Elective versus Therapeutic Neck Dissection in Node-Negative Oral Cancer

Mychal Outlaw, Mercer University College of Pharmacy

In 2013, the National Comprehensive Cancer Network guidelines on head and neck cancers stated that for oral cavity squamous cell carcinoma, the depth of cancerous invasion is the best guide to use when deciding on elective neck dissection. Specifically, for stage T1 and T2 oral cavity squamous cell carcinoma, these guidelines recommended surgical resection of primary site (preferred) or bilateral neck dissection1.

According to a meta-analysis of randomized trials on elective neck dissection versus therapeutic neck dissection, elective neck dissection reduced the risk of disease-specific death compared to the observational alternative. The authors concluded that the reduction found after the analysis supports a need to initiate elective neck dissection in oral cancer with clinical node-negative neck2.

Design Prospective, randomized, controlled trial; N= 500
Objective To evaluate the effect on survival of elective node dissection (ipsilateral neck dissection at the time of the primary surgery) versus therapeutic node dissection (watchful waiting followed by neck dissection for nodal relapse) in patients with lateralized stage T1 or T2 oral squamous cell carcinomas
Study Groups Elective-surgery group (n= 245); therapeutic-surgery group (n= 255)
Methods Patients were randomly assigned to undergo either elective or therapeutic neck dissection in a 1:1 ratio. We evaluated patients for primary tumor and lymph-node involvement using physical examination and ultrasonography of the neck. All patients underwent oral excision of the primary tumor with adequate margins. Patients in the elective-surgery group underwent an ipsilateral selective neck dissection with clearance of the submandibular (level I), upper jugular (level II), and mid-jugular (level III) nodes. Patients in the therapeutic-surgery group underwent the same surgical procedure for the primary tumor and were then monitored, with modified neck dissection (levels I to V) only at the time of nodal relapse. When indicated, radiotherapy was used as an adjuvant treatment in the two study groups. Patients were followed once every 4 weeks for first 6 months. After that, they were followed every 6 weeks for the next 6 months, every 8 weeks for next 12 months, and every 12 weeks thereafter.
Duration January 2004 to June 2014
Primary Outcome Measure Survival
Baseline Characteristics
Characteristic Elective-surgery  (n= 243) Therapeutic-surgery (n= 253)
Male, n (%) 187 (77) 187 (73.9)
Mean age, years 48 48
Tongue as primary site of tumor, n (%) 207 (85.2) 216 (85.4)
T1 tumor stage, n (%) 105 (43.2) 114 (45.1)
T2 tumor stage, n (%) 138 (56.8) 139 (54.9)
Results There were 50 deaths (20.6%) in the elective-surgery group and 79 deaths (31.2%) in the therapeutic-surgery group.   At 3 years, the corresponding overall survival rates for the two groups were 80.0% (95% confidence interval [CI], 74.1 to 85.8) and 67.5% (95% CI, 61.0 to 73.9), respectively.
Adverse Events Common Adverse Events: N/A
Serious Adverse Events: N/A
Percentage that Discontinued due to Adverse Events: N/A
Study Author Conclusions Elective neck dissection at the time of resection of the primary tumor confers an overall survival benefit in patients with early-stage, clinically node-negative oral squamous-cell carcinoma.

Further analysis of this study and its subgroups showed that depth of the primary tumor might explain the lack of benefit seen in some patients undergoing elective neck dissection. Also, considering overall disease-free survival, 81 recurrences (33.3%) were reported among individuals in the elective-surgery group and 146 recurrences (57.7%) were reported in the therapeutic group. Further interpretation of the results showed that one death would be prevented for every eight patients treated with elective neck dissection and one recurrence would be prevented for every four patients treated. One limitation that may be considered is that a higher percent of patients in the elective neck dissection group received adjuvant radiotherapy. The contribution of this to the overall survival rate was not considered.

Overall this study showed that the overall rate of survival and overall rate of disease-free survival was significantly higher in the elective surgery group. Among patients with early-stage oral squamous-cell cancer, elective neck dissection resulted in higher rates of overall and disease-free survival when compared to therapeutic neck dissection3.

References

  1. Head and Neck Cancers. National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology. Version 2.2013. Available at: http://oralcancerfoundation.org/treatment/pdf/head-and-neck.pdf . Accessed August 19, 2015.
  2. Fasunla AJ, Greene BH, Timmesfeld N, Wiegand S, Werner JA, Sesterhenn AM. A meta-analysis of the randomized controlled trials on elective neck dissection versus therapeutic neck dissection in oral cavity cancers with clinically node-negative neck. Oral Oncol 2011;47:320-4.
  3. D’cruz AK, Vaish R, Kapre N, et al. Elective versus Therapeutic Neck Dissection in Node-Negative Oral Cancer. N Engl J Med. 2015;373(6):521-9.
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