Study of Pattern of Lymph Nodal Spread in Pediatric Renal Tumors

Renal tumors and amongst them, Wilms tumor is the mostcommon tumor in children with excellent outcomes. Multimodal approach towardsthe tumor is important, however, surgery in addition has critical role instaging and thus further management of these tumors. Lymph nodes sampling iscrucial in renal tumors since positive lymph nodes upstages the tumor with theresultant upgradation of intensity of treatment in the form of addition ofdoxorubicin and abdominal radiation. About 41% of stage III disease is identifiedon the basis of lymph nodes invasion alone. Intra-operatively, normal lookinglymph nodes may harbor tumor deposits in 4-11% and in contrast enlarged lymphnodes may be negative in 40%.

Nodal assessment and sampling is based on surgeon’sdiscretion with the possibility of not removing sufficient numbers, removal ofonly enlarged nodes or not removing any lymph nodes. NWTS have reportedsampling of minimum seven nodes for better assessment of the lymph node basin.The pattern of lymph nodes metastasis has not been studied in children withrenal tumors and the significance or incidence of skip metastasis is not known.Moreover, there are no guidelines recommended for sampling of retroperitoneallymph nodes. The assumption of sampling only the renal hilar lymphnodes as they are the first echelon lymph nodes is challenged in adultswith renal cell carcinoma since non-hilar nodes may be involved withoutmetastasis in the hilar nodes.

Primary objectives

·        Study ofpattern of lymph nodal spread in pediatric renal tumors.

Secondary objectives

·        Tocorrelate radiological and pathological feature in stage III (i/v/o positivelymph node) disease.

·        Todescribe the incidence of lymph node metastasis in patients undergoing upfrontsurgery and surgery after neoadjuvant chemotherapy.

·        Todefine the minimum number of lymph nodes required for detecting metastasis

All patients with renal tumors will undergo conventionalwork-up including CECT of abdomen/pelvis and thorax. Patients enrolled in CMART(ongoing WT project no: 993) study will also be included. Eligible patient willeither receive preoperative chemotherapy or operated upfront. Surgery will beperformed using abdominal or thoracoabdominal approach and lymph node samplingwill be performed from lymph node stations (described below) after resection ofthe primary tumor.

Lymph node stations (right =R, left =L)- See figure

1)    Right renal tumor

a.    Suprahilarparacaval

b.    Hilarparacaval

c.    Infrahilarparacaval

2)    Left renal tumor

a.    Suprahilarpararotic

b.    Hilarpararotic

c.    Infrahilarpararotic

3)    In all

a.    Interaortocavalsuprahilar

b.    Interaortocavalinfrahilar

For right sided tumor – to remove A,B,C,D and E

For left sided tumor – to remove D,E,F,G and H.

The tumor specimen and lymph nodes will beappropriately labeled and sent for histopathological examination.

The chemotherapy and radiotherapy will be as perthe CMART study protocol.

Inclusion criteria

•      Allrenal tumors <18 years of age at diagnosis

•      Willingto give consent for the study

  Exclusioncriteria

·         Previouslytreated patients,

·         Recurrentor residual disease; and

·         Patientsnot willing for consent.

Lymph node sampling in childhood renal tumors is thestandard of care, however there are no recommendations for lymph node samplingeven in cooperative group studies. A systematic sampling of defined Lymph nodestations will help us to the know the pattern of lymphatic spread and will helpto identify Lymph node which are more likely to have metastatic deposits.  Thismay help us to reduce sampling errors and provide opportunities to correctlystage the patients since Lymph node involvement is very imp in staging and thetreatment of renal tumors.