Radiation Oncology: A Question-Based Review


Steven H. Lin and Ori Shokek

image Background

What is the typical age of presentation for hemangioblastoma?

20–50 yrs is the typical age of presentation for hemangioblastoma (primarily in young adults).

Where do most hemangioblastomas arise anatomically?

Hemangioblastomas arise in the cerebellum. They are the most common primary cerebellar tumor in adults.

What genetic disorder is associated with hemangioblastomas?

Von Hippel-Lindau (VHL; hemangioblastomas, pancreatic/renal cysts, renal cell carcinoma)

Are hemangioblastomas benign/low grade or malignant/high grade?

Benign/low grade (WHO grade 1)

What is the cell of origin or hemangioblastomas, and what is the associated pathology?

Endothelial stem cells; closely packed vascular lesions with a stroma of large oval “foamy” cells

The # of lesions seen in hemangioblastomas correlates with what in terms of etiology?

Single lesion (sporadic, older pts) vs. multiple lesions (familial, younger pts)

What hematologic abnormality is present in pts with hemangioblastomas? Why?

Polycytemia is present because of erythropoietin production by the tumor.

How do hemangioblastomas cause morbidity if not treated?

Local compression and hemorrhage

What are common Sx of hemangioblastoma at presentation?

HA, hydrocephalus, and imbalance

image Workup/Staging

What steps are critical during the workup of a hemangioblastoma?

Thorough neurologic exam and MRI (craniospinal); angiography to aid in embolization before surgery

What is the typical radiographic appearance of a hemangioblastoma?

Eccentric/peripheral cystic mass (70%) in the posterior fossa

How do hemangioblastomas appear on MRI?

On MRI, hemangioblastomas are intensely enhancing.

image Treatment/Prognosis

What are the 2 main Tx approaches for hemangioblastoma?

Surgery (max safe resection is curative) and SRS

What are the LC rates of surgery vs. SRS for hemangioblastomas?

1.     Surgery: 50%–80%

2.     SRS: 85%–90% at 2 yrs, 75% at 5 yrs

What is the SRS dose range used for the Tx of hemangioblastomas?

15–21 Gy to 50% IDL

What does the older dose-response data show for fractionated EBRT for the Tx of hemangioblastomas?

It showed better results with higher doses (Smalley SR et al., IJROBP 1990: better OS with dose >50 Gy; Sung DI et al., Cancer 1982: better survival with 40–55 Gy vs. 20–36 Gy).

What are traditionally employed EBRT doses for hemangioblastomas?

50–55 Gy in 1.8 or 2 Gy/fx

For cystic hemangioblastoma lesions, what component does not have to be removed during surgery?

If there is a –margin, there is no need to remove the entire cyst. In this case, only the mural nodule/tumor should be removed.

When has RT (either SRS or EBRT) been traditionally used in the management of hemangioblastomas?

After recurrence (i.e., after definitive surgery or after STR for recurrence)

For what type of hemangioblastoma lesions is fractionated EBRT a better choice than SRS?

Multiple tumors, larger lesions (>3 cm), and lesions in eloquent regions of the brain

Which hemangio-blastoma pts have a better prognosis after EBRT: VHL+ or VHL+ pts?

VHL + pts have a better prognosis after EBRT. (Princess Margaret Hospital data: Koh ES et al., IJROBP 2007)

What is the prognostic significance of a cyst component after SRS for hemangioblastoma?

LC is worse if the tumor is cystic. (Japan data: Matsunaga S et al., Acta Neurochir 2007)

What is the median time to recurrence after EBRT for hemangioblastoma?

Hemangioblastomas tend to recur 2–4 yrs after EBRT.

What is the pattern of failure after EBRT for pts with hemangioblastoma?

Failure is predominantly local.

image Toxicity

What is the surgical mortality rate of pts treated for hemangioblastoma?

The surgical mortality rate is 10%–20% in pts treated for hemangioblastoma.