Head and Neck Cancer: Post-Treatment Changes

Daniel W. Williams III, MD

Learning Objectives

•  Describe the various types of neck dissections

•  Explain reconstruction techniques used following surgery

•  Describe expected soft tissue changes from irradiation

•  Recognize post-treatment imaging appearance of neck dissections, myocutaneous flaps, and radiation on CT and MRI

In patients treated for H/N Cancer:

Neck Dissection Classification *

1.  Radical neck dissection (RND) 2.  Modified RND 3.  Selective ND (“SND”+ LN levels

removed) 4.  Extended ND (RND plus) * KT Robbins et al. Neck dissection

classification update. Arch Otolaryn Head Neck Surg 2002; 128: 751-758.

Radical neck dissection Structures removed

- LN levels I-V - SCM, IJV, SAN - SM gland

Standard proc. to which other ND’s compared

Cummings, 4th ed. 2005

Normal RND Radical Neck Dissection

Modified RND Structures removed - LN levels I-V

Structures preserved - 1 or more non- lymphatic structures (SCM, IJV, SAN)

Cummings, 4th ed. 2005

Normal Modified RND

Modified RND (IJV & SCM removed)

Selective Neck Dissection Preservation of 1 or more LN levels

(c/w RND):

-  Oral cavity: SND (I-III) -  OP/HP & laryngeal: SND (II-IV) -  Low ant. neck ML structures: SND (VI) - Skin Ca: SND (LN levels adj. to 1°)

Normal SND Selective ND (I-III)

Extended ND

- All structures removed during RND

- Additional LN groups and/or non-lymphatic structures not removed at RND •  Carotid artery •  Paraspinal muscle •  CN’s 10 or 12

Removes:

Cummings, 4th ed. 2005

Extended ND (incl. CN 10)

Imaging Appearance of ND’s •  Depends on type of surgery •  RND/some MRND’s: recognizable Δ’s

– absent structures, neck contour Δ, muscle denerv atrophy / hypertrophy

•  Some MRND/most SND’s: subtle Δ’s

–  loss of fat planes, slight neck contour Δ, surgical scar, ± absent structures

•  Be alert for complications and pitfalls

Complications and Pitfalls •  Complications

–  Perioperative - bleeding, nerve injury, pntx, air embolus/leak, infection/abscess

–  Postoperative – shoulder syndrome, fistulas, CA rupture, IJV thrombosis, facial/cerebral edema

•  Pitfalls –  MC flaps –  Pseudotumors –  IJV stump

Options in Head and Neck Reconstruction

•  Healing by secondary intention •  Primary closure •  Skin grafts (split or full thickness) •  Composite grafts •  Flaps (local, distant pedicled, distant

free)

From Gurtner GC, Evans GR. Advances in head and neck reconstruction. Plast Reconstr Surg 2000;106:672-682; quiz 683

MC Flaps: Uses •  Facilitate wound closure •  Repair surgical defects •  Enables more complete removal of 1° tumor •  Restore optimal function (speech, breathing,

mastication, swallowing) •  Cosmesis (recreation of facial aesthetics) •  Protection (carotid artery during RT, skull

base, orbital apex)

Flap Classification

•  Type of tissue transferred –  Cutaneous –  Myocutaneous –  Osteomyocutaneous

Flap Classification •  Site of origin

–  Local (temporalis) –  Regional (pectoralis major) –  Microvascular free tissue transfer

(radial forearm, iliac crest, lateral thigh, subscapular system, jejunal, “double” free-flap)

MC Flaps: Imaging Appearance

•  Imaging changes usually obvious, but can be quite subtle

•  Pearls: – Compare to pre-treatment exam – Read the op-note or call the surgeon !!!! – Be aware of potential complications and

pitfalls

MC Flaps: CT/MR findings

•  Neck contour change •  Fatty “mass” w/ muscle striations •  Muscle denervation atrophy over time •  Muscle enhancement on MR (often

intense, persists many months) •  Rotational flaps - muscle origin remains

attached; vascular pedicle visible •  “Unusual appearing” bones/other signs

of surgery

Neck contour change; fatty “mass” with muscle striations

Rectus abdominus free flap

Muscle origin remains attached

Pectoralis major flap

Complications/Pitfalls •  Fluid collections, fistulas, IJV

thrombosis, flap ischemia/necrosis, nerve injury, bone nonunion or infection

•  Pseudotumors (muscle denerv. atrophy, muscle hypertrophy, enhancing flap muscle component)

•  Changes or complications assoc. with primary tumor excision, ND or RT

•  Hide early tumor recurrences from PEx

Irradiation in H/N Cancer •  Alone ± chemo or surgery •  Successful RT = disappearance of

tumor or major ↓ tumor volume •  Effects on normal tissue - acute or late/

delayed •  Usually with doses > 6500cGy •  Our task: differentiate between

radiation-induced changes and tumor recurrence!

Irradiation effects on normal tissue

•  Acute – during or immediately after RT –  tissues with rapidly dividing cells (mucous

membranes, skin) – rarely imaged

•  Late/delayed – months to years after RT –  tissues with slowly or non-proliferating

cells (connective tissue, spinal cord)

“Expected” RT Changes (CT/MRI)

•  Reticulation/enhancement of fat •  Loss of fat planes betw. structures •  Skin and platysma muscle thickening •  Edema (supraglottic laryngeal, RTPS) •  Dense salivary glands (fatty Δ later) •  Lymph node enhancement •  Fatty marrow conversion (spine)

“Expected” RT Changes RT Complications

•  Dry eyes/mouth •  Dental caries •  Trismus •  Osteoradionecrosis •  Cataracts •  Optic neuropathy •  Lymphedema

•  CNS abnl’s (trans myelitis, CN palsy, pit. dysfx)

•  Accelerated athero

•  RT-induced tumors

Conclusions •  Perform high quality exams •  Learn types of ND’s and MCF’s your

surgeons use •  Maintain a high index of suspicion when

evaluating post-op scans (!recurrent tumor, new primary, nodes, PNS)

•  Anticipate location of recurrences •  Above all, read the op note/speak to the

surgeon

Thanks