Prognostic Factors of Quantitative Lymphoscintigraphic Findings in Patients with Breast Cancer-Related Lymphedema

Lymphatic remapping by long-term lymphoscintigraphy follow-up in secondary lymphedema after breast cancer surgery

The purpose of the study is to investigate long-term changes on lymphoscintigraphy and their association with clinical factors in breast cancer-related lymphedema (BCRL) patients. This single-center cohort study included BCRL patients who underwent baseline and follow-up lymphoscintigraphy. The percentage of excessive circumference (PEC) of the affected upper limb compared with the unaffected side was used as an indicator of the clinical severity of BCRL. Each 99mTc-phytate lymphoscintigraphy image was categorized according to the Taiwan lymphoscintigraphy staging system. Clinical parameters and the lymphoscintigraphy stage at baseline and follow-up were compared and analyzed. Eighty-seven patients were included. Baseline and follow-up lymphoscintigraphies were performed at median 7 (interquartile range [IQR]: 2‒14) and 78 (IQR: 49‒116) months after surgery, respectively. Both lymphoscintigraphy stage and PEC showed variable change with overall increases in their severity. Stepwise multivariable analysis revealed follow-up lymphoscintigraphy stage (P = 0.001) to be independent variables for PEC at follow-up, however, baseline lymphoscintigraphy stage was not. The clinical courses of BCRL and patients' lymphoscintigraphy patterns showed diverse changes over long-term follow-up. In addition to initial lymphoscintigraphy for diagnosis, lymphatic remapping by follow-up lymphoscintigraphy can be useful to visualize functional changes in the lymphatic system that may guide the optimal management in BCRL.

Efficacy of preoperative lymphoscintigraphy in predicting surgical outcomes of lymphaticovenous anastomosis in lower extremity lymphedema: Clinical correlations in gynecological cancer-related lymphedema

BACKGROUND

Lymphaticovenous anastomosis (LVA) is a promising microsurgical treatment for lower extremity lymphedema (LEL). Lymphoscintigraphy effectively assesses lower limb lymphatic systems before LVA, but its role in predicting the therapeutic outcomes of LVA is indeterminate. In this study we investigate the efficacy of preoperative lymphoscintigraphy using clinical findings to predict outcomes in gynecological cancer-related LEL patients who underwent LVA.

METHODS

A retrospective review was conducted on consecutive gynecological cancer patients with LEL who had undergone LVA between June 2018 and June 2021. The therapeutic efficacy was assessed by measuring the change rate of the lower extremity lymphedema index (LELi) six months after surgery. Clinical data and lymphoscintigraphic findings were analyzed to assess therapeutic efficacy of LVA.

RESULTS

Out of the 60 evaluated legs, 83.3% of the legs showed improved results after LVA. Univariable linear regression analysis revealed that higher preoperative LELi, and ovarian cancer were associated with superior LELi change rate (LC rate). Absence of dermal backflow (DBF) on lymphoscintigraphy was associated with inferior LC rate. Multivariable linear regression analysis identified ovarian cancer and higher preoperative LELi were independently correlated with favorable outcomes, while the absence of DBF was independently correlated with inferior outcomes.

CONCLUSION

The results of this study emphasizes the effectiveness of preoperative lymphoscintigraphy, preoperative LELi, and primary malignancy as predictors of LVA outcomes in gynecological cancer-related LEL patients.

In Vivo Dynamic and Static Analysis of Lymphatic Dysfunction in Lymphedema Using Near-Infrared Fluorescence Indocyanine Green Lymphangiography

BACKGROUND

Near-infrared fluorescence indocyanine green lymphangiography, a primary modality for detecting lymphedema, which is a disease due to lymphatic obstruction, enables real-time observations of lymphatics and reveals not only the spatial distribution of drainage (static analysis) but also information on the lymphatic contraction (dynamic analysis).

METHODS

We have produced total lymphatic obstruction in the upper limbs of 18 Sprague-Dawley rats through the dissection of proximal (brachial and axillary) lymph nodes and 20-Gy radiation (dissection limbs). After the model formation for 1 week, 9 animal models were observed for 6 weeks using near-infrared fluorescence indocyanine green lymphangiography by injecting 6-μL ICG-BSA (indocyanine green-bovine serum albumin) solution of 20-μg/mL concentration. The drainage pattern and leakage of lymph fluid were evaluated and time-domain signals of lymphatic contraction were observed in the distal lymphatic vessels. The obtained signals were converted to frequency-domain spectrums using signal processing.

RESULTS

The results of both static and dynamic analyses proved to be effective in accurately identifying the extent of lymphatic disruption in the dissection limbs. The static analysis showed abnormal drainage patterns and increased leakage of lymph fluid to the periphery of the vessels compared with the control (normal) limbs. Meanwhile, the waveforms were changed and the contractile signal frequency increased by 58% in the dynamic analysis. Specifically, our findings revealed that regular lymphatic contractions, observed at a frequency range of 0.08 to 0.13 Hz in the control limbs, were absent in the dissection limbs. The contractile regularity was not fully restored for the follow-up period, indicating a persistent lymphatic obstruction.

CONCLUSIONS

The dynamic analysis could detect the abnormalities of lymphatic circulation by observing the characteristics of signals, and it provided additional evaluation indicators that cannot be provided by the static analysis. Our findings may be useful for the early detection of the circulation problem as a functional evaluation indicator of the lymphatic system.