Giuditta wrote:
> The following is an email my friend sent me, more about her husband's
> condition...keep in mind that he hasn't had a biopsy just the CT scan. Isn't
> two months a bit long to wait to see what's going on with him? Can they
> determine from a CT scan if a cancer is fast-growing or not?
>
> Thanks,
> Judy
>
> The doctor said that lesions over 5mm are usually cancerous and those under
> 5mm are usually benign. Randall's are 3mm and 4mm at this point. He also
> said that noncalcified lesions are more likely cancerous than calcified
> lesions, and Randall has one of each. The most pressing issue right now is
> the emphysema that showed up on the cat scan. The doctor told him that
> within 1-2 years he will be on oxygen if he does not stop smoking now. He
> started him on Chantix, and he goes back in a couple of months for another
> cat scan to monitor the growth, if any, of the two lesions. If there is any
> growth at all, they will do what they need to do then. Hopefully by then, he
> will be off the cigarettes. http://www.medscape.com/viewarticle/535601
Solitary Pulmonary Nodule: Assessment of a Solitary Pulmonary Nodule
From ACS Surgery Online
Posted 06/07/2006
Shamus R. Carr, MD; Taine T. V. Pechet, MD, FACS
The solitary pulmonary nodule (SPN) is a common finding that is observed in more
than 150,000 persons each year in the United States
The differential diagnosis of an SPN is broad and includes vascular diseases,
infections, inflammatory conditions, congenital abnormalities, benign tumors,
and malignancies [see Table 1 -- omitted].
Although most SPNs are benign, as many as one third represent primary
malignancies, and nearly one quarter may be solitary metastases.1,5,6 Various
approaches have been developed to aid in the characterization and identification
of SPNs. Certain clinical characteristics—such as greater age, history of
tobacco use, and previous history of cancer—have been shown to increase the
likelihood that the SPN is malignant.7 Some authors have attempted to use
Bayes's theorem, logistic regression models, or neural network analysis to
predict the likelihood of malignancy.7–9 Such methods are highly sensitive and
specific, but they are cumbersome and of limited practical use in actual
clinical evaluation of a patient with an SPN.
Appropriate evaluation involves careful assessment of the patient's history and
risk factors for malignancy in conjunction with the results of radiographic
studies [see Investigative Studies -- omitted, below] to develop an
individualized care plan.
Chest Radiography. Whereas the prevalence of lung cancer is low in comparison to
that of breast or prostate cancer, the mortality for lung cancer exceeds that
for breast, prostate, and colon cancer combined. As noted [seeClinical
Evaluation -- omitted, above], the overall 5-year survival rate for lung cancer
patients is dismal, in part because lung cancer is typically identified at a
more advanced stage than other cancers are. Several trials performed before the
advent of CT scanning attempted to employ chest radiography for early screening
of lung cancer, but they were unable to demonstrate that such screening yielded
any better survival than no screening at all.16–18 One explanation for these
disappointing results may be that fewer than 10% of lung cancers are stage I at
presentation.16
Although chest radiography is ineffective as a screening tool for early-stage
lung cancer, it remains a valuable investigative tool in the evaluation of SPNs.
If an SPN's appearance on chest x-rays has not changed for more than 2 years,
the SPN will be benign in more than 90% of cases. In such cases, only yearly
follow-up is typically required; additional diagnostic tests are usually
unnecessary.19,20 Therefore, an effort should always be made to obtain old chest
radiographs if they are known to exist.
Computed Tomography. The advent of CT scanning has led to an increase in the
number of SPNs detected21—but of course, it has also led to an increase in the
number of SPNs found that prove to be benign. Advocates of CT scanning for
assessment of SPNs base their argument on two central points. First, as many as
83% of CT-detected stage I malignancies are not visible on chest x-ray.22
Second, non-small cell lung cancer (NSCLC) is the malignancy most commonly
identified, and the survival rate for stage I NSCLC is relatively high. In
patients whose SPN proves to be NSCLC, the 5-year survival rate is 67% for stage
IA disease. This figure falls rapidly as the disease stage rises: the 5-year
survival rate is 55% for stage IIA NSCLC and only 10% for stage IIIA NSCLC with
mediastinal nodal metastasis.23
Numerous studies have evaluated the use of screening CT both in the general
population and in at-risk groups consisting of older patients with a smoking
history.22,24,25 The greatest drawback to screening CT is the high false
positive rate: nodules are identified on 23% to 66% of all CT scans, depending
on the thickness of the slices,22,26 and nearly 98% of these nodules are
eventually determined to be benign. Sequential CT scanning is often required to
determine whether an SPN is benign or malignant. In 10% to 15% of patients,
however, this determination cannot be made even when two CT scans are compared.
Such patients may be assessed with other imaging modalities (e.g., positron
emission tomography [PET]) or may be referred for transthoracic needle biopsy
(TTNB) or other invasive diagnostic tests.
There is currently some controversy regarding the optimal timing of follow-up CT
scanning after initial identification of an SPN. In the literature, the
recommended interval between initial CT scanning and repeat CT scanning has
ranged from 1 month to 1 year.22,25,26 These varying recommendations are based
on what is considered the doubling time for an SPN. In a study from 2000 that
included 13 patients with a known diagnosis and lesions less than 10 mm in
diameter at initial evaluation, volumetric growth rates were measured to
establish the doubling times of the nodules.10 The doubling times ranged from 51
days to more than 1 year. For malignant lesions, the average doubling time was
less than 177 days, whereas for benign lesions, it was more than 396 days.
In addition to delineating the size and contours of an SPN, CT scans provide
information on its internal characteristics. Certain lesion characteristics
noted on CT, though not absolutely definitive, point more toward a benign
condition, whereas others point more toward malignancy. For example, although
cavitation may occur in either benign or malignant lesions, SPNs with walls
thicker than 16 mm are much more likely to be malignant, whereas those with
walls thinner than 4 mm are much more likely to be benign.27 As another example,
the presence of intranodular fat is a reliable indicator of a hamartoma (a
benign lesion) and is seen in as many as 50% of hamartomas.28 In addition,
calcification is most commonly associated with hamartomas and other benign
nodules. Unfortunately, between one third and two thirds of benign lesions
visualized are not calcified, and as many as 6% of malignant lesions are
calcified.29–31 Finally, increased enhancement (measured in Hounsfield units
[HU]) after injection with intravenous contrast is strongly suggestive of
malignancy. Lesions that enhance by less than 15 HU are most likely benign
(positive predictive value, 99%), whereas lesions that enhance by more than 20
HU are typically malignant (sensitivity, 98%; specificity, 73%).32 Lesions that
enhance by 15 to 20 HU should be considered indeterminate.
Because most SPNs are benign and because the risk of misdiagnosing a malignant
lesion is so great, it is important to make use of all of the data obtained from
CT scanning in the effort to make cost-effective, logical decisions regarding
further evaluation or treatment. Careful evaluation of the size, contours, and
internal characteristics of an SPN on successive CT scans—in conjunction with
thoughtful consideration of the patient's age, smoking history, and occupational
exposure—provides the framework for appropriate treatment. Because the doubling
time is considerably shorter for malignant lesions than for benign lesions, a
repeat CT scan should be performed 3 months after the initial study. If the
lesion is visibly larger on the repeat scan, it is probably malignant, and
further diagnostic evaluation should be carried out with an eye toward
resection. If, however, the lesion is still present and has not grown, a
follow-up CT scan between 3 months and 12 months is warranted; the precise
timing remains controversial and should be determined on the basis of individual
patient and SPN characteristics. New volumetric modeling methods have been
developed that may be capable of detecting conformational changes over much
shorter intervals, but at present, they are not frequently used.33
Positron Emission Tomography. PET is an imaging modality that employs
radiolabeled isotopes of fluorine, carbon, or oxygen; the most commonly used
isotope is 18F-fluorodeoxyglucose (FDG). The rationale for FDG-PET scanning in
the evaluation of SPNs is based on the higher metabolic rate of most
malignancies and the preferential trapping of FDG in malignant cells.34 However,
increased FDG activity can also occur in benign SPNs,35,36 especially those
arising from active granulomatous diseases37,38 or inflammatory processes.39
These benign diseases can produce false positive PET scans and thereby reduce
the sensitivity of the test.
Efforts have been made to increase the sensitivity and specificity of PET
scanning in the diagnosis of SPNs. One such effort involves the use of the
standardized uptake value (SUV), which is a numerical indication of the activity
concentration in a lesion, normalized for the injected dose.45 In many studies,
an SPN is considered malignant when its SUV is higher than 2.5. Because of the
method used to calculate the SUV, however, small tumors (< 1.0 cm) may have an
SUV lower than 2.5 and still be malignant. The reason is that their small volume
causes their true activity concentration to be underestimated, with the result
that their SUV drops below the threshold value for malignancy. In one
prospective study of patients with SPNs, the overall sensitivity of FDG-PET
scanning was 79%, and the overall specificity was 65%.46 When the SPN was
smaller than 1.0 cm, however, all of the scans were negative, even though 40% of
the nodules were malignant.
In cases where the SPN is larger than 1.0 cm and no previous radiographs or CT
scans are available for comparison, PET scanning can provide information that
may facilitate the decision whether to follow the lesion closely or to proceed
with biopsy.
PET scanning has a definite place in the evaluation of SPNs, but it is not
appropriate for every patient. A study that examined the cost-effectiveness of
PET in the evaluation of SPNs concluded that it was cost-effective for patients
who had an intermediate pretest probability of a malignant SPN and who were at
high risk for surgical complications.47
In all other groups, PET was not cost-effective, and CT led to similar outcomes
(in terms of quality-adjusted life years) and to lower costs.
the latest on my friend's husband 
8c4i.3999$4Y.1336@newssvr19.news.prodigy.net ...