the planning target volume (PTV), and OAR were calculated. Postradiotherapy chest computed tomography scans were performed to detect radiation pneumonitis.

Results

XB plans showed a significantly better CI and IHI for the PTVs, compared to the EB plans. Regarding OAR sparing, the XB reduced the high-dose volume at the expense of an increased low-dose volume. In 33 patients whose radiation fields included nipples, IHI was higher in the EB plans, whereas the presence of a nipple in the radiation field did not interfere with the XB. EB-treated patients developed more subclinical radiation pneumonitis.

Conclusion

XB plans were superior to EB plans in terms of PTV coverage (homogeneity and conformity) and high-dose volume sparing in OAR when used as boost irradiation after breast-conserving surgery. A disadvantage of the XB plan was an increased low-dose volume in the OAR, but this was offset by the increased electron energy. Consequently, tailored plans with either XB or EB are necessary to adapt to patient anatomic variance and tumor bed geometric properties.