Active Surveillance Beneficial for Patients With Small Renal Masses

Findings from a study presented at the American Society of Clinical Oncology 2017 Genitourinary Cancers Symposium suggest that active surveillance may be a safe option for patients with small renal masses (SRMs).

Treatment for patients with SRMs less than 4 cm in diameter was called into question, since 20% to 40% of masses are benign. The study authors said that fewer than 20% of SMRs are aggressive, and typically do not metastasize.

Due to the benign and non-aggressive nature of SRMs, patients are likely being overtreated. A majority of previous studies that have used active surveillance to monitor patients with SRMs have been retrospective.

Included in the new study were patients in the DISSRM registry, which includes those 18 and older who have a SRM. Patients included in the registry have chosen to undergo active surveillance or intervention after counseling, according to the study.

At baseline, patients in the active surveillance group underwent axial imaging, with follow-up every 6 to 12 months. Patients were also offered an optional biopsy at baseline.

Intervention was recommended if the tumor was growing more than 0.5 cm per year, a tumor with a diameter greater than 4 cm, or metastatic disease, according to the study.

Of the 615 patients included, 48.5% underwent primary intervention, while 51.5% of patients underwent active surveillance. Only 14.2% of patients under active surveillance progressed to require intervention.

Patients who chose active surveillance were typically older, had worse health, and had smaller tumors. The researchers noted that tumor growth was very low, with only 20.8% of patients experiencing growth larger than 0.5 cm per year, according to the study. Approximately 79.2% of patients experienced slow, if any, tumor growth.

Interestingly, the cancer-specific survival of the patients were similar after 7 years. However, overall survival was observed to be worse among patients in the active surveillance, compared with the primary intervention group. The authors believe that this finding may be attributed to the poor health status of patients in the active surveillance group.

The investigators did not find any cases of metastatic disease among patients in the active surveillance group, including those who experienced disease progression.

“We [may] want to rethink our idea of progression, looking at persistent versus interval growth,” said researcher Ridwan Alam, a medical student at Johns Hopkins University School of Medicine.

Due to these findings, the investigators suggest that treating patients with SRMs with active surveillance may be safe. They also created a DISSRM score to determine which patients may be candidates for active surveillance, but it still needs to be validated, according to the study.

Study co-author Mohammed Allaf, MD, urges that SRMs be renamed to “growths in the kidney” to steer more patients toward active surveillance, since tumors or cancer can result in surgical overtreatment, the presentation concluded.