The aim of our study was to investigate an approach in T1HG patients, which could be a better choice than TURBT to preserve bladder and retained not bad disease prognosis compared with RC. In this study, we confirmed the results that the T1HG patients could gain survival benefit of OS and CSS from PC when matched with TURBT, and most subgroup analysis confirmed the result. Meanwhile, statistical differences were failed to observe between PC and RC on CSS and OS analysis. Moreover, compared to TURBT, multivariate cox regression analysis revealed that PC was a protective factor of OM and CSM in T1HG patients.
Formerly, partial cystectomy has experienced a resurgence. A growing body of literature has argued that PC might be a viable alternative to RC for select muscle-invasive bladder cancer (MIBC) patients(8, 9, 11). Considering potential complications of RC like severe blood loss, infections, paralytic ileus, and issues with wound healing and negative effect on long-term life, urologist and patients transferred their focus on PC, which could preserve a complete bladder and function of voiding, avoids urinary diversion, and maintain sexual function(11). In addition, Umberto Capitanio' study based on the SEER database got similar results, which showed PC did not enervate the prognosis of OS and CSS in selected patients(12). Subsequent retrospective study has also issued a similar conclusion that no differences were seen between PC and RC in metastasis-free or cancer-specific survival(8, 13, 14). However, some critics of partial cystectomy proclaimed that PC was an incomplete cancer operation following a significant risk of recurrence for MIBC patients and delaying the best treatment time(11, 15). T1HG tumour was aggressive cancer but in the early stages comparing to MIBC tumours. Therefore, partial cystectomy might be worth trying as a method of bladder preservation to replace RC.
As far as we know, there were few studies focusing on the impact of TURBT and PC. However, there was research revealed that 50% of patients diagnosed with T1 bladder cancer in the first TURBT displayed residual tumors when a second TURBT was applied, while 10–25% of those patients were confirmed as muscle-invasive bladder cancer(15-18). TURBT showed a lousy power of cancer control and accurate pathology report based on the results of these data. Meanwhile, PC removed local tumors, which deleted full-thickness bladder containing lesions, while the alarm of intraoperative bladder perforation still existed in surgery of TURBT. Furthermore, more pathological data obtaining like muscle infiltration and lymph node metastasis was the superiority of PC(9, 11, 13). Simultaneously, BCG shortage was also a challenge for traditional treatment like TURBT following BCG(19). In summary, PC was a bladder preservation strategy with significant quantity advantages superior to TURBT, and it was an option worth considering for T1HG patients.
In this study, compared with TURBT patients, patients receiving PC tended to be young (71.5±9.830 vs 72.9±10.371, P=0.014) and had a higher proportion of male (85.3% vs 79.2%, P=0.041). When matched with the RC group, the PC group appeared more older (71.5±9.830 vs 67.9±9.625, P<0.001) and were more likely to have a single tumor (58.9% vs 41.8%, P<0.001). This result confirmed with criteria of adopting PC developed by MD Anderson(9, 13). However, a higher proportion of bigger tumours size was observed in the PC group, which might be the cause of insufficient sample size.
Survival analysis in propensity score-matched subgroups was performed to precisely compare the efficacy between PC and TURBT. In the subgroup of age>70, male, tumour size<3cm, multiple, grade Ⅲ and Ⅳ,histology of transitional cell carcinoma and papillary transitional cell carcinoma, T1HG patients with PC all showed better survival outcomes of OS and CSS than those with TURBT. Nevertheless, it failed to gain significant differences in OS and CSS analysis in the subgroup of age<70, female, tumour size>3cm, and single. More similar studies were needed to confirm these results.
Up to our knowledge, it is the first study to propose the idea of performing PC as a method of bladder preservation in T1HG patients. Utilization of propensity matching score method to perform potential confounding factors and reduce selective bias was also the advantage of this study. Detailed subgroup analysis also made the results more convincing. However, there were still some limitations in our study. Firstly, unavoidable selection bias still existed in this retrospective study even PSM was applied. Then, the number of patients receiving PC is still not enough to go further study, and it might be the reason for insignificant differences in subgroup analysis and multivariate cox regression analysis. In addition, the SEER database lacked some important disease outcomes such as tumour recurrence and progression, and they are also essential evaluation indexes for surgery. Ultimately, statistical differences in demographics and clinical characteristics of the study population remained after PSM. The patients of RC and PC group failed to match 1:1 in performing PSM owing to insufficient patients with RC (160 for RC vs 190 for PC after PSM). Consequently, A prospective study with larger sample size and a more rigorous design is needed to verify these results.
Finally, some problems of PC were needed to attach importance to. For some special patients with carcinoma in situ (CIS), tricky tumor location including ureteral orifice and bladder neck and multiple tumors, we need to carefully consider the effect of partial cystectomy for these patients(9, 11, 13). Frequent follow-up or RC might be needed to take for them.