title: Tumor Regression Patterns in Retinoblastoma.
abstract: OBJECTIVE
  To observe the types of tumor regression after treatment, and identify the common pattern of regression in our patients.
  
  
  METHODS
  Descriptive study.
  
  
  METHODS
  Department of Pediatric Ophthalmology and Strabismus, Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan, from October 2011 to October 2014.
  
  
  METHODS
  Children with unilateral and bilateral retinoblastoma were included in the study. Patients were referred to Pakistan Institute of Medical Sciences, Islamabad, for chemotherapy. After every cycle of chemotherapy, dilated fundus examination under anesthesia was performed to record response of the treatment. Regression patterns were recorded on RetCam II.
  
  
  RESULTS
  Seventy-four tumors were included in the study. Out of 74 tumors, 3 were ICRB group A tumors, 43 were ICRB group B tumors, 14 tumors belonged to ICRB group C, and remaining 14 were ICRB group D tumors. Type IV regression was seen in 39.1% (n=29) tumors, type II in 29.7% (n=22), type III in 25.6% (n=19), and type I in 5.4% (n=4). All group A tumors (100%) showed type IV regression. Seventeen (39.5%) group B tumors showed type IV regression. In group C, 5 tumors (35.7%) showed type II regression and 5 tumors (35.7%) showed type IV regression. In group D, 6 tumors (42.9%) regressed to type II non-calcified remnants.
  
  
  CONCLUSIONS
  The response and success of the focal and systemic treatment, as judged by the appearance of different patterns of tumor regression, varies with the ICRB grouping of the tumor.
authors.affiliation: Department of Pediatric Ophthalmology, Al-Shifa Trust Eye Hospital, Rawalpindi.
authors.forename: Saemah Nuzhat
authors.initials: SN
authors.lastname: Zafar
authors.affiliation: Department of Pediatric Ophthalmology, Al-Shifa Trust Eye Hospital, Rawalpindi.
authors.forename: Sorath Noorani
authors.initials: SN
authors.lastname: Siddiqui
authors.affiliation: Department of Pediatric Ophthalmology, Al-Shifa Trust Eye Hospital, Rawalpindi.
authors.forename: Naima
authors.initials: N
authors.lastname: Zaheer
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage* / Q000627:therapeutic use; D016190:Carboplatin / Q000008:administration & dosage / Q000627:therapeutic use; D002675:Child, Preschool; D017679:Cryotherapy; D005047:Etoposide / Q000008:administration & dosage / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007223:Infant; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D008297:Male; D009367:Neoplasm Staging; D010154:Pakistan; D019572:Retinal Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D012175:Retinoblastoma / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014750:Vincristine / Q000008:administration & dosage / Q000627:therapeutic use
chemical_list: D014750:Vincristine; D005047:Etoposide; D016190:Carboplatin