Systemic Vincrstine and Topotecan chemotherapy for Intra-ocular group A, B and C Retinoblastoma – A prospective, single arm study

Data collection

Demographic details (age, sex, diagnosis etc), details of baseline diagnostic investigations, staging investigations, and laboratory diagnostics will be recorded. Treatment details and information on response evaluation will be collected at defined timepoints.

Baseline assessment

Clinical history and physical examination will be conducted at presentation. Complete blood counts, renal function test, liver function test will be done at baseline. Examination under anaesthesia will be done by ocular oncologist. Magnetic resonance imaging (MRI) both orbit and brain will be done.

Laboratory investigations

Complete blood counts, renal function test and liver function test will be done before each chemotherapy cycles. Other investigations if needed will be done as per unit protocol.

Treatment details – systemic chemotherapy

RBM25 protocol includes intravenous vincristine and topotecan chemotherapy as in below mentioned dose and schedule

Vincristine –

more than 10 kg - 1.5 mg per m2 day 1

less than 10 kg – 0.05 mg per kg day 1

Topotecan – age based dose per day for 5 days

Sr no

Age

Dose

|1

0 – 3 months

2.25 mg per m2

|2

3 – 6 months

2.5 mg per m2

|3

6 – 9 months

2.75 mg per m2

|4

more than 9 months

3 mg per m2

 This will be followed by inj Peg – G CSF on day 6 – (24 hours after last dose of chemotherapy).

Complete blood counts will be monitored weekly till recovery. Cycle will be repeated every 21 days from day 1 of the previous chemotherapy.

Pre-requisite for starting chemotherapy

1.     Absolute neutrophil counts more than 1000 per microliter, Platelets more than 75000 per microlitre and signs of count recovery

2.     Direct bilirubin less than 2 mg per dL

3.     SGOT and SGPT less than 3 times ULN

4.     S Creatinine within normal range for age

If the next cycle is delayed more than 28 days from day 1 of the previous chemotherapy cycle due to treatment related toxicity or side effects, topotecan dose will be reduced by 25 percentage for next cycle. Same process would be followed for each cycle.

Maximum four cycles will be delivered. If the child does not

Treatment details – local-focal therapy

Intravitreal topotecan injections will be considered as per ocular oncologist’s assessment and discretion. Cryotherapy would be applied to the peripheral active retinoblastoma lesions anterior to the equator. If needed laser treatment would be applied to the lesions posterior to the equator.

Response assessment

Examination under anaesthesia will be done after first cycle and after that as per ocular oncologist’s discretion and eye will be evaluated for need and feasibility of focal therapy. Response will be recorded as per RB-RECIST criteria. Patient will be taken off protocol in the event of progressive disease. Response will be recorded after 4 cycles of chemotherapy or before that if treatment stopped or discontinued before that in view of complete resolution of disease. Response will be assessed by MRI both orbit and brain and examination under anaesthesia. Response will be recorded per eye, not per individual.

Toxicity monitoring

Patients will be monitored for any treatment related toxicities and adverse events. Toxicities will be recorded as per CTCAE v5 criteria.