▎ WuXi AppTec content team editor
Recently, the journal of Clinical Oncology, an internationally renowned clinical oncology journal, pointed out that low-grade prostate cancer may no longer be called "cancer", and removing such clinical low-risk lesions from prostate cancer may significantly reduce the over-diagnosis and over-treatment of prostate cancer and improve the cost-effectiveness of PSA screening.
The paper emphasizes that low-grade prostate cancer does not invade other organs, and that less than 1 percent of patients develop lesion metastases or die within 15 years of initial diagnosis. Overtreatment of this part of the patient often causes unnecessarily serious side effects, such as sexual dysfunction or urinary incontinence.
Screenshot source: JCO
Prostate-specific antigen (PSA) is an important indicator of prostate cancer detection, but there is still great controversy about the use of PSA to screen for prostate cancer.
On the one hand, abnormal PSA findings may be due to some less serious prostate problems, or even strenuous exercise; on the other hand, the benefits of PSA screening in reducing prostate cancer-related metastasis or death do not necessarily outweigh the accompanying risk of overdiagnosis, overtreatment, and even potential treatment-related death.
When the results of the blood PSA test are abnormal, doctors may recommend that the patient have a biopsy, which is to take a tissue sample of the prostate for analysis. Pathologists score samples by microscopic observation to determine the degree of abnormality in the appearance of prostate cells. It should be noted that according to the pathological diagnosis results, the vast majority of prostate cancer patients may be low-grade (i.e. Gleason score 6) prostate cancer.
More than 50% of men (>50 years of age) have prostate cancer; up to 50% of low-grade patients undergo radiation/surgery; and metastases/mortality rates of less than 1% of low-grade patients within 15 years (US data) (Image source: Reference [1])
Although low-grade prostate cancer meets the pathological criteria for cancer (i.e., lesion cells invade the matrix), such diseased cells do not invade adjacent local structures or form metastases. As a result, low-grade prostate cancer is not significantly invasive and usually does not cause associated symptoms. Previous studies have shown that metastasis/mortality in patients with low-grade prostate cancer is even less than 1% within 15 years.
The paper points out that the main reason for over-diagnosis and over-treatment in prostate cancer is that these "low-level altered cells" are identified as cancer cells. Fear of cancer can lead to overreacting in some patients, and up to 50% of low-grade prostate cancer patients in the clinic will choose to undergo unnecessary surgery or radiation therapy to eradicate these commonly inert cells. However, overtreatment often comes with side effects such as sexual dysfunction or urinary incontinence.
The authors emphasize that patients with low-grade prostate cancer only need to be actively monitored and do not need to be treated immediately. Removing such clinically low-risk lesions from prostate cancer may eliminate the patient's inner fears, thereby significantly reducing overtreatment of prostate cancer and significantly increasing the cost benefits of PSA screening.
In the future, we may be able to name low-grade prostate cancer "epithelial-derived inert lesions (IDLE)" or "indolent tumors that rarely require treatment (INERRT)", thus suggesting that some clinically low-risk prostate cancer patients are exempt from unnecessary treatment.