Radiotherapy Method Can Cut Treatment Time, Maintain Breast Cancer Control

Simultaneous integrated boost radiotherapy not only showed promising breast cancer control, but also can decrease the treatment time for patients with the disease.

Simultaneous integrated boost (SIB) radiotherapy administered for patients with early-detected breast cancer reduces treatment time by at least one week and can be an effective strategy in preventing their disease from returning, as determined in a study published in The Lancet.

SIB is a method of treatment that requires administering a targeted additional dose of radiotherapy while the patient is also undergoing whole-breast treatment.

"IMPORT HIGH has uncovered how we can streamline our delivery of these radiotherapy boosts, giving them simultaneously with whole breast radiotherapy — without impacting the effectiveness of treatment, or causing patients additional side effects. We hope this trial will change clinical practice, allowing women to benefit from sophisticated radiotherapy delivery with shorter treatment times and fewer hospital visits,” Dr. Judith Bliss, professor of Clinical Trials at The Institute of Cancer Research, London, director of the Cancer Research UK-funded ICR-CTSU which is managing the trial, said in a press release.

The study emphasized that prior to the use of SIB radiotherapy, women with a high risk of their cancer relapsing would receive typical radiotherapy treatment, only to return for more treatment to mitigate the chance of the cancer coming back. Returning for additional radiotherapy — known as a sequential boost — meant longer treatment time and more traveling for appointments. However, administering SIB radiotherapy reduced this timeline to about three weeks in total, saving one week’s worth of time.

The researchers on the study analyzed data from a trial called IMPORT HIGH, which included 2,617 patients who were randomly assigned across three groups. There were 871 patients in the first group (control); 874 in the second group; and 872 in the third group. The first group (control) received whole-breast radiotherapy along with an additional boost. The second and third groups each received whole-breast radiotherapy and SIB radiotherapy, both at different dose levels among the two respective groups. The third group received a higher dose of the SIB radiotherapy than the second group.

“(Forty-eight) Gy (Gray, measures amount of radiation absorbed by a patient) SIB delivered in three weeks in (the second group) had similar efficacy to sequential boost delivered over 4.5 weeks, with similar or milder rates of adverse events,” said the authors of the study. “(Fifty-three) Gy SIB in (the third group) had no additional benefit in local cancer control but a higher risk of moderate or marked breast induration.”

In that sense, the authors established that the dose administered in the second group was a proper dose that would reduce the timeline by approximately a week and a half. They also determined that a higher dose of SIB in the third group did not have additional advantages and led to a higher risk of breast thickening and hardening of soft tissues, including skin.

“Some women have to live with permanent breast changes after radiotherapy which may affect their well-being. With SIB, we can deliver high-quality effective radiotherapy whilst minimising toxicity from it,” Dr. Charlotte Coles, professor of Breast Cancer Clinical Oncology at the University of Cambridge, National Institute of Health Research and Care Research (NIHR) professor and chief investigator for the trial, said in the press release.

The researchers also identified the primary endpoint (main result at the end of a study to see if treatment worked), which was ipsilateral breast tumor relapse (IBTR, a recurrent in situ or invasive carcinoma occurring after breast conserving surgery). According to the authors, the five-year IBTR rate was much lower across all three of the treatment groups than they expected. Their findings concluded that 76 of the 2,617 participating patients experienced IBTR by the end of the trial.

Implementing SIB radiotherapy after initial radiotherapy for patients with early-detected breast cancer would save both time and money, according to the authors of the study. By reducing treatment time by at least one week with SIB radiotherapy, it mitigated both time and cost burdens related to travel for patients, caregivers and families. Patients receiving SIB radiotherapy may also return to work sooner.

Regarding general cost, the authors noted that patients would save more money, as the treatment sessions would discount the additional week a typical round of treatment would cost. This would relieve cost burdens of treatment, especially for patients who are lower income, according to the authors.

“This is a careful step towards even shorter courses of radiotherapy that include more complex techniques. By delivering more targeted boost radiotherapy over shorter time periods, women can get on with their lives more quickly,” Coles said.

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