Impact of Primary Tumor Variables on Predicting Nodal Metastasis in Lower Extremity Marjolin’s Ulcer: A Retrospective Cohort Study

Background Marjolin's ulcer or scar carcinoma is a rare disease arising from the conversion of chronic scar into malignancy. Studies show Marjolin's ulcer squamous cell carcinoma has more chances of lymph nodal metastasis and is more aggressive with a worse survival rate. To date, no established guidelines exist for managing regional lymph nodes in cases of Marjolin's ulcer with clinically N0 nodes. Observation vs elective node dissection remains an option. In developing countries, long-term follow-up is not consistently leading to the risk of patients being kept on observation for regional nodes; presenting late with inoperable regional nodes is possible. This study aims to identify clinicopathological factors of lower extremity Marjolin's ulcer, which are associated with a high risk of inguinal lymph node metastasis. Identifying such risk factors may help provide a rationale for performing elective nodal dissection instead of observation in high-risk cases. Material and methods All clinically N0 lower extremity Marjolin's ulcer cases, more than 3 cm in size, treated at King George's Medical University, India, during the last five years, have been included in this study. Demographic, clinical, and pathological data of eligible patients were retrieved from institutional records. Various clinical and pathological factors were studied and correlated with lymph node positivity, and the strength of the correlation was tested using statistical methods. Factors correlated strongly with inguinal lymph node positivity were identified as high-risk factors. Results A total of 66 patients with lower extremity Marjolin's ulcer had no preoperative pathologically confirmed inguinal lymph nodes documented by ultrasonography and fine needle aspiration cytology. All patients underwent surgery for primary, followed by elective, inguinal lymph nodal dissection. The majority were males (n=51/66; 71%), and the most common age group was 30-50 years (n=40/66; 60%). The leg was the most common site (n=31/66; 47%). The least common site was below the ankle (n=14/66; 22%). Maximum dimension ranged from 3 cm to >15 cm, with the majority between 6 and 10 cm (n=40/66; 56%). Extension beyond the scar site was present in 24% (n=15/66) of patients. Most of the lesions in this study were well differentiated, 85% (n=56/66), and moderately differentiated, 15% (n=10/66), and none of the lesions was poorly differentiated. Perineural invasion, lymphovascular invasion, tumor necrosis, and extension below subcutaneous tissue were present in 82%, 14%, 28%, and 26%, respectively. Of 66 patients, 21.2% (n=14/66) had pathological nodal disease after elective nodal dissection. Perineural invasion (p<0.0001), depth of lesion (p<0.0001), and tumor necrosis (p=0.0002) had a statistically significant correlation with node metastasis. On ROC curve analysis, 7.5 cm was the cut-off size, above which chances of nodal metastasis increased significantly. Conclusions Marjolin's ulcer patients with no preoperative positive nodes may be segregated into high-risk and low-risk groups as per their risk of harboring cancer cells in regional lymph nodes. Those having one or more of the following risk factors should be classified as high risk: dimension more than 7.5 cm, presence of perineural invasion, tumor necrosis, and deep tumors extending below subcutaneous tissue. We recommend that such patients undergo prophylactic regional lymph node dissection instead of observation during primary surgery.