Watchful waiting tied to worse survival for some rectal-cancer patients

Last Updated: 2019-01-18

By Reuters Staff

NEW YORK (Reuters Health) - A new study suggests caution in opting for a watch-and-wait strategy in patients with rectal cancer who achieve a complete clinical response (cCR) to neoadjuvant chemoradiation.

Clinicians from Memorial Sloan Kettering Cancer in New York have observed that rectal-cancer patients with cCR who opted for a watch-and-wait strategy had "excellent" rectal preservation and pelvic tumor control, but poorer survival and a higher incidence of distant progression relative to similar patients who underwent total mesorectal excision and achieved a pathologic complete response (pCR).

In a report online January 10 in JAMA Oncology, the study team notes that a watch-and-wait (WW) approach for patients with rectal cancer following cCR to neoadjuvant therapy is currently not standard, but has become more widely practiced and increasingly demanded by patients after cCR.

The WW strategy "may be safe for most patients, but better risk stratification is needed for more precise patient selection to identify those at high risk of local regrowth who are not optimal candidates," write Dr. Philip Paty and colleagues.

The researchers analyzed five-year outcomes in 113 patients with rectal cancer and cCR who were managed with the WW approach of active surveillance and possible salvage surgery, and 136 rectal cancer patients who underwent surgery and had a pCR at resection.

Rectal preservation was achieved in 82% of patients managed with the WW strategy. All 22 local regrowths were detected on routine surveillance visits, and 20 (91%) were successfully salvaged.

However, at five years, overall survival was significantly lower in the WW group versus the surgical group (73% vs. 94%), as was disease-free survival (75% vs. 92%).

A higher rate of distant metastasis was also observed in patients in the WW group who had local regrowth versus those who did not (36% vs. 1%, P<0.001).

The worse survival outcomes in the WW group is "likely due to selection bias and could be due to higher rates of distant metastases in patients with local regrowth," the researchers say.

"These data," they conclude, "advise a measure of caution as we weigh the risks of WW for each patient with the benefits of organ preservation and quality of life. The data also suggest that although WW may be effective in most patients, better risk stratification is needed to inform more precise patient selection and to better understand which patients should be excluded from a WW strategy to minimize local failure and distant progression."

In an editor's note published with the study, Dr. Charles Thomas, Jr., of Oregon Health and Science University in Portland wonders whether WW is ready for prime time.

"Within the lower foregut community," he writes, "there currently exists a high level of excitement regarding the potential use of sphincter preservation for patients with invasive adenocarcinoma of localized rectal cancer. A series of studies have suggested that there may indeed be a subset of patients who do not require a standard radical surgical procedure ... following a clinical complete response (cCR) to chemoradiotherapy."

The Memorial Sloan Kettering group is leading a prospective, multicenter phase 2 study and the results are "eagerly awaited," notes Dr. Thomas.

"For now, unless the care team is truly multidisciplinary and thus primed to evaluate, treat, and diligently follow-up patients in a close manner, the WW approach may not be in the best interest of the patient. In such cases, hold tight because it is likely that we will have stronger prospective data that may provide a sound foundation for evidence-based recommendations on how best to identify optimal candidates and guidelines for execution of watch- and-wait care in resectable rectal cancer," he concludes.

The study had no commercial funding.

SOURCE: https://bit.ly/2FzeioL and https://bit.ly/2Dddl31

JAMA Oncol 2019.