NEW ORLEANS—Putting off treatment for non-melanoma skin cancer—even as long as a year—does not appear to increase the risk of adverse consequences, specifically metastases, according to data reported here at the American Academy of Dermatology Annual Meeting.
“We found no evidence to show that a time delay of up to one year from diagnosis to Mohs micrographic surgery impacts subclinical spread of non-malignant skin cancer,” said Joseph Diehl, a fourth-year medical student in the division of dermatology at the David Geffen School of Medicine at the University of California at Los Angeles.
Diehl and colleagues conducted a retrospective chart review of all patients at West Los Angeles Veterans Affairs Medical Center who underwent Mohs Micrographic Surgery for biopsy-proven non-melanoma skin cancer from 2004 to 2007.
A total of 242 individuals were identified who had 289 lesions that fit the study criteria—most importantly for this study, having recorded the size of the lesion at the time of presentation and at the time of Mohs surgery. Two hundred twenty-five were diagnosed as basal cell carcinoma and 64 were squamous cell carcinoma; analysis was limited to 283 of the lesions.
“Patients at our facility were waiting many months, sometimes more than a year, for Mohs micrographic surgery due to a shortage of Mohs surgeons. We wondered if we were doing them a disservice by having them wait that long for treatment,” Diehl said.
“Non-melanoma skin cancers can have high morbidity and cost but are rarely fatal. The lack of impact on quality of life and possibly the lack of Mohs surgeons may cause delay in seeking or obtaining treatment. If long delays are associated with increased tumor size, this could impact recurrence rates, financial cost, and cosmetic outcome.”
The researchers investigated whether delay of treatment from biopsy to Mohs surgery results in a large tumor size or involves more Mohs layers, using post-Mohs micrographic surgery defect size as a proxy for final tumor size in calculating that difference.
Of the 283 lesions analyzed, the median cancer diameter change from biopsy to sugary did not change. There was also no change in the diameter of median size of the 255 primary tumors or in the median diameter change among the 28 recurrent tumors.
Similarly, there was no diameter change from the median, neither in the 219 patients with basal cell carcinoma nor in the 64 patients with squamous cell carcinoma.
“We found no correlation whatsoever between size of the tumors and time to treatment,” Diehl said in his poster discussion presentation. “We did not observe any trend in delay among lesions when we looked at the size of the tumor at presentation.”
The mean diameter of the lesions at presentation was about 0.9 cm, and the mean Mohs surgery defect size was about 1.8 cm. The median diameter change of 0.8 cm for the 119 patients who presented with tumors less than 1 cm in size was similar to the 104 patients with tumors greater than 1 cm in size at presentation—also a median increase of 0.8 cm.
The researchers measured diameter increase in centimeters by the size of the tumor as presentation biopsy to the size of the Mohs surgery defect. In most cases the Mohs surgery defect was larger than the original tumor size in order to obtain sufficient negative margins. However, Diehl noted that in some cases, the combination of the biopsy and the slow growth of the tumor resulted in Mohs defect diameter sizes that were smaller than the original lesions.
The findings showed, he said, that it didn't matter if the tumor was on the trunk or extremities, the ear, forehead, lip, cheek, nose, periorbital area, temple, or scalp. The median size of the tumors did not fall outside the first to third quartiles for any position.
“It was hard to compare data because the numbers of lesions in each position was so small, but we did not see any statistical difference.” The number ranges from seven lesions seen on the scalp to 45 on the ears.
David Remis, MD, a dermatologist with Group Health Olympia Medical Center in Washington, commented, “In my experience I have seen very similar things with patients diagnosed with non-melanoma skin cancer. I have had patients who waited a year or longer without any appreciable growth in their tumors. You can wait much longer, especially with these basal type cancers.”
And the moderator of the session at which the study was presented, Keyvan Nouri, MD, Professor of Medicine at the Miller School of Medicine at the University of Miami, suggested that in future work the research should separate basal cell and squamous cell outcomes. “These are really very different types of cancer,” he noted.
Because the patient population was from a Veterans Affairs hospital, 99% of the study cohort were men; 99% of them were Caucasian, and their average age was 70.1. The median delay between diagnosis and Mohs surgery was 127 days. The average delay was 141 days. The time from diagnosis to treatment ranged from 14 to 761 days.
Diehl acknowledged that while the researchers did not observe evidence that delay of up to a year from biopsy to surgery made a difference in tumor size, the research also does not truly provide evidence that it does not make a difference in tumor growth or outcome.
“It remains to be seen if non-melanoma skin cancer of a certain size, histologic subtype, or anatomic site might undergo faster growth and need more urgent treatment. Lack of agreement and the limitations of our and previous studies support the need for prospective investigation of surgical delay and Mohs micrographic surgery outcomes.”