Radiation Oncology: A Question-Based Review

Orbital and Intraocular Primary Eye Lymphomas

Boris Hristov and Roland Engel

image Background

Under what type of lymphomas are intraocular/orbital lymphomas classified?

Intraocular/orbital lymphomas are classified as non-Hodgkin lymphomas (B-cell histology > T-cell histology).

What is the median age of onset? What are the 2 main types of eye lymphoma?

The median age of onset is 50–60 yrs (females > males). The 2 main types are intraocular and orbital/ocular adnexa lymphoma.

What % of pts with primary intraocular lymphomas develop CNS Dz within 3 yrs?

60%–80% of pts with intraocular lymphomas develop CNS Dz.

What % of pts with primary CNS lymphomas develop intraocular involvement?

25% of pts with primary CNS lymphoma develop intraocular involvement.

What is the recurrence rate after Tx of intraocular lymphomas?

The recurrence rate after Tx is ~50%.

Intraocular lymphoma is bilat in what % of pts? How about orbital/adnexa lymphoma?

1.     Intraocular: 80%

2.     Orbital: 20%

What is a common chromosomal trans-location in intraocular lymphoma? What % of pts have this translocation?

t(14:18) is a common translocation in intraocular lymphoma. 56% of pts have this translocation.

Ocular lymphoma cells are usually positive for which 2 important immunohistochemical markers?

Ocular lymphomas usually stain positive for CD20 and bcl-2.

What type of lymphoma accounts for most lymphomas of the ocular adnexa?

MALT lymphoma accounts for most lymphomas of the ocular adnexa.

Which ocular lymphoma has a male predominance and is associated with mycosis fungoides?

Ocular lymphoma of T-cell histology occurs predominantly in males and is associated with mycosis fungoides.

With what infectious agent has orbital MALT been associated? What site is often involved?

Chlamydia psittaci has been associated with orbital MALT lymphomas. The lacrimal gland is often involved.

Lymphoma of what orbital structure has a high propensity for LN spread?

Lacrimal gland lymphoma has a high propensity for LN spread (>40% are LN+).

Which lymphomas have a better prognosis: orbital or intraocular?

Orbital lymphomas tend to be indolent, whereas intraocular lymphomas are aggressive with a high propensity for CNS involvement.

image Workup/Staging

What are common presenting Sx of ocular/orbital lymphomas?

Blurred vision, floaters, pain (uveitis/vitritis), and proptosis (if retro-orbital)

What must the physical exam portion of the workup include?

The physical exam portion must include an ophthalmologic exam (fundscopy, slitlamp exam) as part of the workup.

What lab/pathology tests are required during the workup?

CSF/vitrectomy, BM Bx, CBC, LFTs, ESR

What imaging is recommended for ocular/orbital lesions?

MRI brain/orbits, ocular US, CT C/A/P (PET/CT if MALT: Perry C et al., Eur J Haematol 2007)

What staging system is used for eye lymphomas?

Ann Arbor staging system:

1.     Stage IE: localized eye lymphomas

2.     Stage II: cancer located in 2 separate regions

3.     Stage III: cancer on both sides of diaphragm, including 1 organ or area near LNs or spleen

4.     Stage IV: diffuse or disseminated involvement of ≥1 extralymphatic organs (e.g., liver, BM, or nodular involvement of lungs)

What is the most widely used classification system for lymphomas of the eye?

REAL (Revised European-American Classification of Lymphoid Neoplasms): 3 classes–indolent, aggressive, and highly aggressive

image Treatment/Prognosis

What is the Tx paradigm for orbital lymphoma?

Orbital lymphoma Tx paradigm: RT alone (low grade) or CRT (if intermediate/high grade)

What RT doses are used for orbital lymphoma?

30 Gy (MALT, low grade) and 30–40 Gy (high grade, based on chemo response)

What is the Tx paradigm for intraocular lymphoma?

Intraocular lymphoma Tx paradigm: chemo +/− RT. These are treated more like primary CNS lymphomas.

What area is irradiated in intraocular lymphoma?

The orbits ( +/− whole brain) are irradiated in intraocular lymphoma.

What chemo agent is typically used for intraocular lymphomas?

High-dose methotrexate (Mtx). Intraocular/intravitreal Mtx and Rituxan are usually employed.

What chemo regimens are typically used for high-grade orbital/ocular adnexa lymphomas?

Cyclophosphamide HCl/doxorubicin/Oncovin/prednisone + Rituxan (R-CHOP) or cyclophosphamide/vincristine/Adriamycin/dexamethasone) (CVAD) are typically used for high-grade orbital lymphomas.

What is 1 additional option for refractory/relapsed Dz?

Radioimmunotherapy (RIT) with Bexxar (I-131) or Zevalin (yttrium-90) is another option for refractory/relapsed Dz.

What RT technique can be utilized for ant (eyelid, conjunctival) lesions?

Ant orthovoltage or electron fields can be employed for ant eye lesions.

How is lens shielding accomplished with an ant orthovoltage field?

A lead shield is suspended in the beam to shield the lens (limits lens dose to 5%–10%).

What are some poor prognostic factors for ocular/orbital lymphomas?

High-grade Dz, advanced Dz (stage IVE), and symptomatic Dz

image Toxicity

Above what cumulative dose (standard fractionation) is lens opacification seen?

Lens opacification is seen with doses >13–16 Gy.

What toxicities are associated with RIT?

Myelosuppression, myelodysplastic syndrome, and acute myeloid leukemia

What is the min dose to induce cataracts with a single fx vs. multiple fx of RT?

Doses of 2 Gy (single fx) and 4–5 Gy (multiple fx) can induce cataracts.

Is cataract induction a stochastic or deterministic late effect? Explain.

Deterministic. There is a threshold and the severity/latency are dose related.

Which region of the lens is affected most by RT?

The post subcapsular region of the lens is affected most by RT.

What is the dose tolerance of the retina/optic nerves?

The dose tolerance of retina/optic nerves is 50 Gy.

What is the dose tolerance of the lacrimal glands?

The dose tolerance of the lacrimal apparatus is 26–30 Gy.

Above what dose can painful keratitis be seen?

Doses >60 Gy can cause painful keratitis.