Local Excision for Rectal Cancer Increasing, but Inferior

Megan Brooks

December 04, 2013

Rates of local excision for higher-risk stage I rectal cancer continue to increase in the United States, and it is not clear why.

Total mesorectal excision is firmly established as the standard of care for most stage I rectal cancers. Currently, local excision is only considered an acceptable definitive surgical procedure for T1N0 rectal cancers that are less than 3 cm in size, are well to moderately differentiated, and do not involve lymphovascular or perineural invasion.

"The use of local excision alone for higher-risk stage I rectal cancers is an inferior oncologic approach, but despite this, we are seeing a rise in use of local excision," said Karyn B. Stitzenberg, MD, MPH, assistant professor of surgical oncology at the Lineberger Comprehensive Cancer Center and University of North Carolina, Chapel Hill.

"Clinicians need to appropriately consider the trade off between local oncologic control and morbidity and quality of life when discussing surgical options with patients," she told Medscape Medical News.

Upward Trend Continues

A National Cancer Data Base (NCDB) study found a steady increase in the use of local excision for stage I rectal cancers from 1989 to 2003 (Ann Surg. 2007;245:726-733). This trend has continued, as can be seen in the study by Dr. Stitzenberg's team, which were published in the December 1 issue of the Journal of Clinical Oncology.

The researchers reviewed all patients in the NCDB diagnosed with rectal cancer from 1998 to 2010. They found that local excision was used to treat 46.5% of patients with T1 tumors and 16.8% with T2 tumors. Use of local excision increased steadily over the study period (P < .001). For T1 cancers, rates of local excision rose from 39.8% in 1998 to 62.0% in 2010; for T2 cancers, rates rose from 12.2% to 21.4%.

These data show that guideline-based adoption of local excision for the treatment of low-risk stage I rectal cancer is increasing. "However, use of [local excision] is also increasing for higher-risk rectal cancers that do not meet guideline criteria for [local excision]," the researchers note.

"It is not clear whether this trend is concerning," Dr. Stitzenberg told Medscape Medical News.

"If local excision is being used in the context of a balanced discussion of the risks of local recurrence and decreased survival versus long-term morbidity, or if local excision is being used in the context of a clinical trial, then it may be appropriate," she said. However, more information is needed to understand if this approach is being used appropriately in practice, she added.

The researchers found that local excision was used most often in women, black patients, very old patients, those without private health insurance, those with well-differentiated tumors, and those with T1 tumors.

The use of adjuvant radiation for stage I tumors decreased over the study period, independent of surgical procedure or tumor stage. "Although some of this decrease may be related to a shift in paradigm to neoadjuvant therapy, it is clear that the use of local excision as a single-modality therapy is increasing," the researchers explain.

Patient Choice?

The data reported suggest that there is a "near tripling of the risk of local recurrence following local therapy compared with radical surgery, and decrease in disease-specific but not overall survival," writes Robert D. Madoff, MD, from the University of Minnesota in Minneapolis, in an accompanying editorial.

He notes that there are several reasons local excision might lead to treatment failure.

"First, despite the advantages of transanal endoscopic microsurgery over conventional transanal excision, both approaches create a raw surface in the mesorectum where tumor cells can at least theoretically implant. More importantly, because the mesorectum is left largely or entirely untouched in local excision, success of the approach is critically dependent on proper patient selection. Undiagnosed metastases in regional lymph nodes are not treated and serve as the nidus for eventual locoregional recurrence," he writes.

What is driving the move to local excision for rectal cancer?

There are several possibilities, Dr. Madoff says. "First, imaging of rectal cancer by [endorectal ultrasound] or MRI has increasingly become a routine part of preoperative patient evaluation. A radiology report of a T1N0M0 cancer — even if staging accuracy is often imperfect — inevitably offers a tempting target for local therapy," he points out.

Also, the technique of local excision has improved.

"While conventional transanal excision remains suitable for low-lying cancers, mid- to upper-third cancers are better removed using [transanal endoscopic microsurgery], a technique that results in fewer fragmented specimens and fewer positive margins," Dr. Madoff notes.

He adds that transanal minimally invasive surgery is a newer variation of transanal endoscopic microsurgery, but there are no reports yet of long-term outcomes.

Perhaps "most importantly," he writes, "patients, or surgeons, or a combination of the 2 are declaring a real preference for less invasive approaches to early rectal cancer. In the face of the risks of radical resection, who can blame them?"

Still, Dr. Madoff notes that it is "hard to justify local excision on purely oncologic grounds." He points out that no randomized controlled trials have compared local excision with [total mesorectal excision] for clinical stage T1N0 disease, and individual case series "consistently show a marked increase in local recurrence rates with local excision compared with radical surgery."

The data from Dr. Stitzenberg and colleagues "confirm the widely held view that local excision alone is not adequate therapy for T2 tumors," Dr. Madoff notes.

"Oncologically," Dr. Madoff says, total mesorectal excision "by a qualified surgeon offers the most reliable route to the best results achievable today. Local excision, with or without chemoradiotherapy, is a compromise, though one that most get away with — provided that the surgeon complies strictly with published guidelines. Its benefits in terms of avoidance of complications, stomas, and impaired quality of life are not to be denied. But there is no room for giving a wink and a nod to adverse histopathologic features or questionable resection margins in the resected specimen, and conversion to [total mesorectal excision] surgery is required if any of these features are present."

"With respect to T2 tumors, local excision alone is clearly inadequate therapy with prohibitive failure rates. Additional prospective data are needed to better assess the true efficacy of adjuvant chemoradiotherapy and its impact on sexual and GI function," he writes.

The authors and Dr. Madoff have disclosed no relevant financial relationships.

J Clin Oncol. 2013;31:4273-4275, 4276-4282. Editorial, Abstract

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