BOMB trial: First results of stereotactic radiotherapy to primary breast tumor in metastatic breast cancer patients

Palliative radiation therapy for locally advanced breast cancer

PURPOSE OF REVIEW

Globally, breast cancer is the most commonly diagnosed cancer in women. Locally advanced breast cancers (LABCs) may necessitate palliative radiation therapy (RT) due to the severity of the patients' symptoms, inoperability, or other reasons precluding curative-intent treatment such as poor performance status and patient comorbidities. This review aims to discuss current evidence on palliative RT in LABC.

RECENT FINDINGS

Advanced targeted RT techniques have led to improvements in local control with reduced treatment-related toxicities. Emerging short-course palliative RT prescriptions offer feasible options that avoid delay in systemic therapy. Additionally, recent studies also highlight approaches for integrating palliative RT with systemic therapies.

SUMMARY

Palliative RT plays a vital role in managing symptoms and enhancing quality of life for LABC patients. However, there is currently no consensus on the optimal prescriptions for palliative RT in these patients. Standardized reporting of palliative RT studies is needed for robust comparison of efficacy and toxicity between various treatment regimens. Furthermore, future research on the optimal integration of RT with novel systemic agents is needed.

Unlocking survival benefits: primary tumor resection in de novo stage IV breast cancer patients

BACKGROUND

For patients with de novo stage IV breast cancer (BC), the conditions under which the primary tumor resection (PTR) may offer benefit remain unclear.

METHODS

The SEER database provides treatment data for patients with de novo stage IV BC. We screened cases of metastatic BC diagnosed from 2010 to 2015, with primary endpoints of overall survival (OS) and cancer-specific survival (CSS).

RESULTS

9252 patients with stage IV de novo BC were enrolled. For OS, median survival time (MST) was 38 months with systematic treatment (ST) compared to 52 months with ST plus PTR (p < 0.001). For CSS, MST was 38 months for ST versus 54 months for ST plus PTR (p < 0.001). The results of the Cox proportional hazards regression analysis regarding PTR, for OS: bone metastasis (aHR 0.664, 95%CI 0.583-0.756, p < 0.001); liver-lung metastasis (aHR 0.528, 95%CI 0.327-0.853, p = 0.009). For CSS: bone metastasis (aHR 0.655, 95%CI 0.571-0.751, p < 0.001); liver-lung metastasis (aHR 0.549, 95%CI 0.336-0.889, p = 0.017). Kaplan-Meier analysis indicated that in patients with bone metastases and liver-lung metastases, PTR could improve survival outcomes.

CONCLUSION

Liver-lung metastases and bone metastases in patients with de novo stage IV BC could enhance both OS and CSS through PTR.

The Promising Effects of Lattice Radiotherapy for Large, Fungating, or Ulcerating Breast Cancers: A Prospective Single-center Study

BACKGROUND/AIM

To evaluate the safety and efficacy of lattice radiotherapy (LRT) for large, inoperable breast cancers.

PATIENTS AND METHODS

In this prospective study, patients who underwent LRT for breast tumors that were ulcerating/fungating/extensively eroding the chest wall, and were ineligible/unwilling for surgery, were enrolled from May 2021 to Nov 2023. Baseline Eastern Cooperative Oncology Group (ECOG) status, pre- and post-LRT numerical rating scale (NRS), and post-LRT changes in quality of life (QoL) were recorded. Survival outcomes were reported at 6 months and 1-year. Median rates of survival and dosimetric parameters were calculated. Kaplan-Meier curves for overall survival (OS), cancer-specific survival (CSS), and failure of local control (LC) were constructed.

RESULTS

Ten patients (8 females) underwent LRT. The median age was 76 years (range=57-99 years) and the median ECOG performance status was 2.5 (range=1-4). The planned schedule was completed by 9/10 patients, accounting for a 90% compliance rate. Among patients with pain (n=7), NRS rapidly reduced from 7 (range=5-10) to 3 (range=1-6). The median equivalent uniform dose was 0.71 Gy (0.09-1.59 Gy). The actuarial rates of 6-month LC, CSS, and OS were 75%, 89%, and 61%, respectively, with only LC rate changing to 50% at 1 year. Two patients had local relapse at the six-month and 1-year follow-up, respectively, after having achieved a complete response at three months, and two others died of COVID-19 infection and ischemic stroke.

CONCLUSION

LRT was found to be effective and safe in palliating symptoms among patients with large inoperable breast tumors.

Palliative Radiotherapy for Symptomatic Primary Tumors in Patients With Locally Advanced Breast Cancer

Breast cancer remains a significant health concern for women, with a significant number of women facing unresectable, symptomatic, and advanced disease that severely affects their quality of life. Palliative radiotherapy (RT) is a well-established modality for managing such cases and alleviating symptoms. Recent advancements in systemic therapies and the resulting increase in long-term survival rates have not only heightened the need for retreatment in certain patients, but have also emphasized the importance of achieving durable local control. Additionally, inconsistencies in RT referral timing and variations in disease severity and extent contribute to diverse RT objectives and expected outcomes. The optimal dose fractionation for RT remains underexplored. Furthermore, a deeper understanding of breast radiobiology, along with the introduction of ultra- and moderately hypofractionated regimens and the widespread adoption of conformal techniques such as intensity-modulated RT, has diversified the approaches in RT dose and target volume. This review aimed to provides a comprehensive summary of the current evidence on the efficacy, outcomes, and toxicity profiles of palliative RT for symptomatic breast cancer. It highlights the need for more optimized regimens and further research to address the evolving treatment landscape and differing expectations of patients and physicians regarding RT.

Locoregional Ablative Radiation Therapy for Patients With Breast Cancer Unsuitable for Surgical Resection

PURPOSE

Patients with breast cancer who are unsuitable for surgical resection are typically managed with palliative systemic therapy alone. We report outcomes of 5-fraction ablative radiation therapy for nonresected breast cancers.

METHODS AND MATERIALS

This is a retrospective analysis of an institutional registry of patients with breast cancer who were unsuitable for resection and underwent 35 to 40 Gy/5 fractions to the primary breast tumor or regional lymph nodes from 2014 to 2021. Primary outcomes were cumulative incidence of local failure and grade ≥3 toxicity (Common Terminology Criteria for Adverse Events, version 5.0).

RESULTS

We reviewed 57 patients who received 61 treatment courses (median age of 81 years; range, 38-99). Unresectable tumor (10%), patient refusal (18%), medical inoperability (35%), and metastatic disease (37%) were the causes of not having surgery. Five patients (8%) had previously undergone adjuvant locoregional radiation therapy. Fifty-four percent (n = 33/61) of treatment courses targeted the breast only, 31% (n = 19/61) both the breast and lymph nodes, and 15% (n = 9/61) the lymph nodes only. Sixty-seven percent (n = 35/52) of the courses that targeted the breast were delivered with partial breast irradiation and 33% (n = 17/52) with whole breast radiation therapy (median dose of 25 Gy in 5 fractions) ± simultaneous integrated boost to the primary tumor. Most primary tumors (65%, n = 34/52) and target lymph nodes (61%, n = 17/28) were treated with a dose of 35 Gy in 5 fractions. Most treatments (52%) were delivered with intensity modulated radiation therapy (IMRT). Radiation therapy was delivered daily (20%), every other day (18%), twice weekly (36%), or weekly (26%). The 2-year cumulative incidence of local failure was 11.4% and grade≥3 toxicity was 15.1%. The grade ≥3 toxicity was 6.5% for IMRT treatments, versus 7.7% for non-IMRT treatments targeting partial breast or lymph nodes (hazard ratio, 1.13, P = .92), versus 38.9% for non-IMRT treatments targeting the entire breast (hazard ratio, 6.91, P = .023). All grade ≥3 toxicity cases were radiation dermatitis. No cases of brachial plexopathy were observed.

CONCLUSIONS

Thirty-five to 40 Gy in 5 fractions is a safe and effective breast stereotactic body radiation therapy (SBRT) regimen and may be an attractive option for patients who are not surgical candidates. Highly conformal techniques (ie, IMRT or partial breast irradiation) were associated with a reduced risk of toxicity and should be the preferred treatment approaches.

Five-Fraction High-Conformal Ultrahypofractionated Radiotherapy for Primary Tumors in Metastatic Breast Cancer

PURPOSE

To report on the local control and toxicity of 5-fraction, high-conformal ultrafractionated radiation therapy (RT) for primary tumors in patients with metastatic breast cancer (MBC) who did not undergo planned surgical intervention.

METHODS

We retrospectively reviewed 27 patients with MBC who underwent 5-fraction high-dose ultrafractionated intensity-modulated RT for their primary tumors between 2017 and 2022 at our institution. A median dose of 66.8 Gy (range, 51.8-83.6 Gy) was prescribed to the gross tumor, calculated in 2-Gy equivalents using an α/β ratio of 3.5, along with a simultaneous integrated boost of 81.5%. The primary endpoint of this study was local control.

RESULTS

The median tumor size and volume were 5.1 cm and 112.4 cm3, respectively. Treatment was generally well tolerated, with only 15% of the patients experiencing mild acute skin toxicity, which resolved spontaneously. The best infield response rate was 82%, with the objective response observed at a median time of 10.8 months post-RT (range, 1.4-29.2), until local progression or the last follow-up. At a median follow-up of 18.3 months, the 2-year local control rate was 77%. A higher number of prior lines of systemic therapy was significantly associated with poorer 2-year local control (one-two lines, 94% vs three or more lines, 34%; p = 0.004). Post-RT, 67% of the patients transitioned to the next line of systemic therapy, and the median duration of maintaining the same systemic therapy post-RT was 16.3 months (range, 1.9-40.3).

CONCLUSION

In our small dataset, 5-fraction, high-conformal ultrahypofractionated breast RT offered promising 2-year local control with minimal toxicity. Further studies are warranted to investigate the optimal dose and role in this setting.