<prompt> Which is the ideal timing for staing radiotherapy in Wilms tumour after surgery?Within 10 daysWithin 2 weeksWithin 3 weeksAny time after surgery  <response>: The postoperative radiotherapy in Willms tumor should be staed within 10 days of surgery. Delayed initiation of treatment beyond 10days after surgery result in higher risk of abdominal recurrence. Chief indications of radiotherapy in Wilms tumor are: Abdominal radiotherapy is preferred for: All stage II,III, IV tumors All anaplastic tumors beyond stage I All clear cell sarcoma of kidney Abdominal relapse Chest radiotherapy is given for lung metastasis. Ref: Schwazs Principles of Surgery, 9e Chapter 39 