Patients with nonmetastatic rectal cancer who achieve a complete clinical response (CR) following neoadjuvant chemoradiation therapy (CRT) and sustain this complete CR for 3 years are unlikely to experience either a local recurrence or development of distant disease, according to results of a retrospective analysis reported in Lancet Oncology.
Given the postoperative morbidity and mortality risks associated with radical rectal cancer surgery, the “watch and wait” approach, characterized by close, long-term surveillance without surgery in patients with nonmetastatic rectal cancer who achieve a clinical CR following neoadjuvant CRT, is increasingly being viewed as an attractive alternative to surgery.
However, as noted by the study investigators, “the risk of local regrowth or distant metastases after a clinical CR to neoadjuvant CRT after non-operative management of rectal cancer remains an important drawback for the widespread uptake of watch and wait in clinical practice.”
This analysis used data included in the International Watch & Wait Database (IWWD) for patients with nonmetastatic rectal cancer from 47 cancer clinics and 15 countries who underwent “watch and wait” surveillance following achievement of a clinical CR with neoadjvuant CRT.
The primary exploratory study end points were 2-year conditional local regrowth-free survival for those patients who sustained a clinical CR for 1 year (ie, 3 years total), and 2-year conditional distant metastasis-free survival for those patients who remained free of distant metastasis for 3 years (ie, 5 years total). These assessments were also made for those without local disease recurrence at 3-, and 5-years, and those without distant disease at 1-, and 5-years.
Included in the analysis were 793 adult patients from the IMMD with Stage I to III rectal cancer who achieved a clinical CR, defined as “the presence of white scars and telangiectasias, and the absence of any irregularity, mass, ulceration, or stenosis during clinical assessment,” as well as radiologic imaging findings consistent with complete tumor regression, following neoadjuvant CRT and were managed by a “watch and wait” approach between November 25, 1991 and December 31, 2015.
Baseline characteristics of this patient cohort at disease diagnosis included clinical T stage III disease in approximately two-thirds of patients, and clinical node-positive rectal cancer and a diagnosis of Stage III rectal cancer in 57% and 60% of patients, respectively. Median follow-up was 55.2 years.
Two-year conditional local regrowth-free survival was 88·1%, 97.3%, and 98.6% for patients who were without a local disease recurrence at 1 year, 3 years, and 5 years, respectively.
Two-year conditional distant disease-free survival was 93·8%, 97·8%, and 96.6% for those who were without distant metastasis at 1, 3, and 5 years, respectively.
In their concluding remarks, the study investigators noted that “the results of our study suggest that the risk of local regrowth in patients who have a sustained clinical complete response for 3 years is 5% or less [and] … “the risk of systemic recurrence is low after 3 years of being recurrence-free.”
They further added that “although a substantial amount of inherent bias derived from large databases warrants cautious interpretation of the results, this information should be taken into consideration when developing surveillance guidelines for patients with rectal cancer undergoing organ-preservation strategies, and for the design of future studies of different treatment strategies, follow-up [programs], and adjuvant therapies.”
Fernandez LM, Sao Juliao GP, Figueiredo NL, et al. Conditional recurrence-free survival of clinical complete responders managed by watch and wait after neoadjuvant chemoradiotherapy for rectal cancer in the International Watch & Wait Database: a retrospective, international, multicentre registry study. Lancet Oncol. Published online December 11, 2020. doi:10.1016/S1470-2045(20)30557-X