Abstract
Simple SummaryBoth short- and long-course neoadjuvant radiotherapy (NA-RT) followed by surgery have been adopted as standard treatments for locally advanced rectal cancer (LARC). We hypothesized that a modified short-course radiotherapy (mSC-RT) using an accelerated hyperfractionated regimen, with a dose of 2.5 Gy twice daily up to a total dose of 25 Gy in 10 fractions, can provide a favorable therapeutic ratio in comparison with the conventional regimens. Ninety-seven consecutive LARC patients undergoing mSC-RT followed by delayed surgery were analyzed in this retrospective study. Additionally, potential prognostic factors for overall survival (OS) were also assessed. The results showed that mSC-RT followed by delayed surgery achieved equivalent anti-tumor efficacy and acute toxicity that were comparable with long- and short-course NA-RT, respectively. A neutrophil-to-lymphocyte ratio (NLR) ≥ 1.83 was independently associated with poor OS in LARC patients receiving mSC-RT. Thus, mSC-RT can be a promising alternative to both standard long- and short-course NA-RT regimens.This study aimed to assess the clinical outcomes and predictive factors of neoadjuvant modified short-course radiotherapy (mSC-RT) for locally advanced rectal cancer (LARC). Data from 97 patients undergoing mSC-RT followed by radical surgery for LARC were retrospectively analyzed. A 2.5 Gy dose twice daily up to a total dose of 25 Gy in 10 fractions was administered through mSC-RT, and this was delivered with oral chemotherapy in 95 (97.9%) patients. Radical surgery was performed 6 (range, 3–13) weeks after mSC-RT. The median follow-up among surviving patients was 43 (8–86) months. All patients completed neoadjuvant radiotherapy with no acute toxicity grade ≥ 3. Three- and five-year local control rates were 96.3% and 96.3%, respectively. Three- and five-year overall survival (OS) rates were 92.7% and 79.8%, respectively. Univariate analyses revealed that poor OS was associated with no concurrent administration of capecitabine, C-reactive-protein-to-albumin ratio ≥ 0.053, carcinoembryonic antigen ≥ 3.4 ng/mL, and neutrophil-to-lymphocyte ratio (NLR) ≥ 1.83 (P = 0.045, 0.001, 0.041, and 0.001, respectively). Multivariate analyses indicated that NLR ≥ 1.83 was independently associated with poor OS (p = 0.018). mSC-RT followed by delayed surgery for LARC was deemed feasible and resulted in good clinical outcomes, whereas poor OS was associated with high NLR.
Highlights
Neoadjuvant radiotherapy (NA-RT) combined with chemotherapy and total mesorectal excision has been adopted as the standard treatment for locally advanced rectal cancer (LARC)
We have previously reported the tolerability and efficacy of modified short-course radiotherapy using an accelerated hyperfractionated regimen that was combined with such oral chemotherapy along with clinical features [16,17,18]
Univariate analyses revealed that the following factors were significantly associated with poor overall survival (OS): no concurrent administration of capecitabine, high C-reactive-proteinto-albumin ratio (CAR), high carcinoembryonic antigen (CEA) level, and high neutrophil-to-lymphocyte ratio (NLR) (Table 5, Figure 2)
Summary
Neoadjuvant radiotherapy (NA-RT) combined with chemotherapy and total mesorectal excision has been adopted as the standard treatment for locally advanced rectal cancer (LARC). In terms of the interval between short-course NA-RT and surgery, the Stockholm III randomized study compared preoperative short-course RT followed by immediate or delayed surgery and showed a significantly higher pathological complete response rate in the delayed surgery group with an interval of 4–8 weeks than in the immediate surgery group [11]. They showed that the postoperative complication rate was significantly lower in the delayed surgery group [12]. Short-course radiotherapy with delayed surgery has been considered to be a feasible alternative to short-course NA-RT with immediate surgery and long-course NA-RT
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