ABSTRACT
Objective:
To investigate the influence of extending the waiting
time on
tumor regression after neoadjuvant chemoradiology (nCRT) in
patients with locally advanced
rectal cancer (LARC).
Methods:
Clinicopathological data from 728 LARC
patients who completed nCRT
treatment at the First Affiliated
Hospital, Naval Medical
University from January 2012 to December 2021 were collected for retrospective
analysis. The primary
research endpoint was the sustained complete response (SCR). There were 498
males and 230
females, with an age (M(IQR)) of 58 (15) years (range 22 to 89 years).
Logistic regression models were used to explore whether waiting
time was an independent factor affecting SCR. Curve fitting was used to represent the relationship between the cumulative occurrence rate of SCR and the waiting
time. The
patients were divided into a conventional waiting
time group (4 to <12 weeks, n=581) and an extended waiting
time group (12 to<20 weeks, n=147). Comparisons regarding
tumor regression,
organ preservation, and surgical conditions between the two groups were made using the t
test, Wilcoxon rank sum test, or χ2 test as appropriate. The Log-rank test was used to elucidate the
survival discrepancies between the two groups.
Results:
The SCR rate of all
patients was 21.6% (157/728). The waiting
time was an independent influencing factor for SCR, with each additional day corresponding to an OR value of 1.010 (95%CI 1.001 to 1.020, P=0.031). The cumulative rate of SCR occurrence gradually increased with the extension of waiting
time, with the fastest increase between the 9th to <10th week. The SCR rate in the extended waiting
time group was higher (27.9%(41/147) vs. 20.0%(116/581), χ2=3.901, P=0.048), and the
organ preservation rate during the follow-up period was higher (21.1%(31/147) vs. 10.7%(62/581), χ2=10.510, P=0.001). The 3-year local
recurrence/regrowth-free
survival rates were 94.0% and 91.1%, the 3-year
disease-free survival rates were 76.6% and 75.4%, and the 3-year overall
survival rates were 95.6% and 92.2% for the conventional and extended waiting
time groups, respectively, with no statistical differences in local
recurrence/regrowth-free
survival, disease-free survival and overall
survival between the two groups (χ2=1.878, P=0.171; χ2=0.078, P=0.780; χ2=1.265, P=0.261).
Conclusions:
An extended waiting
time is conducive to
tumor regression, and extending the waiting
time to 12 to <20 weeks after nCRT can improve the SCR rate and
organ preservation rate, without increasing the difficulty of
surgery or altering the oncological outcomes of
patients.