A recent study compared the efficacy and safety of 3 vs. 6 cycles of carboplatin, etoposide, and vincristine chemotherapy in treating unilateral high-risk retinoblastoma post-enucleation. Conducted in two centers in China, this noninferiority trial involved 187 children. It aimed to establish whether a shorter chemotherapy regimen could achieve comparable outcomes to longer regimens, with fewer side effects.
The 6-cycle regimen was adopted from other oncology fields, but the “optimal number of postoperative adjuvant cycles for high-risk retinoblastoma remains unclear due to scant randomized clinical trial data,” the investigators described in their JAMA Ophthalmology article. Indeed, because extended chemotherapy regimens may cause serious adverse effects, the researchers noted the general consensus that the minimal effective dosage to achieve anticancer benefits is optimal for chemotherapy.
The 5-year disease-free survival rate was 90.4% in the 3-cycle group vs. 89.2% in the 6-cycle group, which met the noninferiority margin. As the researchers described, this primary outcome measure was defined as time from randomization to first instance of local recurrence, regional relapse, distant metastasis, contralateral retinoblastoma, second primary cancer, or death from any cause. Median follow-up was approximately 58 months, which allowed researchers to assess long-term outcomes in both groups effectively.
Patients in the 3-cycle group experienced fewer adverse events, including neutropenia, nausea, and weight loss, compared to those in the 6-cycle group. Specifically, severe neutropenia occurred in 10% of patients in the 3-cycle group vs. 21% in the 6-cycle group. The shorter regimen also reduced treatment-related costs by more than 40% and showed less decline in patient quality of life metrics. It also lowered the overall burden on families and the healthcare system and enhanced accessibility for more patients.
“Retinoblastoma is the leading cause of intraocular malignancies in children, with an estimated 8,000 new cases worldwide each year,” the investigators wrote. Approximately an eighth of those cases occur in low to middle-income countries, such as China and India, where treatment access can be challenging and survival rates are noticeably lower, ranging from 35% to 77%, in contrast to the 98% rate in high-income countries.
These findings suggest 3 cycles of CEV chemotherapy may offer similar efficacy to the standard 6 cycles with lower toxicity and reduced economic burden, which could encourage adherence among families who experience financial stress as a barrier to treatment.
A full list of author disclosures can be found in the published research.
