Considerar Ganglio Centinela en pacientes con Carcinoma Epidermoide de alto riesgo.

Sentinel Node Biopsy May Be Underused for High-Risk Squamous Cell Carcinoma

By Marilynn Larkin

November 22, 2017

NEW YORK (Reuters Health) – Sentinel lymph node biopsy (SLNB) is underused and prophylactic lymph node dissection overused in high-risk squamous cell carcinoma (SCC), researchers suggest.

"Cutaneous SCC is the second most common cancer worldwide and has displayed a sharp increase in incidence during the last two decades," Dr. Ashley Wysong of the University of Southern California, Los Angeles told Reuters Health.

Although SCC generally is characterized by low morbidity and mortality, "a subset of cases have elevated local recurrence, metastasis, and death," she said by email. "The single most important predictor of mortality in patients with SCC is the development of lymph node metastasis."

"Updates to SCC staging . . . identify a subset of patients, T2b and T3, with a 30%-50% risk of occult lymph node metastasis found on SLNB," she noted. "Despite this, there remains a lack of standardization in the work-up and management of these patients."

"In melanoma," she noted, "it is standard of care to offer SLNB for patients with T1b melanoma, (which has) an SLNB positivity rate of 7%-10%."

To investigate the use of SLNB in SCC, Dr. Wysong and colleagues created a database of all high-risk patients with the disease treated at UCLA since 2006. Patient and tumor characteristics were documented, as were treatment modality and whether SLNB was performed.

Preliminary data suggest that less than 0.1% of patients with high-risk SCC tumors underwent SLNB, according to the authors' research letter in JAMA Dermatology, online November 15.

By contrast, 14% underwent complete lymph node dissections, of which slightly more than half (56.7%) had microscopic metastasis to local lymph nodes. The rest (43.3%) were free of metastasis.

"Overall, we found prophylactic lymph node dissection to be overused and SLNB underused in high-risk SCC," the authors concluded. "Future prospective studies are needed to further elucidate the use of SLNB in SCC."

Three experts commented on the findings in emails to Reuters Health.

Dr. Richard Keidan, director of the Multidisciplinary Melanoma and Skin Cancer Clinic at Beaumont Hospital in Royal Oak, Michigan, observed, "SLNB should essentially eliminate and replace the use of an elective lymphadenectomy, thereby saving many patients a major operation that offers no benefit when the pathology is negative."

"I strongly agree that lymphadenectomy should not be used in high-risk patients with clinically negative nodes (and agree) that SLNB is significantly underused in patients with SCC," he said.

Dr. Vernon Sondak, Chair, Department of Cutaneous Oncology at Moffitt Cancer Center in Tampa, stated categorically, "I personally don't believe in and do not utilize SLNB for cutaneous SCC."

"The 'high-risk' categories that are currently defined have never been shown to have a suitable yield of positive sentinel lymph nodes – which we would define as a minimum of 5% of cases having a positive sentinel node in a young healthy patient or 10% of cases having a positive sentinel node in an older patient or one with comorbid conditions," he explained.

"So the fact that very few patients in the study underwent SLNB does not bother me in the slightest."

"However, I have never used nor ever even heard of a patient with cutaneous SCC undergoing a prophylactic lymph node dissection," he continued. "We do not do this for any form of cutaneous malignancy, including melanoma, Merkel cell carcinoma and SCC, and we essentially should never be doing a lymph node dissection for any skin cancer without a proven diagnosis of nodal metastases."

Dr. Sondak observed, "We have found that database studies like this one are prone to attribution error, wherein a node dissection is consider to be 'prophylactic' because there is no biopsy report found at that institution - but there is one at another institution, as happens routinely when the biopsy is done at a small hospital or outpatient office prior to referral to a major center for definitive surgery."

"Lymph node dissection is an important part of the treatment of node-positive cutaneous SCC, but in my view it should only be done in the setting of biopsy-proven, clinically detected nodal disease," he emphasized.

"I agree that future prospective studies are needed to determine if there is any role for SLNB in cutaneous SCC. Until those studies are done," he concluded, "patients with clinically negative nodes should be followed without surgery, and ultrasound of the lymph nodes should be used when necessary to augment physical examination."

Dr. Sarah Tuttleton Arron, Associate Director of the Dermatologic Surgery and Laser Center at the University of California, San Francisco, said, "I am not surprised by the low use of SLNB in this study. However, I don't think I would describe it as 'underuse.'"

"While the (new) staging system increases our ability to predict which SCCs are likely to have poor outcomes, there is no data that SLNB improves mortality from SCC," she observed. "Perhaps this is appropriate use - we just don't have the data to support SLNB."

"I would hesitate to draw major conclusions from this study, (which uses) data from a single hospital, which is a major referral center and not generalizable to the entire U.S. population," Dr. Arron concluded.

SOURCE: http://bit.ly/2yVAe6p

JAMA Dermatol 2017.

Reuters Health Information © 2017 

Cite this article: Sentinel Node Biopsy May Be Underused for High-Risk Squamous Cell Carcinoma - Medscape - Nov 20, 2017.