Prognosis of rectal cancer patients improves with downstaging by intensified neoadjuvant radiochemotherapy - a matched pair analysis

Neoadjuvant Radiotherapy Dose Escalation in Locally Advanced Rectal Cancer: a Systematic Review and Meta-analysis of Modern Treatment Approaches and Outcomes

AIMS

Improving pathological complete response (pCR) rates after neoadjuvant chemoradiotherapy for locally advanced rectal cancer may facilitate surgery-sparing treatment paradigms. Radiotherapy boost has been linked to higher rates of pCR; however, outcomes in moderately escalated inverse-planning studies have not been systematically evaluated. We therefore carried out a systematic review and meta-analysis of radiation dose-escalation studies in the context of neoadjuvant therapy for locally advanced rectal cancer.

MATERIALS AND METHODS

A systematic search of Pubmed, EMBASE and Cochrane databases for synonyms of 'rectal cancer', 'radiotherapy' and 'boost' was carried out. Studies were screened for radiotherapy prescription >54 Gy. Prespecified quality assessment was carried out for meta-analysis inclusion suitability. Pooled estimates of pCR, acute toxicity (grade ≥3) and R0 resection rates were determined with random-effects restricted maximum-likelihood estimation. Heterogeneity was assessed with Higgins I² and Cochran Q statistic. Subset analysis examined outcomes in modern inverse-planning studies. Meta-regression with permutation correction was carried out for each outcome against radiation dose, radiotherapy technique, boost technique, chemotherapy intensification and other patient- and treatment-related cofactors.

RESULTS

Forty-nine primary and three follow-up publications were included in the systematic review. Pooled estimates of pCR, toxicity and R0 resection across 37 eligible publications (n = 1817 patients) were 24.1% (95% confidence interval 21.2-27.4%), 11.2% (95% confidence interval 7.2-17.0%) and 90.7% (95% confidence interval 87.9-93.8%). Within inverse-planning studies (17 publications, n = 959 patients), these rates were 25.7% (95% confidence interval 21.0-31.1%), 9.8% (95% confidence interval 4.6-19.7%) and 95.3% (95% confidence interval 91.6-97.4%). Regression analysis did not identify any significant predictor of pCR (P > 0.05).

CONCLUSIONS

Radiotherapy dose escalation above 54 Gy is associated with high rates of pCR and does not seem to increase the risk of acute grade ≥3 toxicity events. pCR rates approaching 25% may be achievable utilising moderate escalation (54-60 Gy) with modern inverse-planning techniques; however, a clear dose-response relationship was not identified in regression analysis and additional evidence is awaited given the prevalence of heterogenous single-arm studies to date.

Neoadjuvant radio-chemotherapy prolongs healing of anastomotic leakage after rectal resection treated with endoscopic vacuum therapy

BACKGROUND

Neoadjuvant radiochemotherapy (nRCT) is an important component in the treatment of advanced rectal cancer. Endoscopic vacuum therapy (EVT) has become the treatment of choice for anastomotic leakage after rectal resection in many institutions in Germany. Published case series report on average success and stoma reversal rates of more than 80%. However, so far, there is no distinct report on the potential influence of nRCT on EVT.

METHODS

A total of 11 patients treated with EVT for anastomotic leakage after nRCT and rectal resection were retrospectively compared with a cohort of eight patients with rectal anastomotic leakage without neoadjuvant treatment. Primary endpoints were death, treatment success, and long-term preservation of intestinal continuity. Secondary endpoint was the duration of treatment. Statistical analysis was performed using Statistical Package for Social Science (SPSS) version 23.0.

RESULTS

There was no difference in mortality (0%), success rate (90.9% versus 100%, p = 0.381), or long-term preservation of continuity (63.6% versus 62.5%, p = 0.960). After nRCT, patients showed a significant longer duration of EVT (31.1 days versus 15.9 days, p = 0.040) which was associated with a significantly higher number of sponge applications (9.6 versus 5.0, p = 0.042).

CONCLUSIONS

In our analysis, EVT showed success in over 90% of patients with anastomotic leakage after rectal resection for colorectal cancer, regardless of neoadjuvant treatment. However, in case of anastomotic leakage, nRCT seems to be associated with the need for a significant longer duration of EVT.

Thymidine phosphorylase and hypoxia-inducible factor 1-α expression in clinical stage II/III rectal cancer: association with response to neoadjuvant chemoradiation therapy and prognosis

The aim of this study was to determine whether pretreatment status of thymidine phosphorylase (TP), and hypoxia-inducible factor alpha (HIF-1α) could predict pathologic response to neoadjuvant chemoradiation therapy with oxaliplatin and capecitabine (XELOXART) and outcomes for clinical stage II/III rectal cancer patients. A total of 180 patients diagnosed with clinical stage II/III rectal cancer received XELOXART. The status of TP, and HIF-1α were determined in pretreatment biopsies by immunohistochemistry (IHC). Tumor response was assessed in resected regimens using the tumor regression grade system and TNM staging system. 5-year disease free survival (DFS) and 5-year overall survival (OS) were evaluated with the Kaplan-Meier method and were compared by the log-rank test. Over expression of TP and low expression of HIF-1α were associated with pathologic response to XELOXART and better outcomes (DFS and OS) in clinical stage II/III rectal cancer patients (P < 0.05). Our result suggested that pretreatment status of TP and HIF-1α were found to predict pathologic response and outcomes in clinical stage II/III rectal cancer received XELOXART. Additional well-designed, large sample, multicenter, prospective studies are needed to confirm the result of this study.

Efficacy of different treatment strategies for stage Ⅱ-Ⅲ rectal cancer

AIM: To compare the efficacy of four treatment strategies for stage Ⅱ-Ⅲ rectal cancer and analyze prognostic factors.

METHODS: A retrospective study was conducted on 230 patients who were pathologically diagnosed with stage Ⅱ-Ⅲ rectal cancer and underwent pelvic intensity modulated radiotherapy and concurrent fluorouracil based chemotherapy between January 2010 and December 2013 at Affiliated Tumor Hospital of Xinjiang Medical University, including 68 cases receiving neoadjuvant chemoradiotherapy combined with surgery (group A), 70 cases receiving postoperative chemoradiation (group B), 51 cases receiving neoadjuvant chemoradiotherapy without surgery (group C), and 41 cases receiving radical chemoradiation (group D). (Neo-) adjuvant radiotherapy was delivered at 50 Gy in 25 fractions, and radical radiotherapy was delivered at 60-66 Gy in 30-33 fractions. Surgical patients were treated by total mesorectal excision. Time interval between radiotherapy and surgery was 4-8 wk.

RESULTS: The follow-up rate was 93.4%, and 144 patients completed the 3-year follow-up. Local recurrence in 3 years was noted in 53 cases, and 44 cases had distant metastasis in the four groups; both the 3-year recurrence rate and distant metastasis rate had no statistical significance among different groups. The 3-year overall survival (OS) and disease-free survival (DFS) rates were statistically different (P = 0.001, 0.004). The rates of OS (86.76%) and DFS (76.27%) in group A were significantly higher than those in the other groups. Complete (R0) tumor resectability was 98.5% in group A and 78.5% in group B. Main toxicities were grade 1-2 adverse events. Multivariate analysis demonstrated that neoadjuvant chemoradiotherapy without surgery (P = 0.002), age (P = 0.021) and circumferential tumor (P = 0.029) were prognostic factors.

CONCLUSION: Neoadjuvant chemoradiotherapy combined with surgery can achieve a higher R0 resection rate and higher OS and DFS than other treatments, representing an effective method for stage Ⅱ-Ⅲ rectal cancer. Neoadjuvant chemoradiotherapy without surgery, age and circumferential tumor are prognostic factors.

Tumor regression in rectal cancer after intensified neoadjuvant chemoradiation: a morphometric and clinicopathological study

BACKGROUND

High interobserver variation is a well known drawback of conventional tumor regression grading, and reaching consensus among pathologists may require a considerable effort. Therefore, in this study, morphometry was tried to assess tumor regression, and its prognostic role was explored.

METHODS

Tumor regression was quantified by a point counting method to yield tumor area fraction (TAF) as an index of remaining vital tumor.

RESULTS

In a series of 104 patients with clinically advanced rectal cancer treated with neoadjuvant radiochemotherapy, TAFs were distributed continuously towards complete regression which was observed in 8.7% of the cases. Plotting TAFs grouped by a conventional regression grading (Dworak's) revealed considerable overlap between groups. In a control series of untreated cancers, only TAFs of cancers with an expansive invasive border were setoff clearly from TAFs obtained for the study cases, but TAFs of control cases with an infiltrative invasive border and mucinous carcinomas extended well into the range of TAFs recorded for regressing tumors. Locoregional recurrence (N = 10) was significantly associated with perineural tumor infiltration and capsule transgressing lymph node metastasis/tumor deposits but not with the degree of tumor regression. Overall survival was better for patients with major regressions (≤20th percentile by morphometry, or Dworak regression grade (DRG) 4/5), although statistical significance was not reached.

CONCLUSIONS

Morphometry of tumor regression is feasible and explains why conventional regression grading is so difficult to perform. Assessment of tumor regression, by subjective grading or morphometry, does not appear to convey major prognostic information, at least not substantially beyond histopathological tumor staging. This observation discourages expending too much effort on developing this aspect of the pathomorphological workup of the resection specimens.