(UroToday.com) The 2023 American Urological Association (AUA) annual meeting held in Chicago, IL, hosted the late-breaking abstracts in cancer session. Dr. Song Jiang presented the results of a comparative study of newly diagnosed high-grade Ta (HG Ta) urothelial carcinoma of the bladder treated with intravesical chemotherapy versus Bacillus Calmette Guerin (BCG) during the BCG shortage.
The ongoing BCG shortage emphasizes the need for contemporary data to best allocate BCG when supplies are limited. At the Memorial Sloan Kettering Cancer Centre (MSKCC) during times of BCG shortage, BCG utilization was restricted to only those with HG T1 or carcinoma in situ (CIS), thus patients with HG Ta without CIS were “naturally randomized” to receive either BCG or intravesical chemotherapy. The period of BCG shortage, and associated restrictions, at their institution occurred between 2019 and April 2020, as illustrated in the figure below.
This analysis included 166 patients treated with HG Ta without CIS. Of these, 111 received induction BCG and 55 induction chemotherapy. Patients were required to undergo re-TURBT within 45 days of initial diagnosis if not diagnosed at MSKCC, and the majority of patients did not receive maintenance chemotherapy or BCG. The median follow-up was 18 months for the chemotherapy treated group and 24 months for the BCG group. Despite the “natural randomization” of the study, the groups were well balanced with regards to baseline characteristics. Most of the patients were male, the tumour size was comparable between the two groups with an almost even split between tumors greater ≥ 3cm and below 3 cm, and there were no significant differences in tumor multiplicity or size. However, 71% of the patients in the chemotherapy group had solitary tumors and 29% multifocal disease.
The investigators showed that there were no significant differences in the primary outcome of recurrence-free survival between treatment groups (p=0.47). In the BCG group, 88% and 74% were free of recurrence at 6 at 12 months, respectively, compared to 83% and 76% in the chemotherapy group.
The investigators assessed the association of clinicopathologic variables and recurrence using univariable Cox regression. In this analysis, the investigators identified that tumor multiplicity was the only variable associated with an increased risk of recurrence (p=0.011) Age at diagnosis, gender, tumor size or intravesical treatment were not significant predictors of an increased risk of recurrence.
The cumulative risk of high-grade recurrences was similar between both groups, with 78% not having a high-grade recurrence in the chemotherapy group vs 82% in the BCG at 12 months of follow-up.
Progression was defined as ≥ T1 disease or radical cystectomy. The progression-free survival rate reported by Dr Jiang was 89% at 12 months for both groups (p=0.95).
They performed Targeted exon sequencing of pre-treatment tumors in 59 patients and demonstrated no significant differences between treatment groups in terms of disease recurrence. Ongoing work by their team should help identify predictors of response for chemotherapy in the future.
Dr. Jiang ended his presentation by concluding that there is comparable clinical efficacy between intravesical chemotherapy and BCG immunotherapy in the setting of HG Ta bladder tumors without CIS. Dr Jiang suggested that based on these results chemotherapy appears to be a viable alternative to BCG for induction therapy during BCG shortage.
Presented by: Song Jiang, MD, PhD, Urological Oncology fellow at The Memorial Sloan Kettering Cancer Centre.
Written by: Julian Chavarriaga, MD – Society of Urologic Oncology (SUO) Clinical Fellow at The University of Toronto, @chavarriagaj on Twitter during the 2023 American Urological Association (AUA) Annual Meeting, Chicago, IL, April 27 – May 1, 2023