Update on advances and controversy in rectal cancer treatment

Changes in the multidisciplinary treatment of rectal cancer have been recently proposed. We performed a comprehensive review of the current data on neoadjuvant and adjuvant treatment of rectal cancer, focussing on chemoradiotherapy treatment and timing of surgery. Six components were proposed as the framework for the treatment of rectal cancer: neoadjuvant therapy and changing patterns in patient selection, long- or short-course radiotherapy, adverse effects of radiotherapy, timing of surgery, non-operative management of rectal cancer and postoperative adjuvant therapy. Lack of a consistent difference in terms of local recurrence has been observed between short-course radiotherapy and long-course chemoradiotherapy. Indications for preoperative radiotherapy have been reconsidered in the last years. An interval of 10-11 weeks seemed to be the optimal timing, with no impact on patient safety. Since assessment criteria of clinical complete response are not well defined, and the basis for non-operative management of rectal cancer is still not clear, further investigations are required. There is controversy about standard treatments for patients with locally advanced rectal cancer that are being analyzed by ongoing studies. Tailored treatments could avoid over-treatment for a large number of patients without any impairment of the oncologic results.

The multidisciplinary approach to the treatment of rectal cancer: 2015 update

The multidisciplinary approach to the management of rectal cancer continues to evolve with developments in surgery, radiation therapy as well as systemic chemotherapy. Refinement of surgical techniques to improve organ preservation, selective use of neoadjuvant (or adjuvant) therapies, improvements in staging modalities and emerging criteria for the selection of tailored therapies are some of the advancements made over the last three decades. In addition, neoadjuvant treatment alternatives, multimodality sequencing and adaptive therapies based on treatment response continue to be a subject of clinical investigation. The current article reviews the salient topics related to the multidisciplinary treatment of resectable rectal cancer.

A population-based cohort study on adherence to practice guidelines for adjuvant chemotherapy in colorectal cancer

BACKGROUND

The value of adjuvant chemotherapy in colorectal cancer is well studied, and guidelines have been established. Little is known about how treatment guidelines are implemented in the everyday clinical setting.

METHODS

This national population-based study on nearly 34,000 patients with colorectal cancer evaluates the adherence to present clinical guidelines for adjuvant chemotherapy. Virtually all patients with colorectal cancer in Sweden during the years 2007-2012 and data from the Swedish Colorectal Cancer Registry were included.

RESULTS

In colon cancer stage III, adherence to national guidelines was associated with lower age, presence of multidisciplinary team (MDT) conference, low co-morbidity, and worse N stage. The MDT forum also affected whether or not high-risk stage II colon cancer patients were considered for adjuvant chemotherapy. Rectal cancer patients both in stage II and III were considered for adjuvant chemotherapy less often than colon cancer patients, but the same factors influenced the decision. Adjuvant chemotherapy was started later than eight weeks after surgery in 30% of colon cancer patients and in 38% of rectal cancer patients.

CONCLUSIONS

In Sweden, the adherence to national guidelines for adjuvant chemotherapy in colon cancer stage III is acceptable in younger and healthier patients. MDT conferences are of major importance and affect whether patients are recommended for adjuvant chemotherapy. Special consideration needs to be given to certain subgroups of patients, particularly older patients and patients with poorly differentiated tumors. There is a need to shorten the waiting time until start of chemotherapy.

Validation of the 12-gene colon cancer recurrence score as a predictor of recurrence risk in stage II and III rectal cancer patients

BACKGROUND

The 12-gene Recurrence Score assay is a validated predictor of recurrence risk in stage II and III colon cancer patients. We conducted a prospectively designed study to validate this assay for prediction of recurrence risk in stage II and III rectal cancer patients from the Dutch Total Mesorectal Excision (TME) trial.

METHODS

RNA was extracted from fixed paraffin-embedded primary rectal tumor tissue from stage II and III patients randomized to TME surgery alone, without (neo)adjuvant treatment. Recurrence Score was assessed by quantitative real time-polymerase chain reaction using previously validated colon cancer genes and algorithm. Data were analysed by Cox proportional hazards regression, adjusting for stage and resection margin status. All statistical tests were two-sided.

RESULTS

Recurrence Score predicted risk of recurrence (hazard ratio [HR] = 1.57, 95% confidence interval [CI] = 1.11 to 2.21, P = .01), risk of distant recurrence (HR = 1.50, 95% CI = 1.04 to 2.17, P = .03), and rectal cancer-specific survival (HR = 1.64, 95% CI = 1.15 to 2.34, P = .007). The effect of Recurrence Score was most prominent in stage II patients and attenuated with more advanced stage (P(interaction) ≤ .007 for each endpoint). In stage II, five-year cumulative incidence of recurrence ranged from 11.1% in the predefined low Recurrence Score group (48.5% of patients) to 43.3% in the high Recurrence Score group (23.1% of patients).

CONCLUSION

The 12-gene Recurrence Score is a predictor of recurrence risk and cancer-specific survival in rectal cancer patients treated with surgery alone, suggesting a similar underlying biology in colon and rectal cancers.

Neoadjuvant therapy before surgical treatment

Neoadjuvant treatment in terms of preoperative radiotherapy reduces local recurrence in rectal cancer, but this improvement has little if any impact on overall survival. Currently performed optimal quality-controlled total mesorectal excision (TME) surgery for patients in the trial setting can be associated with very low local recurrence rates of less than 10% whether the patients receive radiotherapy or not. Hence metastatic disease is now the predominant issue. The concept of neoadjuvant chemotherapy (NACT) is a potentially attractive additional or alternative strategy to radiotherapy to deal with metastases. However, randomised phase III trials, evaluating the addition of oxaliplatin at low doses plus preoperative fluoropyrimidine-based chemoradiotherapy (CRT), have in the main failed to show a significant improvement on early pathological response, with the exception of the German CAO/ARO/AIO-04 study. The integration of biologically targeted agents into preoperative CRT has also not fulfilled expectations. The addition of cetuximab appears to achieve relatively low rates of pathological complete responses, and the addition of bevacizumab has raised concerns for excess surgical morbidity. As an alternative to concurrent chemoradiation (which delivers only 5-6 weeks of chemotherapy), potential options include an induction component of 6-12 weeks of NACT prior to radiotherapy or chemoradiation, or the addition of chemotherapy after short-course preoperative radiotherapy (SCPRT) or chemoradiation (defined as consolidation chemotherapy) which utilises the "dead space" of the interval between the end of chemoradiation and surgery, or delivering chemotherapy alone without any radiotherapy.

Short-course radiotherapy followed by neo-adjuvant chemotherapy in locally advanced rectal cancer--the RAPIDO trial

BACKGROUND

Current standard for most of the locally advanced rectal cancers is preoperative chemoradiotherapy, and, variably per institution, postoperative adjuvant chemotherapy. Short-course preoperative radiation with delayed surgery has been shown to induce tumour down-staging in both randomized and observational studies. The concept of neo-adjuvant chemotherapy has been proven successful in gastric cancer, hepatic metastases from colorectal cancer and is currently tested in primary colon cancer.

METHODS AND DESIGN

Patients with rectal cancer with high risk features for local or systemic failure on magnetic resonance imaging are randomized to either a standard arm or an experimental arm. The standard arm consists of chemoradiation (1.8 Gy x 25 or 2 Gy x 25 with capecitabine) preoperatively, followed by selective postoperative adjuvant chemotherapy. Postoperative chemotherapy is optional and may be omitted by participating institutions. The experimental arm includes short-course radiotherapy (5 Gy x 5) followed by full-dose chemotherapy (capecitabine and oxaliplatin) in 6 cycles before surgery. In the experimental arm, no postoperative chemotherapy is prescribed. Surgery is performed according to TME principles in both study arms. The hypothesis is that short-course radiotherapy with neo-adjuvant chemotherapy increases disease-free and overall survival without compromising local control. Primary end-point is disease-free survival at 3 years. Secondary endpoints include overall survival, local control, toxicity profile, and treatment completion rate, rate of pathological complete response and microscopically radical resection, and quality of life.

DISCUSSION

Following the advances in rectal cancer management, increased focus on survival rather than only on local control is now justified. In an experimental arm, short-course radiotherapy is combined with full-dose chemotherapy preoperatively, an alternative that offers advantages compared to concomitant chemoradiotherapy with or without postoperative chemotherapy. In a multi-centre setting this regimen is compared to current standard with the aim of improving survival for patients with locally advanced rectal cancer.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01558921.

Systemic inflammatory response is a predictor of outcome in patients undergoing preoperative chemoradiation for locally advanced rectal cancer

AIM

Current management of locally advanced rectal cancer includes neoadjuvant chemoradiation in selected patients to increase the chance of a tumour-free circumferential resection margin. There is uncertainty over the role of and selection criteria for additional systemic therapy in this group of patients. In this retrospective study we investigate the association between markers of systemic inflammatory response (SIR) and outcome from treatment.

METHOD

One hundred and fifteen patients with locally advanced rectal cancer undergoing preoperative chemoradiation had recording of full blood count parameters including neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratios (PLR). Postoperative surgical margins (R status) and pathological stage were documented. Outcome measures were overall survival (OS), time to local recurrence (TTLR) and disease-free survival (DFS). Cox regression analysis was performed to identify predictors of outcome.

RESULTS

Only NLR and R status were significant predictors for all outcome measures on univariate and multivariate analysis. Elevated NLR (≥5) was associated with decreased OS, [hazard ratio (HR) and 95% CI, 7.0 (2.6-19.2)], decreased TTLR [HR 3.8 (1.3-11.2)] and shorter DFS [HR 4.1 (1.7-9.8)]. Median survival for patients with an elevated NLR was 18.8 months compared with 54.4 months without an elevated NLR (P<0.001).

CONCLUSION

In addition to postoperative R-status, an elevated NLR is also a valuable prognostic marker in patients undergoing chemoradiation for locally advanced rectal carcinoma. It is associated with worse OS, TTLR and DFS. An elevated NLR may be a useful additional tool in guiding the decision-making process for adjuvant or neoadjuvant therapies.

Patients with rectal cancer receiving adjuvant chemotherapy have an increased survival: a population-based longitudinal study

BACKGROUND

The aim of this study was to investigate whether or not the use of adjuvant chemotherapy in stage III rectal cancer varies between regions and over time, and if this has had an effect on survival rates.

PATIENTS AND METHODS

Patients from the Uppsala/Örebro region below 75 years-of-age, operated 1995-2002 and registered in the Swedish Rectal Cancer Register, were monitored between 1995 and September 2008. A multivariate Cox proportional hazard regression model was used for analysis. Overall survival was described using the Kaplan-Meier method.

RESULTS

Four hundred and thirty-six patients with stage III rectal cancer were included. Adjuvant chemotherapy was given to 42% of the patients (proportions varying from 13% to 77% among counties), and there were substantial increases over time. The 5-year overall survival was 65.8% [95% confidence interval (CI) 50-84] for patients having adjuvant chemotherapy compared with 45.6% (95% CI 39-52) for patients not treated with chemotherapy. The multivariate hazard ratio for death was 0.65 (95% CI 0.5-0.8) for patients treated with adjuvant chemotherapy.

CONCLUSIONS

The use of adjuvant chemotherapy for rectal cancer has increased, but varies considerably between hospitals/counties. In this cohort, those having adjuvant chemotherapy had a longer overall survival.

Neoadjuvant chemotherapy in MRI-staged high-risk rectal cancer in addition to or as an alternative to preoperative chemoradiation?

BACKGROUND

For patients with resectable rectal cancer chemoradiation (CRT) or short-course preoperative radiotherapy (SCPRT) reduces locoregional failure, without extending disease-free survival (DFS) or overall survival (OS). Compliance to postoperative adjuvant chemotherapy is poor. Neoadjuvant chemotherapy (NACT) offers an alternative strategy.

METHODS

A systematic computerised database search identified studies exploring NACT alone or NACT preceding/succeeding radiation. The primary outcome measure was pathological complete response (pCR). Secondary outcome measures included acute toxicity, surgical morbidity, circumferential resection margin, locoregional failure, DFS and OS.

RESULTS

Four case reports, 12 phase I/II studies, 4 randomised phase II and one randomised phase III study evaluated chemotherapy before CRT. Four prospective studies reviewed chemotherapy after CRT. Three phase II studies investigated chemotherapy using FOLFOX plus bevacizumab without radiotherapy. In 24 studies of 1271 patients, pCR varied from 7% to 36%, but with no impact on metastatic disease.

CONCLUSIONS

NACT before CRT delivers does not compromise CRT but has not increased pCR rates, R0 resection rate, improved DFS or reduced metastases. NACT following CRT is an interesting strategy, and the utility of NACT alone could be explored compared with SCPRT or CRT in selected patients with rectal cancer where the impact of radiotherapy on DFS and OS is marginal.

Gender-specific acute organ toxicity during intensified preoperative radiochemotherapy for rectal cancer

Patients with locally advanced rectal cancer (cUICC stages II/III) are typically treated with preoperative 5-fluorouracil-based (5-FU-based) radiochemotherapy (RCT). However, trials are currently being conducted to improve the complete remission rates and the systemic control by combining 5-FU with oxaliplatin. The primary objective was to identify the subgroups of rectal cancer patients who were at risk for high-grade toxicity. All 196 patients who were included in the present study were treated with 50.4 Gy and chemotherapy that included either 5-FU (n = 115) or 5-FU+oxaliplatin (n = 81). The preoperative RCT was followed by a total mesorectal excision and adjuvant chemotherapy. Acute toxicity was monitored weekly and a toxicity grade ≥3 (Common Toxicity Criteria) for a skin reaction, cystitis, proctitis, or enteritis was defined as high-grade acute organ toxicity. After RCT with 5-FU+oxaliplatin, complete tumor remission was achieved in 13.6% of the patients and in 11.3% after RCT with 5-FU alone. Complete irradiation dosages of 50.4 Gy were given to 99% (5-FU) and 95% (5-FU+oxaliplatin) of the patients. Concomitant chemotherapy was fully administered in 95% of the patients treated with 5-FU compared with the 84% of patients treated with 5-FU+oxaliplatin. A significantly higher proportion of acute organ toxicity was found in the patients who were treated with 5-FU+oxaliplatin compared with those who were treated with 5-FU. Additionally, women with a low body mass index were at the highest risk for acute organ toxicity. These results suggest that there are basic clinical parameters, such as gender and body mass index, that may be potential markers for generating individual risk profiles of RCT-induced toxicity.