2B or Not 2B? Shoulder Function After Level 2B Neck Dissection: A Randomized Controlled Study
Condition: Head and Neck Squamous Cell Carcinoma
MeSH terms: Squamous Cell Carcinoma of Head and Neck
Study type: Interventional

Summary: 
      Many types of head and neck cancers will have local spread to the neck. As such selective
      neck dissection is performed as part of the treatment. The neck is divided into various
      levels. Selective neck dissection targets areas that are most likely to harbor cancer cells
      for specific types of head and neck cancers. Level IIB has been particularly controversial in
      the last few years, as the rate of cancer spread to this area has been shown to be quite low
      (0-8%). Moreover, because the spinal accessory nerve (involved in shoulder function) runs
      through this area, there is theoretical risk of causing post-operative shoulder weakness. As
      such, the question of whether removing level IIB, knowing that there is low chance of it
      containing disease spread, is worth risking decreased shoulder function. Some would argue
      that all potential diseased sites should be removed at all costs. While other advocate that a
      balance between disease cure and function should be maintained. However, what needs to be
      determined is just what impact does dissecting IIB have on shoulder function. At our
      institution, the rate of poor shoulder function associated with selective neck dissection has
      been perceived as being quite low. This study is designed to test this observation.

      Hypothesis: Neck dissection including level IIb in head and neck cancer patients will not
      lead to worse shoulder function and quality of life than when level IIb is preserved.
    

Detailed description: 
      The lymphatic fluid of upper aerodigestive tract (UADT) drains into various levels of the
      neck. When cancer occurs in the UADT, the potential for local metastatic spread to the neck
      exists, thus necessitating treatment of the neck. Ideally all potential neck structures,
      which could harbor cancer cells or provide a dock for recurrence, would be eradicated.
      Unfortunately, such radical treatments have shown to cause extreme rates of morbidity with
      little extra oncologic benefit. Thus, head and neck oncologists have strived to create
      treatment paradigms, which maximize cure rates while minimizing morbidity. Finding this
      intricate balance has translated to selective neck dissection (SND) and post-operative RT.1

      Increased understanding of lymphatic drainage patterns in the head and neck has lead to
      widespread use of SND. Through removal of lymphatics in neck levels with the highest risk of
      harboring cancer cells, based on primary tumor site, important neck structures may be
      preserved. As such, the treatment remains oncologically sound and avoids the morbidity
      associated with its predecessor, the radical neck dissection. 1

      One of the structures preserved in the SND is the spinal accessory nerve (SAN), which is
      responsible for providing motor innervation to the sternocleidomastoid (SCM) and trapezius
      muscles. Thus, it is intricately involved in shoulder function. The nerve exists the skull
      base at the jugular foramen and obliquely passes through neck level II. It then passes
      posterior to the SCM and eventually enters the trapezius muscles. Through this trajectory, it
      divides level II into IIa (anterior to the SAN) and IIb (posterior to the SAN).

      It is known that shoulder function significantly deteriorates when level V is dissected.2
      This is likely due to traction and devascularization injury of the longest portion of the SAN
      in the neck. As such, practice has become such that level V is left intact in cases where it
      does not harbor detectable disease or when occult disease incidence is very low. Due to the
      intimate relationship of IIb with the SAN, there is also potential for injury to the nerve in
      this area.2 As such, debate has arisen to the necessity of including IIb in the neck
      dissection specimen. Studies have shown that the prevalence of occult nodal disease in IIb
      ranges from 0-8.7.5% depending on the overall n stage of the neck.3-5 These figures have lead
      head and neck surgeons to weigh the benefits of not excising lymphatic tissue with low nodal
      metastatic rates versus excising the area and decreasing post-operative shoulder function.6

      Because the incidence of occult metastases in IIb is low3-5, it has become standard of care
      in many centers to spare IIb, if it is oncologically feasible, in SND to preserve shoulder
      function. Because these patients receive post-operative RT it is thought that the RT will
      address any occult disease. Unfortunately, relying on RT poses two problems:

        1. occult disease may not respond to the RT

        2. leaving level IIb intact provides a lymphatic route of recurrence despite undergoing RT
           By surgically removing all portals of lymphatic disease spread these issues above can be
           eliminated.

      The goal of this study is to demonstrate that the minimal manipulation of the SAN associated
      with IIb dissection will not have a significant impact on post-operative shoulder function.
      If this is the case, the standard of practice should be changed to include IIb in the SND
      specimen in cases where level IIa is dissected as well. This would eliminate any further
      lymphatic tissue, which may harbor disease.

      Note: At the University of Alberta, some head and neck surgeons prefer to spare IIb in SND,
      while others prefer to resect it. Thus, the protocol in this study does not manipulate
      current standards of practice.

      *Reference numbers correspond to articles in the "Citations" section. The citations are in
      order of appearance in the above text.
    

Intervention name(s): Selective Neck Dissection Excluding Level 2B; Selective Neck Dissection Including Level 2B
Intervention type(s): Procedure; Procedure
Intervention description(s): Selective neck dissection is performed. Level 2a is dissected; level 2b is not dissected.; Selective neck dissection is performed. Level 2a is dissected; level 2b is also dissected.
Other intervention name(s): Not 2B; 2B
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: head and neck cancer; oral cancer; oropharyngeal cancer; laryngeal cancer; selective neck dissection; submuscular recess; level 2b