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Sent: Tuesday, May 22, 2012 3:26 PM

Subject: CT lung screening at CCH

We will be accepting patients for lung cancer screening at CCH starting on June 1. The low dose protocols, in accord with the National Lung Screening Trial (NLST), are in place on all of the CT scanners.
Typical CTDI(vol) should average about 2-3 mGy with an estimated average effective dose of
about 1.5 mSv. No breast shield due to very low mAs. At this time, screening is recommended for high risk individuals only, for 3 years and until age 74. Patients will sign a consent form indicating potential for false positives, radiation issues, etc. The study will show up in RIS as "lung screening" or a slight variation of this.

We need to standardize our method for measuring nodules. We need to be precise about our recommendations/follow-up. Also, we should not deviate from the provided recommendations so as to best replicate NLST results.

Nodules should be measured per NLST and Fleischner Society protocol: use mean diameter, which is the mean of the longest diameter of the nodule and its perpendicular diameter. Example: 9x7 mm nodule would be reported as an 8 mm nodule. (If one reports this as a 9x7 mm nodule, this may create confusion as some clinicians may believe that this is a 9 mm nodule.)

Please see attachments in regard to follow-up algorithms. The National Comprehensive Cancer Network guidelines are mostly an adaptation of the Fleischner guidelines for high risk patients, and proposed guidelines by Godoy, et al. for semisolid nodules. (http:/www/radiology.rsna.org/content/253/3/606.full)

For solid or part-solid nodules, there is an attached chart for the initial screening study. There is a second chart which refers to ground glass/nonsolid nodules.

There is a third chart for a new nodule at annual or follow-up CT. New nodule is defined as greater than or equal to 3 mm in mean diameter. Smaller nodules were felt to be not truly "new", but difficult to visualize and/or not clinically significant. The definition of "an increase is size" is important. For nodules less than or equal to 15mm: increase in mean diameter of greater than or equal to 2 mm in any nodule or solid portion of a part solid nodule compared to baseline scan. For nodules greater than or equal to 15mm: increase in mean diameter or greater than or equal to 15% compared to baseline scan. Rapid increase in size should raise suspicion of inflammatory etiology or malignancy other than NSCLC.

An additional attachment includes the entire parent document. Marilyn will laminate the charts and place in CCH offices.

The follow-up recommendations, which I created from the charts, will also be added as a group Powerscribe shortcut "lung screening". Always use this shortcut after the impression, for lung screening studies only. Do not use for routine chest studies at normal dose. Continue to use Fleischner shortcut for routine (nonscreening) studies.

The shortcut summarizes the recommendations from the charts:

National comprehensive Cancer Network Guidelines Version 1.1012 recommends follow-up for low dose lung cancer CT screening (LDCT) as follows:

For solid or part solid nodules less than or equal to 4 mm, follow-up LDCT for 3 years. Nodules greater than 4-6 mm, LDCT in 6 months, then if stable, follow-up LDCT in 12 months, then annually for two more years; nodules greater than 6-8 mm, LDCT in 3 months, then if stable, LDCT in 6 months, then 12 months, then annually for two more years. For nodules greater than 8 mm, consider PET-CT. For solid endobronchial nodule, follow-up LDCT in 1 month (immediately after vigorous coughing). Any increase in size of nodules may warrant biopsy, surgical excision or bronchoscopy.

For ground glass or nonsolid nodules, the recommendations are as follows: less than 5 mm, LDCT in 12 months, then if stable LDCT annually for at least two more years. If increases in size or develops solid components, LDCT in 3-6 months or consider surgical excision. For nodules 5-10 mm, LDCT in 6 months. If stable, LDCT annually for at least two more years. If increases in size or develops solid components, surgical excision. For nodules greater than 10 mm, LDCT in 3-6 months, then if stable LDCT in 6-12 months, biopsy or consider surgical excision. If increases in size or develops solid components, surgical excision. If increases in size or develops solid components, surgical excision.

For new nodule at annual CT or follow-up LDCT, and if there is no suspected infection/inflammation, follow-up is the same as above. If there is suspected infection/inflammation, consider treating with antimicrobials and repeating LDCT in 1-2 months. If resolved, annual LDCT. If resolving, radiologic follow-up to stability or resolution. If persistent or enlarging, PET-CT.

New nodule is defined as greater than or equal to 3 mm in mean diameter. The definition of an increase in size is as follows: For nodules less than or equal to 15 mm: increase in mean diameter of greater than or equal to 2 mm in any nodule or solid portion of a part solid nodule compared to baseline scan. For nodules greater than or equal to 15 mm: increase in mean diameter of greater than or equal to 15% compared to baseline scan. Rapid increase in size should raise suspicion of inflammatory etiology or malignancy other than NSCLC.

Please note that there is uncertainty about the appropriate duration of screening and the age at which screening is no longer appropriate. The guidelines suggest that screening may be appropriate until age 74.

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For nodules that require anything other than a follow-up LDCT, use "nurse navigator" shortcut to alert the nurse navigator that PET-CT, biopsy, possible surgical excision or course of antimicrobials is recommended.

NLST reference article from NEJM:
http:/www/www.nejm.org/doi/full/10.1056/NEJMoa1102873#t=articleTop

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What to do about incidental abdominal findings on low dose studies:

Please see excerpts from an ACR white paper in regard to suggestions- not rigid doctrine- for abdominal findings that may be seen on low dose studies. Perhaps print, and review when you have more time to read.

Incidental abdominal findings:
http:/www/www.jacr.org/article/S1546-1440(10)00330-3/fulltext#sec15

The Incidental Findings Committee recommends the following for low-dose unenhanced CT examinations for renal masses:

  1. It may be appropriate to interpret incidental renal masses as simple cysts unless suspicious features noted above are convincingly present. The argument for adopting this approach is even stronger when considering small (<3 cm) masses, particularly those <1 cm. The smaller the mass (even when solid), the more likely it is benign. Furthermore,masses <1 cm may not be able to be fully characterized, even if renal mass-protocol CT or MRI was performed. Although this represents a consensus opinion of the committee, no data are yet available to support this approach.
  2. If a renal mass is small (<3 cm), homogeneous, and >70 HU, recent data
    suggest that the mass can be confidently diagnosed as a benign
    hyperattenuating cyst (Bosniak category II) [43].

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The Incidental Findings Committee recommends the following for low-dose unenhanced CT examinations for liver masses:

  1. In low-risk and average-risk patients, sharply marginated, low-attenuation (<20 HU) solitary or multiple masses may typically not need further evaluation.
  2. Small, solitary masses less than or equal to 1.5 cm that are not cystic and are discovered on unenhanced or standard-dose or low-dose scans in low-risk and average-risk patients may typically not need further evaluation.

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The Incidental Findings Committee recommends the following for low-dose unenhanced CT examinations for adrenal masses:

  1. Because attenuation should not be altered by a low-dose technique, if the mean attenuation of an adrenal mass is less than or equal to 10 HU
    on a low-dose CT examination, one may conclude that the adrenal mass is likely to be a benign adenoma.
  2. If a lesion is >10 HU and 1 to 4 cm in an asymptomatic patient without cancer, 1-year follow-up CT or MRI may be considered, if no prior studies for comparison are available. Prior examinations that show stability for greater than or equal to 1 year can eliminate the need for further workup, so every effort should be made to obtain prior CT or MRI examinations in these situations.
  3. For adrenal masses >4 cm, dedicated adrenal MRI or CT should be considered to further characterize.

Pancreas

The recommendations shown in the pancreatic flowchart (Figure 5 [of white paper article]) also apply to low-dose unenhanced CT examinations. The importance of comparison with prior CT or MRI examinations cannot be overemphasized to potentially avoid further workup. Specifically, for lesions <2 cm, stability greater than or equal to 1 year is highly suggestive of a benign lesion and may eliminate the need for follow-up imaging.
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SB

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Related Links

Lung Screen (.pdf)

LCS - 2 (.pdf)

LCS - 3 (.pdf)

LCS - 4 (.pdf)

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