Intermediate-fraction neoadjuvant radiotherapy for rectal cancer

Efficacy of Neoadjuvant Therapy in Improving Long-Term Survival of Patients with Resectable Rectal Cancer: A Meta-Analysis

BACKGROUND

The impact of neoadjuvant therapy on long-term prognosis of patients with resectable rectal cancer is currently unknown.

OBJECTIVE

This study aimed to explore the long-term prognosis of patients with resectable rectal cancer following treatment with neoadjuvant therapy.

METHODS

Four major databases (PubMed, Web of Science, Embase, Cochrane library) were searched to identify relevant articles published between January 2000 and July 2020. The main outcome indicators were the 5-year overall survival (OS) and disease-free survival (DFS).

RESULTS

The meta-analysis revealed that 5-year OS (HR: 0.88, 95% Cl: 0.83-0.93) and DFS (HR: 0.95, 95% Cl: 0.91-0.98) were higher in patients with resectable rectal cancer after receiving neoadjuvant therapy than those treated with upfront surgery. Subgroup analysis demonstrated that the long-term survival of patients in Asia and Europe could benefit from neoadjuvant therapy. The neoadjuvant short-course radiotherapy (SCRT) and neoadjuvant chemo-radiotherapy (CRT) improved the 5-year OS and DFS of patients with stage Ⅱ-Ⅲ rectal cancer and mid/low rectal cancer. Further research found that patients with stage Ⅱ only had an increase in OS, while patients with stage Ⅲ have improved 5-year OS and DFS.

CONCLUSION

Neoadjuvant therapy improved the long-term survival of patients with mid/low rectal cancer in stage Ⅱ-Ⅲ (especially stage Ⅲ). Additionally, patients in Asia and Europe seemed to be more likely to benefit from neoadjuvant therapy. For the treatment, we recommend neoadjuvant SCRT and neoadjuvant CRT for resectable rectal cancer.

Surgery may not benefit patients with locally advanced rectal cancer who achieved clinical complete response following neoadjuvant chemoradiotherapy

PURPOSE

We compared the long-term outcome of the watch and wait (WW) strategy and surgery in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

This prospective cohort study included 84 patients who achieved clinical complete response (cCR) after neoadjuvant chemoradiotherapy (NCRT). They were divided into the WW group (n = 58) and surgery group (SG, n = 26). Patients in the SG underwent total mesorectal excision. The study site was the Peking University Cancer Hospital.

RESULTS

Eighty-four patients were included (58 and 26 in the WW group and SG, respectively). A total of 76·9% of the patients in the SG achieved pathological complete response (pCR) and 23·1% of the patients had a residual tumor. The total recurrence and metastasis rate was 15·4% (4/26) in the SG and 18·9% (11/58) in the WW group. There was no significant difference in the recurrence and metastasis rate between the two groups. In the WW group, 9 cases developed tumor regrowth during follow-up and underwent salvage surgery. The overall survival rate of the WW group (96·6% vs 92·3%) was not significantly different from that of the SG (P > 0·05). The WW patients also retained their anal sphincter function and avoided surgery-related complications.

CONCLUSION

The WW strategy is a feasible treatment option in patients with cCR after NCRT. Surgery may not bring benefits to these cCR patients.

Combination of radiotherapy and suppression of Tregs enhances abscopal antitumor effect and inhibits metastasis in rectal cancer

Background

Distant metastasis is the major cause of mortality in patients with locally advanced rectal cancer (LARC) following neoadjuvant chemoradiotherapy. Local radiotherapy can trigger an abscopal response to metastatic tumor cells. However, the abscopal effect is a rare event. CD4+ regulatory T (Treg) cell is a highly immune-suppressive subset which impedes immune surveillance against cancer, prevents the development of effective antitumor immunity and promotes tumor progression. We assume that the exploitation of the proimmunogenic effects of radiotherapy with anti-CD25 or anti-Cytotoxic T-Lymphocyte Associated Protein 4 (anti-CTLA4) monoclonal antibodies (mAbs) may enhance the local and abscopal effects in rectal cancer and improve the therapeutic outcome.

Methods

mRNA expression profiling of 81 pretreatment biopsy samples from LARC patients who received neoadjuvant radiotherapy (nRT) was performed to analyze the correlation between gene expression and prognosis. A retrospective analysis of patients with rectal cancer with distant metastasis or synchronous extracolonic cancers was performed to evaluate the abscopal effect of radiotherapy on rectal cancer. Two different dual-tumor mouse models were established to investigate the efficacy of single dose and dose-fractionated radiotherapy combined with anti-CD25 or anti-CTLA4 and anti-Programmed cell death 1 ligand 1 (anti-PD1) mAbs on the local tumor growth and liver metastasis. The univariate Cox regression analysis, one-way analysis of variance, Dunnett’s test, a mixed-effect linear model and Kaplan-Meier survival analysis were used to calculate p values.

Results

The proportion of Tregs in pre-nRT biopsies was negatively correlated with prognosis (p=0.007). The retrospective analysis showed that regressing liver metastases were infiltrated by CD8+ T cells. In contrast, stable/progressing metastases and synchronous extracolonic cancers were characterized by PD1+ T cells and Tregs infiltration. Animal experiment results demonstrated that the combination of radiotherapy and anti-CD25/CTLA4 mAb resulted in a significant increase in CD8+ T cells and CD8+/CD4+ ratio in primary and secondary tumors compared with the irradiation alone group (all p<0.05 or p<0.01). The combined treatment was able to decrease Tregs, PD1+CD8+ and PD1+CD4+ T cells (p<0.05), suppress locally irradiated and distal unirradiated tumor growth, and improve overall survival rate. Radiotherapy in conjunction with anti-CTLA4 reduced liver metastasis (p<0.05).

Conclusions

These data indicated that radiotherapy plus depletion of Tregs was able to improve the antitumor response and generate an abscopal effect.

Dose-time fractionation schedules of preoperative radiotherapy and timing to surgery for rectal cancer

Chemoradiotherapy (CRT) is extensively used prior to surgery for rectal cancer to provide significantly better local control, but the radiotherapy (RT), as the other component of CRT, has been subject to less interest than the drug component in recent years. With considerable developments in RT, the use of advanced techniques, such as intensity-modulated radiotherapy (IMRT) in rectal cancer, is garnering more attention nowadays. The radiation dose can be better conformed to the target volumes with possibilities for synchronous integrated boost without increased complications in normal tissue. Hopefully, both local recurrence and toxicities can be further reduced. Although those seem to be of interest, many issues remain unresolved. There is no international consensus regarding the radiation schedule for preoperative RT for rectal cancer. Moreover, an enormous disparity exists regarding the RT delivery. With the advent of IMRT, variations will likely increase. Moreover, time to surgery is also quite variable, as it depends upon the indication for RT/CRT in the clinical practices. In this review, we discuss the options and problems related to both the dose-time fractionation schedule and time to surgery; furthermore, it addresses the research questions that need answering in the future.

Feasibility of relatively low neoadjuvant radiation doses for locally advanced rectal cancer: A propensity score-matched analysis

BACKGROUND

Neoadjuvant chemoradiation therapy is part of the standard treatment of locally advanced rectal cancer (LARC). Although various options for modifying preoperative radiotherapy protocols have been researched and proposed, there is still no consensus as to the most appropriate dose regimen of neoadjuvant therapy for this disease.

AIM

To evaluate the effects of relatively low-dose radiation regimens on tumor regression and clinical outcomes in rectal cancer patients treated with neoadjuvant CRT followed by mesorectal excision.

METHODS AND RESULTS

We retrospectively analyzed patients with LARC who underwent neoadjuvant concurrent chemoradiation (CCRT) in our hospital from June 2010 to December 2015. A total of 259 consecutive patients were enrolled, receiving 42 to 44 Gy (RLD, n = 31), 46 Gy (SD1, n = 69), or 50 Gy (SD2, n = 159) of CRT, combined with either capecitabine/oxaliplatin or capecitabine only or mFOLFOX6, followed by total mesorectal excision. A 1:4 propensity score matching was employed, and all patients in the RLD group were matched with 124 patients in the SD2 group. Rates of pCR, 3-year local/regional recurrence (LRR), overall survival (OS), and disease-free survival (DFS) in the RLD group were all not significantly different (0.313 for pCR; 0.884 for LRR; and 0.762 for OS; 0.101 for DFS) from those in SD1 and SD2 groups. The RLD group showed a lower incidence of grade 3 to 4 hematologic toxicity than SD2 group (0.019). A propensity score analysis demonstrated no significant differences in the pCR rates and 3-year outcomes between the RLD and SD2 group.

CONCLUSION

Relatively low-dose regimen (≤44 Gy) of neoadjuvant CRT combined with standard concurrent chemotherapy appears to be both safe and effective in Chinese patients with LARC. Further testing by prospective randomized trials is needed.

Surgical complications after different therapeutic approaches for locally advanced rectal cancer

BACKGROUND

Preoperative radiochemotherapy is widely used in locally advanced rectal cancer. It can improve local control of rectal cancer. However, some researchers believe it increases the incidence of surgical complications. They doubt its safety. Patients with locally advanced rectal cancer receive three different treatments in our hospital, including long-course radiochemotherapy, short-course radiotherapy, and surgery directly. We can compare their differences in postoperative complications.

AIM

To investigate surgical complications caused by different preoperative radiotherapy regimens.

METHODS

We retrospectively analyzed 1197 patients admitted between 2008 and 2010 with locally advanced rectal cancer. Three hundred and forty-six patients were treated with preoperative long-course radiochemotherapy (25 × 2 Gy) followed by total mesorectal excision (TME) 6–8 wk later, and 259 patients received short-course radiotherapy (10 × 3 Gy) and subsequently TME 7–10 d later. The remaining 592 patients underwent TME alone without neoadjuvant therapy. According to Clavien–Dindo classification, surgical complications were evaluated for up to 30 d after discharge from hospital.

RESULTS

There were no deaths in 30 d in all groups after treatment. The major complications were anastomotic leakage and perineal wound complications. The results suggested that both long-course [odds ratio (OR) = 3.624, 95% confidence interval (CI): 1.689–7.775, P = 0.001] and short-course (OR = 5.150, 95%CI: 1.828–14.515, P = 0.002) radiotherapy were associated with anastomotic leakage. Temporary ileostomy was a protective factor for anastomotic leakage (OR = 6.211, 95%CI: 2.525–15.385, P < 0.001). The severity of anastomotic leakage did not increase in patients following preoperative radiotherapy (P = 0.411). Compared with TME alone, short-course radiotherapy was associated with an increase in perineal wound complications (OR = 5.565, 95%CI: 2.203–14.057, P < 0.001), but long-course radiotherapy seemed safe regarding this complication (OR = 1.692, 95%CI: 0.651–4.394, P = 0.280). Although the severity of perineal wound complications increased in patients following short-course radiotherapy (P < 0.001), additional intervention was not necessary.

CONCLUSION

Radiotherapy increased the incidence but not severity of anastomotic leakage. Short-course radiotherapy was also accompanied with perineal wound complications, but intervention appeared unnecessary to ameliorate the complications.

Associations of tumor regression grade with outcomes in patients with locally advanced rectal cancer treated with preoperative two-week course of radiotherapy

PURPOSE

Studies concerning tumor regression grade (TRG) after two-week course of radiotherapy (RT) are limited. We tried to assess associations of TRG and outcomes in patients with locally advanced rectal cancer (LARC) treated with preoperative two-week course of RT.

METHODS

356 consecutive LARC patients were retrospectively assessed. Patients with complete/intermediate (TRG1-3) and poor (TRG4-5) regressions were compared for overall survival (OS), disease-free survival (DFS) and metastasis-free survival (MFS).

RESULTS

By univariate analysis, pretreatment and postoperative factors including TNM stages, ypT, ypN, surgical procedure, pathological grade, and TRG impacted survival outcomes. Complete/intermediate regressions (TRG1-3) had significantly improved survival outcomes compared with poor ones (TRG4-5) (5y-OS, 85.8% vs. 65.8%, P=0.001; 5y-DFS, 76.0% vs. 53.7%, P<0.001; 5y-MFS, 84.2% vs. 66.7%, P<0.001). Multivariate analysis showed that ypN (P<0.001) and pathological grade (P=0.018) were the most important independent prognostic factors for DFS. ypT (P=0.014) and ypN (P=0.001) were the independent prognostic factors for MFS. Meanwhile, ypT (P=0.009), ypN (P=0.001), surgical procedure (p=0.001), and TRG (p=0.019) were the independent prognostic factors for OS.

CONCLUSIONS

Complete/intermediate TRG regressions had a more favorable prognosis than the poor group. When treated with preoperative two-week course of RT; ypT, ypN, surgical procedure, and TRG seem to affect OS.

A Retrospective Analysis on Two-week Short-course Pre-operative Radiotherapy in Elderly Patients with Resectable Locally Advanced Rectal Cancer

To validate that a two-week short-course pre-operative radiotherapy regimen is feasible, safe, and effective for the management of elderly patients with locally advanced rectal cancer (LARC), we retrospectively analyzed 99 radiotherapy-naive patients ≥70 years of age with LARC. Patients received pelvic radiation therapy (3D-CRT 30Gy/10f/2w) followed by TME surgery; some patients received adjuvant chemotherapy. The primary endpoint was OS, while the secondary endpoints were DFS, safety and response rate. The median follow-up time was 5.1 years. The 5-year OS and DFS rates were 58.3% and 51.2%, respectively. The completion rate of radiotherapy (RT) was 99.0% (98 of 99). Grade 3 acute adverse events, which resulted from RT, occurred in only 1 patient (1.0%). In addition, no grade 4 acute adverse events induced by RT were observed. All 99 patients (100%) were able to undergo R0 surgical resection, and 68.6% of the patients received sphincter-sparing surgery. The rate of occurrence of clinically relevant post-operative complications was 12.1%. Three patients (3.0%) achieved pathologic complete responses, and forty-three patients (43.4%) achieved pathologic partial responses. The rates of T-downsizing and N-downstaging were 30.3% and 55.7%, respectively. Therefore, we believe that a two-week short-course pre-operative radiotherapy is feasible in elderly patients with resectable LARC.

Role of a liver-first approach for synchronous colorectal liver metastases

AIM: To evaluate the feasibility and survival outcomes of a liver-first approach.

METHODS: Between January 2009 and April 2013, 18 synchronous colorectal liver metastases (sCRLMs) patients with a planned liver-first approach in the Hepatopancreatobiliary Surgery Department I of the Beijing Cancer Hospital were enrolled in this study. Clinical data, surgical outcomes, morbidity and mortality rates were collected. The feasibility and long-term outcomes of the approach were retrospectively analyzed.

RESULTS: Sixteen patients (88.9%) completed the treatment protocol for primary and liver tumors. The main reason for treatment failure was liver disease recurrence. The 1 and 3 year overall survival rates were 94.4% and 44.8%, respectively. The median survival time was 30 mo. The postoperative morbidity and mortality were 22.2% and 0%, respectively, following a hepatic resection, and were 18.8% and 0%, respectively, after a colorectal surgery.

CONCLUSION: The liver-first approach appeared to be feasible and safe. It can be performed with a comparable mortality and morbidity to the traditional treatment paradigm. This approach might offer a curative opportunity for sCRLM patients with a high liver disease burden.

Rectal cancer patients after neoadjuvant radiotherapy (30Gy/10f) with negative lymph node may not benefit from postoperative adjuvant chemotherapy: a retrospective study

OBJECTIVE

The purpose of this study is to evaluate whether adjuvant chemotherapy could bring oncologic benefit to all patients who underwent neoadjuvant radiotherapy (30Gy/10f).

METHODS

Rectal cancer patients receiving preoperative radiotherapy between July 2002 and April 2009 were retrospectively identified.

RESULTS

A total of 225 patients were enrolled in this study. One hundred thirty-one patients received postoperative adjuvant chemotherapy, and 94 patients did not. The 120 ypN+ and 105 ypN- patients were divided into chemo and non-chemo groups. Two groups of patients did not show any significant difference in terms of gender, age, ypT stage, preoperative serum carcinoembryonic antigen (CEA) level, differentiation, circumferential margin (CRM), lymphovascular invasion (LVI), surgical approach, local recurrence, and distant metastasis (P > 0.05). Survival analysis showed that in ypN+ patients, the 5-year overall survival (OS) rate and 5-year disease-free survival (DFS) rate in chemo group were both significantly higher than non-chemo group (P < 0.05). In ypN- patients, the 5-year OS rate and 5-year DFS rate did not show any significant difference in the two groups (P > 0.05). Subgroup analysis showed that the 5-year OS rate and 5-year DFS rate in ypT0-2 N- patients (P > 0.05) and ypT3-4 N- patients (P > 0.05) did not show any significant difference, either.

CONCLUSIONS

Based on a Chinese protocol, patients with ypN- stage may not benefit from adjuvant chemotherapy, regardless of the ypT stage, while the ypN+ patients may benefit from adjuvant chemotherapy. More randomized clinical trials are needed in the future.

Intermediate Neoadjuvant Radiotherapy Combined With Total Mesorectal Excision for Locally Advanced Rectal Cancer: Outcomes After a Median Follow-Up of 5 Years

BACKGROUND

We previously reported the oncologic results for intermediate neoadjuvant radiotherapy (nRT) plus total mesorectal excision (TME) for locally advanced rectal cancer in a retrospective study. The objective of the present study was to further investigate the efficacy and long-term outcomes after this nRT regimen.

PATIENTS AND METHODS

From 2002 to 2011, 382 patients with resectable locally advanced rectal cancer were treated at the Peking University Cancer Hospital with 30 Gy of intermediate nRT in 10 fractions (biologic equivalent dose, 36 Gy) plus TME. Surgery, RT, and pathologic examination were standardized. The primary endpoints were local recurrence-free survival (LRFS), cancer-specific survival (CSS), and overall survival (OS).

RESULTS

The median patient age at the initial treatment was 58 years (range, 22-85 years). The median patient follow-up time was 5.5 years. The estimated 5-year LRFS, CSS, and OS were 93.6%, 79.0%, and 73.6%, respectively. Of the 382 patients, 4 (1%), 4 (1%), 4 (1%), and 11 (2.9%) patients died of postoperative complications, secondary malignancies, cardiovascular and/or neurologic events, or other causes, respectively. Seven patients (1.8%) developed late-onset ileus and died after conservative treatment in peripheral hospitals.

CONCLUSION

The 10-fraction intermediate nRT regimen reported in the present study is efficient and safe. The long-term outcome is acceptable. This treatment schedule is useful as an alternative that provides efficiency, patient convenience, and low medical costs.

Prognostic value of CD45RO(+) tumor-infiltrating lymphocytes for locally advanced rectal cancer following 30 Gy/10f neoadjuvant radiotherapy

AIM

This study aims to evaluate the prognostic value of CD45RO(+) tumor-infiltrating lymphocytes (TILs) in locally advanced rectal cancer treated with 30 Gy/10 fraction (10 f) neoadjuvant radiotherapy.

METHODS

This retrospective study involved 185 patients with locally advanced rectal cancer who underwent 30 Gy/10 f nRT (biologic equivalent dose, 30 Gy) followed by total mesorectal excision (TME) between August 2003 and October 2009. The density of CD45RO(+) TILs was assessed by immunohistochemistry using an image-analysis system and tissue microarray and was evaluated for its association with histopathologic features along with disease-free survival (DFS).

RESULTS

Following neoadjuvant radiotherapy, the median density of CD45RO(+) TILs is 654/mm(2). High density of CD45RO(+) TILs was significantly associated with increased T and N downstaging effect (p = 0.006; p = 0.014), lesser-advanced T stage (p = 0.003) and TNM stage (p = 0.022). Prolonged DFS (89.0 vs. 68.1%) was also observed in CD45RO(+Hi) cases. On multivariate regression model, CD45RO(+) TILs (p = 0.026; odds ratio (OR), 0.436 (95% confidence interval (CI), 0.209-0.907)), tumor differentiation (p = 0.057; OR, 1.878 (95% CI, 0.982-3.593)), ypT stage (p = 0.066; OR, 2.383 (95% CI, 0.943-6.025)), and ypN stage (p = 0.009; OR, 2.612 (95% CI, 1.266-5.388)) were independent factors for DFS.

CONCLUSION

The density of CD45RO(+) TILs cannot only predict tumor downstaging and ypTNM stage for rectal cancer following 30 Gy/10 f nRT but also promisingly predict long-term outcomes. These findings may be used to stratify patients and make alternative strategy of adjuvant treatment.

Tumor regression grades: potential outcome predictor of locally advanced rectal adenocarcinoma after preoperative radiotherapy

AIM

To analyze tumor regression grade (TRG) for prognosis of locally advanced rectal adenocarcinoma (LARA) treated with preoperative radiotherapy.

METHODS

One hundred and ninety patients with clinical stage II/III LARA were studied. All patients underwent radical surgery (between 2004 and 2010) after 30-Gy/10-fraction preoperative radiotherapy (pre-RT). All 190 patients received a short course of pre-RT and were reassessed for disease recurrence and survival; the slides of surgical specimens were reviewed and classified according to Mandard TRG. We compared patients with good response (Mandard TRG1 or TRG2) vs patients with bad/poor response (Mandard TRG3-5). Outcomes evaluated were 5-year overall survival (OS), 5-year disease-free survival (DFS), and local, distant and mixed recurrence. Fisher's exact test or χ(2) test, log-rank test and proportional hazards regression analysis were used to calculate the probability that Mandard TRG was associated with patient outcomes.

RESULTS

One hundred and sixty-six of 190 patients (87.4%) were identified as Mandard bad responders (TRG3-5). High Mandard grade was correlated with tumor height (41.7% < 6 cm vs 58.3% ≥ 6 cm, P = 0.050), ypT stage (75% ypT0-2 vs 25% ypT3-4, P = 0.000), and ypN stage (75% ypN0 vs 25% ypN1, P = 0.031). In univariate survival analysis, Mandard grade bad responders had significantly worse OS and DFS than good responders (TRG1/2) (OS, 83.1% vs 96.4%, P = 0.000; DFS, 72.3% vs 92.0%, P = 0.002). In multivariate survival analysis, Mandard bad responders had significantly worse DFS than Mandard good responders (DFS 3.8 years (95%CI: 1.2-12.2 years, P = 0.026).

CONCLUSION

Mandard grade good responders had a favorable prognosis. TRG may be a potential predictor for DFS in LARA after pre-RT.

Intermediate neoadjuvant radiotherapy for T3 low/middle rectal cancer: postoperative outcomes of a non-controlled clinical trial

Background

The benefits of adjuvant radiotherapy in rectal carcinoma are well known. However, there is still considerable uncertainty about the optimal radiation treatment. There is an ongoing debate about the choice between very short treatments immediately followed by surgical resection and prolonged treatments with delayed surgery. In this paper, we describe an interim analysis of a non-controlled clinical trial in which radiotherapy delivered with intermediate dose/duration was followed by surgery after about 2 weeks to improve local control and survival after curative radiosurgery for cT3 low/middle rectal cancer.

Methods

Preoperative radiotherapy (36 Gy in 3 weeks) was delivered in 248 consecutive patients with cT3NxM0 rectal adenocarcinoma within 10 cm from the anal verge, followed by surgery within the third week after treatment completion.

Results

166 patients (66.94%) underwent anterior resection, 80 patients (32.26%) the Miles' procedure and 2 patients (0.8%) the Hartmann's procedure. Local resectability rate was 99.6%, with 226 curative-intent resections. The overall rate of complications was 27.4%. 5-year oncologic outcomes were evaluated on 223 patients. The median follow-up time was 8.9 years (range 5-17.4 years); local recurrence (LR) rate and distal recurrence (DR) rate after 5 years were 6.28% and 21.97%, respectively. Overall survival was 74.2%; disease free survival was 73.5%; local control was 93.4 % and metastasis-free survival was 82.1%.

Conclusions

preoperative radiotherapy with intermediate dose/duration and interval between radiotherapy and surgery achieves high local control in patients with cT3NxM0 rectal cancer, and high DR rate seems to be the major limitation to improved survival.

Expression of HER-2 in rectal cancers treated with preoperative radiotherapy: a potential biomarker predictive of metastasis

BACKGROUND

Evidence suggests HER-2 overexpression may be predictive of prognosis in colorectal cancer patients, though this remains controversial.

OBJECTIVES

This study was performed to assess the prognostic value of HER-2 expression in locally advanced rectal cancer patients after preoperative radiotherapy.

PATIENTS AND METHODS

HER-2 expression was evaluated based on immunohistochemical (IHC) staining of resected specimens from 142 mid-to-low rectal cancer patients. Fluorescence in situ hybridization (FISH) was performed to confirm HER-2 overexpression in samples with an IHC score of 2+. Tumor regression grading (TRG) of the primary tumors was determined semiquantitatively using a tumor regression grading scheme advocated in the AJCC Cancer Staging Manual 7 edition.

RESULTS

When the total staining intensity was evaluated, 106 samples (74.6%) showed barely-perceptible positivity (0-1+; HER-2--negative), 15 samples (10.6%) showed moderate positivity (2+) and 21 samples (14.8%) showed strong positivity (3+, HER-2 positive). FISH confirmed that 2 cases showing moderate HER-2 positivity (2+) overexpressed HER2. There was no significant difference between the HER-2 positive and -negative groups with respect to age, gender, TRG, TNM stage, downstaging status, lymphovascular invasion or tumor differentiation. A significant correlation was found between HER-2 overexpression and the incidence of distant metastasis (p = 0.005). Subgroup analysis revealed this correlation was not significant (p = 0.247) in the radiation-insensitive (TRG0-2) subgroup, whereas a significant correlation (p = 0.026) between HER-2 overexpression and distant metastasis was found in the radiation-resistant (TRG3) subgroup. Multivariate analysis identified ypN stage (OR = 0.473, p = 0.002)and overexpression of HER-2 (OR = 3.704, p = 0.008) as independent risk factors for distant metastasis. There was no correlation between HER-2 overexpression and disease-free survival or overall survival among the study population.

LIMITATIONS

We reported that HER-2 overexpression was correlated with distant metastasis in rectal cancer patients, especially in the radiation-insensitive group. However, there are certain limitations. First, this study was limited due to the fact that the number of rectal patients enrolled was only 142, which is relatively small. Second, HER-2 expression was measured by IHC with a positive ratio around 15%, which is fairly high according to the literature. Also, we collected the tissue samples preoperatively. It would be interesting to know the HER-2 expression levels pre- and postradiotherapy, as well as their correlation with local recurrence or distant metastasis. Finally, in rectal cancer patients, there is little information published on HER-2 and its role in tumor progression and metastasis. Therefore, we are pursuing the regulatory molecule underlined.

CONCLUSIONS

HER-2 is overexpressed in around 15% of rectal cancer patients who receive neoadjuvant radiotherapy. Moreover, HER-2 overexpression could be a predictive biomarker of distant metastasis in rectal cancer patients after preoperative radiotherapy, especially patients showing a poor response to neoadjuvant radiotherapy.