Meeting NewsPerspective

Accelerated partial breast irradiation effectively prevents recurrence in early breast cancer

SAN ANTONIO — Accelerated partial breast irradiation after surgery appeared as effective as whole breast irradiation for preventing recurrence among patients with early breast cancer, according to 10-year follow-up results from the randomized phase 3 APBI IMRT Florence trial presented at San Antonio Breast Cancer Symposium.

The findings suggest that the less invasive partial breast procedure could be a reasonable alternative to whole breast irradiation.

“This research is a small piece of the puzzle,” Icro Meattini, MD, clinical oncologist in the radiation oncology unit at University of Florence in Italy, told Healio. “However, this trial does add robust evidence in favor of accelerated partial breast irradiation over whole breast irradiation. There is a reduction in overall treatment time, improvements in outcomes and an increase in the quality of life among patients who underwent accelerated partial breast irradiation.”

The trial included 520 women aged older than 40 years (median age, 62.8 years) with stage I or stage II breast cancer (maximum tumor size, 25 mm).

Researchers randomly assigned half of the women to accelerated partial breast irradiation, which consisted of a total 30 Gray of radiation to the tumor bed in five daily fractions. The other half of women received whole breast irradiation, which consisted of a total of 50 Gray administered in 25 daily fractions to the whole breast, plus a 10-Gray boost to the tumor bed in five daily fractions.

Most patients had hormone receptor-positive, HER2-negative breast cancer, and the majority were aged older than 50 years. The treatment groups were well-balanced with regard to age, tumor type, tumor size and adjuvant endocrine treatment.

An analysis performed after 5 years of follow-up showed no significant differences in ipsilateral tumor recurrence and OS between the two approaches.

The updated results were based on median follow-up of 10 years in both groups.

Results showed no statistically significant differences between women assigned accelerated partial breast irradiation and those assigned whole breast irradiation with regard to breast cancer recurrence (3.3% vs. 2.6%), OS (92.7% vs. 93.3%), breast cancer-specific survival (97.6% vs. 97.5%) or distant metastasis-free survival (96.9% vs. 96.9%).

Ten-year cumulative incidence estimates of locoregional recurrence were 3.9% (95% CI, 2.24-5.56) with accelerated partial breast irradiation vs. 3% (95% CI, 1.53-4.47) with whole breast irradiation. The difference did not reach statistical significance.

The differences in contralateral breast cancers (0.9% vs. 3.5%) and deaths (7.3% vs. 6.7%) between the accelerated partial breast irradiation and whole breast irradiation groups also failed to reach statistical significance.

The study’s relatively small sample size served as the primary limitation, Meattini said.

Still, these findings may help clinicals become more comfortable recommending accelerated partial breast irradiation for patients with lower risk for recurrence.

The once-daily regimen does not appear to compromise outcomes, and it also may produce an improved quality of life and minimize toxicity while reducing treatment time and costs, he said.

“We have not been able to identify a group of patients for whom we can safely omit radiation, but we can safely stratify patients according to individual disease biology,” Meattini told Healio. “Also, for partial breast irradiation, we should focus on dissection before irradiation, because this is where the future is headed.” – by Jennifer Southall

Reference:

Meattini I, et al. Abstract GS4-06. Presented at: San Antonio Breast Cancer Symposium; Dec. 10-14, 2019; San Antonio.

Disclosure: The Radiation Oncology Unit of Florence University Hospital supported the study. Meattini reports no relevant financial disclosures. Please see the abstract for all other authors’ relevant financial disclosures.

 

 

SAN ANTONIO — Accelerated partial breast irradiation after surgery appeared as effective as whole breast irradiation for preventing recurrence among patients with early breast cancer, according to 10-year follow-up results from the randomized phase 3 APBI IMRT Florence trial presented at San Antonio Breast Cancer Symposium.

The findings suggest that the less invasive partial breast procedure could be a reasonable alternative to whole breast irradiation.

“This research is a small piece of the puzzle,” Icro Meattini, MD, clinical oncologist in the radiation oncology unit at University of Florence in Italy, told Healio. “However, this trial does add robust evidence in favor of accelerated partial breast irradiation over whole breast irradiation. There is a reduction in overall treatment time, improvements in outcomes and an increase in the quality of life among patients who underwent accelerated partial breast irradiation.”

The trial included 520 women aged older than 40 years (median age, 62.8 years) with stage I or stage II breast cancer (maximum tumor size, 25 mm).

Researchers randomly assigned half of the women to accelerated partial breast irradiation, which consisted of a total 30 Gray of radiation to the tumor bed in five daily fractions. The other half of women received whole breast irradiation, which consisted of a total of 50 Gray administered in 25 daily fractions to the whole breast, plus a 10-Gray boost to the tumor bed in five daily fractions.

Most patients had hormone receptor-positive, HER2-negative breast cancer, and the majority were aged older than 50 years. The treatment groups were well-balanced with regard to age, tumor type, tumor size and adjuvant endocrine treatment.

An analysis performed after 5 years of follow-up showed no significant differences in ipsilateral tumor recurrence and OS between the two approaches.

The updated results were based on median follow-up of 10 years in both groups.

Results showed no statistically significant differences between women assigned accelerated partial breast irradiation and those assigned whole breast irradiation with regard to breast cancer recurrence (3.3% vs. 2.6%), OS (92.7% vs. 93.3%), breast cancer-specific survival (97.6% vs. 97.5%) or distant metastasis-free survival (96.9% vs. 96.9%).

Ten-year cumulative incidence estimates of locoregional recurrence were 3.9% (95% CI, 2.24-5.56) with accelerated partial breast irradiation vs. 3% (95% CI, 1.53-4.47) with whole breast irradiation. The difference did not reach statistical significance.

The differences in contralateral breast cancers (0.9% vs. 3.5%) and deaths (7.3% vs. 6.7%) between the accelerated partial breast irradiation and whole breast irradiation groups also failed to reach statistical significance.

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The study’s relatively small sample size served as the primary limitation, Meattini said.

Still, these findings may help clinicals become more comfortable recommending accelerated partial breast irradiation for patients with lower risk for recurrence.

The once-daily regimen does not appear to compromise outcomes, and it also may produce an improved quality of life and minimize toxicity while reducing treatment time and costs, he said.

“We have not been able to identify a group of patients for whom we can safely omit radiation, but we can safely stratify patients according to individual disease biology,” Meattini told Healio. “Also, for partial breast irradiation, we should focus on dissection before irradiation, because this is where the future is headed.” – by Jennifer Southall

Reference:

Meattini I, et al. Abstract GS4-06. Presented at: San Antonio Breast Cancer Symposium; Dec. 10-14, 2019; San Antonio.

Disclosure: The Radiation Oncology Unit of Florence University Hospital supported the study. Meattini reports no relevant financial disclosures. Please see the abstract for all other authors’ relevant financial disclosures.

 

 

    Perspective
    Stephanie Bernik

    Stephanie Bernik

    This study offers exciting news for patients with early-stage breast cancer. This study showed that the 10-year rates of recurrence were similar to the 5-year rates, and it adds to the growing body of research that suggests more is not always better. Being able to reduce the amount of time it takes for a woman to complete a course of radiation will open the door to this modality to women who previously opted for mastectomies due to inability to get to a radiation facility. Many women do not live close to a treatment center, but they might now consider spending a week away from home compared with more than a month. This also allows patients to get back to work and to their family. Larger studies may be needed to confirm these findings, and cosmetic outcomes and effects of exposure to higher daily dosing of radiation on other organs also need to be examined.

    • Stephanie Bernik, MD, FACS
    • Icahn School of Medicine at Mount Sinai

    Disclosures: Bernik reports no relevant financial disclosures.

    Perspective
    Alphonse G. Taghian

    Alphonse G. Taghian

    This is not the first trial to show partial breast irradiation and whole breast irradiation are equivalent. During last year’s San Antonio Breast Cancer Symposium, the NRIG B39 trial and the Canadian RAPID trial both showed that local failure was similar [with these two approaches]. More evidence is now building. All of these trials, which started more than 10 years ago, are now coming to maturity and they are all pointing to the same results: We can perform partial breast irradiation, which will take only 1 week of treatment, and we will achieve the same results.

    This provides much more convenience to the patient but, more importantly, when we perform partial breast irradiation, we treat only a small part of the breast where the cancer is. We treat less tissue and expose less tissue to radiation, and we treat only 20% to 30% of the volume of the breast. Another important implication is that partial breast irradiation will cost less than whole breast irradiation.

    It is important to emphasize that this treatment is not good for everybody. It is good for early breast cancer and for low-grade ductal carcinoma in situ. For early breast cancer, the node should be negative.

    This trial is another success story with partial breast irradiation.

    • Alphonse G. Taghian, MD
    • Massachusetts General Hospital Cancer Center
      Harvard Medical School

    Disclosures: Taghian reports no relevant financial disclosures.

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