Wilms tumour experience in a South African centre

Pediatr Blood Cancer 2006;46:465–471

Wilms Tumour Experience in a South African Centre

Alan Davidson, MBChB, FCP Paed,1* Patricia Hartley, MBChB, FCP Paed,1 Farieda Desai, MBChB, FCP Paed,1

John Daubenton, MD, FCP Paed,1 Heinz Rode, MBChB, MMed, FCS, FRCS,2

and Alastair Millar, MBChB, FRCS, FRACS2

INTRODUCTION

There are few reported series of Wilms tumour from

Africa. Hadley et al. [1] reported on 78 black South African

children from KwaZulu-Natal with Wilms tumour. They

noted a high proportion of advanced local and metastatic

disease (53%were stages III and IV) aswell as generally poor

outcomes. In addition, treatment was compromised by a high

incidence of nutritional and infective co-morbidity. Of the 78

children, 8 declined treatment or absconded and 16 died

during or prior to pre-operative chemotherapy. Only 54

(69%) came to nephrectomy, 31 primarily and 23 after

chemotherapy with or without radiotherapy. Long-term

survival of this group was not reported. Zaghloul et al. [2]

more recently confirmed a high proportion of advanced

disease (51% were stages III and IV) in a series of 112

children in Egypt, but reported good results for non-

metastatic tumours (10 year actuarial survival of 94% for

stage I, 86% for stage II and 71% for stage III). We have

utilised primary surgery followed by chemotherapy in a

South African setting for many years and this study presents

our results.

METHODS

The study was a retrospective analysis of all patients

diagnosed with unilateral Wilms tumour at Red Cross

Children’s Hospital between January 1979 and December

2003. Twenty patients who presented with bilateral Wilms

tumour and 11 who presented with clear cell sarcoma of the

kidney were excluded from analysis. Details of presentation,

histology and management were extracted from patient

records.

Red Cross Children’s Hospital is an academic referral

hospital attached to the University of Cape Town. The

oncology unit treats children from the Eastern and Western

Cape provinces, a combined area of almost 300,000 sq. km

with a population of 10.9 million [3]. About half the patients

come from outside the greater Cape Town area, many from

under-resourced rural areas. The Western Cape, and in

particular the greater Cape Town area (population 3.1

million), has undergone considerable change in its demo-

graphy in recent years. Recent census figures show that

around 54% of the population is mixed race and about 20%

white, with an increasing number of black residents—

currently 26% [3]. There is considerable poverty—33% of

households live at or below the poverty line of $300 month

[4].

The hospital is state-funded, and fees are based on

parental income, with most families paying only nominal

sums, and a few with sufficient income or medical insurance

paying on a fee for service basis—15% of the Wilms tumour

patients in this series had medical insurance.

The oncology unit is staffed by three full time consultants,

and has a reliable supply of all necessary chemotherapeutic

agents and access to appropriate supportive care in the form

of a paediatric intensive care unit, safe blood products and

modern broad-spectrum antibiotics. Surgery is performed by

a small team of highly experienced surgeons, and radio-

therapy is administered by qualified radiation oncologists.

Background. In Africa, Wilms tumour frequently presents withadvanced disease. This study reports our results over 25 years using theNational Wilms Tumour Study Group (NWTSG) approach of primarysurgery followed by chemotherapy. Procedure. A retrospectiveanalysis was performed on all patients diagnosed with unilateralWilms tumour between January 1979 and December 2003. Results.The records of 188 childrenwith newly diagnosedWilms tumour wereexamined. Of these 57 (30.3%) were stage I, 33 (17.6%) were stage II,60 (31.9%) were stage III and 38 (20.2%) were stage IV. Twenty-fourpatients (12.8%) had unfavourable histology (UFH). The estimated 5-year overall survival (OS) for the whole group was 80.5% (84.8% for

favourable histology (FH) and 51.6% for UFH). Among those with FH,estimated 5-year OS was 94.4% for stage I, 96.2% for stage II, 84.9%for stage III and 54.2% for stage IV. There was no difference in OSbetween those FH stage III tumours that were operable and thosedeemed inoperable. Intra-operative spillage was uncommon (8%),and did not increase local relapse rate. Conclusions. National WilmsTumour Study Group protocols employed in an African setting withhighly competent and experienced surgical care, produced results fornon-metastatic FHWilms tumour comparable to those of the NWTSG.Pediatr Blood Cancer 2006;46:465–471. � 2005 Wiley-Liss, Inc.

Key words: chemotherapy; histology; stage; surgery; Wilms tumour

� 2005 Wiley-Liss, Inc.DOI 10.1002/pbc.20388

——————1Haematology-Oncology Service, Red Cross Children’s Hospital,

School of Child and Adolescent Health, University of Cape Town,

Cape Town, South Africa; 2Department of Paediatric Surgery, Red

Cross Children’s Hospital, School of Child and Adolescent Health,

University of Cape Town, Cape Town, South Africa

*Correspondence to: Alan Davidson, Ward G1, Red Cross Children’s

War Memorial Hospital, Private Bag Rondebosch, Cape Town 7700,

South Africa. E-mail: [email protected]

Received 7 June 2004; Accepted 24 January 2005

Standard practice throughout this period was that patients

were assessed at diagnosis and primary surgery was under-

taken where possible. All patients were staged radio-

graphically with chest X-ray and ultrasound abdomen, and

since 1986, computed tomography of the abdomen and chest.

For tumours deemed inoperable, pre-operative chemother-

apy was given after fine needle aspiration biopsy. These

tumours were regarded as stage III.

Chemotherapy protocols changed over time with treat-

ment duration varying from 15 months initially to 18 weeks

(all stage I and favourable histology (FH) stage II) and

24 weeks (all other stages) currently. All patients received

vincristine and actinomycin. Patients with stage III and IV

tumours also received doxorubicin—300 mg/m2 until 1998,

and 5 mg/kg (equivalent to 150 mg/m2) since 1999. Before

1989, stages I–IV received 20 Gray renal bed irradiation.

Subsequently, only those with local stage III received renal

bed irradiation (currently 1,080 cGray in six fractions), and

those with pulmonary metastases received pulmonary

irradiation (currently 1,200 cGray in eight fractions).

From the outset, all patients with unfavourable histology

(UFH) received vincristine, actinomycin, doxorubicin

(300 mg/m2) and cyclophosphamide. Stage I patients with

UFH were excluded from this in 1989 and now receive only

vincristine and actinomycin. Since 1999, stage II–IV

tumours with diffuse anaplastic histology have been treated

with vincristine, actinomycin, doxorubicin (7.5 mg/kg

equivalent to 225 mg/m2), cyclophosphamide and etoposide.

Stage II–IV tumours with focal anaplasia have been treated

with vincristine, actinomycin and doxorubicin (5 mg/kg

equivalent to 150 mg/m2).

Relapse was treated with surgery, local and pulmonary

radiotherapy (depending on site), as well as a variety of

chemotherapeutic regimes including vincristine, actinomy-

cin, doxorubicin, cyclophosphamide, ifosfamide, etoposide

and carboplatin. Relapse-free survival (RFS) and overall

survival (OS) were estimated by the method of Kaplan and

Meier. Survival analysis was performed using Statistica 6.1

(Statsoft, Inc. 1984–2003).

RESULTS

Patient Characteristics

One hundred eighty-eight children were diagnosed with

Wilms tumour during the 25-year study period. There were

77 males and 111 females representing a male: female ratio

of 2:3. Age at diagnosis ranged from 0.24 to 12.87 years. The

median age at presentation was 39.2 months. There were 24

white patients (12.8%), 85 mixed-race patients (45.2%) and

79 black patients (42%).

Most presented with an abdominal mass or distension

(77%). Abdominal pain occurred in 48 patients (25.5%) and

macroscopic haematuria in 18 (9.6%). Thirty-two patients

(17%) were hypertensive at diagnosis and two of these

presented in cardiac failure.Weight was below the 3rd centile

of weight for age in 39 patients (20.7%). Therewere only two

cases of renal failure; onewith creatinine>2.5mg/dl and one

with a massive tumour, raised urea and normal creatinine,

and oliguria (urine output <0.5 ml/kg/hr).

Thirteen patients had associated abnormalities. These

included five with urogenital abnormalities, four with

hemihypertrophy, three with aniridia and one with Beck-

with–Wiedemann syndrome. One patient with no associated

physical abnormalities, whose sibling had a Wilms tumour

and renal dysplasia, was found to have a deletion of

chromosome 11. There were four patients with unrelated

syndromes (alagille syndrome, moebius syndrome, chron-

drodysplasia punctata and ectodermal dysplasia).

Fifty-seven childrenwere stage I (30.3%), 33were stage II

(17.6%), 60 were stage III (31.9%) and 38 were stage IV

(20.2%). Stage IV disease constituted 8.3% of the tumours

among white patients, 17.6% of the tumours among mixed-

race patients and 26.6% of the tumours among black patients.

Of those with metastatic disease, 34 (89.4%) had lung

metastases. Six of these 34 patients also had liver metastases,

and three others had isolated liver metastases. One had

central nervous systemmetastases. Inferior vena cava tumour

thrombus was present at diagnosis in 11 cases (5.9%), five

with extension into the right atrium. Characteristics of the

study population are shown in Table I, and those of the stage

IV patients are shown in Table II.

Of the 137 tumours operable at diagnosis, 118 were

weighed. Seventy-five (63.6%)weighedmore than 550 g and

of these, 24 (20.3%) weighed more than 1 kg. In order to

make comparison with NWTS-3, 79 (66.9%) had tumours

larger than 500 g. Of the 28 operable stage III tumours that

were weighed, 23 (82.1%) exceeded 550 g and of these, 10

(35.7%) were more than 1 kg.

There were 24 patients (12.8%) with UFH. Thirteen

(6.9%) had diffuse anaplasia and 11 had focal anaplasia.

Fifty-fivepercent of the patientswith focal anaplasia and23%

of those with diffuse anaplasia had stage IV disease. UFH

was seen in 29.2% of white patients, 8.2% of mixed-race

patients and 12.7% of black patients. Twenty-four patients

(12.8%) had nephroblastomatosis. Rhabdomyomatous ele-

ments were noted in the histology of 20 cases (10.6%).

Patient Outcomes

Length of follow-up varied from 4.1 to 303.8 months with

amean of 117.5months. Of the 142 patients that are alive and

disease free, 106 are now more than 5 years from diagnosis.

Eight were lost to follow-up less than 5 years from diagnosis.

Thirty-eight patients have died, 34 as a result of disease,

2 due to treatment-related complications (anthracycline-

induced cardiomyopathy and undiagnosed intestinal obstruc-

tion) and 2 from infection (gastroenteritis and adenoviral

pneumonia).

Estimated 5-year OS for the whole group was 80.5%,

84.8% for FH tumours and 51.6% for UFH tumours.

Pediatr Blood Cancer DOI 10.1002/pbc

466 Davidson et al.

Estimated 5-year RFS for thewhole groupwas 74.8%, 78.9%

for FH tumours and 47.1% for UFH tumours.

Estimated 5-year OS for FH tumours by stage was 94.4%

for stage I, 96.2% for stage II, 84.9% for stage III and 54.2%

for stage IV. Kaplan–Meier curves are shown in Figure 1.

When stage IV FH patients were analysed in cohorts, the

estimated 5-yearOS for 1984–1993was 62.9%, compared to

49% for 1994–2003 (log-rank P value¼ 0.43). The esti-

mated 5-year RFS by stage for FH tumours was 86.3% for

stage I, 84.7% for stage II, 83.6% for stage III and 51.6% for

stage V.

In the group of patients with FH stage III tumours, the

estimated 5-year OS was 84.9% for those that had primary

surgery, compared to 84.4% for those that were deemed

inoperable and had pre-operative chemotherapy (log-rank P

value¼ 0.83).

Three of the 11 patients with inferior vena cava tumour

thrombus had primary surgery. Eight were deemed inoper-

able and received chemotherapy initially. Two patients, one

from each group, died early as a result of thromboembolus

and vascular decompensation. Successful surgery was

carried out in nine cases, three of these on cardiopulmonary

TABLE I. Patient Characteristics and Outcome by Stage

Total Stage I Stage II Stage III Stage IV

Patients (%) 188 57 (30.3) 33 (17.6) 60 (31.9) 38 (20.2)

Black (% of total) 79 17 (21.5) 10 (12.7) 31 (39.2) 21 (26.6)

Mixed-race (% of total) 85 32 (37.6) 15 (17.6) 23 (27.1) 15 (17.6)

White (% of total) 24 8 (33.3) 8 (33.3) 6 (25) 2 (8.3)

Tumour weight

Inoperable 41 0 0 23 18

Operable 137 57 33 37 10

Operable (weighed) 118 49 31 28 10

Weight <550 g 22 15 5 1

Weight 550-999 g 22 10 13 6

Weight >1,000 g 5 6 10 3

Histology

Favourable histology 164 56 28 51 29

Focal anaplasia 11 1 1 3 6

Diffuse anaplasia 13 0 4 6 3

Outcome

Achieved remission 175 57 33 57 28

Relapse 32 7 6 9 10

Local 8 3 1 1 3

Lung 17 2 3 6 6

Liver 2 1 0 1 0

Multiple 5 1 2 1 1

Alive disease free (%) 142 (75.5) 52 (91.2) 28 (84.8) 44 (73.3) 18 (47.4)

Died of disease 34 3 2 11 18

Lost/unrelated death 12 2 3 5 2

TABLE II. Characteristics of the Stage IV Wilms Tumour Patients

Total Black Mixed race White

Histology

Favourable 29 (14) 16 (7) 13 (7) 0

Focal anaplasia 6 (2) 4 (0) 0 2 (2)

Diffuse anaplasia 3 (0) 1 (0) 2 (0) 0

Stage IV WT by race 38 21 15 2

All WT by race 188 79 85 24

Percentage of stage IV WT by race 20.2% 26.6% 17.6% 8.3%

Cohort

1979–1983 1 0 1 0

1984–1993 18 11 7 0

1994–2003 19 10 7 2

Site Lung Lung and liver Liver Brain

Metastases 28 6 3 1

Entries within parenthesis are alive disease free.


Wilms Tumour Experience in South Africa 467

bypass. Six are alive and disease free, and three died of

progressive disease or following relapse.

Thirteen of the 29 FH stage IV tumours did poorly. Six

failed to achieve remission and seven patients relapsed. Only

one of the children who relapsed has survived.

Neither rhabdomyomatous histology nor nephro-

blastomatosis conferred a poorer outcome, with estimated

5-year OS of 82.6% and 82.6%, respectively. Of the

20 patients with rhabdomyomatous histology, 40%

were inoperable with a 75% response rate to primary chemo-

therapy. This is comparable to the 81.6% response rate seen

among FH tumours that were inoperable at diagnosis.

Considering the small group of patients with UFH, those

with focal anaplasia fared as poorly as those with diffuse

anaplasia; estimated 5-year OS of 54.6% compared to 50.4%

(log-rank P value¼ 0.65). Six of the 11 patients in the focal

anaplasia group were stage IV compared to only 3 of the

13 patients with diffuse anaplasia. Four of the five deaths in

those with focal anaplasia occurred in the six stage IV

tumours.

When the patients were analysed by race, there is a trend

that does not achieve statistical significance for white

patients to do better than mixed-race and black patients.

Estimated 5-year OS was 91.1%, 84.0% and 72.9%,

respectively (Chi-square P value¼ 0.13). However, when

metastatic disease was excluded, there was no difference

between the groups—estimated 5-year OS was 90.2%,

89.5% and 86.9% (Chi-square P value¼ 0.92). Kaplan–

Meier curves are shown in Figures 2 and 3. Table II

shows that a higher proportion of black children (26.6%)

had metastatic disease compared to mixed-race (17.6%)

or white children (8.3%), and that nearly one quarter

(23.8%) of black stage IV patients had UFH. Estimated 5-

year OS for black children with stage IV disease was

35.9% compared to 59.3% for mixed-race children (log-

rank P value¼ 0.16). Notably, when UFH tumours were

excluded from analysis, the estimated 5-year OS was still

lower for black FH stage IV patients at 49.1% compared

to 60.6% for mixed-race FH stage IV patients (log-rank

P value¼ 0.45). Both thewhite childrenwho presentedwith

stage IV disease had focal anaplasia and are alive and

disease free.

Relapse

Relapse occurred in 32 children of whom 20 were

still receiving chemotherapy. The remaining 12 relapsed

2 months–3.5 years after completing therapy. Of the

175 patients who achieved remission, the rate of relapse by

stage was as follows: stage I 12.3%, stage II 18.2%, stage III

15.8%, stage IV 35.7%. The number of relapses by stage is

shown in Table I. The commonest site of relapse was

pulmonary, occurring in 17 cases. There were eight local

relapses, two liver relapses and five relapses at multiple sites.

Eight patients (25%) had UFH and two patients (6.3%) had

nephroblastomatosis.

Fig. 1. Estimated 5-year overall survival (OS) Favourable histology Wilms tumour 1979–2003. [Color figure can be viewed in the online issue,

which is available at www.interscience.wiley.com.]


468 Davidson et al.

Salvage was good for stage I and II (8 survivors out of 13)

but poor for stage III and IV (2 survivors out of 19). Salvage

was better for pulmonary relapse (6 survivors out of 17) than

for local relapse (2 survivors out of 8). Only one of the eight

patients with UFH survived. Five of those 12 (41.7%) who

relapsed off treatment are alive and disease free. By contrast

only 5 of the 20 (25%) who relapsed on treatment were

survivors.

Fig. 2. Estimated 5-year OS by race Stage I–IVWilms tumour 1979–2003. [Color figure can be viewed in the online issue, which is available at

www.interscience.wiley.com.]

Fig. 3. Estimated 5-year OS by race Stage I–III Wilms tumour 1979–2003. [Color figure can be viewed in the online issue, which is available at

www.interscience.wiley.com.]



Complications of Treatment

Complications of treatment were relatively few. One

hundred twelve patients received anthracyclines initially or

at relapse, the cumulative dose ranging from 90 to 440 mg/

m2. Of these, 77 received a cumulative dose of over 250 mg/

m2, two of whom received over 350 mg/m2. Two of the

112 (1.8%) patients developed cardiomyopathy. One

received 430 mg/m2 as well as pulmonary radiotherapy and

died of cardiomyopathy. The other received 300mg/m2 and is

alive on antifailure treatment.

Eleven patients received ifosfamide for resistant disease or

at relapse, the cumulative dose ranging from 18 to 72 g/m2.

One patient developed nephrogenic diabetes insipidus and

Fanconi’s syndrome after 36 g/m2 and subsequently died of

disease. There are only three survivors, 66.1–105.9 months

from diagnosis, all with normal renal tubular reabsorption of

phosphate.

One patient developed veno-occlusive disease after

dactinomycin, and one infant suffered a brief unexplained

apnoea after vincristine and dactinomycin. There are no

secondary malignancies to date.

Complications of surgery occurred in 41 (21.8%) patients.

There was rupture or spillage as defined by the NWTSG

(beyond the flank) in 12, and local spillage in five.

Considering only the 137 operable tumours there were 11

with NWTSG-defined spillage (8%). All were treated with

vincristine, actinomycin and doxorubicin as well as renal bed

irradiation (10–20 Gray). Of the 122 FH tumours that were

operable, 10 had NWTSG-defined spillage. In this group

there were no local relapses but two pulmonary relapses, and

no difference in estimated RFS between those with spill

(80%) and those without (84.4%) (log-rank P value¼ 0.64).

Of interest is that of the five patients who experienced local

spillage—all were treated with vincristine and actinomycin,

and one before 1989 with renal bed radiotherapy—there were

three relapses, one local and two pulmonary. The patient with

local relapse was salvaged with three drugs and renal bed

irradiation.

Post-operative small bowel obstruction occurred in

17 cases (9%) and wound sepsis in three. There were two

cases of wound dehiscence and one patient had major

bleeding during surgery (defined as more than 50 ml/kg of

blood loss). This patient was not tested for acquired von

Willebrand disease. Routine partial thromboplastin time

(PTT) testing has been undertaken for several years. Only one

child had a prolonged PTTandwas found to have normal von

Willebrand factor activity.

DISCUSSION

How does our group compare with larger reported series

such as those of the NWTSG? The mild predominance of

female patients is unusual, but the age distribution is typical

with a median of 39.2 months-median age of presentation in

NWTSG is 36.5 months for boys and 42.5 months for girls

[5]. Poor nutrition was a common problem, and our figure of

20.7% below the 3rd centile of weight for age is conservative

in a series where 20.3% of the tumours weighed more than

1,000 g. Renal failure was extremely uncommon, consistent

with the 0.25% reported by NWTSG for unilateral Wilms

tumours [6].

More patients had advanced disease than those on

NWTSG studies; 31.9% of our patients were stage III and

20.2% stage IV compared to 21% and 11%, respectively of

NWTS-3 [7]. There were also larger tumours; 66.9% of our

patients had tumours larger than 500 g compared to 49% of

the patients on NWTS-3 [8]. Moreover, 63.6% were more

than 550 g, aweight belowwhich tumours are associatedwith

a good prognosis especially in children younger than 2 years

of age [9]. There were more anaplastic tumours (12.8%) in

our series than in NWTS-3 (3.9%) [7]. IVC thrombosis was

comparable to the 4% rate reported by the NWTSG [10].

NWTSG currently reports a 4-year OS for patients with

FHWilms tumour that approaches 90% [5]. Four-year OS for

stage I through IV reported by NWTS-3 were 95.6%, 91.1%,

90.9%, and 80.9%, respectively [11]. Hence, our results are

comparable for non-metastatic Wilms tumour, but disap-

pointing for patients with stage IV disease. Significantly,

recent stage IV patients (1994–2003) did no better than those

in earlier years (1984–1993). Our stage III patients fared

equally well regardless of their amenability to surgery at

diagnosis. Notably, tumour size was not an obstacle to

resection with 35.7% exceeding 1,000 g.

The results of our UFH are surprising in that focal

anaplasia fared as poorly as diffuse anaplasia. NWTS-3 and -

4 reported a 4-yearOS of 52.2% for stage II–IV tumourswith

diffuse anaplasia [12]. There was a small group of children

with focal anaplasia with a 100%OS. In our series, the larger

number of stage IV tumours among those with focal

anaplasia (54.5%) probably accounts for their poor outcome.

Hadley [1] pointed to a poor prognosis for black patients in

SouthAfricawithWilms tumour, and noted a high proportion

of advanced local and metastatic disease, as well as

nutritional and infective co-morbidity. Our results show

that black patients with non-metastatic disease do as well as

other patients. Metastatic disease was seen relatively more

frequently in black patients and conferred a very poor

prognosis. In part this is explained by a higher proportion of

stage IV tumours with UFH, but even black children with FH

metastatic disease fared worse than their mixed-race

counterparts.

There is an approximately 15% risk of recurrence in

Wilms tumour [13]. Lungs, liver, contralateral kidney and

renal bed are the commonest sites, and risk factors include

stage, histology, advanced age at diagnosis, tumour size, and

lymph node involvement. In addition, spillage or pre-

operative rupture has been demonstrated to be a risk factor

for local recurrence [14], and nephroblastomatosis has been

cited as an independent risk factor for both relapse [15] and

contralateral disease [16]. In our series, UFH and high stage


470 Davidson et al.

were associatedwith increased relapse.Nephroblastomatosis

occurredmore frequently in our series than the 4.5% reported

in the literature [8], but did not confer additional risk of

relapse. Spill or rupture was also not associated with

increased risk of local relapse.

Post-relapse survival on NWTS-2 and -3 was best for

tumours of low stage and FH, pulmonary relapse and those

relapses occurring more than 12 months after diagnosis [17],

and this was what we experienced. In the literature,

rhabdomyomatous change is associated with a poor response

to chemotherapy [18], but a generally favourable outcome

when treated by surgery [19]. However, the response rate in

our serieswas nopoorer among thosewith rhabdomyomatous

histology than other FH Wilms tumours.

The rate of surgical complications was low in our series.

NWTSG-defined intra-operative spillage or rupture occurred

in 8%; much less frequently than the 20% reported by

NWTS-4 [20]. At 9%, the frequency of small bowel

obstruction was comparable to the 6.9% reported by

NWTS-3. All other complications were negligible.

NationalWilmsTumourStudyGroup protocols employed

in an African setting with appropriate surgical expertise,

produced results for non-metastatic favourable histology

Wilms tumour comparable to the NWTSG. Results for

metastatic disease and UFH tumours were poor. A recent

review of Wilms tumour treatment concluded that there is

very little to choose between primary surgery and pre-

operative chemotherapy in the face of modern, expert care

[20]. Early surgery is recommended where circumstances

allow; our results show that this approach is possible outside a

developed world setting.

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Wilms tumour experience in a South African centre