Int. J. Radiation Oncology Biol. Phys., Vol. 78, No. 1, pp. 72–78, 2010Copyright � 2010 Elsevier Inc.

Printed in the USA. All rights reserved0360-3016/$–see front matter

robp.2009.07.1729

doi:10.1016/j.ij

CLINICAL INVESTIGATION Brain

PROGNOSTIC FACTORS AFTER EXTRANEURAL METASTASIS OFMEDULLOBLASTOMA

ALI MAZLOOM, M.D.,* AZY H. ZANGENEH, M.P.H.,y AND ARNOLD C. PAULINO, M.D.*z

*Department of Radiology, Section of Radiation Oncology, The Methodist Hospital, Houston, Texas; yDivision of Health Promotionand Behavioral Sciences, The University of Texas School of Public Health, Houston, Texas; and zDepartment of Radiation Oncology,

The Methodist Hospital, Houston, Texas

ReprinHospital,DB1-077441-4493

Present

Purpose: To review the existing literature regarding the characteristics, prognostic factors, treatment, and survivalof patients with medulloblastoma, who develop extraneural metastasis (ENM).Methods and Materials: A PubMed search of English language articles from 1961 to 2007 was performed, yielding47 articles reporting on 119 patients. Factors analyzed included age, time interval to development of ENM, ENMlocation, central nervous system (CNS) involvement, treatment, and outcome.Results: Sites of ENM included bone in 84% of patients, bone marrow in 27% of patients, lymph nodes in 15% ofpatients, lung in 6% of patients, and liver in 6% of patients. Median survival was 8 months after diagnosis of ENM.The 1-, 2-, and 5-year overall survival (OS) rates after diagnosis of ENM were 41.9%, 31.0%, and 26.0%, respec-tively. The 1-, 2-, and 5-year progression-free survival (PFS) rates after diagnosis of ENM were 34.5%, 23.2%, and13.4%, respectively. For patients without CNS involvement at the time of ENM diagnosis, the 1-, 2-, and 5-year OSrates for those treated with and without radiotherapy (RT) were 82.4%, 64.8%, and 64.8% vs. 51.0%, 36.6%, and30.5%, respectively (p = 0.03, log-rank test). RT did not significantly improve OS or PFS rates for those with CNSinvolvement. Concurrent CNS involvement, ENM in the lung or liver, a time interval of <18 months to developmentof ENM, and a patient age of <16 years at ENM diagnosis were found to be negative prognostic factors for both OSand PFS.Conclusions: Several prognostic factors were identified for patients with ENM from medulloblastoma. Patientswithout concurrent CNS involvement, who received RTafter ENM diagnosis had an OS and PFS benefit comparedto those who did not receive RT. � 2010 Elsevier Inc.

Medulloblastoma, Extraneural, Extracranial, Metastasis, Radiotherapy.

INTRODUCTION

Medulloblastoma is the most common brain tumor in chil-

dren and accounts for 15 to 20% of cases (1). Of all the

pediatric brain tumors, medulloblastoma has one of the high-

est rates of metastasis outside the central nervous system

(CNS) (2–5), with 7 to 10% of cases developing extraneural

metastasis (ENM) (6–10). In 1936, Nelson (11) reported the

first case of medulloblastoma that had metastasized outside

of the CNS. Subsequently, a number of case series or reports

of ENM of medulloblastoma have been published (12–29).

Patients diagnosed with ENM have traditionally been treated

with different chemotherapeutic agents including vincristine,

cisplatin, carboplatin, and cyclophosphamide (4, 30); how-

ever, despite treatment, ENM has historically been associated

with a poor prognosis (30). In addition, the relative rarity of

this disease has made systematic study difficult. The purpose

of this study was to perform a comprehensive literature

t requests to: Arnold C. Paulino, M.D., The MethodistDepartment of Radiation Oncology, 6565 Fannin St.,

, Houston, TX 77030. Tel: (713)-441-4820; Fax: (713)-; E-mail: apaulino@tmhs.orged in part at the 45th Annual Meeting of the American

72

review and analysis of reported cases to identify the charac-

teristics, prognostic factors, and survival of these patients.

METHODS AND MATERIALS

MEDLINE/PubMed searches of English language articles per-

taining to ENM from medulloblastoma were performed using

a combination of key words: extraneural, metastasis, metastatic,

extracranial, and medulloblastoma. Eligibility for inclusion in the

study included diagnosis of medulloblastoma with ENM prior to

death. Patients who were diagnosed with ENM at autopsy were ex-

cluded from this study. We found 47 articles reporting 119 patients,

published from 1961 to 2007, that met the above-described criteria

(2, 4, 6–10, 12, 20, 21, 23, 24, 26, 30–63). Articles were reviewed

carefully to ensure that the same patient was not counted more

than once in the study (47, 64). Table 1 lists the published reports,

the year of publication, and the number of cases of patients with

ENM from medulloblastoma.

Society of Clinical Oncology, Orlando, FL, May 29 – June 2, 2009.Conflict of interest: none.Received April 8, 2009, and in revised form July 8, 2009.

Accepted for publication July 16, 2009.

Table 1. Studies reporting cases of extraneural metastasisfrom medulloblastoma

Study (reference)Year of

publicationNo. ofcases

Chan et al. (39) 2000 8Miyake et al. (53) 1964 1Booher and Shmidtknecht (9) 1977 1Leo et al. (30) 1997 1Nathanson and Kovacs (54) 1978 2Krouwer et al. (46) 1991 1Lassman (47) 1976 4Donner (41) 2005 1Das and Dalby (21) 1977 3Paterson (12) 1961 7Friedman et al. (4) 1986 4Lewis et al. (10) 1973 1Bates (8) 1973 1Brutschin and Culver (36) 1973 3Rochkind et al. (6) 1991 1Stolzenberg et al. (59) 1970 1Lowery et al. (49) 1982 6Mahoney et al. (51) 1986 1Duffner and Cohen (42) 1981 2Varan et al. (2) 2006 6Wendland et al. (63) 2006 1McComb et al. (26) 1981 6Watterson et al. (62) 1993 1Black and Keats (35) 1964 3Cottu et al. (7) 1994 1Allen and Helson (33) 1981 2Millot et al. (52) 1999 2Paulino (56) 2003 7Brown et al. (20) 1977 1Raimondi and Tomita (24) 1979 3Brydon and Carey (37) 1991 1Spencer et al. (58) 1984 4Akyuz et al. (32) 1999 1Ramsay et al. (57) 1995 1Eberhart et al. (43) 2003 7Vieco et al. (61) 1989 4Bach et al. (34) 1968 1Ahmad et al. (31) 2002 1Parkinson et al. (55) 1974 2Jackson and Graham (23) 1978 1Lefkowitz et al. (48) 1990 1Corrin and Meadows (40) 1967 1Vanneste (60) 1983 1Kleinman et al. (45) 1981 2Kessler et al. (44) 1975 1Chamberlain et al. (38) 1988 7Lundberg et al. (50) 1992 1

Fig. 1. Time interval from diagnosis of primary tumor to ENM ofmedulloblastoma.

Extraneural medulloblastoma d A. MAZLOOM et al. 73

Factors analyzed for each patient included gender, age at diagno-

sis of medulloblastoma, time interval from medulloblastoma diag-

nosis to development of ENM (<18 or >18 months), involvement

of the CNS at the time of ENM, location of ENM, treatment, pro-

gression, and survival. A chi-square test was used to compare the

dichotomous and categorical variables. Estimates of progression-

free survival (PFS) and overall survival (OS) were performed using

the Kaplan-Meier method and were calculated from the time of

ENM (65). For comparisons of survival curves according to site

of metastasis, time interval to metastasis, CNS involvement at

the time of ENM, and treatment parameters, the log-rank test

was used.

RESULTS

Patient characteristicsWe identified 119 patients with ENM from medulloblas-

toma. Of these 119 patients, 63 (52.9%) patients were male

and 37 (31.1%) patients were female; the gender was not

reported for 19 (16.0%) patients. The median age at initial

diagnosis of medulloblastoma was 14 years (range, 0.33–

66 years).

Tumor characteristicsThe time interval from initial diagnosis to extraneural re-

lapse was known in 107 patients. Three (2.8%) patients had

ENM at initial diagnosis of medulloblastoma. The median

time to develop ENM was 16 months (range, 0–164 months).

The time intervals to develop ENM are displayed in Fig. 1. Ap-

proximately 80% of cases occurred by 36 months. Tissue diag-

nosis of ENM was available for 98 of 111 (88.3%) cases, where

the method of diagnosis of ENM was mentioned. In 13 (11.7%)

cases, ENM was diagnosed radiographically; in 8 of the 13

(61.5%) cases, there was concomitant CNS involvement.

The sites of ENM were available for 109 patients. Bone

was the most common site of ENM, as seen in 92 (84.4%)

cases. Of the 92 patients with bone metastasis, 22 (23.9%) pa-

tients had solitary bone involvement. ENM was found in the

bone marrow in 29 (26.9%) patients, the lymph nodes in 16

(14.7%) patients, the lung in 7 (6.4%) patients, the liver in 7

(6.4%) patients, and in other sites in 14 (12.8%) patients, in-

cluding pancreas, retroperitoneum, pleura, paranasal sinuses,

skin, oral cavity, and connective tissue. Of the 29 patients

with bone marrow involvement, 22 (75.9%) patients also

had radiographic evidence of bone metastasis.

Treatment characteristicsInformation about the treatment of ENM was available for

108 patients. Treatment regimens administered included che-

motherapy combined with radiotherapy (RT) in 20 (18%) pa-

tients, chemotherapy alone in 50 (46%) patients, and

RT alone in 18 (17%) patients. Seven patients underwent sur-

gical resection, alone in 1 (1%), followed by chemotherapy in

Fig. 2. OS for patients with extraneural relapse of medulloblastomawith (solid line) and without (dotted line) CNS involvement at thetime of extraneural relapse; p < 0.0001, log rank test.

74 I. J. Radiation Oncology d Biology d Physics Volume 78, Number 1, 2010

2 (2%), followed by RT in 3 (3%) or followed by surgery and

chemotherapy in 1 (1%). No treatment was administered in

the case of 14 (13%) patients. Of the 23 patients for whom

data were available regarding the location of RT after diagno-

sis of ENM, 19 (83%) patients received RT to sites of ENM,

while 4 (17%) patients received RT to the CNS alone. For the

19 patients who received RT to sites of ENM, 15 (78.9%)

patients received RT to bone. Survival outcome was reported

for 112 of 119 patients. The median follow-up for these

patients after the diagnosis of ENM was 7 months (range,

0–300 months). The median follow-up for surviving patients

after the diagnosis of ENM was 24 months (range, 1–300

months). At last follow-up, 16 of 119 (13.4%) patients had

no evidence of disease, 73 (61.3%) patients had died of dis-

ease, and 19 (16.0%) patients were alive with disease. The

median survival for patients with ENM from medulloblas-

toma was 8 months. The 1-, 2-, and 5-year OS rates after

the diagnosis of ENM were 41.9%, 31.0%, and 26.0%,

respectively. The 1-, 2-, and 5-year PFS rates after the diag-

nosis of ENM of medulloblastoma were 34.5%, 23.2%,

13.4%, respectively.

For the 104 patients with available data regarding the type

of treatment and survival, 40 patients underwent RT and

64 did not. The median survival times for patients who re-

ceived RT and for those who did not were 24 and 8 months,

respectively. For patients who received RT, the 1-, 2-, and

5-year OS rates were 58.3%, 44.4%, and 44.4%, respectively,

whereas for those who did not receive RT, the rates were

35.2%, 24.8%, and 12.4%, respectively (p = 0.019, log-

rank test). The 1-, 2-, and 5-year PFS rates for patients who

received RT were 47.5%, 32.1%, and 24.1%, respectively,

whereas for those who did not receive RT, the rates were

29.0%, 18.8%, and 5.2%, respectively (p = 0.025, log-rank

test). For patients who received chemotherapy, the 1-, 2-,

and 5-year OS rates were 49.3%, 33.6%, and 23.7%, respec-

tively, whereas for those who did not receive chemotherapy,

the rates were 34.5%, 30.7%, and 30.7%, respectively

(p = 0.12, log rank test). The 1-, 2-, and 5-year PFS rates for

patients who received chemotherapy were 40.9%, 25.4%,

and 8.1%, respectively, whereas for those who did not receive

chemotherapy, the rates were 26.5%, 20.6%, and 20.6%, re-

spectively (p = 0.39, log rank test). There was no statistical

difference between OS or PFS according to whether or not

the patients underwent surgery as treatment for ENM of

medulloblastoma.

CNS involvementCNS involvement was present at the time of extraneural re-

lapse in 55 of 112 (49.1%) patients with available data; CNS

involvement was not reported for 7 patients. Median survival

times for patients with and without CNS involvement at the

time of extraneural relapse of medulloblastoma were 5 and

24 months, respectively. For patients with CNS involvement,

the 1-, 2-, and 5-year OS rates were 12.8%, 9.6%, and 6.4%,

respectively, whereas for those without CNS involvement,

the rates were 64.2%, 48.2%, and 45.1%, respectively (p <

0.0001, log rank test) (Fig. 2). The 1-, 2-, and 5-year PFS

rates for those with CNS involvement were 8.2%, 6.2%,

and 0%, respectively, whereas for those without CNS in-

volvement, they were 55.4%, 36.7%, and 25.6%, respec-

tively (p < 0.0001, log rank test). For patients with CNS

involvement at the time of extraneural relapse of medullo-

blastoma, the 1-, 2-, and 5-year OS rates for patients treated

with RT were 22.8%,15.2%, and 15.2%, respectively,

whereas for those who were not treated with RT, rates were

10.0%, 10.0%, and 0%, respectively (p = 0.56, log rank

test). The 1-, 2-, and 5-year PFS rates for patients with

CNS involvement treated with RT were 17.6%, 11.8%, and

0%, whereas for those who were not treated with RT, the

rates were 4.0%, 4.0%, and 0%, respectively (p = 0.5, log

rank test). For patients without CNS involvement at the

time of extraneural relapse of medulloblastoma, the 1-, 2-,

and 5-year OS rates for patients treated with RT were

82.4%, 64.8%, and 64.8%, respectively, whereas for those

who did not receive RT, the rates were 51.0%, 36.6%, and

30.5%, respectively (p = 0.03, log rank test) (Fig. 3). The

1-, 2-, and 5-year PFS rates for patients without CNS involve-

ment who were treated with RT were 69.6%, 47.4%, and

42.7%, whereas for those who did not receive RT, the rates

were 45.5%, 29.4%, and 11.2%, respectively (p = 0.04, log

rank test). Cause of death was reported for 59 cases. For pa-

tients with concomitant CNS involvement, the CNS was the

predominant cause of death as seen in 25 of 33 (75.6%) cases.

For patients without concomitant CNS involvement at the

time of diagnosis of ENM, the predominant cause of death

was ENM as seen in 21 of 26 (80.8%) cases.

Site of ENMThe median survival for patients with ENM to the lungs or

liver was 2 months. The OS (p = 0.002, log rank test) and PFS

(p < 0.0001, log rank test) of these patients were lower than

those with ENM to other locations. A total of 75% of patients

with lung or liver involvement had CNS involvement at the

Fig. 3. OS for patients with extraneural relapse of medulloblastomaand without concurrent CNS involvement treated with (solid line[n = 23]) and without (dotted line [n = 33]) radiotherapy; p = 0.03,log rank test.

Extraneural medulloblastoma d A. MAZLOOM et al. 75

time of extraneural relapse, while only 46.7% of patients

without lung or liver ENM had CNS involvement at this

time (p = 0.065). The frequency of concomitant CNS in-

volvement in the different ENM sites is presented in Table 2.

Patient age at ENMFor the 100 patients for whom data were available regard-

ing age at the time of ENM diagnosis, 48 patients were

<16 years old, and 52 patients were $16 years old. Median

survival time for patients of <16 years at the time of extraneu-

ral relapse was 6 months, while for those who were $16 years

old, it was 22 months. For patients younger than 16 years at

the time of ENM, the 1-, 2-, and 5-year OS rates were 26.3%,

18.4%, and 15.3%, respectively, whereas for patients older

than 16 years, the rates were 56.1%, 38.1%, and 27.4%, re-

spectively (p = 0.002, log rank test). The 1-, 2-, and 5-year

PFS rates for those younger than 16 years at the time of

ENM were 21.9%, 15.4%, and 7.7%, respectively, whereas

for those who were $16 years, the rates were 44.2%,

25.5%, and 10.6%, respectively (p = 0.023, log rank test). Pa-

tients who were younger than 16 years of age had a shorter

duration to ENM development. Sixty-seven percent of those

younger than 16 years old had a duration to metastasis of <18

months, whereas 38% of those who were 16 years old or older

had a duration to metastasis of <18 months (p = 0.003).

Table 2. Frequency of concomitant CNS in

Involvement

No. of c

Bone Bone marrow

Concomitant CNS involvement 41 (44.6) 12 (41.3)No concomitant CNS involvement 46 (50.0) 13 (44.8)Unknown 5 (5.4) 4 (13.8)Total 92 (100) 29 (100)

Time interval to development of ENMFor the 100 patients for whom data were available regarding

the time interval from initial diagnosis of medulloblastoma to

ENM development and survival outcome, 53 patients had a du-

ration to relapse of <18 months, and 47 patients had a duration

to relapse of $18 months. For patients with a time interval to

ENM of <18 months the 1-, 2-, and 5-year OS rates were

25.4%, 13.4%, and 13.4, respectively, whereas for those

with a time interval to metastasis of $18 months, rates were

60.6%, 48.0%, and 34.3%, respectively (p = 0.001, log rank

test) (Fig. 4). For patients with a time interval to ENM of

<18 months, the 1-, 2-, and 5-year PFS rates were 21.6%,

9.8%, and 2.0%, respectively, whereas for those with a time

interval to metastasis of $18 months, the rates were 46.8%,

33.2%, and 15.4%, respectively (p = 0.003, log rank test). Pa-

tients with a time interval of <18 months were less likely to be

treated with RT after diagnosis of ENM (27.3%) than those

with a time interval of $18 months (45.6%, p = 0.05).

Time era of publicationPatients in articles published before 1980 were reported to

have a worse PFS (p = 0.0003) than patients in articles

published from 1980 and beyond. There were no differences

in OS rates (p = 0.14). The 5-year OS and PFS rates for pa-

tients reported in articles published prior to 1980 were

11.6% and 2.7%, while the rates were 32.2% and 19.0%, re-

spectively, for patients reported in articles published from

1980 and beyond.

DISCUSSION

Medulloblastoma is a highly malignant tumor that has

been reported to spread both within and outside the CNS.

Liwnicz and Rubinstein (66) reported that glioblastomas

are the most common CNS tumors to spread extraneurally,

but as a proportion of their primary tumor, medulloblastomas

are the most likely to have ENM. Despite the propensity for

extraneural spread, the majority of reports in the literature are

limited to case reports or series, and to our knowledge, very

limited data exist for the prognosis of patients with ENM

from medulloblastoma. We therefore conducted the current

review in order to compile the existing literature data on

this topic and to help determine the prognostic factors and

treatment modalities that affect the outcome of patients

with ENM from medulloblastoma.

In our review of the literature, we concur with previous re-

ports that medulloblastoma patients who develop ENM have

volvement according to site of ENM

ases (% of total) with CNS involvement at:

Lung Liver Lymph nodes Other sites

5 (71.4) 6 (85.7) 6 (37.5) 9 (62.5)2 (28.6) 1 (14.3) 10 (62.5) 5 (37.5)0 (0) 0 (0) 0 (0) 0 (0)7 (100) 7 (100) 16 (100) 14 (100)

Fig. 4. OS for patients according to the time interval to the develop-ment of ENM, comparing time to ENM of $18 months (solid line)with <18 months (dotted line); p = 0.001, log rank test.

76 I. J. Radiation Oncology d Biology d Physics Volume 78, Number 1, 2010

a poor outcome, with a median survival of 8 months

(43, 45). ENM is rare at the initial diagnosis of medulloblas-

toma, and about half of the patients who develop ENM had

concurrent CNS disease. RT improved the prognosis of

patients without concurrent CNS involvement at the time

of ENM. Since medulloblastoma is a radiosensitive tumor,

irradiation of oligometastasis is a reasonable therapeutic

approach. Patients with concurrent CNS involvement did

not have an OS or PFS benefit after RT. This is likely be-

cause CNS disease could not be controlled as the radiation

oncologist could not administer full doses of radiation to

the CNS secondary to previous craniospinal irradiation

(67). The finding that approximately two-thirds of patients

with extraneural relapse and no CNS involvement were alive

at 2 years after receiving RT is encouraging, and therefore,

irradiation to sites of oligometastasis such as those found in

bony sites should be recommended when feasible. Advances

in radiotherapy treatment delivery such as stereotactic body

radiotherapy and stereotactic radiosurgery may make radio-

therapy to previously irradiated sites, such as brain, and sites

that are difficult to irradiate because of acute toxicity, such

as liver, feasible.

As in other studies, bone and bone marrow were the most

common sites of ENM, followed by lymph nodes, lung, and

liver (6, 68). Patients with either lung or liver involvement

had a worse prognosis than patients with ENM at other sites.

Patients with ENM to the lungs and/or liver had a median sur-

vival of 2 months, which was significantly less than the

8-month median survival of patients without lung or liver in-

volvement. This may be due to the fact that patients with lung

or liver metastases were more likely to have CNS involve-

ment at the time of ENM, a parameter noted to have a negative

prognostic impact.

Our findings also indicate that the time interval from the

diagnosis of primary tumor to ENM is an important parame-

ter in the survival of patients with ENM. Patients with a time

interval of $18 months had better OS and PFS than those

with a time interval of <18 months. The significance of the

time interval to relapse has been shown in other cancers, rec-

ognizing the importance of this time interval (69, 70). One

may speculate that the importance of this interval is due to

the aggressive nature of the primary tumor. That is, the

more aggressive the tumor, the earlier it will relapse, and

the earlier it may result in the death of a patient. In addition,

patients with a shorter time interval to extraneural relapse

were less likely to be treated with RT, a factor which had

a beneficial effect on prognosis. Another finding of note

was that patients who were $16 years of age at the time of

ENM had a better overall prognosis than patients who were

<16 years of age. This may be due to the association between

age and duration to ENM. Patients younger than 16 years old

had a shorter duration to ENM, a factor associated with

a worse prognosis.

Certainly, there are limitations in this study. The first lim-

itation is the inherent selection bias, as cases reported in the

literature are often published due to their rare or unusual pre-

sentation. In addition, data were gathered from a 40-year span

from different institutions, and there were significant ad-

vances in diagnosis, radiotherapy, and chemotherapy over

this period. We were unable to perform a multivariate analy-

sis because not all the information gathered was available for

every patient. This study, nevertheless, is important because

it gives us information about prognostic factors which may

impact the direction of future clinical studies. It also informs

us that RT to sites of ENM may be beneficial, as shown by

better OS and PFS of patients without concurrent CNS

disease who were irradiated.

CONCLUSIONS

On the basis of our literature review, we found that RT im-

proves the prognosis of ENM patients without CNS involve-

ment. We also identified negative prognostic factors such as

lung or liver metastasis and time interval to develop ENM in

patients of <18 years of age and of <16 years of age at time of

ENM.

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