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Breast cancer accounts for 12.5% of all new cancer cases each year worldwide, making it the most prevalent cancer at the moment. In 2020, an estimated 7.8 million women were diagnosed with breast cancer. From the 1930s until the 1970s, there was no change in the mortality of breast cancer. In nations with early detection programs coupled with various forms of treatment to remove invasive diseases, improvements in survival started in the 1980s. Treatment can be quite successful, especially if it is found early. A combination of surgery, radiation therapy, and medication is frequently used to treat breast cancer. A relapse could often occur, Risk factors are high tumor burden and young age.
SIB can be applied to the tumor bed
Clinical studies and data obtained from pathological breast specimens indicate that the majority of ipsilateral breast tumor relapses take place close to the area that was originally excised after resection, the tumor bed. A boost roughly cuts the chance of breast tumor relapse, according to randomized trials of breast-conserving surgery followed by whole-breast radiation with or without a tumor-bed boost. Breast tumor relapse should be minimized because it is an important life event for patients and frequently necessitates mastectomy and systemic therapy, even if individual boost trials have not demonstrated an overall survival advantage over whole-breast radiation alone.
Dose-escalated simultaneous integrated boost radiotherapy in early breast cancer (IMPORT HIGH) was aimed at comparing sequential boost to simultaneous integrated boost, in order to shorten the treatment period while maintaining excellent local control and similar to or reduced toxicity. This was a randomized, open-label, non-inferiority, phase-3 trial that involved young women 18 and above. Intensity-modulated radiation treatment (IMRT) and image-guided radiation therapy (IGRT) are used in this approach to overcome the limitations of boost radiotherapy. To more accurately express the risk of relapse, the dose intensity can be varied throughout the breast during IMRT. A simultaneous integrated boost (SIB), also known as an increase in dose per fraction, can be applied to the tumor bed. Gold seeds or titanium surgical clips were used to localize the tumor bed, allowing for the planning of radiation and assisting in IGRT verification.
Patients underwent annual follow-up appointments for ten years following radiation. Clinical staff, patients, and use of images were used to independently evaluate late adverse effects. In a population with a higher risk of relapse, the data demonstrated that the incidence of ipsilateral breast tumor recurrence (IBTR) was lower than expected by 5 years across all therapy groups. With no statistically significant variations in rates across trial groups, the prevalence of mild or noticeable late normal tissue adverse events was low in all groups for clinician-reported, patient-reported, and photographic assessments. Whether the increase is given sequentially or simultaneously, IBTR rates are low in this group of breast cancer patients who are at higher risk.
Patients and their families have less stress thanks to SIB, which also lowers travel expenses and speeds up return to work. The approach allows radiotherapy time slots to be utilized for other patients, which is an effective use of resources for healthcare providers.
This technique allows the radiation dose to be delivered to the tumor bed in large amounts while still providing the surrounding breast tissue with a standard dose and the breast tissue’s periphery, which has the lowest risk of relapse, with a slightly lower dose. The largest randomized trial to date, IMPORT HIGH, compares dose-escalated SIB to conventional sequential boost.
Coles, C. E., Haviland, J. S., Kirby, A. M., Griffin, C. L., Sydenham, M. A., Titley, J. C., Bhattacharya, I., Brunt, A. M., Chan, H. Y. C., Donovan, E. M., Eaton, D. J., Emson, M., Hopwood, P., Jefford, M. L., Lightowlers, S. V., Sawyer, E. J., Syndikus, I., Tsang, Y. M., Twyman, N. I., & Yarnold, J. R. (2023). Dose-escalated simultaneous integrated boost radiotherapy in early breast cancer (IMPORT HIGH): a multicentre, phase 3, non-inferiority, open-label, randomised controlled trial. The Lancet, 401(10394), 2124-2137. https://doi.org/10.1016/S0140-6736(23)00619-0