Comparative analysis of lymph node metastases in patients with ypT0-2 rectal cancers after neoadjuvant chemoradiotherapy

Lymph node metastasis following chemoradiotherapy in advanced rectal cancer: ypT2-focused analyses of total mesorectal excision specimens

BACKGROUND

Non-radical management is an option for good responders to neoadjuvant chemoradiotherapy in mid-to-low rectal cancer. This study aimed to analyze risk factors for lymph node metastasis in patients with ypT2 rectal cancer, exploring the possibility of non-radical management.

METHODS

We included patients with ypT2 rectal cancer who received neoadjuvant chemoradiotherapy followed by total mesorectal excision between January 2004 and December 2022. Clinicopathological parameters were evaluated to identify risk factors for lymph node metastasis.

RESULTS

Among the 198 patients, 158 (79.8%) had ypT2N0 and 40 (20.2%) had ypT2N+. In univariable analyses, the risk factors of lymph node metastasis were perineural invasion (48.0% vs. 16.3% without perineural invasion, P < 0.001), female sex (30.0% vs. 14.8% with male sex, P = 0.011), and clinically positive nodes after neoadjuvant chemoradiotherapy (32.6% vs. 16.4% with negative nodes, P = 0.017). These factors were confirmed as independent risk factors in multivariable analyses: perineural invasion (odds ratio [OR]: 4.50; 95% confidence interval [CI]: 1.79-11.29; P < 0.001), female sex (OR: 2.62; 95% CI: 1.24-5.52; P = 0.012) and clinical node involvement after neoadjuvant chemoradiotherapy (OR: 2.28; 95% CI: 1.03-5.05; P = 0.012). The rate of lymph node metastasis in patients with ypT2 rectal cancer without any of these three risk factors was 12.5%.

CONCLUSIONS

This study revealed a high probability of lymph node metastasis in patients with ypT2 rectal cancer, even in the absence of identifiable risk factors. We confirm that lymph node metastasis should be considered in ypT2 rectal cancer.

Therapeutic strategies for ypT1 rectal cancer after neoadjuvant chemoradiotherapy: a retrospective cohort study

PURPOSE

The optimal treatment of ypT1 rectal cancer after neoadjuvant chemoradiotherapy (nCRT) remains controversial. This study aimed to determine whether local excision is non-inferior to radical surgery and whether adjuvant chemotherapy (ACT) would improve survival in patients with ypT1 rectal cancer after nCRT.

METHODS

We enrolled 1212 and 91 patients with ypT1 rectal cancer underwent nCRT followed by radical surgery from the SEER database (2004-2018) and the Zhejiang Cancer Hospital (ZJCH) (2010-2022), respectively. Another 62 patients underwent LE were also identified from SEER registries. Propensity score matching was performed to balance baseline characteristics between patients in different treatment groups.

RESULTS

Regional nodal metastasis was histopathologically detected in 257 patients (20.7%) within the SEER cohort, showing a significant association with poor cancer-specific survival (CSS) and overall survival (OS). Consistent findings were also observed in the ZJCH cohort. After 1:1 propensity score matching (60 pairs), no significant differences were observed between the extended resection and local excision groups in CSS (hazard ratio [HR] 0.88, P = 0.785) and OS (HR 0.81, P = 0.450). Patients with regional nodal metastases were more likely to receive ACT, while no apparent survival benefit was observed with additional ACT after PSM adjusting (187 pairs). Notwithstanding, for individuals younger than 50 years, ACT might provide a survival benefit in CSS (HR 0.25, P = 0.033) and OS (HR 0.30, P = 0.022).

CONCLUSION

Although patients with ypT1 rectal cancer have a non-negligible risk for nodal metastasis, oncologic outcomes of local excision following nCRT seem to be comparable to radical surgery. ACT could not effectively improve prognosis in patients with ypT1 tumors, except for those younger than 50 years of age.

Local excision versus total mesorectal excision for rectal cancer patients with clinical complete or near-complete response after neoadjuvant chemoradiotherapy

PURPOSE

Local excision is an effective approach for managing rectal cancer exhibiting substantial regression after neoadjuvant chemoradiotherapy. The purpose of this study is to compare the outcomes between local excision and total mesorectal excision in rectal cancer patients achieving clinical complete or near-complete response after neoadjuvant chemoradiotherapy.

METHODS

This is a retrospective cohort study that includes a consecutive series of rectal cancer patients who responded well to neoadjuvant chemoradiotherapy followed by surgery. A total of 180 rectal cancer patients at a single institution during a 12-year period are included. The main outcomes include short-term outcomes, oncological outcomes, and functional outcomes between the two groups.

RESULTS

A total of 180 patients were included in the study. Sixty-one (33.9%) received local excision and 119 (66.1%) received total mesorectal excision. The baseline characteristics were generally balanced between the two groups. The local excision group demonstrated a significantly shorter operative time, less blood loss, and shorter hospital stay (p < 0.001). 3-year overall survival rates were 97.5% (95% CI, 0.93-1.00) and 95.5% (95% CI, 0.91-1.00) between the two groups (p = 0.38). The local excision group exhibited significantly higher 3-year local recurrence rates 15.7% (95% CI, 0.74-0.97) vs 4.2% (95% CI, 0.92-1.00) (p = 0.017), yet lower 3-year distant metastasis rates 9.6% (95% CI, 0.82-1.00) vs 12.6% (95% CI, 0.81-0.94) (p = 0.33) and lower 3-year disease-free survival rates 76.8% (95% CI, 0.64-0.92) vs 84.7% (95% CI, 0.78-0.92) (p = 0.56) comparing with the total mesorectal excision group. The local excision group demonstrated significantly better functional outcomes compared with the total mesorectal excision group (p < 0.001).

CONCLUSION

Patients who achieve either clinical complete or near-complete response after neoadjuvant chemoradiotherapy are suitable candidates for local excision. The local excision group demonstrated superior short-term and functional outcomes, and the oncological outcomes were not compromised.

Clinicopathological factors predict residual lymph node metastasis in locally advanced rectal cancer with ypT0-2 after neoadjuvant chemoradiotherapy

PURPOSE

Residual lymph node metastases (RLNM) remained a great concern in the implementation of organ-preserving strategies and led to poor prognosis in locally advanced rectal cancer (LARC). In this study, we aimed to identify the clinicopathological factors correlated with RLNM in LARC patients with ypT0-2 after neoadjuvant chemoradiotherapy (NCRT).

METHODS

We retrospectively analyzed 417 patients histologically diagnosed middle-low LARC after NCRT and total mesorectal excision (TME), whose pathological staging was ypT0-2. All patients received pelvic magnetic resonance imaging (MRI) before NCRT. The radiation doses were 50-50.6 Gy for the planning gross tumor volume and 41.8-45 Gy for the planning target volume, respectively. A nomogram for predicting RLNM was constructed using a binary logistic regression. Nomogram performance was assessed by receiver operating characteristic (ROC) curve, calibration curve, decision curve analysis (DCA) and clinical impact curve (CIC).

RESULTS

After surgery, 191 patients (45.8%) were ypT0, 43 patients (10.3%) were ypT1 and 183 patients (43.9%) were ypT2, and a total of 49 patients (11.8%) were found the presence of RLNM. Multivariable analyses identified MRI-defined mesorectal fascia (MRF)-positive, high-grade histopathology at biopsy, advanced ypT-category, and the presence of perineural invasion (PNI) as the predictive factors. The nomogram, incorporating all these predictors, showed good discrimination and calibration efficacy, with the areas under the ROC curve of 0.690 (95% CI: 0.610-0.771). Both DCA and CIC demonstrated that this nomogram has good clinical usefulness.

CONCLUSION

The nomogram model can predict RLNM in patients with ypT0-2 tumors. It can help select suitable patients for performing organ-preserving strategies after NCRT.

Nonoperative Management of dMMR/MSI-H Colorectal Cancer following Neoadjuvant Immunotherapy: A Narrative Review

Immunotherapy with PD-1 blockade has achieved a great success in colorectal cancers (CRCs) with high microsatellite instability (MSI-H) and deficient mismatch repair (dMMR), and has become the first-line therapy in metastatic setting. Studies of neoadjuvant immunotherapy also report exciting results, showing high rates of clinical complete response (cCR) and pathological complete response. The high efficacy and long duration of response of immunotherapy has prompt attempts to adopt watch-and-wait strategy for patients achieving cCR following the treatment. Thankfully, the watch-and-wait approach has been proposed for nearly 20 years for patients undergoing chemoradiotherapy and has gained ground among patients as well as clinicians. In this narrative review, we combed through the available information on immunotherapy for CRC and on the watch-and-wait strategy in chemoradiotherapy, and looked forward to a future where neoadjuvant immunotherapy as a curative therapy would play a big part in the treatment of MSI-H/dMMR CRC.

Predictors of Nodal Disease in Rectal Cancer Patients with Complete Mucosal Response to Neoadjuvant Therapy

BACKGROUND

Some patients with locally advanced rectal cancer (LARC) achieve complete mucosal response following neoadjuvant therapy (NAT) and may be candidates for watch and wait strategy. This study aimed to identify predictors of nodal disease in patients with LARC who had a complete mucosal response to NAT.

METHODS

This case-control study included patients with LARC who were treated with NAT in the National Cancer Database between 2004 and 2019. Patients with complete mucosal response, defined as pathologic T0, were identified and classified according to the status of the pathologic N stage into complete response (pT0, pN0) and complete mucosal response with positive nodal disease (pT0, pN +). The two groups were compared regarding baseline demographics and tumor characteristics to determine the predictors of nodal disease after NAT.

RESULTS

A total of 5529 patients (59.7% male) with a mean age of 59.6 ± 12.2 years had a complete mucosal response following NAT. Nodal disease was detected in 443 (8%) patients with a complete mucosal response. Independent predictors of nodal disease were clinical N + stage (OR: 1.87, p < 0.001), mucinous histology (OR: 3.8, p = 0.003), and lymphovascular invasion (OR = 4.01, p < 0.001). The clinical T stage was inversely related to the risk of nodal disease.

CONCLUSIONS

Despite having a complete mucosal response following NAT, 8% of patients had nodal disease. Clinical evidence of nodal involvement on preoperative assessment, mucinous tumor histology, and lymphovascular invasion predicted nodal disease after NAT. These findings should be considered when making a decision on watch and wait strategy in patients with clinical complete response.

Short- and long-term outcomes in ypT2 rectal cancer patients after neoadjuvant therapy and local excision: a multicentre observational study

BACKGROUND

Although local excision (LE) after neoadjuvant treatment (NT) has achieved encouraging oncological outcomes in selected patients, radical surgery still remains the rule when unfavorable pathology occurs. However, there is a risk of undertreating patients not eligible for radical surgery. The aim of this study was to evaluate the outcomes of patients with pathological incomplete response (ypT2) in a multicentre cohort of patients undergoing LE after NT and to compare them with ypT0-is-1 rectal cancers.

METHODS

From 2010 to 2019, all patients who underwent LE after NT for rectal cancer were identified from five institutional retrospective databases. After excluding 12 patients with ypT3 tumors, patients with ypT2 tumors were compared to patients with ypT0-is-1 tumors). The endpoints of the study were early postoperative and long-term oncological outcomes.

RESULTS

A total of 177 patients (132 males, 45 females, median age 70 [IQR 16] years) underwent LE following NT. There were 46 ypT2 patients (39 males, 7 females, median age 72 [IQR 18.25] years) and 119 ypT0-is-1 patients (83 males, 36 females, median age 69 [IQR 15] years). Patients with pathological incomplete response (ypT2) were frailer than the ypT0-is-1 patients (mean Charlson Comorbidity Index 6.15 ± 2.43 vs. 5.29 ± 1.99; p = 0.02) and there was a significant difference in the type of NT used for the two groups (long- course radiotherapy: 100 (84%) vs. 23 (63%), p = 0.006; short-course radiotherapy: 19 (16%) vs. 17 (37%), p = 0.006). The postoperative rectal bleeding rate (13% vs. 1.7%; p = 0.008), readmission rate (10.9% vs. 0.8%; p = 0.008) and R1 resection rate (8.7% vs. 0; p = 0.008) was significantly higher in the ypT2 group. Recurrence rates were comparable between groups (5% vs. 13%; p = 0.15). Five-year overall survival was 91.3% and 94.9% in the ypT2 and ypT0-is-1 groups, respectively (p = 0.39), while 5-year cancer specific survival was 93.4% in the ypT2 group and 94.9% in the ypT0-is-1 group (p = 0.70). No difference was found in terms of 5-year local recurrence free-survival (p = 0.18) and 5-year distant recurrence free-survival (p = 0.37).

CONCLUSIONS

Patients with ypT2 tumors after NT and LE have a higher risk of late-onset rectal bleeding and positive resection margins than patients with complete or near complete response. However, long-term recurrence rates and survival seem comparable.

Risk of nodal disease in patients with MRI-detected extramural vascular invasion in rectal cancer: a systematic review and meta-analysis

BACKGROUND

The impact of magnetic resonance imaging-detected extramural vascular invasion (mrEMVI) in distant metastasis is well known but its correlation with prevalence of lymph node metastasis is less studied. The aim of this systematic review and meta-analysis was to assess the prevalence of nodal disease in mrEMVI-positive and negative cases in rectal cancer.

METHODS

Following guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses, a systematic literature search in PubMed, Web of Science, Cochrane Library, and EMBase was carried out to identify relevant studies published up to May 2019.

RESULTS

Our literature search generated 10 studies (863 and 1212 mrEMVI-positive and negative patients, respectively). The two groups (mrEMVI-positive and negative) were significantly different in terms of nodal disease status (odds ratio [OR] 3.15; 95% confidence interval [CI] 2.12-4.67; p < 0.001). The prevalence of nodal disease was 75.90% vs 52.56% in the positive mrEMVI vs negative mrEMVI group, respectively (p < 0.001). The prevalence of positive lymph node in positive mrEMVI patients treated with neoadjuvant/adjuvant chemoradiotherapy (nCRT/CRT) (OR 2.47; 95% CI 1.65-3.69; p < 0.001) was less compared with the patients who underwent surgery alone (OR 6.25; 95% CI 3.74-10.44; p < 0.001).

CONCLUSION

The probability of positive lymph nodes in cases of positive mrEMVI is distinctly greater compared with negative cases in rectal cancer. Positive mrEMVI indicates risk of nodal disease prevalence increased by threefold in rectal cancer.

Watch and wait approach in rectal cancer: Current controversies and future directions

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.

A Nine-Gene Signature for Predicting the Response to Preoperative Chemoradiotherapy in Patients with Locally Advanced Rectal Cancer

Preoperative chemoradiotherapy (PCRT) and subsequent surgery is the standard multimodal treatment for locally advanced rectal cancer (LARC), albeit PCRT response varies among the individuals. This creates a dire necessity to identify a predictive model to forecast treatment response outcomes and identify patients who would benefit from PCRT. In this study, we performed a gene expression study using formalin-fixed paraffin-embedded (FFPE) tumor biopsy samples from 156 LARC patients (training cohort n = 60; validation cohort n = 96); we identified the nine-gene signature (FGFR3, GNA11, H3F3A, IL12A, IL1R1, IL2RB, NKD1, SGK2, and SPRY2) that distinctively differentiated responders from non-responders in the training cohort (accuracy = 86.9%, specificity = 84.8%, sensitivity = 81.5%) as well as in an independent validation cohort (accuracy = 81.0%, specificity = 79.4%, sensitivity = 82.3%). The signature was independent of all pathological and clinical features and was robust in predicting PCRT response. It is readily applicable to the clinical setting using FFPE samples and Food and Drug Administration (FDA) approved hardware and reagents. Predicting the response to PCRT may aid in tailored therapies for respective responders to PCRT and improve the oncologic outcomes for LARC patients.

Local excision following chemoradiotherapy in T2-T3 rectal cancer: current status and critical appraisal

Local excision following chemoradiotherapy in rectal cancer is an organ-preserving procedure which aims at reducing morbidity and functional disorders associated with total mesorectal excision (TME) in selected patients. Although TME after chemoradiotherapy remains the gold standard for locally advanced mid and low rectal cancer, in the last years multicenter research trials have offered encouraging oncologic results which have allowed to preserve the rectum in patients with a pathologic complete response after chemoradiotherapy. A review of the available literature on this topic was conducted to define the state of the art of this conservative approach and to focus on the most controversial aspects concerning local excision performed after chemoradiotherapy, in particular tumor scatter and lymph node status, completion and salvage surgery, morbidity and quality of life. The analysis of these topics should be considered, in trial setting or in current practice, for their clinical implications. Oncologic outcomes of recent trials are encouraging for part of the patients presenting T2 rectal cancer; however, TME still remains the standard treatment in clinical practice. In such cases, local excision should include a surgical safety margin of at least 1 cm from the resection margin to achieve a true negative margin from residual tumor cells. The selection of the patients should be carefully performed and their consensus extremely detailed because TME is necessary in about 30% of cases. Failing that, morbidity and quality of life are negatively affected. However, about half of these patients refuse radical surgery (45%), thus undergoing only palliative care.

"Watch and Wait" for complete clinical response after neoadjuvant chemoradiotherapy for rectal cancer

The management of rectal cancer has evolved substantially over recent decades, becoming increasingly complex. This was once a disease associated with high mortality and limited treatment options that typically necessitated a permanent colostomy, has now become a model for multidisciplinary evaluation, treatment and surgical advancement. Despite advances in the rates of total mesorectal excision, decreased local recurrence and increased 5-year survival rates, the multimodal treatment of rectal cancer is associated with a significant impact on long-term functional and quality of life outcomes including risks of bowel, bladder and sexual dysfunction, and potential need for a permanent stoma. There is great interest in strategies to decrease the toxicity of treatment, including selective use of radiation, chemotherapy or even surgery. The modern concept of selective use of surgery for patients with rectal cancer are based on the observed pathological complete response in approximately 10-20% of patients following long-course chemoradiation therapy. While definitive surgical resection remains the standard of care for all patients with non-metastatic rectal cancer, a growing number of studies are providing supportive evidence for a watch-and-wait, organ preserving approach in highly selected patients with rectal cancer. However, questions regarding the heterogeneity of patient selection, optimal method for inducing pathological complete response, methods and intervals for assessing treatment response and adequacy of follow-up remain unanswered. The aim of this review is to provide an up-to-date summary of the current evidence for the watch-and-wait management of rectal cancer following a complete clinical response after neoadjuvant chemoradiation.

The risk of nodal disease in patients with pathological complete responses after neoadjuvant chemoradiation for rectal cancer: a systematic review, meta-analysis, and meta-regression

BACKGROUND

This systematic review and meta-analysis seek to evaluate the prevalence of nodal disease in rectal cancer patients with pathological complete responses (pCR) after neoadjuvant chemoradiotherapy (ypT0N+).

METHODS

This study conformed to the PRISMA guidelines. A search was performed on major databases to identify relevant articles. Meta-analyses of pooled proportions were performed on rectal cancer with pCR and ypT0N+. Meta-regression was undertaken to identify sources of heterogeneity, and the Newcastle-Ottawa Scale (NOS) was employed to assess the risk of bias.

RESULTS

A total of 18 studies were included, totaling 7568 patients. The overall risk of bias was low, since all studies scored 6 and above out of 9 on the NOS. Preoperatively, the pooled proportions of patients with T3/T4 tumors and clinically positive nodal disease were 84.08% (95% CI 74.19 to 91.99%) and 52.14% (95% CI 35.02 to 69.00%) respectively. The prevalence of pCR in the whole pool was 18.52% (95% CI 13.31 to 24.35%; I² = 93.85%; P = 0.00), and meta-regression showed a significantly negative relationship with patient age (β = - 0.03, 95% CI - 0.03 to - 0.02; P = 0.00). The pooled prevalence of ypT0N+ was 4.61% (95% CI 2.41 to 7.28%; I² = 52.27%; P = 0.01), and meta-regression demonstrated a significantly positive relationship with male gender (β = 1.06, 95% CI 1.00 to 1.12; P = 0.04).

CONCLUSION

There is a small risk of ypN+ in patients with pCR after neoadjuvant CRT and surgery for rectal cancer. However, further research is warranted to establish these findings and to identify predictive factors for this specific group of patients.

Organ Preservation Among Patients With Clinically Node-Positive Rectal Cancer: Is It Really More Dangerous?

BACKGROUND

Select patients with complete clinical response to chemoradiation have been managed without radical surgery. The presence of radiologic evidence of nodal metastases at baseline could be a risk factor for local tumor regrowth, more advanced stage at the time of recurrence, and worse distant metastases-free survival.

OBJECTIVE

The purpose of this study was to compare the outcomes of patients with baseline node-positive and node-negative cancer after neoadjuvant chemoradiation and complete clinical response managed nonoperatively.

DESIGN

This was a retrospective review of consecutive patients with nonmetastatic distal rectal cancer undergoing neoadjuvant chemoradiation.

PATIENTS

Consecutive patients with clinical and radiologic evidence of complete clinical response at 8 to 10 weeks were managed nonoperatively and enrolled in a strict follow-up program (watch and wait). Patients with incomplete clinical response or tumor regrowth after initial complete clinical response were referred to surgery.

MAIN OUTCOMES MEASURES

Surgery-free and distant metastases-free survival were compared between patients according to nodal status at baseline.

RESULTS

A total of 117 patients with node-positive and 218 with node-negative cancer at baseline were reviewed. Overall, 62 (53.0%; node positive) and 135 (61.9%; node negative) achieved a complete clinical response and were managed nonoperatively (p = 0.13). Patients with baseline node-positive cancer had similar rates of pathologic nodal metastases at the time of recurrence. Five-year surgery-free (39.7% vs 46.8%; p = 0.2) and distant metastases-free survival (77.5% vs 80.5%; p = 0.49) were similar between baseline node-positive and node-negative patients.

LIMITATIONS

This was a retrospective study with a small sample size and possible inaccurate nodal staging.

CONCLUSIONS

Patients with rectal cancer with node-positive cancer at baseline who develop a complete clinical response after neoadjuvant chemoradiation are not at increased risk for local tumor regrowth or development of more advanced disease at the time of recurrence. These patients seem to be safe candidates for organ-preserving strategies after achieving complete clinical response. See Video Abstract at http://links.lww.com/DCR/A902.

Poorer Oncologic Outcome of Good Responders to PCRT With Remnant Lymph Nodes Defies the Oncologic Paradox in Patients With Rectal Cancer

INTRODUCTION

We evaluated the oncologic outcome of (y)pT0-2N+ rectal cancer and investigated the impact of metastatic lymph nodes (LNs) on oncologic outcome in the setting of preoperative chemoradiotherapy (PCRT).

MATERIALS AND METHODS

The records of 1403 patients who underwent surgery for rectal cancer between January 2005 and December 2012 were analyzed. The patients were categorized according to the pathologic stage, including 728 patients with ypT0-2 and 675 with ypT3-4 disease. The oncologic outcomes in terms of the 5-year recurrence-free survival (RFS) and overall survival (OS) were analyzed.

RESULTS

Metastatic LNs were observed in 11.5% (n = 84) of patients with ypT0-2 and 42.9% (n = 290) of patients with ypT3-4 disease. The RFS and OS were stratified according to ypT and ypN stage as ypT0-2N0, T0-2N+, T3-4N0, and T3-4N+. The ypT0-2N+ group had slightly lower RFS and OS than those in the ypT3-4N0 group. LN metastasis was significantly associated with RFS in both ypT0-2 and ypT3-4 disease, with a stronger association for ypT0-2 disease (hazard ratio, 3.473, 95% confidence interval, 2.058-5.261; P < .001 for ypT0-2 and hazard ratio, 2.038; 95% confidence interval, 1.601-2.684; P < .001 for ypT3-4, respectively).

CONCLUSION

The oncologic outcomes of ypT0-2N+ disease were not favorable compared with those of ypT3-4N0 disease. These outcomes dispute the survival paradox traditionally believed for non-PCRT-treated patients with rectal cancer, and highlight the underestimated significance of post-PCRT nodal involvement. The prognostic importance of metastatic LNs should be considered when deciding the surgical strategy after PCRT. Further studies including larger numbers of patients with sufficient follow-up are needed to verify the oncologic impact of metastatic LNs within tumors contained within the bowel wall after PCRT.

Local excision in mid-to-low rectal cancer patients who revealed clinically total or near-total regression after preoperative chemoradiotherapy; a proposed trial

BACKGROUND

Preoperative chemoradiotherapy (pre-CRT) followed by total mesorectal excision (TME) is currently a standard therapy for locally advanced mid-to-low rectal cancer. Less aggressive, organ-preserving option such as local excision (LE) or watchful wait can alternatively be used for patients who respond well to pre-CRT. High-resolution rectal magnetic resonance imaging (MRI) is one of the most useful methods to assess pre-CRT response, and the MERCURY group has shown that the MR tumor regression grade (mrTRG) correlated with the pathologic TRG. The aim of this study is to compare postoperative complication and oncologic outcomes between LE and TME in mid-to-low rectal cancer patients whose tumors are mrTRG grade 1 (radiological complete remission) or 2 (predominant fibrosis; near-complete remission) after pre-CRT.

METHODS

A prospective, double-arm, randomized, open-labeled, single center, clinical trial will be conducted in patients with mid-to-low rectal cancer whose tumors are mrTRG 1/2 after pre-CRT at the Asan Medical Center, Seoul, Korea, after approval from the Institution Review Board. Patient medical records will be de-identified using a serial number to protect personal information. Inclusion criteria will include rectal adenocarcinoma with an inferior border < 8 cm from the anal verge, mrTRG 1/2, age > 20, and provision of informed consent. Postoperative complications will be assessed by Clavien-Dindo Classification Grade. Oncologic and functional outcomes will be collected and risk factors related to these outcomes will be investigated.

DISCUSSION

We believed that the rate of postoperative complication of LE will be comparable to that of TME in mid-to-low advanced rectal cancer patients with a favorable response after pre-CRT.

TRIAL REGISTRATION

KCT0002579 ( https://cris.nih.go.kr ) Dec-2017.

Non-operative treatment outcome for rectal cancer patient with clinical complete response after neoadjuvant chemoradiotherapy

BACKGROUND

Among rectal cancer patients, some of good responders after neoadjuvant chemoradiotherapy (nCRT) are considered for non-operative treatments to avoid postoperative morbidities and permanent stoma. However, oncologic feasibility of non-operative treatment has not been fully understood.

METHODS

From 2008 to 2017, we retrospectively reviewed patient's records who had lower or mid rectal cancer and diagnosed to clinical complete response by magnetic resonance imaging after nCRT. Clinical differences and oncologic outcomes were compared among Radical surgery (RS), Local excision (LE) and Wait-and-see (WS) group.

RESULTS

Number of 129, 25, 15 patients included to RS, LE, WS groups. Local recurrence was frequent type of recurrence in both of LE and WS group (RS; 31.3%, LE; 80%, WS; 66.7%), and many patients in WS group omitted salvage treatment (RS; 75%, LE; 100%, WS; 33.3%). 5-years local-recurrence/disease-free survival rate (LRFS, DFS) between RS and LE were similar between each group, but WS showed significantly inferior outcomes than that of RS (LRFS; p = 0.001, DFS; p = 0.001). In multivariate analysis, WS protocol (OR; 7.163, 95% CI; 1.995-25.715) and cT4 stage (OR; 8.206, 95% CI; 1.596-42.198) were independent factors for LRFS.

CONCLUSIONS

Wait-and-see group showed high rate of rejection of salvage treatments for recurrence, and poor oncologic outcomes. However, recent low-level evidences reported favorable outcome of WS protocol when salvage treatment was followed after recurrence. It seems that the application of WS protocol should be postponed until the results of randomized-controlled trials are available. Local excision seems to be good alternative option to radical surgery when salvage treatment is followed.

Effect of Responsiveness of Lymph Nodes to Preoperative Chemoradiotherapy in Patients With Rectal Cancer on Prognosis After Radical Resection

BACKGROUND

The influence of lymph node (LN) response to preoperative chemoradiotherapy (PCRT) has not been well evaluated for prognosis and additional use of adjuvant treatment after PCRT in rectal cancer patients. The aim of this study was to evaluate the prognostic effect of LN regression grade (LRG) in rectal cancer after PCRT and radical resection.

PATIENTS AND METHODS

From 2008 to 2011, 389 patients with rectal cancer treated with PCRT followed by radical resection were identified. The pathologic LRG (pLRG) score was determined on the basis of the proportion of tumor cells and fibrosis. The sum of the pLRG of each evaluated LN was used as the final LRG score, LRG-sum. Cox regression analysis was used to evaluate the association of LRG-sum and recurrence-free survival (RFS).

RESULTS

The distribution of LRG-sum was significantly associated with tumor regression grade of the primary tumor (P < .001). LRG-sum showed different values even in patients with the same number of metastatic LNs. LRG-sum was confirmed as the most relevant associated factor among LN-related variables with RFS along with ypT stage in multivariate analysis. Patients were categorized according to the cutoff points of LRG-sum distribution: LRG1 (LRG-sum 0 to ≤3), LRG2 (LRG-sum 3 to ≤21), and LRG3 (LRG-sum >21). RFS showed a significant difference according to LRG group (P < .001) and showed more effective difference in RFS in the same ypN stage subgroup on the basis of the number of metastatic LNs.

CONCLUSION

LRG was a prognostic factor of oncologic outcomes of rectal cancer. LN response to PCRT might help in prognostication and determination of treatments after PCRT.

Does total regression of primary rectal cancer after preoperative chemoradiotherapy represent "no tumor" status?

Purpose

Insistence that total regression of primary tumor would not represent long-term oncologic outcomes has been raised. Therefore, this study aimed to evaluate the outcomes of these patients after preoperative chemoradiotherapy (PCRT) and radical surgery and to evaluate the associated risk factors.

Methods

We included 189 patients with rectal cancer who showed total regression of the primary tumor after PCRT, followed by radical resection, between 2001 and 2012. Recurrence-free survival (RFS) was calculated using the Kaplan-Meier method, and the results were compared with 77 patients with Tis rectal cancer who received only radical resection. Factors associated with RFS were evaluated using Cox regression analysis.

Results

Sphincter-saving resection was performed for 146 patients (77.2%). Adjuvant chemotherapy was administered to 168 patients (88.9%). During the follow-up period, recurrence occurred in 17 patients (9%). The 5-year RFS was 91.3%, which was significantly lower than that of patients with Tis rectal cancer without PCRT (P = 0.005). In univariate analysis, preoperative CEA and histologic differentiation were associated with RFS. However, no factors were found to be associated with RFS.

Conclusion

RFS was lower in patients with total regression of primary rectal cancer after PCRT than in those with Tis rectal cancer without PCRT, and it would not be considered as the same entity with early rectal cancer or "disappeared tumor" status.

Magnetic resonance tumour regression grade and pathological correlates in patients with rectal cancer

BACKGROUND

Evidence to support the specific use of magnetic resonance tumour regression grade (mrTRG) is inadequate. The aim of this study was to investigate the pathological characteristics of mrTRG after chemoradiotherapy (CRT) for rectal cancer and the implications for surgery.

METHODS

Patients undergoing long-course CRT (45-50 Gy plus a booster dose of 4-6 Gy) for mid or low rectal cancer (cT3-4 or cN+ without metastasis) between 2011 and 2015 who had post-CRT rectal MRI before surgery were included retrospectively. Three board-certified experienced radiologists assessed mrTRG. mrTRG was correlated with pathological tumour regression grade (pTRG), ypT and ypN. In a subgroup of patients with mrTRG1-2 and no tumour spread (such as nodal metastasis) on MRI, the projected rate of completion total mesorectal excision (TME) if they underwent transanal excision (TAE) and had a ypT status of ypT2 or higher was estimated, and recurrence-free survival was calculated according to the operation (TME or TAE) that patients had actually received.

RESULTS

Some 439 patients (290 men and 149 women of mean(s.d.) age 62·2(11·4) years) were analysed. The accuracy of mrTRG1 for predicting pTRG1 was 61 per cent (40 of 66), and that for ypT1 or less was 74 per cent (49 of 66). For mrTRG2, these values were 22·3 per cent (25 of 112) and 36·6 per cent (41 of 112) respectively. Patients with mrTRG1 and mrTRG2 without tumour spread were ypN+ in 3 per cent (1 of 29) and 16 per cent (8 of 50) respectively. Assuming mrTRG1 or mrTRG1-2 with no tumour spread on post-CRT MRI as the criteria for TAE, the projected completion TME rate was 26 per cent (11 of 43) and 41·0 per cent (41 of 100) respectively. For the 100 patients with mrTRG1-2 and no tumour spread, recurrence-free survival did not differ significantly between TME (79 patients) and TAE (21) (adjusted hazard ratio 1·86, 95 per cent c.i. 0·42 to 8·18).

CONCLUSION

Patients with mrTRG1 without tumour spread may be suitable for TAE.

Local excision for ypT2 rectal cancer following preoperative chemoradiation therapy: it should not be justified

PURPOSE

Among individuals who respond well to preoperative chemoradiation therapy (CRT) for ypT0-1, local excision (LE) could provide acceptable oncological outcomes. However, in ypT2 cases, the oncological safety of LE has not been determined. This study aimed to compare oncological outcomes between LE and total mesorectal excision of ypT2-stage rectal cancer after chemoradiation therapy and investigate the oncological safety of LE in these patients.

METHODS

We included 351 patients who exhibited ypT2-stage rectal cancer after CRT followed by LE (n = 16 [5%]) or total mesorectal excision (TME) (n = 335 [95%]) after preoperative CRT between January 2007 and December 2013. After propensity matching, oncological outcomes between LE group and TME group were compared.

RESULTS

The median follow-up period was 57 months (range, 12-113 months). In the LE group, local recurrence occurred more frequently (18 vs. 4%; p = 0.034) but not distant metastases (12 vs. 11%; p = 0.690). The 5-year local recurrence-free (76 vs. 96%; p = 0.006), disease-free (64 vs. 84%; p = 0.075), and overall survival (79 vs. 93%; p = 0.045) rates of the LE group were significantly lower than those of the TME group. After propensity matching, 5-year local recurrence-free survival of the LE group was significantly lower than that of the TME group (76 vs. 97%, p = 0.029).

CONCLUSION

The high local failure rate and poor oncological outcomes for ypT2-stage rectal cancer patients who undergo CRT followed by LE cannot be justified as an indication for LE. Salvage surgery should be recommended in these patients.

Model predicting the ypN0 status after good response to chemoradiotherapy in rectal cancer

BACKGROUND

The purpose of this study was to identify the predictive factors for ypN0 status in tumors with good pathologic response to chemoradiotherapy (CRT).

METHODS

A retrospective chart review was conducted on patients at two tertiary cancer center who underwent rectal resection after good response to CRT between 2000 and 2013.

RESULTS

No preoperative treatment (oxaliplatin use, radiotherapy boost of 5,4 Gy, delay CRT-surgery) impacted on the ypN status. In the multivariate analysis, only a ypT<3 (HR 7.5 [2,9-19.5]) was significant and no lymphovascular invasion (HR 8,9 [1.6-49.8]) was limited to significance.The best model predicting the ypN0 status used only the ypT status<3. The major part (92.2%) of patients with ypT0-2 tumors had no LN invasion.

CONCLUSION

The risk of lymph node involvement metastases was only 7.8% for the patients with an ypT0-2 status. A fullthickness transanal resection coud be the futur treatment of these patients.

Long-term outcomes in patients with ypT0 rectal cancer after neoadjuvant chemoradiotherapy and curative resection

Objective

For patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy (NCRT), significant pathological response of the primary tumor has been proposed to identify candidates for organ preservation. However, this does not address metastatic lymph nodes in the mesorectum. The aim of this study was to assess the incidence of lymph node metastases in ypT0 patients treated with NCRT and curative resection and to explore risk factors associated with survival.

Methods

This was a retrospective study of patients with ypT0 rectal cancer after NCRT and curative resection at a tertiary care center in China from 2005 to 2014.

Results

A total of 60 (18.6%) patients who underwent surgery after NCRT and achieved ypT0 were enrolled in this study; one patient was excluded owing to lack of follow-up. Of these 59 patients, lymph node metastases were found in the mesorectum (ypT0N+) in eight (13.6%) patients. After a median follow-up of 52 months, 5-year recurrence-free survival (82.7% vs. 62.5%, P=0.014) and overall survival (OS) (90.9% vs. 70.0%, P=0.032) were much higher in ypN0 than ypN+ patients. Multivariate analyses showed that ypN+ status (P=0.009) and perioperative blood transfusion (BT) (P=0.001) were significantly independent risk factors associated with recurrence; however, no factor was correlated with 5-year OS.

Conclusions

Patients with ypT0N0 rectal cancer can achieve excellent long-term outcomes; however, positive lymph nodes or tumor deposits can still be found in 13.6% of ypT0 patients. Nodal positivity in the mesorectum and perioperative BT are independent risk factors for recurrence.

Outcomes of persistent lymph node involvement after neoadjuvant therapy for stage III rectal cancer

INTRODUCTION

Lymph node involvement is a well-known predictor of recurrent rectal cancer in patient who did not undergo neoadjuvant therapy patients. The role of persistent lymph node disease after neoadjuvant treatment, however, is debatable. This study compares outcomes of patients with clinical, stage III rectal cancer who had nodal disease on surgical pathology after neoadjuvant treatment to patients with negative nodes.

METHODS

We reviewed retrospectively a consecutive cohort of all clinical, American Joint Committee on Cancer stage III rectal cancer patients who received neoadjuvant chemoradiotherapy and had an R0 resection at the Massachusetts General Hospital between 2004 and 2015.

RESULTS

A total of 166 patients met the inclusion criteria, of whom 53 had persistent nodal disease on pathologic examination. This group had a greater rate of local and distant disease recurrence and a shorter median recurrent disease-free survival than patients with a complete nodal response. In multivariable analyses for disease recurrence, disease free survival was greater for patients without positive results in lymph nodes on pathologic examination.

CONCLUSION

Persistent nodal involvement after neoadjuvant therapy is associated with an increased risk of distant metastases and a shorter disease-free survival. Identifying patients with treatment-resistant lymph nodes preoperatively and adjusting neoadjuvant treatment might result in better outcomes.

Nodal Disease in Rectal Cancer Patients With Complete Tumor Response After Neoadjuvant Chemoradiation: Danger Below Calm Waters

BACKGROUND

A subset of patients with rectal cancer who undergo neoadjuvant chemoradiation therapy will develop a complete pathologic tumor response. Complete nodal response is not universal in these patients and is difficult to assess clinically. Quantifying the risk of nodal disease would allow for targeted therapy with either radical resection or "watchful waiting."

OBJECTIVE

This study aimed to identify risk factors for residual nodal disease in ypT0 rectal adenocarcinoma.

DESIGN

This is a retrospective case control study.

SETTINGS

The National Cancer Database 2006 to 2014 was used to identify patients for this study.

PATIENTS

Patients with stage II/III rectal adenocarcinoma who completed chemoradiation therapy followed by resection and who had ypT0 tumors were included. Patients with metastatic disease and <2 lymph nodes evaluated were excluded. Patients were divided into 2 groups: node positive and node negative.

MAIN OUTCOME MEASURES

The main outcome was nodal disease. The secondary outcome was overall survival.

RESULTS

A total of 42,257 patients with stage II/III rectal cancer underwent chemoradiation therapy and radical resection; 4170 (9.9%) patients had ypT0 tumors and 395 (9.5%) were node positive. Of patients with clinically node-negative disease (ie, pretreatment imaging), 6.2% were node positive after chemoradiation therapy and resection. In multivariable analysis, factors predictive of nodal disease included increasing (pretreatment) clinical N-stage, high tumor grade (3/4), perineural invasion, and lymphovascular invasion. Higher clinical T-stage was inversely associated with residual nodal disease. Overall 5-year survival was significantly different between patients with ypN0, ypN1, and ypN2 disease (87.4%, 82.2%, and 62.5%, p = 0.002).

LIMITATIONS

This study was limited by the lack of clinical detail in the database and the inability to assess recurrence.

CONCLUSIONS

Ten percent of patients with ypT0 tumors had positive nodes after chemoradiation therapy and resection. Factors associated with residual nodal disease included clinical nodal disease at diagnosis and poor histologic features. Patients with any of these features should consider radical resection regardless of tumor response. Others could be suitable for "watchful waiting" strategies. See Video Abstract at http://links.lww.com/DCR/A458.

Organ-Preserving Strategies for the Management of Near-Complete Responses in Rectal Cancer after Neoadjuvant Chemoradiation

In recent years, organ preservation has been considered a feasible alternative to total mesorectal excision for patients with locally advanced rectal cancer with a clinical complete response to neoadjuvant therapy. However, the degree of tumor response to neoadjuvant therapy is variable. A fraction of the patients who did not achieve a complete response had grossly visible tumors. These patients, with clearly incomplete clinical response, need a total mesorectal excision. In addition, some patients with a significant tumor response still have some abnormalities in the bowel wall, such as superficial ulceration or tissue nodularity, which, while not conclusive for the presence of a tumor, are indicative of the possibility of a residual tumor in the bowel wall or in mesorectal lymph nodes. The management of patients with a so-called near-complete clinical response to neoadjuvant therapy is controversial. In this article, we will review the clinical and radiological criteria that define a clinical response to neoadjuvant therapy, possible treatment strategies, and follow-up protocols. We will also discuss patient and tumor characteristics that in our opinion can be useful in selecting the most appropriate treatment alternative. Although organ preservation and quality of life are important, the primary goal of treatment for these patients should be local tumor control and long-term survival.

Local Excision and Endoscopic Resections for Early Rectal Cancer

Radical surgery is considered as the standard treatment for rectal cancer. Transanal local excision has been considered an interesting alternative for the management of selected patients with rectal cancers for many decades. Different approaches had been considered for local excision, from endoscopic submucosal dissection to resections using platforms, such as transanal endoscopic microsurgery or transanal minimally invasive surgery. Identifying the ideal candidate for this approach is crucial, as a local failure after local excision is associated with poor outcomes, even for an initial early rectal tumor. In this article, the diagnostic tools and criteria to select patients for local excision, the different modalities used, and the outcomes are discussed.

The effect of adjuvant chemotherapy on survival and recurrence after curative rectal cancer surgery in patients who are histologically node negative after neoadjuvant chemoradiotherapy

AIM

The aim of this study was to evaluate whether adjuvant chemotherapy will affect recurrence rate or disease-free and overall survival in patients with rectal adenocarcinoma who were staged with MRI node-positive disease (mrN+) preoperatively. These patients underwent neoadjuvant chemoradiotherapy with curative rectal cancer surgery and their pathological staging was negative for nodal disease (ypN0). There is no consensus on the role of adjuvant chemotherapy in such patients.

METHOD

Patients who received neoadjuvant chemoradiotherapy and underwent curative rectal cancer surgery for rectal adenocarcinoma staged as [mrTxN+M0] on MRI staging and who on pathological staging were found to be [ypTxN0M0] were retrospectively identified from January 2008 December 2012 from two tertiary referral centres (Royal Marsden Hospital, London and Saint-Andre Hospital, Bordeaux).

RESULTS

One hundred and sixty-three patients were recruited and, after propensity matching at a ratio of 2:1, n = 80 patients were divided to receive adjuvant (n = 28) or no adjuvant treatment (n = 52). A comparison of adjuvant chemotherapy vs no adjuvant therapy showed that the mean overall survival was 2.67 vs 3.60 years (P = 0.42) and disease-free survival was 2.27 vs 3.32 years (P = 0.14).

CONCLUSION

This study found no significant difference in survival or disease recurrence between patients who received adjuvant chemotherapy and patients who did not. There is no clear evidence to support or dismiss the use of adjuvant chemotherapy for patients who were node positive on preoperative MRI and node negative on histopathological staging. Further multicentre prospective randomized trials are needed to identify the appropriate treatment regime for this group of patients.

Prediction of N0 Irradiated Rectal Cancer Comparing MRI Before and After Preoperative Chemoradiotherapy

BACKGROUND

The prediction of lymph node status using MRI has an impact on the management of rectal cancer, both before and after preoperative chemoradiotherapy.

OBJECTIVE

The purpose of this study was to maximize the negative predictive value and sensitivity of mesorectal lymph node imaging after chemoradiotherapy because postchemoradiation node-negative patients may be treated with rectum-sparing approaches.

DESIGN

This was a retrospective study.

SETTINGS

The study was conducted at a tertiary care hospital.

PATIENTS

Sixty-four patients with locally advanced rectal cancer who underwent preoperative chemoradiotherapy and MRI for staging and the assessment of response were evaluated.

MAIN OUTCOME MEASURES

The sums of the sizes of all mesorectal lymph nodes in each patient on both prechemoradiotherapy and postchemoradiotherapy imaging data sets were calculated to determine the lymph node global size reduction rates, taking these to be the outcomes of the histopathologic findings. Other included measures were interobserver agreement regarding the prediction of node status based on morphologic criteria and the diagnostic performance of contrast-enhanced images.

RESULTS

Using a cutoff value of a 70% lymph node global size reduction rate with only 15 node-positive patients on histopathology, the sensitivity in the prediction of nodal status and negative predictive value were 93% (95% CI, 70.2%-98.8%) and 97% (95% CI, 82.9%-99.8%) for observer 1 and 100% (95% CI, 79.6%-100%) and 100% (95% CI, 62.9%-100%) for observer 2. The areas under the receiver operating characteristic curves for the 2 observers were 0.90 (95% CI, 0.82-0.98; p < 0.0001) for observer 1 and 0.65 (95% CI, 0.50-0.79; p = 0.08) for observer 2. The efficacy of the morphologic criteria and contrast-enhanced images in predicting node status was limited after chemoradiotherapy.

LIMITATIONS

This study is limited by its small sample size and retrospective nature.

CONCLUSIONS

Assessing the lymph node global size reduction rate value reduces the risk of undetected nodal metastases and may be helpful in better identifying suitable candidates for the local excision of early stage rectal cancer. See Video Abstract at http://links.lww.com/DCR/A412.

Oncologic Outcome of ypT1-2N0 Rectal Cancer After Neoadjuvant Chemoradiotherapy Compared With pT1-2N0 Rectal Cancer

OBJECTIVE

To investigate the oncologic outcome of ypT1-2N0 mid and lower rectal cancer after chemoradiotherapy (CRT) compared with pT1-2N0 rectal cancer.

METHODS

We compared the oncologic outcome of patients with mid and lower rectal cancer who underwent preoperative CRT and who did not, between February 2005 and August 2012.

RESULTS

Compared with patients who did not receive preoperative CRT, patients who received preoperative CRT did not have significantly different clinicopathologic features except clinical stage and distal resection margin. The 5-year disease-free survival (DFS) rates were lower in patients who received preoperative CRT than those who did not (84.4% vs. 95.5%, P=0.029). Preoperative CRT was a prognostic factor affecting 5-year DFS in patients with pathologically proven stage T1N0 mid and lower rectal cancer (HR, 11.157; 95% CI, 1.735-71.762; P=0.011) CONCLUSIONS:: ypT2N0 rectal cancer after neoadjuvant CRT showed shorter DFS compared with pT2N0 rectal cancer.

Long-term outcomes in ypT0 rectal cancers: An international multi-centric investigation on behalf of Italian Society of Surgical Oncology Young Board (YSICO)

AIM

To investigate the outcome and pattern of survivals of rectal cancer patients presenting a complete or nearly complete tumor response after neo-adjuvant treatment.

METHODS

Young surgeons <40 years old affiliated to the Italian Society of Surgical Oncology (YSICO) from 13 referral centers for colorectal cancer treatment, were invited to participate a retrospective study. Records from patients treated from 2005 to 2015 with a pathological diagnosis of ypT0/ypTis were retrieved and pooled in a common data-base for statistical purposes. All clinical and pathological variables were reviewed. Univariate and multivariate analyses were conducted with the end-point of survivals.

RESULTS

Two hundreds and sixty-one patients were analyzed including 237 ypT0 and 24 ypTis. Nodal positive patients were 8.7%. More than sixty-six percent of the patients did not perform adjuvant chemotherapy, with a statistical difference comparing N0 versus N+ patients (66.8% vs 40.9%, p 0.02). Mean follow-up was of 47.6 months. Twenty-two relapses were observed, 91.6% at a distant site. The mean time to recurrence was of 35.3 months. On univariate analysis, the use of adjuvant chemotherapy correlated with better OS exclusively in ypT0N + patients and not in ypT0N0. Univariate and multivariate analyses documented nodal positivity as the only prognostic factor correlated with a worse OS.

CONCLUSION

Recurrences were mostly diagnosed at a distant site and within the third year of follow-up. Nodal positivity was the only variable independently correlated with a worse OS. Univariate analysis documented a benefit for the use of adjuvant chemotherapy treatment exclusively in ypT0N + rectal cancers.

Outcome and Salvage Surgery Following "Watch and Wait" for Rectal Cancer after Neoadjuvant Therapy: A Systematic Review

BACKGROUND

Currently there is no reliable test to predict pathological complete response following neoadjuvant chemoradiotherapy for rectal cancer. However, there is increasing interest in using clinical complete response as a surrogate marker, allowing a subset of patients with locally advanced rectal cancer to be allocated into a "watch and wait" pathway. Little is known about the oncological safety of the "watch and wait" approach or the rate of salvage surgery in cases of tumor regrowth. This information is critical for the implementation of this approach.

OBJECTIVE

The aim of this study is to assess the rate of salvage surgery and associated oncological outcomes for patients who develop a tumor regrowth with the "watch and wait" approach.

DATA SOURCES

Relevant studies were identified through PubMed, Embase, and Google Scholar search.

STUDY SELECTION

A systematic review was undertaken of studies assessing patients selected for the "watch and wait" approach according to PRISMA guidelines.

MAIN OUTCOME MEASURES

The associated tumor regrowth, salvage surgery, and disease-free and overall survival rates were assessed.

RESULTS

Five retrospective and 4 prospective observational studies were included into the analysis, with a total of 370 patients in the "watch and wait" group, of which 256 (69.2%) had persistent clinical complete response. Of those who had tumor regrowth, salvage surgery was possible in 83.8%. There was no difference in overall survival and disease-free survival between patients who received immediate surgery and the "watch and wait" group.

LIMITATIONS

The limitations of this study include its retrospective nature and small sample size. Furthermore, there is significant heterogeneity between study protocols, including the short median follow-up, given that tumor regrowth and distant metastasis may manifest at a later time point.

CONCLUSION

The majority of patients with tumor regrowth can be salvaged with definite surgery after "watch and wait." However, there is insufficient evidence to draw firm conclusions on the oncological safety of this approach; therefore, it is currently not the standard of care for locally advanced rectal cancer.

Is the pathological regression level of metastatic lymph nodes associated with oncologic outcomes following preoperative chemoradiotherapy in rectal cancer?

PURPOSE

The oncologic impact of the lymph node (LN) regression level after preoperative chemoradiotherapy (PCRT) has not been thoroughly evaluated. Hence, this study aimed to examine whether the regression level of metastatic LNs following PCRT is associated with oncologic outcomes in rectal cancer.

RESULTS

The optimal number of cut points for LRG sum was determined to be three. The three LRG groups demonstrated different distributions according to the ypT and ypN stages (p < 0.001 for both). However, the distribution of the LRG groups was not associated with the TRG of the primary tumor (p = 0.527). The RFS significantly differed according to the LRG groups (p = 0.001). Moreover, the differences in RFS remained when the LRG groups were analyzed within each separate ypN stage. The LRG group was confirmed as a factor associated with RFS in the multivariate analysis (p=0.018), while the ypN stage was not (p=0.4).

PATIENTS AND METHODS

We analyzed the outcomes of 142 rectal cancer patients diagnosed with ypN1 disease after PCRT followed by radical resection. The pathological responses of the primary tumor and LNs to PCRT were evaluated using the tumor regression grade (TRG) and LN regression grade (LRG), respectively. The impact of LRG on recurrence-free survival (RFS) was analyzed. The K-adaptive partitioning for survival data method was applied to determine the optimal number of cut points for the LRG-sum and the optimal number of subgroups.

CONCLUSION

The LRG as an indicator of response to PCRT should be considered as a prognostic determinant in rectal cancer patients. Future large-scale prospective studies are needed to confirm this finding.

The impact of the radiation-induced regression of positive nodes on survival in patients with rectal cancer treated with chemoradiotherapy

BACKGROUND

Although preoperative chemoradiotherapy exerts a destructive effect on positive lymph nodes, microscopic examination reveals different degrees of tumor regression. The aim of the present study is to investigate the impact of the radiation-induced regression of positive nodes on survival in patients with rectal cancer treated with preoperative chemoradiotherapy.

METHODS

From 2001 to 2015, 229 patients with T3 rectal cancer underwent total mesorectal excision after preoperative chemoradiotherapy. The patients were classified into 3 groups according to their lymph node status: residual cancer cells in positive nodes (Group A), total regression of positive nodes after preoperative chemoradiotherapy with complete fibrosis (Group B), and the entire lymph node filled with lymph nodules and the absence of fibrosis (Group C). The survival of the 3 groups was compared, and a Cox model was used to evaluate the prognostic value of the regression of the positive nodes by preoperative chemoradiotherapy.

RESULTS

Groups A, B, and C included 57, 18, and 154 patients, respectively. Group B showed significantly better overall survival than Group A (P = .041) and similar outcomes to Group C (P = .383). Among the patients with positive lymph nodes prior to treatment (Groups A and B), the total regression of the positive nodes after preoperative chemoradiotherapy was the only independent factor to be associated with good overall survival (hazard ratio; 6.26, 95% confidence interval; 1.28-113.0, P = .020).

CONCLUSION

Total regression of positive nodes by preoperative chemoradiotherapy improves the prognosis of patients with rectal cancer with positive lymph nodes prior to treatment.

DWI for Assessment of Rectal Cancer Nodes After Chemoradiotherapy: Is the Absence of Nodes at DWI Proof of a Negative Nodal Status?

OBJECTIVE

When considering organ preservation in patients with rectal cancer with good tumor response, assessment of a node-negative status after chemoradiation therapy (CRT) is important. DWI is a very sensitive technique to detect nodes. The study aim was to test the hypothesis that the absence of nodes at DWI after CRT is concordant with a ypN0 status.

MATERIALS AND METHODS

A retrospective study was performed of 90 patients with rectal cancer treated with CRT followed by restaging MRI at 1.5 T, including DWI (highest b value, 1000 s/mm²). Two independent readers counted the number of nodes visible in the mesorectal compartment on DW images obtained after CRT. The number of nodes on DWI (0 vs ≥ 1) was compared with the number of metastatic nodes at histopathology or long-term clinical follow-up (yN0 vs yN-positive status).

RESULTS

Seventy-one patients had a yN0 status, and 19 had a yN-positive status. For 10 patients, no nodes were observed at DWI, which was concordant with a yN0 status in 100% of cases. In the other 61 patients with a yN0 status, the median number of nodes detected at DWI was three (range, 1-17 nodes). To differentiate between yN0 and yN-positive status, sensitivity was 100%, specificity was 14%, the positive predictive value was 24%, and the negative predictive value was 100%.

CONCLUSION

Although the absence of nodes at DWI is not a frequent finding, it appears to be a reliable predictor of yN0 status after CRT in patients with rectal cancer. DWI may thus be a helpful adjunct in assessing response after CRT and may help select patients for organ-saving treatment.

A scoring system basing pathological parameters to predict regional lymph node metastasis after preoperative chemoradiotherapy for locally advanced rectal cancer: implication for local excision

Local excision is an alternative to radical surgery that is indicated in patients with locally advanced rectal cancer (LARC) who have a good response to chemoradiotherapy (CRT). Regional lymph node status is a major uncertainty during local excision of LARC following CRT. We retrospectively reviewed clinicopathologic variables for 244 patients with LARC who were treated at our institute between December 2000 and December 2013 in order to identify independent predictors of regional lymph node metastasis. Multivariate analysis of the training sample demonstrated that histopathologic type, tumor size, and the presence of lymphovascular invasion were significant predictors of regional nodal metastasis. These variables were then incorporated into a scoring system in which the total scores were calculated based on the points assigned for each parameter. The area under the curve in the receiver operating characteristic analysis was 0.750, and the cutoff value for the total score to predict regional nodal metastasis was 7.5. The sensitivity of our system was 73.2% and the specificity was 69.4%. The sensitivity was 77.8% and the specificity was 51.2% when the scoring system was applied to the testing sample. Using this system, we could accurately predict regional nodal metastases in LARC patients following CRT, which may be useful for stratifying patients in clinical trials and selecting potential candidates for organ-sparing surgery following CRT for LARC.

High nodal positivity rates even in good clinical responders after chemoradiation of rectal cancer: is organ preservation feasible?

AIM

Local excision (LE) is emerging as a treatment option for rectal cancer responding well to chemoradiation. However, it does not address the mesorectal nodal burden. We aimed to identify the factors influencing nodal positivity and subsequently defined a low-risk group by including only patients at low risk.

METHOD

A single-centre, retrospective database analysis was carried out of patients with radically resected rectal cancer after neoadjuvant chemoradiation.

RESULTS

This study included 524 patients with predominantly low rectal tumours. Nodal positivity among ypT0, T1 and T2 groups was 14.7%, 28% and 30%, respectively. Multivariate analysis with stepwise logistic regression identified the following low-risk features: age ≥ 40 years, nonsignet ring cell carcinoma (SRCC) histology and pathological complete response (pCR). Sixty-nine patients fulfilling all three criteria were analysed and the nodal positivity was found to be 10.1%, which implies that, if these patients had been selected for LE, one in 10 would have had positive mesorectal nodes.

CONCLUSION

Even in patients with low-risk criteria (pCR, non-SRCC histology and age ≥ 40 years), the residual positive nodal disease burden is 10%. Whether this high incidence of residual nodal disease translates into a similar risk of locoregional recurrence if an organ-preservation strategy is adopted is unclear.

Long-Term Outcome of Rectal Cancer With Clinically (EUS/MRI) Metastatic Mesorectal Lymph Nodes Treated by Neoadjuvant Chemoradiation: Role of Organ Preservation Strategies in Relation to Pathologic Response

BACKGROUND

Organ preservation strategies are under investigation for patients with locally advanced rectal cancer (LARC) who achieve a complete pathologic response in the primary tumor (ypT0) after neoadjuvant chemoradiation therapy (CRT). This study explored the value of this approach for cN+ patients.

METHODS

Data were retrieved from our institutional prospective rectal cancer database. Tumors with mesorectal lymph nodes larger than 5 mm shown on endorectal ultrasonography, pelvic magnetic resonance imaging, or both were staged as cN+.

RESULTS

The study population comprised 226 patients (142 men and 84 women; median age, 64 years) with LARC who underwent CRT followed by surgery including total mesorectal excision (TME) (n = 179) and full-thickness local excision (LE) (n = 47) between 1996 and 2013. At staging, 123 patients (54.4 %) were cN+. In 65 cases (28.7 %), ypCR was observed. Metastatic mesorectal lymph nodes (ypN+) were detected in 41.6 % of the cN+ patients and in 2.8 % of the cN0 patients (P < 0.01). Among the cN+ patients, 16 % of the ypT0 cases were ypN+ compared with 51.8 % of the no-ypT0 cases (P < 0.01). Among the cN+ patients who underwent TME, the 5-year disease-specific survival (DSS) and disease-free survival (DFS) rates were respectively 100 and 91.6 % for the ypT0 patients compared with 71.2 and 58.0 % for the no-ypT0 patients (P = 0.01). Among the ypN+ patients, the 5-year DSS and DFS rates were both 100 % for the ypT0 cases compared with 59.1 and 43.3 % for the no-ypT0 patients. Among the cN+ and ypT0 patients, the 5-year DSS and DFS were respectively 100 and 85.7 % for the TME patients compared with 100 and 91.6 % for the LE patients. In the multivariate analysis, ypT0 was the only independent prognostic factor.

CONCLUSIONS

Protocols aimed at organ preservation in LARC that achieve ypT0 after CRT can be offered also to cN+ patients.

Good and complete responding locally advanced rectal tumors after chemoradiotherapy: where are the residual positive nodes located on restaging MRI?

PURPOSE

Aim of this study was to evaluate the distribution of persistent mesorectal lymph node metastases on restaging MRI in patients with a good or complete response of their primary tumor (ypT0-2) after CRT for locally advanced rectal cancer.

METHODS

Two hundred and twenty eight locally advanced rectal cancer patients underwent CRT, which resulted in a good response (downstaging to yT0-2) in 144 patients. Forty-nine patients were excluded (no surgery/insufficient follow-up or lacking lesion-by-lesion histology results). This resulted in a final study group of 95 yT0-2 patients. For the patients with a yN(+)-status, a detailed lesion-by-lesion comparison between restaging MRI and histology was performed to evaluate the characteristics and distribution of the individual N(+)-nodes.

RESULTS

7/95 patients (7%) had a yT0-2N(+) status (11/880 (1%) N(+) nodes): no N(+) were found below the tumor level, 55% of the N(+) nodes were located at the level of the tumor, and 45% proximal to the tumor (at a median distance of 1.4 cm above the tumor level). In axial plane, 82% of the nodes were located at the ipsilateral circumference of the tumor, at a median distance of 0.9 cm from the tumor/rectal wall.

CONCLUSIONS

The incidence of persistent metastatic mesorectal nodes after CRT in patients with a good tumor response after CRT is very low. No N(+) nodes are found below the tumor level. All N(+) nodes are located at the level of or proximal to the primary tumor, of which the majority very close to the tumor/lumen.

Stage-Dependent Frequency of Lymph Node Metastases in Patients With Rectal Carcinoma After Preoperative Chemoradiation: Results from the CAO/ARO/AIO-94 Trial and From a Comparative Prospective Evaluation With Extensive Pathological Workup

BACKGROUND

For patients with ycT1/2 rectal carcinomas after neoadjuvant chemoradiotherapy, local excision instead of radical surgery has increasingly been discussed as a way to avoid postoperative morbidity associated with radical surgery.

OBJECTIVE

The purpose of this study was to determine the incidence of lymph node metastases in total mesorectal excision specimens with ypT0, ypT1/2, and ypT3/4 rectal cancers.

DESIGN

This is a prospective and retrospective cohort study.

SETTINGS

This study was conducted in tertiary referral hospitals that are part of the German Rectal Cancer Study Group.

PATIENTS

A total of 479 patients with stage II and III rectal cancers treated within phase III trials of the German Rectal Cancer Study Group were evaluated. Specimens from 81 patients treated in the Working Group of Surgical Oncology/Working Group of Radiation Oncology/Working Group of Medical Oncology of the Germany Cancer Society (CAO/ARO/AIO-04) trial were prospectively studied with extensive microscopic screening of the entire mesorectum. The frequency and localization of nodal metastases were specified and compared with those of 398 patients having received neoadjuvant chemoradiation within the CAO/ARO/AIO-94 trial.

MAIN OUTCOME MEASURES

Frequency and localization of mesorectal lymph node metastases in patients with ypT0, ypT1/2, or ypT3/4 cancer were measured.

RESULTS

A mean number of 28.0 ± 13.7 nodes were detected per specimen within the prospective group. A total of 25% of patients in the ypT1/2 group had nodal metastases compared with 40% in the ypT3/4 group. Patients with node-positive ypT1/2 had a mean number of 2.2 metastases, and 55% of these metastases were located far from the primary lesion in the proximal mesorectum. Within the CAO/ARO/AIO-94 cohort (n = 398), 19% of patients with ypT1/2 (ypT1 = 22%; ypT2 = 18%) had ypN+ status compared with 43% with ypT3/4 cancers (ypT3 = 40%; ypT4 = 73%).

LIMITATIONS

Low numbers of patients with ypT0 limited the evaluation of nodal metastases in pathologic complete responders.

CONCLUSIONS

Even in good responders (ypT1/2), >20% of rectal carcinomas still harbored residual lymph node metastases. Local excision for patients with ycT1/2 rectal cancers would, thus, miss metastases in a considerable percentage and might involve the risk of significant undertreatment in a number of patients.

[Lymph node metastases in ypT1/2 rectal cancer after neoadjuvant chemoradiotherapy : The Achilles heel of organ-preserving operative procedures?]

BACKGROUND

For patients with rectal cancer and complete remission (ypT0) or with good response and residual tumor restricted only to the bowel wall (ypT1-2) after neoadjuvant chemoradiotherapy (CRT), local excision has been suggested as an alternative to avoid the significant morbidity and functional deficits associated with total mesorectal excision (TME). The aim of this investigation was to investigate the incidence, distribution and tumor-related localization of mesorectal lymph node (LN) metastases in TME specimens with complete remission (ypT0), intramural (ypT1-2) and extramural (ypT3-4) residual tumor tissue.

PATIENTS AND METHODS

Specimens of TME from 81 patients with locally advanced rectal cancer (UICC II-III) undergoing neoadjuvant CRT within the phase III German rectal cancer trial CAO/ARO/AIO-04 were prospectively evaluated. The entire mesorectal compartment was microscopically screened after complete paraffin embedding. The number and localization of all detectable LN metastases were documented in relation to the primary tumor.

RESULTS

Whereas 50 patients (62 %) had ypT3-4 rectal cancer after neoadjuvant CRT, 20 patients (25 %) presented with residual tumor within the bowel wall (ypT1-2), 11 patients (14 %) had pathological complete remission (ypT0), an average of 28 ± 13.7 LN were detected per specimen and 25 patients (31 %) had residual LN metastases after CRT. Although the incidence of LN metastases was higher in the ypT3-4 group (40 %), 25 % of patients in the ypT1-2 group with intramural residual tumor had a mean number of 2.2 residual LN metastases of which 55 % were located far from the primary lesion in the proximal mesorectum. None of the patients with ypT0 status (complete response) had residual LN metastases.

CONCLUSION

Even in patients with good response and post-CRT tumor tissue restricted only to the bowel wall (ypT1-2), there is still a considerable risk for residual LN metastases. Local excision of residual rectal cancer was accompanied by a higher rate of local failure and radical surgery with TME should remain the standard treatment in these patients. To date, valid selection criteria for patients eligible for organ-sparing surgery are still lacking.

Local excision of low rectal cancer treated by chemoradiotherapy: is it safe for all patients with suspicion of complete tumor response?

PURPOSE

The purpose of this study is to assess if local excision (LE) could be proposed if suspicion of complete tumor response (CR) after neoadjuvant chemoradiotherapy (CRT) for low rectal cancer (LRC) and this despite a potential risk of nodes (N+) or other tumor deposits (OTD) left in place. The aim was to assess in patients with LRC treated by CRT: (a) pathologic results of LE and total mesorectal excision (TME) in case of preoperative suspicion of CR and (b) the risk of N+ or OTD on TME if ypT0-Tis-T1 tumor.

PATIENTS

Among 202 patients with LRC after CRT, 33 (16 %) with suspicion of CR underwent LE (n = 20) because of comorbidities and/or indication of definitive stoma or TME (n = 13). Pathologic examination of LE and TME specimens and oncological outcomes were assessed. Furthermore, 40/202 patients with pathologic CR on TME specimen (ypT0-Tis-T1) were assessed for possible N+ or OTD.

RESULTS

In the 33 patients with suspicion of CR: (a) after LE, tumor was ypT0-Tis-T1 in only 15/20 cases (75 %); (b) after TME, tumor was ypT0-Tis-T1 in only 7/13 cases (54 %). Among 40 patients with ypT0-Tis-T1 tumor on TME specimen, 4 (10 %) presented N+ and/or OTD.

CONCLUSION

In LRC with suspicion of CR after CRT, LE deserves a word of caution: 25 % of patients have in fact ypT2-T3 tumors. Furthermore, in patients with ypT0-Tis or T1 on TME specimen, a 10 % risk of N+ and/or ODT is observed. Thus, patient with suspicion of CR after CRT and treated by LE is exposed to a possible incomplete oncologic treatment.

Locally advanced rectal cancer: Preliminary results of rectal preservation after neoadjuvant chemoradiotherapy

INTRODUCTION

The standard treatment for locally advanced rectal cancer is total mesorectal excision. However, organ preservation has been proposed for tumors with good response to neoadjuvant treatment. The aim of this study was to evaluate the oncologic results of this strategy.

METHODS

This is a retrospective cohort study (2005-2014) including a consecutive series of patients with rectal adenocarcinoma with complete or almost complete clinical response after preoperative chemo-radiotherapy, that were treated according to a strategy of preservation of the rectum.

RESULTS

A total of 204 patients with rectal cancer received neoadjuvant therapy. Thirty (14.7%) had a good response and were treated with rectal preservation (23 «Watch and Wait» and 7 local resections). Median follow-up was 46 months (interquartile range: 30-68). In the group of «Watch & Wait», 4 patients had local recurrence before 12 months (actuarial local recurrence rate=18.5%). All of them underwent salvage surgery (2 with radical surgery and 2 local resections) without any further recurrence. Disease-free survival actuarial rate at 3 years follow-up was 94.1% (95% CI 82.9-100). None of the 7 patients that were treated by local excision had local recurrence. The organ preservation rate for the whole group was 93%.

CONCLUSION

The strategy of organ preservation in locally advanced rectal cancer is feasible in cases with good response to neoadjuvant therapy. When implemented in a highly selected group of patients this strategy is associated with satisfactory oncologic results.

Implications for selecting local excision in locally advanced rectal cancer after preoperative chemoradiation

Local excision may offer the possibility of organ preservation for the management of locally advanced rectal cancer after neoadjuvant chemoradiotherapy (CRT). However, the oncological outcomes of this strategy have been largely associated with the risk of nodal metastases. In this study, Surveillance, Epidemiology, and End Results Program (SEER)-registered rectal cancer patients, and patients from Fudan University Shanghai Cancer Center (FUSCC) after preoperative chemoradiation were combined to analyze the incidence of lymph node metastasis. The results showed that there was a high risk for residual lymph node metastasis among patients even with complete pathologic response of primary tumor after preoperative CRT (12.6–13.2%). However, in the selected group of patients with pre-CRT MRI staging cN0 rectal cancer, there was only one ypN+ case (3.3%) in ypT0–1 group. These results suggest that pre-CRT MRI staging cN0 patients achieved ypT0–1 of bowel wall tumor may be suitable for local resection.

Definitive Chemoradiotherapy ("Watch-and-Wait" Approach)

Preoperative chemoradiotherapy (CRT) followed by total mesorectal excision has been the standard of care for locally advanced patients with rectal cancer. Some patients achieve a pathologic complete response (pCR) to CRT and the oncologic outcomes are particularly favorable in this group. The role of surgery in patients with a pCR is now being questioned as radical rectal resection is associated with significant morbidity and long-term effects on quality of life. In an attempt to better tailor therapy, there is an interest in a "watch-and-wait" approach in patients who have a clinical complete response (cCR) after CRT with the goal of omitting surgery and allowing for organ preservation. However, a cCR does not always indicate a pCR, and improved clinical and imaging modalities are needed to better predict which patients have achieved a pCR and therefore can safely undergo a "watch-and-wait" approach. This article reviews the current data on nonoperative management and on-going controversies associated with this approach.