Treatment Paradigm

Question 1

What is the recommended initial Tx for LCH?

Answer 1

Pts with multisystem LCH should initially be treated with a combination of prednisone and vinblastine for 6 wks f/b re-evaluation and maintenance therapy if they have responded to therapy.

Question 2

What are the indications for RT in LCH?

Answer 2

Painful or unstable unifocal or multifocal bone lesions and Tx of extraosseous ST or organ involvement.

Question 3

When is RT not indicated in LCH?

Answer 3

RT is not indicated for sclerotic LCH lesions and collapsed vertebral lesions (only indicated if such lesions are painful).

Question 4

What data support the use of RT for localized osseous LCH lesions?

Answer 4

German meta-analysis (Olschwski T et al., Strahlenther Onkol 2006): LC was 96% and CR was 93% for single-system Dz with RT.

Question 5

What are the commonly used doses and volumes for LCH?

Answer 5

DI: 15 Gy to pituitary/hypothalamus

Bone (small margin): 5–10 Gy

Adults: 15–24 Gy (in 2 Gy/fx)

Question 6

When is chemo used in LCH?

Answer 6

Multisystem Dz (e.g., if fever, pain, severe skin involvement, failure to thrive, and organ dysfunction)

Question 7

What systemic agents are used for LCH?

Answer 7

Prednisone (1st-line), then vinblastine. Single-agent chemo is as good as multiagent chemo. Vincristine can also be used.

Question 8

How are asymptomatic, organ-confined LCH lesions managed?

Answer 8

Asymptomatic LCH lesions are typically observed.

Question 9

How is a symptomatic bony LCH lesion managed?

Answer 9

A symptomatic bony LCH lesion is typically managed by Sg (curettage, excision) and/or local injection of steroids.

Question 10

How are symptomatic LCH skin lesions managed?

Answer 10

Symptomatic LCH skin lesions are managed by topical therapy with nitrogen mustard, steroids, or systemic therapy.

Question 11

How is LCH of the eye, ear, spine, or weight-bearing bones managed?

Answer 11

LCH of these areas is managed by systemic steroids or local RT.

Question 12

How is asymptomatic multifocal LCH Dz with organ dysfunction managed?

Answer 12

Such asymptomatic LCH Dz is typically observed.

Question 13

How is symptomatic multifocal LCH Dz with organ dysfunction managed?

Answer 13

Symptomatic multifocal LCH Dz with organ dysfunction is managed by systemic therapy (as described above). If the pt is symptomatic due to organ failure, consider transplant (liver, lung).

Question 14

What is the long-term OS for solitary LCH lesions?

Answer 14

The OS for solitary LCH lesions is ∼100%.

Question 15

What is the long-term OS for multisystem LCH with organ dysfunction?

Answer 15

The long-term OS for multisystem LCH with organ dysfunction is 33%–54%.

Question 16

What is the long-term OS for multisystem LCH without organ dysfunction?

Answer 16

The long-term OS for multisystem LCH without organ dysfunction is 82%–96%.

Question 17

What is the RT TD 5/5 dose threshold for developing hypopituitarism?

Answer 17

The TD 5/5 for hypopituitarism is 40–45 Gy (GH levels decrease first with doses as low as 18 Gy, then LH/FSH, then TSH/ACTH).

Question 18

What is the role of RT in managing localized bone or soft tissue LCH?

Answer 18

Historically, RT was used as both a diagnostic and therapeutic intervention. However, excellent control rates of 70% to 90% are seen after surgical excision for localized bone or soft tissue LCH. Radiation in this case is reserved for residual disease or local relapse after surgery.

Question 19

Which patients with LCH may benefit most from radiation therapy?

Answer 19

Patients with multifocal LCH or with organ dysfunction, painful lesions despite chemotherapy, disfiguring bone or soft tissue lesions, and bones at substantial immediate risk for fracture.

Question 20

What is the most common complication of CNS involvement in LCH?

Answer 20

Diabetes insipidus from lesions in the posterior pituitary or pituitary stalk. This is diagnosed by high to normal plasma sodium concentrations, especially if urine osmolality is less than plasma osmolality.

Question 21

What common long-term sequelae are seen after treatment of Langerhans cell histiocytosis?

Answer 21

DI (18%), GH deficiency and short stature (5%), hypothyroidism (2.5%), deafness (2.5%), and orthopedic sequelae.