Diagnosis: Nephroblastoma (Wilms’ Tumor)

Case history:

The patient is a 5 year old female, weight 16.7 kg, height 114 cm. Her parents report that the patient had a growth deficit due to cow’s milk intolerance at 9 months. She had her adenoids removed in --- and she was diagnosed with a bilateral inguinal hernia during her last hospitalization in ---.

The patient was brought to the emergency room on --- due to occasional left abdominal swelling.

An ultrasound showed the presence of a solid mass adhered to the top of the left kidney.

After being transferred to ---- Hospital in ---, the patient had a Total Body CAT scan with contrast medium, a chest x-ray and a range of blood chemistry tests (in her urine: Vanilmandelic acid 7.2 and homovanillic acid 12.5), which allowed a diagnosis of stage I Wilms’ Tumor (the mass was contained and no metastases were found).

On ----, the patient was transferred to the Oncology Unit where a catheter was installed to begin chemotherapy in accordance with the International Pediatric Oncology regimen: 4 sessions, two of which with Vincristine 1 mg and Actinomycin D 750 mcg, and 2 with only one medication prior to surgery in week 5, and then 5 more weeks of chemotherapy.

Questions:

The patient’s father would like to know whether you can confirm the diagnosis and stage of the pathology, and the recovery rate at this stage. He asks whether you agree with the chemotherapy treatment prior to surgery, or if it would be best to have the surgery first in order to establish the exact histology of the tumor.

The patient’s father would also like to know whether a histology test after chemotherapy would be affected by the medications and result in erroneous assessment of the type and/or degree of the condition, if the first positive sign is a reduction of the mass following chemotherapy. He further asks whether you believe that any other diagnostic and/or laboratory tests should be carried out in addition to those in the appended list.

Lastly, the patient’s father would like to know whether any lifestyle, hygiene and diet requirements should be followed during and after treatment, and whether surgery should be performed by a surgical team or a by urology team.

Medical Report:

Thank you for the referral and the copy of the medical records for this patient.

This is a second opinion based on the attached clinical information. I have not performed a clinical examination of the patient. This second opinion has been requested on behalf of the patient by Medical Opinion.

The patient is a 5 year old girl with a suspected diagnosis of stage 1 Wilms´ tumor.

Her history includes failure to thrive at 9 months of age due to cow´s milk intolerance, and adenoidectomy in ---. The patient was also diagnosed with bilateral inguinal hernia during her hospitalization in ----.

The child´s current presentation was an incidental finding of left abdominal swelling. Laboratory tests included complete blood count, platelet count, renal function tests, liver function tests, serum calcium and urinalysis, all of which were normal.

The reports of the abdominal US, total body CT together with normal values of catecholamine metabolites (which rules out neuroblastoma) seem to support the diagnosis of stage 1 Wilms´ tumor.

Looking carefully at the attached images, I do agree with the radiologist that the tumor staging is consistent with stage 1. Nevertheless, although there is a high probability that the mass is a Wilms´ tumor, the definitive diagnosis and staging could be defined only after a pathological examination of the mass and the lymph nodes.

To assess the actual pathology, the patient should have undergone surgery prior to chemotherapy. This attitude reflects the protocol adopted by American oncologists in the late 1960s, followed by five comprehensive studies, known as the National Wilms´ Tumor Study (NWTS), attempting to determine optimal treatment for the different stages of Wilms´ tumor. According to NWTS, the initial treatment in cases similar to the case here under discussion, should include surgery, and then followed by chemotherapy only after a definitive diagnosis and staging were determined. NWTS investigators recommended immediate nephrectomy because the administration of prenephrectomy chemotherapy may be associated with the following undesirable outcomes: 1. Administration of chemotherapy to a patient with a benign disease; 2. Administration of chemotherapy to a patient with a different histology type of malignant tumor; 3. Modification of tumor histology; or 4. Loss of staging information.

Contrary to this way of thinking, in the early 1970s a newly established European group called the International Society of Pediatric Oncology (SIOP) conducted comprehensive prospective protocols in which pre-operative chemotherapy was followed by surgery. SIOP hypothesizes that this approach usually results in tumor shrinkage, reducing the risk of intra-operative spill (Lemerle et al., 1976). It is also postulated that the neo-adjuvant therapy will treat micro-metastases, leading to a more favorable stage distribution at the time of surgery. Finally, SIOP have claimed that the risk of non-cancerous lesion is only 1%.

Although the National Wilms´ Tumor Study Group and the International Society of Pediatric Oncology differ regarding the merits of pre-operative chemotherapy, outcomes of patients treated with either up-front nephrectomy or pre-operative chemotherapy have been excellent.; children with stage 1 and a favorable histology have 4-5 years event free survival that approaches 90%.

According to SIOP 9 the patient should receive 4 weeks of pre-nephrectomy treatment with vincristine and dactinomycin. However, for selected patients, shorter courses of vincristine/dactinomycin or vincristine alone show equivalent results compared to current regimens (D´Angio, Curr. Opi Urol, 2005).

In my opinion, no further diagnostic or laboratory tests are currently needed in addition to those that have already been done.

Regarding lifestyle, hygiene and diet during and after treatment:

The chemotherapy administered to the patient usually does not cause severe side effects. Thus, we do not limit diet in any way. Nevertheless we instruct our patients´ parents to carefully wash all fresh fruit and vegetables, and to try to avoid pastries from restaurants during chemotherapy. In cases where the white cell counts are going down, we recommend avoiding exposure of the child to people, but usually the patient does not need to be in isolation.

We also do not recommend performing physical effort for 6-7 weeks after surgery.

Surgery should be performed by the most experienced team at the patient´s institution, either by the surgeons or the urologists; I would also recommend considering fixing the patient´s hernias at the time of the nephrectomy.

If we can be of any further help to you, please contact us through Medical Opinion.

I wish the patient a fast and complete recovery.

Sincerely yours

Dr----