Clinical trial NCT06780059: Effects of Radiotherapy in Borderline and Malignant Phyllodes Tumors After R0 Resection
Official title: Effects of Radiotherapy on Recurrence and Survival in Borderline and Malignant Phyllodes Tumors After R0 Resection: a Propensity Score Analysis
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Radiotherapy, Adjuvant
Phyllodes Breast Tumor
Prognosis
Lead sponsor: Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University
Sponsor class: OTHER
First posted: 2025-01-17
Enrollment: 480
Sex: FEMALE
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients pathologically diagnosed with BoPT and MPT who underwent surgery at three medical institutions in China: Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Sun Yat-sen University Cancer Center, and the Third Affiliated Hospital of Nanchang University.

Brief summary: Breast phyllodes tumors (PT) are rare fibroepithelial neoplasms originating from stromal tissue and account for less than 1% of all breast tumors. The World Health Organization (WHO) classifies PT into benign, borderline, and malignant subtypes based on pathological features such as mitotic activity, cellular atypia, tumor margin invasion, and stromal composition 1. The presence of malignant heterologous elements characterizes the tumor as malignant 2. Surgery is the primary treatment. However, even after R0 resection, borderline phyllodes tumors (BoPT) and malignant phyllodes tumors (MPT) patients remain face a high risk of local recurrence, with rates of 15%-20% and 25%-30%, respectively. Moreover, metastases occur almost merely in MPT, with a distant metastasis rate reaching 22%.

Adjuvant radiotherapy has attracted attention for its potential to improve local control and reduce recurrence, but the role after R0 resection in PT patients remains unclear. Radiotherapy significantly reduces local recurrence rates in BoPT and MPT but shows no substantial benefit in benign cases. However, a meta-analysis by Yu et al. found that this effect is limited to MPT. Additionally, the effect of radiotherapy on survival rates in PT remains controversial. Most existing studies are retrospective and face limitations such as small sample sizes. The rarity of PT and conflicting evidence of impact of radiotherapy necessitate further study. While prospective trials are difficult due to limited cases, well-designed retrospective studies can offer valuable insights. In this study, the investigators also analyzed prognostic factors and identified subgroups to provide a clinical reference for the application of postoperative radiotherapy in BoPT and MPT patients.


Eligibility criteria: Inclusion Criteria:

* patients who were initially diagnosed with BoPT or MPT and underwent R0 resection surgery

Exclusion Criteria:

* patients who had their initial surgery at other hospitals without accurate baseline data
* patients who received radiotherapy before surgery
* those presenting with initial distant metastasis before treatment
* patients lost to follow-up after treatment
* patients with a history of or concurrent breast cancer or precancerous lesions in the ipsilateral breast or with breast cancer in the contralateral breast

Primary outcomes:
measure: 5-year Local Recurrence-free Survival
timeFrame: Five years
Secondary outcomes:
measure: 5-year Overall Survival
timeFrame: Five years
Other outcomes:
Locations:
city: Guangzhou
country: China
facility: Sun Yat-sen University Cancer Center
state: Guangdong
city: Guangzhou
country: China
facility: Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University
state: Guangdong
city: Nanchang
country: China
facility: Third Hospital of Nanchang
state: Jiangxi
Study officials:
References:
citation: Macdonald OK, Lee CM, Tward JD, Chappel CD, Gaffney DK. Malignant phyllodes tumor of the female breast: association of primary therapy with cause-specific survival from the Surveillance, Epidemiology, and End Results (SEER) program. Cancer. 2006 Nov 1;107(9):2127-33. doi: 10.1002/cncr.22228.
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