Investigators have proposed a risk stratification model that may help identify patients who could benefit from adjuvant radiation therapy (RT) for muscle-invasive bladder cancer (MIBC), according to a recent paper published in Urologic Oncology.
The model predicts the likelihood of locoregional recurrence (LRR) following RC based on T stage, N stage, and lymphovascular invasion (LVI) status.
A team led by Vedang Murthy, MD, of Tata Memorial Centre in Mumbai, India, developed the model using findings from a study aimed at assessing patterns of recurrence in patients with MIBC following RC. The study included 188 patients divided into low-risk, intermediate-risk, and high-risk groups based on T stage, N stage, and LVI status.
Of the 188 patients, 70 (37.2%) received neoadjuvant chemotherapy, 128 (68.1%) had T3/4 disease, and 66 (35.1%) had node-positive disease.
Of 55 patients who had a recurrence, 31 had a component of LRR: 8 (4%) had local failure, 22 (11.5%) had regional failure, and 1 (0.5%) had both local and regional failure, Dr Murthy and colleagues reported. Among the 31 patients who experienced LRR, 26 did so within the first 2 years after RC.
The median time to LRR was 8.2 months. The cumulative incidence of LRR in the low-, intermediate-, and high-risk groups was 7.1%, 21.6%, and 35%, respectively. Compared with the low-risk group, the intermediate- and high-risk groups had approximately 3.4-fold and 5.3-fold increased odds of LRR.
The authors acknowledged study limitations. The retrospective design renders the study prone to inherent biases. In addition, the study was conducted at a single institution and included a relatively small sample size.
Noting that LLR can occur in up to one-third of patients with high-risk pathologic features despite chemotherapy, Dr Murthy told Renal & Urology News, “As treatment of LRR is morbid and ineffective, there is a need to identify these patients and prevent pelvic recurrence. The role of adjuvant radiotherapy is promising in this setting.”
Murthy V, Bakshi G, Manjali JJ, et al. Locoregional recurrence after cystectomy in muscle invasive bladder cancer: Implications for adjuvant radiotherapy. Published online February 8, 2021. Urol Oncol. doi:10.1016/j.urolonc.2021.01.015