Morcellation may worsen staging of renal tumors

December 1, 2006

Cleveland-Understaging of renal tumors on the basis of clinical criteria appears problematic when tumors are morcellated during laparoscopic nephrectomy, according to a Mayo Clinic study presented at the 2006 World Congress of Endourology here.

Cleveland-Understaging of renal tumors on the basis of clinical criteria appears problematic when tumors are morcellated during laparoscopic nephrectomy, according to a Mayo Clinic study presented at the 2006 World Congress of Endourology here.

"In this cost-conscious world, we're trying to tailor follow-up based on the risks that a patient may have. In this paper, we show that gauging follow-up based on [tumor] size and clinical staging will not accurately predict whether this patient will live or die from his disease," said lead study author Amy E. Krambeck, MD, a urology resident at the Mayo Clinic, Rochester, MN, working with Michael L. Blute, MD, and colleagues.

The retrospective analysis considered all patients in the Mayo Clinic nephrectomy registry who underwent nephrectomy for organ-confined renal cell carcinoma. Of those 2,676 patients, 195 (7.3%) subsequently were diagnosed with pT3 disease (tumor invasion into the perinephric fat), as confirmed by preoperative radiologic imaging reports. Patients were assigned to one of three groups according to the size of their tumor: 24 (12.3%) had tumors ≤4 cm, 60 (30.8%) had tumors >4 cm and ≤7 cm, and 111 (56.9%) had tumors larger than 7 cm.

Eight patients (4.1%) were identified from among these groups as having extrarenal invasion on preoperative imaging, and, interestingly, almost half had tumors less than 7 cm in size. The remainder (five of eight) had tumors larger than 7 cm.

Among patients identified with pT3a renal tumors, approximately half had T1 tumors of 7 cm or less; however, 5% of those who had tumors >4 cm and ≤7 cm had had evidence of extrarenal invasion on their preoperative imaging, Dr. Krambeck explained.

"It may look like an organ-confined tumor, but you really won't know what you're dealing with until you remove the specimen and pathologically review it," she said.

Dr. Krambeck noted that the reason some urologists prefer to have tissue morcellated is that it allows the specimen to be removed through a port site and the incision remains small. Leaving the specimen intact requires a longer incision and may extend the patient's recovery time, "but I think, today, in order to do good cancer surgery, you need to be aggressive," she said.

"Once you morcellate, you lose those tissue points; you no longer can determine if there's renal sinus invasion or perinephric fat or what exactly is involved with the tumor," Dr. Krambeck warned.

No patient in the study with a T1 tumor less than 4 cm had extrarenal invasion. Thus, the authors concluded, tumor morcellation may exacerbate the already common problem of understaging tumors on the basis of clinical criteria.

"Confirming clinical staging data with data from the specimen is absolutely necessary to accurately predict outcome in these patients," Dr. Krambeck said.