Archived Policies - Medicine


Fiberoptic Analysis of Colorectal Polyps

Number:MED201.022

Effective Date:08-15-2003

End Date:11-14-2006

Coverage:

Fiberoptic analysis of colorectal polyps is considered experimental or investigational.

Description:

During a colonoscopy or sigmoidoscopy as a screening test for colorectal cancer, the physician must often decide which polyp should be removed for histologic diagnosis. While hyperplastic polyps are considered benign without malignant potential, adenomatous polyps are thought to represent one of the earliest stages in the progression to a malignancy. Identification of these premalignant lesions is considered one of the cornerstones of colorectal cancer prevention. The physician must thus balance the time and potential morbidity of removing all polyps, many of which will be benign, versus removal of those polyps most likely to be adenomatous. Recently a spectrophotometry technique has been developed as an adjunct to colonoscopy that is intended to distinguish between normal and precancerous tissue. This system is based on the observation that benign and malignant tissues emit different patterns and wavelengths of fluorescence after exposure to a laser light. One such device, the Optical Biopsy System (SpectraScience, Minneapolis MN), was approved by the Food and Drug Administration (FDA) in 2000. This system consists of an optical fiber emitting a laser that is directed against 3 different regions of the same polyp.  The subsequent fluorescent signal is collected, measured, and analyzed by a proprietary system software, and classifies a polyp as suspicious (i.e. adenomatous) or not suspicious (i.e. hyperplastic).

The FDA-labeled indication reads as follows:

The SpectraScience Optical Biopsy System is indicated for use as an adjunct to lower gastrointestinal endoscopy. The device is intended for the evaluation of polyps less than 1 cm in diameter that the physician has not already elected to remove. The device is only to be used in deciding whether such polyps should be removed (which includes submission for histological examination).

Rationale:

The FDA approval was based on a prospective, non-randomized phase II study involving 101 subjects from 5 sites. The data from this trial have not been published in a peer-reviewed journal but are available as an FDA summary of safety and effectiveness. Patients who participated in the study had undergone a prior lower GI endoscopic procedure with at least one polyp identified and were referred for an additional colonoscopy exam, in which fiberoptic analysis of the polyps was performed. At the time of the colonoscopy, the physicians documented whether or not the polyp was considered hyperplastic or adenomatous and whether or not they would remove the polyp. The fiberoptic probe was then applied to 3 different portions of the polyp and a segment of normal adjacent mucosa. The physician did not know the results of the analysis and thus the test did not affect patient treatment. The effectiveness of the analysis was then calculated as its ability to correctly identify adenomatous polyps (ie, sensitivity) and to correctly identify hyperplastic polyps (ie, the specificity), either alone or in conjunction with the physician assessment. The sensitivity and specificity of the physician assessment alone was 82.7% and 50%, respectively, compared to a combined sensitivity and specificity of 96.3% and 33%, respectively. In other words, fiberoptic analysis identified additional adenomatous polyps that the physician had classified as hyperplastic and presumably would not have removed based on visual assessment alone. This increase in sensitivity comes at the price of a decrease in sensitivity, as more hyperplastic polyps will undergo biopsy. However, according to the FDA, the risk of taking biopsies of additional hyperplastic polyps is minimal.

The clinical significance of these results and their effect on patient management is difficult to interpret from the data presented. It is not clear how the physician decided to select additional polyps for fiberoptic analysis (it is not entirely clear whether all polyps were analyzed and then underwent biopsy), or whether the same results could be obtained by simply randomly taking a biopsy of a subset of polyps that were considered hyperplastic on visual assessment. While adenomatous polyps are considered premalignant lesions, the evolution to cancer is a slow process requiring 7 to 8 years, and thus the immediate removal of all adenomatous polyps is not required. In addition, the finding of an adenomatous polyp serves as a marker that the patient should undergo more frequent endoscopic exams. It is well known that the current practice of visual inspection of polyps will certainly miss some adenomatous polyps, but this lack of sensitivity is considered acceptable if at least one adenomatous polyp is identified and the patient undergoes more frequent screening.

Contract:

Each benefit plan, summary plan description or contract defines which services are covered, which services are excluded, and which services are subject to dollar caps or other limitations, conditions or exclusions. Members and their providers have the responsibility for consulting the member's benefit plan, summary plan description or contract to determine if there are any exclusions or other benefit limitations applicable to this service or supply. If there is a discrepancy between a Medical Policy and a member's benefit plan, summary plan description or contract, the benefit plan, summary plan description or contract will govern.

Coding:

None


Medicare Coverage:

None

References:

Optical Biopsy System: Summary of Safety and Effectiveness. www.fda.gov

BCBSA Medical Policy Reference Manual, Fiberoptic Analysis of Colorectal Polyps, 2/15/2002, 2.01.51

Policy History:

Archived Document(s):

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