Skip to Main Content


Precancerous (Premalignant) Changes

++ ++
Table Graphic Jump Location
Table 19–1. Precancerous (Premalignant) Lesions.

As noted in the previous chapter, the lag period encompasses that span of time between initiation of the carcinogenic process and the clinical detection of cancer. The sequential multiple hits that are an essential part of carcinogenesis occur during the first part of this period, extending from a few years through 3 or more decades, producing the first neoplastic cell. Repeated division of this cell and its progeny (the malignant clone), sufficient to produce a clinically detectable neoplasm (approximately 109 cells), occupies additional months or years constituting the remainder of the lag period. In most instances, no clinical or morphologic abnormalities are apparent throughout this time. However, in some cases, an intermediate abnormal, nonneoplastic growth pattern may be detected. Such an abnormality is a precancerous (preneoplastic) lesion.


It is important to recognize precancerous lesions when they occur because surgical excision is curative (the potentially malignant tissue having been removed). While hyperplasias and metaplasias are not per se premalignant, if sustained they may progress to dysplasia, which does carry a high risk of conversion to malignancy. Most benign neoplasms progress to malignancy only rarely, but in some the risk is high (Table 19-1), and these then also are considered premalignant lesions. Again, the detection of dysplasia in a benign tumor is a warning sign.


Occult Cancer


Invasive cancer is usually lethal, but progression of disease varies. Small prostatic cancers are found incidentally—ie, in patients who died of other causes without any clinical evidence of prostate cancer—at autopsy in about 30% of men over age 60 years. This figure rises to 90% of men over age 90 years. These cancers are called occult because they remained small and did not become manifest clinically during life.


Another example of long-standing hidden cancer is delayed metastatic disease (occult metastases). Patients who have been treated for melanoma and breast cancer sometimes develop evidence of metastatic disease 15–20 years later. It has been proposed that occult cancers and delayed metastases may represent ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessPhysiotherapy Full Site: One-Year Subscription

Connect to the full suite of AccessPhysiotherapy content and resources including interactive NPTE review, more than 500 videos, Anatomy & Physiology Revealed, 20+ leading textbooks, and more.

$595 USD
Buy Now

Pay Per View: Timed Access to all of AccessPhysiotherapy

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.