OPTimizing Irradiation through Molecular Assessment of Lymph node (OPTIMAL): a randomized open label trial

Escalation and De-Escalation of Adjuvant Radiotherapy in Early Breast Cancer: Strategies for Risk-Adapted Optimization

Postoperative radiotherapy (RT) is recommended after breast-conserving surgery and mastectomy (with risk factors). Consideration of pros and cons, including potential side effects, demands the optimization of adjuvant RT and a risk-adapted approach. There is clear de-escalation in fractionation-hypofractionation should be considered standard. For selected low-risk situations, PBI only or even the omission of RT might be appropriate. In contrast, tendencies toward escalating RT are obvious. Preoperative RT seems attractive for patients in whom breast reconstruction is planned or for defining the tumor location more precisely with the potential of giving ablative doses. Dose escalation by a (simultaneous integrated) boost or the combination with new compounds/systemic treatments may increase antitumor efficacy but also toxicity. Despite low evidence, RT for oligometastatic disease is becoming increasingly popular. The omission of axillary dissection in node-positive disease led to an escalation of regional RT. Studies are ongoing to test if any axillary treatment can be omitted and which oligometastatic patients do really benefit from RT. Besides technical improvements, the incorporation of molecular risk profiles and also the response to neoadjuvant systemic therapy have the potential to optimize the decision-making concerning if and how local and/or regional RT should be administered.

OPTimizing Irradiation through Molecular Assessment of Lymph node (OPTIMAL): a randomized clinical trial

BACKGROUND AND PURPOSE

In breast cancer (BC) patients, the involvement of four or more lymph nodes (LN) is an indication of regional irradiation. The optimal treatment strategy remains unclear when fewer nodes are involved and lymphadenectomy is not performed. We designed a clinical trial to show the non-inferiority of Incidental (INC) compared to intentional (INT) irradiation of axillary nodes in patients with early-stage BC and low burden LN involvement.

MATERIALS AND METHODS

BC patients, cN0 (n = 487) undergoing breast conservation surgery and sentinel node biopsy, with total tumor load assessed by OSNA (One-Step Nucleic Acid Amplification) of 250-15,000 copies mRNA CK19/µL in sentinel LN were randomized to receive INC or INT nodal irradiation. The primary endpoint was 5-year disease-free survival (DFS). Secondary endpoints were locoregional recurrence (LRR), distant recurrence (DR), and acute and chronic toxicity (CT).

RESULTS

Five-years DFS were 93.7% (INC) and 93.8% (INT) (difference 0.1% [one-sided 95% CI < 5.7%]; non-inferiority p = 0.075). Cumulative Incidences of LRR were 3.5% (INC) and 3.4% (INT) (difference of 0.1% [<4.8%]; p = 0.021), and 5% (INC) and 3.5% (INT) (difference 1.4% [<6.0%]; non-inferiority p = 0.101) for DR. CT was more Incident with INT (26.9%) than with INC (19.2%), though the difference was not statistically significant (HR 1.39 [95% CI: 0.92, 2.10]; p = 0.11).

CONCLUSION

Intentional does not outperform incidental irradiation by more than 5.7% in terms of 5-year DFS, 4.8% for LRR, and 6% for DR.

REGISTRATION NUMBER

ClinicalTrials.gov Identifier: NCT02335957.

Survival and recurrence with or without axillary dissection in patients with invasive breast cancer and sentinel node metastasis

To evaluate overall survival and locoregional recurrence between patients with invasive breast tumours and sentinel node metastasis undergoing sentinel lymph node dissection (SLND) alone and those undergoing complete axillary lymph node dissection (ALND). In this retrospective cohort study, we reviewed the medical records of patients with invasive breast carcinoma who underwent lumpectomy at a public university hospital in Brazil between 2008 and 2018. We evaluated the overall survival and the locoregional recurrence using Kaplan-Meier and Cox regression analyses, respectively. Overall, 97 participants who underwent lumpectomy were enroled; 41 in the ALND group, and 56 in the SLND group, according to Z0011 criteria. Only 17% of the patients in the ALND group had an additional biopsy-proven axillary disease, and 83% were treated with complete dissection unnecessarily. The 5-year survival rates were 80.1% and 87.5% for SLND and ALND, respectively (p = 0.376). Locoregional recurrence was rare (1.7% and 7.3% in the SLND and ALND, respectively; p = 0.3075). Overall survival and locoregional recurrence were similar between the two groups. The de-escalation of ALND to SLND in women with metastasis in the sentinel lymph node treated with conservative surgery and radiotherapy that meet the Z0011 criteria is feasible even in developing countries.