Long‐term outcomes of real world ‘watch and wait’ data for rectal cancer after neoadjuvant chemoradiotherapy

Abstract

Aim A 'watch and wait' (W&W) strategy after neoadjuvant long-course chemoradiotherapy (NACRT) remains controversial. Whilst encouraging short-term data exist, the strategy will be judged on long-term data. We present long-term, real-world UK data from a single National Health Service trust. Methods An analysis was performed of a prospectively maintained W&W database over 9 years between 2010 and 2018. Outcome measures include incidence and time to regrowth and overall and disease-free survival. Results We diagnosed 563 rectal cancers in 9 years. In all, 283 patients underwent rectal resection (50.3%). NACRT was used in 155 patients for margin-threatened tumours on staging MRI. Forty-nine patients (31.6%) experienced either a 'near complete' or a complete clinical response (cCR) at their 10 weeks post-NACRT assessment (MRI and endoscopy). The median age was 69 years (range 44-83), and the male to female ratio was 32:17. The median follow-up was 38 months (range 12-96). The median tumour distance from the anal verge was 7 cm (1-15 cm). Twenty-two patients had a cCR on initial assessment and 27 patients had a 'near' cCR. Of those 27 who experienced a 'near' cCR, 17 (63%) progressed to cCR on repeat assessment and 10 (37%) did not. Of these 10 patients, seven underwent standard surgical resection and three were unfit for surgery. R0 for the seven with delayed resection was 100%. Of 39 patients (22 cCR and 17 'near' cCR who progressed to cCR) (25.2% of those receiving NACRT), six patients experienced local regrowth (15.4%). The median time to local regrowth was 29 months (15-60 months). One of these six patients underwent salvage abdominoperineal resection, one was advised to have contact radiotherapy and four opted against surgery and also had contact radiotherapy. The overall survival was 100% at 2 years and 90% at 5 years. Disease-free survival was 90.47% at 2 years and 74.8% at 5 years. Conclusion A W&W treatment strategy was employed safely in this patient cohort with acceptable rates of local regrowth and survival. Keywords rectal cancer, watch and wait, complete response, neoadjuvant chemoradiotherapy What does this paper add to the literature? This paper provides an account of a watch and wait rectal cancer programme with long-term results in a single large district general hospital in the UK, demonstrating that this treatment protocol can be employed with success in a real-world practice.

Could the conservative approach be considered safe in the treatment of locally advanced rectal cancer in case of a clinical near-complete or complete response? A retrospective analysis

“…However, one of the most important issues in the conservative treatment strategy is the occurrence of LR: a rate between 19 and 25% of LR has been reported in LARC patients managed with a conservative approach. Nevertheless, salvage surgery with R0 resection is possible while preserving local disease control [13] , [21] . In our analysis, LR occurred in 8 patients (15,4%) in the conservative approach group with a median interval from the end of nCRT of 15,2 months and 95% of LR events occurred within 24 months.…”

“…However, there is no lack of conflicting voices regarding the efficacy and safety of these approaches. The percentage of patients with local regrowth (LR) varies widely, from 6% in a Dutch study [18] to 19-69% in other studies [19][20][21][22]. Tumor regrowth also appears to correlate with an increased risk of distant metastases (DM) [23].…”

Re-staging and follow-up of rectal cancer patients with MR imaging when “Watch-and-Wait” is an option: a practical guide

“…Patients with dense fibrosis or with dense fibrosis and minimal residual intermediate signal may be considered near-complete responders [ 52 , 53 ].…”

“…A small focal area of high signal intensity on high b value DWI is admissible for a near-complete response [ 53 ].…”

“…Regarding lymph node involvement, the only study on near-complete response mentioning lymph nodes considers “suspicious” lymph nodes, whether mesorectal or sidewall, should not be present on re-staging MR imaging [ 53 ]. As such, the same criteria as for complete responders should be applied (Fig.…”