Tongue cancer patients who have compartmental tongue surgery live longer and have fewer recurrences of the disease compared with those who undergo conventional surgery, a new retrospective study found (Oral Oncology, January 22, 2011).
Cancer of the tongue is aggressive, as evidenced by its locally invasive behavior and a propensity to metastasize to cervical lymph nodes. Surgery remains the main approach to treating early-stage tongue cancer; the goal is to remove the primary tumor and as much surrounding tissue as necessary to ensure that all macroscopic disease is eradicated. This is thought to provide the best chance that microscopic disease -- the potential source of recurrence -- is also removed.
"According to this 'more is better' approach, it is widely accepted that >1 cm of apparently healthy tissue beyond the macroscopic margin of the disease should be removed," according to researchers from the European Institute of Oncology in Milan, Italy.
However, at present the overall survival for advanced tongue cancer is only about 50%, a number that has not changed substantially in three decades, noted Luca Calabrese, MD, and colleagues. In fact, although better disease-free survival is associated with wide, clear resection margins and negative nodes, studies have found that up to 25% of tongue cancer patients with negative margins develop recurrence at the primary tumor site, they wrote.
Stopping tumor progression
They believe a better option for long-term survival is compartmental tongue surgery (CTS), a technique that removes the anatomofunctional units containing the primary tumor, eliminating the disease and potential muscular, vascular, glandular, and lymphatic pathways that can spread the disease and its recurrence (Acta Otorhinolaryngolica Italica, October 2009, Vol. 29:5, pp. 259-264). In addition, the surgeon identifies the territory at risk for metastatic representation -- that is, the muscular, neurovascular, and glandular tissues that form a bridge between the primary tumor and the cervical lymphatic chain.
"Since cancer progresses following the path of least resistance, it is possible to define an anatomical compartment that confines the tumor, and whose boundaries (layers of fascia) form a barrier to tumor spread," the Oral Oncology study authors wrote. "Complete removal of such a compartment is therefore the goal of compartmental surgery and has resulted in significant improvements in local disease control compared to wide resection."
The research team developed CTS based on anatomical study of macroscopic specimens from tongue cancer patients, they noted.
"We found that in the tongue, and contrary to some reports, the tumor behaved in an identical manner to tumors in musculoskeletal compartments of the extremities: tumor cell migration occurred longitudinally from the primary extending along and between the intrinsic and extrinsic muscle fibers, as noted by others, and progression was deflected by the anatomical boundaries of the compartment," they wrote.
Retrospective study
For the Oral Oncology paper, they conducted a retrospective study of 193 patients with squamous cell carcinoma (SCCA) of the tongue and found that local disease control was achieved in 88.4% of CTS patients (16.8% improvement on standard surgery) and the overall survival rate was 70.7% (27.3% improvement).
Fifty patients who were treated between October 1995 and July 1999 received standard surgery (resection margin >1 cm), while 143 patients who were treated between July 1999 and January 2008 received CTS. All patients were older than age 18 and had been treated for stages II-IV SCCA of the tongue or base of the tongue who underwent major ablative surgery followed by reconstruction.
Prophylactic tracheotomies (surgical or percutaneous), separate from the neck dissection field, were performed on all patients. Lateral neck dissection was performed depending on the primary lesion and clinical/radiological status of the neck.
CTS was associated with significantly decreased risk of local recurrence at five years (p = 0.006), whereas there was no difference in distant relapse risk at five years (p = 0.011). Overall survival was also better in the CTS group: The risk of dying (from any cause) within five years was about one-third of the standard surgery group (p = 0.0012).
"CTS introduces a rationale to what constitutes an adequate margin: Complete removal of the involved muscle(s) affords oncologic radicality as it removes the most likely path of disease spread and potential sites of residual disease foci," the researchers wrote.
However, they noted, the CTS patients in the study received significantly more chemotherapy plus radiotherapy than the standard group, which may have contributed to the good control rates.
Even so, they believe that changing from circumferential to longitudinal compartmental resection amounts to a paradigm shift in the surgical approach to locally advanced SCCA of the tongue.
"Our clinical experience also indicates that compartmental surgery permits a rational and functionally conservative approach to demolition, and we are seeking to demonstrate this in a prospective evaluation of quality of life and functional rehabilitation in patients with locally advanced disease," they wrote.
The markedly improved outcomes in CTS patients after five years, compared with those treated by standard surgery, suggest CTS as an important new approach in the surgical management of tongue cancer, the authors concluded.
However, some oral surgeons questioned the advantages of CTS over standard surgery with negative margins. Tamer Ghanem, MD, PhD, director of head and neck oncology and reconstructive surgery at Detroit's Henry Ford Hospital, noted that since two-thirds of the patients (CTS group) in the Oral Oncology study received radiation or chemo/radiation therapy, "any microscopic disease beyond the standard margin should be in the treatment field."
"The more tongue that's removed, the worse the swallowing and speech outcomes," Dr. Ghanem told DrBicuspid.com. "Surgeons use their judgment, and often the 'compartmental tongue' boundaries are utilized if the standard margin of 1 cm will leave very little tissue between the standard margin and compartmental boundary."
In addition, he said, it is difficult to make definitive conclusions since because the study is non-randomized and the time difference between the two groups is quite significant. Also, the sample size of the CTS group is nearly three times that of the standard surgery group (143 vs. 50).
"It is unclear why CTS surgery would be better than standard surgery with negative margins," Dr. Ghanem concluded.
Copyright © 2011 DrBicuspid.com
