Does the number of lymph nodes involved predict survival?

This study examined the predictors of survival in prostate cancer that has spread to the lymph nodes.

Prostate cancer (PC) is being diagnosed at earlier stages due to modern screening techniques, particularly the prostate-specific antigen (PSA) testing (an enzyme in the blood that is elevated in PC patients). Despite these advances, approximately 15% of PC patients are found to have cancer spread to the lymph nodes at the time of diagnosis. All men with lymph node involvement are said to have pN1 PC. Assigning cancer to a group, or stage, based on disease characteristics (such as lymph node involvement) is a way to determine treatment and prognosis. However, some men with pN1 PC have fewer lymph nodes involved, and these men tend to have higher survival rates than do men with more lymph nodes involved. There is no specific way to determine survival rates for men with differing amounts of lymph node involvement. The current study evaluates ways to predict prognosis in PC that has spread to one or more lymph nodes.

In this study, 1107 pN1 PC patients were followed up over an 8 to 10-year period. Each patient underwent radical prostatectomy (surgical removal of the prostate), extended pelvic lymph node dissection (removal of lymph nodes close to the prostate), and adjuvant hormonal therapy, or aHT (treatment following surgery to block hormone-related tumor growth). 386 patients also received adjuvant radiation therapy, or aRT.

Survival rates were 82% and 87% for patients receiving aHT and both aHT and aRT, respectively. Disease characteristics that predicted worse survival rates included a higher number of lymph nodes involved, a Gleason score (a score assigned to tumors based on how cancer cells look under a microscope which helps determine the aggressiveness of the cancer) of 8 or higher, and higher PSA levels. 

This study concluded that including all prostate cancer patients with lymph node involvement in one group may not lead to the most accurate prediction of survival. Multiple disease characteristics, including the number of lymph nodes involved, were found to influence the prognosis of patients with prostate cancer.

This study included patients who were treated in the past (retrospective study), rather than following patients throughout their treatment and determining their outcomes. Retrospective studies are found to provide weaker statistical information.

Discuss with your doctor the best course of action for your situation.