5 THINGS YOU SHOULD KNOW ABOUT WATCH&WAIT STRATEGY FOR RECTAL CANCER
1.- What is the watch & wait strategy?
2.- Who are the adequate candidates to be enrolled in this strategy?
3.- Advantages and Disadvantages of the watch and wait strategy.
4.- Which is the appropriate follow-up once a patient is included in this program?
5.- Published results
1. What is the Watch&Wait strategy?
The Watch&Wait strategy is a non-operative management for patients with rectal cancer who develop a clinical complete response after neoadjuvant therapy (chemoradiotherapy or radiotherapy alone). Angelita Habr-Gama and her team, from São Paulo in Brazil, published in 2004 their first long-term outcomes of a cohort of patients managed according to this strategy. It is currently being practiced in 15 countries all over the world, according to the International Watch & Wait Database. Despite of this, many aspects of the W&W approach are undefined or controversial, especially when it comes to oncological safety in patients who experience tumor regrowth.
2. Who are the adequate candidates to be enrolled in this strategy?
As a general rule, all those patients who achieve a clinical complete response after neoadjuvant therapy can be managed with a watchful waiting strategy.
CLINICAL COMPLETE RESPONSE is defined as following:
· No evidence of tumor when assessed by digital rectal examination (DRE), endoscopy-biopsy and MRI.
One issue becomes crucial in this process: the assessment of tumor response. Reassessment should be done in all patients after neoadjuvant therapy and it could be challenging due to numerous uncertainties including optimal timing for reassessment and clinical/radiological tools for such purpose. Anyway, all the patients should meet all the criteria mentioned about (clinical and radiological).
Also, there are different categories of patients who are suitable for the W&W strategy:
· Patients not fit for radical resection: patients whose comorbidities or performance status preclude any attempt at radical operation. Some of them achieve clinical complete response but surgery will never be an option. We have to remember that the essence of active surveillance is in patients who are able to avoid surgery but to whom the procedure will be considered when necessary.
· Patients who wish to avoid abdominoperineal excision (APE) at any cost: At present, it is not possible to advise a patient who is facing an APE what the likelihood is that preoperative CRT will succeed in achieving a complete response and thus the likely success of a W&W approach.
3. Advantages and Disadvantages of the Watch&Wait strategy.
· Avoidance of the perioperative mortality of 1–2% associated with total mesorectal excision.
· Avoidance of long-term morbidity, such as urinary and sexual dysfunction.
· Reduce the rate of temporary or permanent colostomy.
· It’s difficult to assess clinical complete response, as it doesn’t correlate exactly with the complete pathological response.
· Lack of evidence regarding the appropriate timing for reassessment and strict monitoring is required.
· Treatment of local regrowth is a major concern.
4. Which is the appropriate follow-up once a patient is included in this program?
Once we know that a patient is suitable for W&W strategy, the follow-up should be done as following:
· Digital rectal examination, proctoscopy, CEA every 1 or 2 months + MRI or CT scan every 6 months during the first 2 years.
· Digital rectal examination, proctoscopy, CEA every 6 months + MRI or CT scan annually from the 3rd to the 5th year.
· If we have evidence of relapse during follow up, salvage surgery should be offered at any time.
5. Published results
According to the international watch & wait database:
· Local regrowth occurred with a 2-year rate of 25.2%.
· 88% of local regrowth was diagnosed within the first 2 years.
· Local regrowths were located in the bowel wall in 97%.
· 78% of patients with local regrowth had TME resection, 99% with curative intention.
· In those who underwent salvage surgery: R0 resection in 88%, in 6% tumor margins were positive (R+) and in 6% margin involvement was unknown.
· Distant metastases were diagnosed in 8% of patients during follow-up. Most frequently located in lungs (62%), followed by liver (41%).
· For patients with a sustained clinical complete response, the 5-year disease-specific survival was 97.3% and 5-year overall survival was 87.9%. For patients with local regrowth, the 5-year disease-specific survival was 84% and 5-year overall survival 75.4%