Contralateral Nodal Relapse (CLNR) in Well Lateralized Oral Cavity Cancer Treated Ipsilaterally with Surgery and Adjuvant Radiotherapy with or without Concurrent Chemotherapy: A Retrospective Audit

Abstract

<h3>Purpose/Objective(s)</h3> Elective treatment of contralateral neck is a matter of debate in well lateralized oral squamous cell carcinoma (OSCC). The current study was done to evaluate the incidence, pattern of contralateral nodal relapse (CLNR), outcomes and risk factors predicting CLNR in well lateralized OSCC treated with unilateral surgery and adjuvant ipsilateral radiotherapy with or without concurrent chemotherapy. <h3>Materials/Methods</h3> Consecutive patients of well lateralized OSCC treated with surgery and adjuvant radiotherapy ± chemotherapy between 2012 to 2017 were included in this study. Data regarding demography, histo-pathological features, treatment and outcomes were retrieved from hospital case files and electronic medical records (EMR), Radiation Oncology Information System (ROIS) and Treatment Planning System (TPS). Primary cancers of tongue, floor of mouth, disease in the midline or crossing midline and patients receiving elective treatment to contralateral neck were excluded. The primary endpoint of the study was to determine the incidence of CLNR and contralateral nodal relapse free survival (CLNRFS). CLNRFS was determined from the date of surgery till documented clinico-radiological or histological evidence of CLNR or death or last follow up. Univariable and multivariable analysis was done to identify all potential predictive factors for CLNR. <h3>Results</h3> Of 1120 patients of OSCC treated with surgery and radiotherapy, 208 patients were eligible for the current study. At a media follow-up for 45 months, 21 (10%) patients had isolated contralateral nodal relapse and additional 9 (4.3%) patients had bilateral nodal relapse. CLNR was most common at level IB (n=13, 61.9%) followed by level II in patients with isolated CLNR. Only 1 patient had isolated contralateral level IV metastasis. Total six (28.6%) patients could be salvaged with surgery with and without radiotherapy. 3 of the 6 patients developed distant metastasis and succumbed to the disease and 3 were alive and diseases free at last follow up. Local recurrence was the most common pattern of failure (21%) in the entire group. The 5-year CLNRFS was 82.5% and 5-year overall survival was 57.7%. Higher rate of CLNR was observed in patients with ipsilateral nodal disease (p=0.001), ≥2 positive lymph nodes (0.006, level IB (0.002) or II note(p=0.000), extranodal extension (p=0.001) and perineural invasion (p=0.021) on univariable analysis. More than equal to 2 positive ipsilateral positive lymph node was identified as independent prognostic factor for CLNR on multivariable analysis (p=0.007). <h3>Conclusion</h3> The incidence of contralateral nodal failure is low in ipsilaterally located and unilaterally treated OSCC. Patients with multiple ipsilateral nodal disease may be considered for elective treatment of contralateral neck especially level IB either with surgery or radiotherapy.