Oncologists are sharing a wealth of research at San Antonio Breast Cancer Symposium 2024, including updates on HER2-enriched breast cancer, lymph node biopsy risks, and patient QOL. This roundup provides a quick look at some of the findings presented at the meeting.
Addressing Modifiable Risk Factors in HER2-Enriched Disease
Elizabeth Cespedes Feliciano, ScD, SM, presented a study on the impact of visceral adiposity (VAT) on breast cancer survival. Greater adiposity may promote tumor progression and increase mortality in breast cancer, but the evidence is limited for subtypes like HER2-enriched. Prior studies have relied on BMI but have shown inconsistent results. This study directly measured visceral adiposity (VAT) with imaging.
- The study included patients with stage 2 or 3 breast cancer treated at Kaiser Permanente Northern California (2005–2015).
- The researchers used CT scans to measure VAT at the third lumbar vertebra, scaled to height (cm²/m²).
- The study population (mean age: 56 years) had a high prevalence of overweight (30%) and obesity (38%).
- Tumor subtypes included HER2-enriched (25%), Basal-like (31%), Luminal B (22%), and Luminal A (22%).
- Higher VAT (in 39% of patients) was not associated with overall cancer-specific mortality (HR, 0.98; 95% CI, 0.78–1.24).
- Within the HER2-enriched subtype, higher VAT doubled the cancer-specific mortality risk (HR, 2.00; 95% CI, 1.19–3.34), and high VAT tumors had enriched expression of stroma (eg, FAP, COL6A3) and mammary stemness genes (eg, VIM, DDR2).
- Main Takeaways: Visceral adiposity significantly impacted survival in HER2-enriched breast cancer by influencing gene expression linked to the tumor microenvironment. The findings offer additional evidence to support targeting excess adiposity as a modifiable risk factor in patients with breast cancer.
Evaluating Sentinel Lymph Node Biopsy Safety
Rates of breast cancer-related lymphedema (BCRL) following sentinel lymph node biopsy (SLNB) are poorly defined. Lyndsey Kilgore, MD, presented a study wherein a research team evaluated lymphedema incidence post-SLNB to inform discussions on surgical risks and lymphedema surveillance.
- The study was a retrospective review of 324 patients with breast cancer who underwent SLNB (2014–2017).
- Clinicians took bioimpedance spectroscopy measurements preoperatively, postoperatively, and regularly over 3 years.
- BCRL was diagnosed in patients if they had persistently abnormal spectroscopy measurements (>3 SD above baseline), confirmed by follow-up after a month.
- 18% (n=58) of patients had a single abnormal reading, but 71% (n=41) normalized without intervention.
- Confirmed BCRL occurred in 5% (n=17) of patients; most cases (88%) were stage 0.
- Only 0.6% of all patients were affected by persistent BCRL (pBCRL) after self-directed interventions.
- Development of pBCRL was associated only with the number of positive lymph nodes (P=0.01); not with age, BMI, radiotherapy, chemotherapy, or nodes examined.
- Main Takeaways: BCRL incidence following SLNB was low, and pBCRL was uncommon when detected early and treated with home interventions. Isolated abnormal spectroscopy readings often reflected fluctuations, not true BCRL, emphasizing the importance of repeat bioimpedance spectroscopy measurements before diagnosis. The authors concluded that SLNB was a safe procedure with low BCRL risk.
Improving QOL During Breast Cancer Treatment
Sonia Servitja, MD, PhD, presented research on topical treatments for chemotherapy-induced peripheral neuropathy (CIPN). Chemotherapy drugs contribute to CIPN by sensitizing thermosensitive receptors in nociceptive terminals. Therefore, the researchers compared treatment outcomes with a standard hydrating cream (A) versus a nociceptive formulation (B).
- The study was a randomized, double-blind trial involving 121 patients with stage 2-3 breast cancer.
- Participants applied creams daily, increasing to twice daily with sensory symptoms.
- 60% of participants developed distal CIPN during chemotherapy treatment.
- Cream B delayed sensory symptom onset (66.7% for cream B vs 49% for cream A).
- Cream B reduced CIPN incidence and improved symptoms (as measured by the Leonard scale).
- The recipients received both creams well; two participants withdrew due to pruritus.
- Main Takeaways: Topical modulation with a nociceptive cream delayed CIPN onset and alleviated symptoms. The researchers noted their study demonstrates a potential strategy for improving CIPN management and patient QOL.
