Postoperative Radiation for Skin Cancers


The table above  is from a study of aggressive skin cancers (basosquamous cancer) and shows the factors that increased the risk of a local recurrence:

  

Patients can be treated either with surgery or radiation. For some larger cancers or those considered "high risk" radiation may be necessary after surgery. The risk factors that would indicate a high risk of relapse and the need for postoperative radiation would include: positive surgical margins, perineural invasion, large or high grade cancers, invasion into bone or positive lymph node spread or rapid recurrences after previous surgery. There is a lot written about radiation if perineural invasion is seen (go here). 

PostOp radiation is the standard for squamous cancers of the skin (esp the face area)  if the path report shows high risk features (go here).

The NNCN 2004.1 states:

"If any non-melanoma skin cancer shows evidence of substantial perineural involvement (ie, involvement of more than just a few small sensory nerve branches), postoperative radiotherapy should be considered. If appropriately sized surgical margins are positive after an excision, Mohs surgery or a CCPDMA equivalent should beconsidered. If such a surgical procedure is not appropriate therapy, postoperative radiotherapy should be considered instead. Patients with positive findings on either FNA or open biopsy of a lymph node should receive regional lymph node dissection. A palpable intraparotid mass, in the presence of a facial tumor, should be treated with superficial parotidectomy. In both settings, adjuvant radiotherapy should be considered if more than one lymph node greater than 3 cm in diameter is present or if there is evidence of extracapsular spread."  High risk factors for squamous cancer of the skin can decrease the survival rates (see study.)

As far as the question of proper surgical margins the NCCN (2004.1) makes the following comments:  " Excision With Postoperative Margin Assessment Another therapeutic option for both basal cell and squamous cell ancers is POMA, consisting of standard surgical excision followed by postoperative pathologic assessment of margins. The surgical margins chosen by the panel for low-risk tumors are based on the work of Zitelli et al. Their analysis indicated the excision of basal cell or squamous cell tumors less than 2 cm in diameter and clinically well circumscribed should result in complete removal (with a 95% confidence interval) if 4-mm surgical margins are used. Any peripheral rim of erythema around a squamous cell cancer must be included in what is considered to be the tumor. The panel expanded the surgical margins for squamous cell cancers: the margins are 4 to 6 mm because of this issue and concerns about achieving complete removal. The indications for this approach were also expanded to include (1) re-excision of low-risk primary basal cell and squamous cell cancers located on the trunk and extremities (area L regions) if positive margins are obtained after an initial excision with POMA and (2) primary excision of larger tumors located in L regions deemed high risk because of their size, if 10-mm margins can be taken. If lesions can be excised with the recommended margins, then sideto- side closure, skin grafting, or secondary intention healing (ie, all closures do not rotate tissue around and alter where residual "seeds" of tumor might be sitting) are all appropriate reconstructive approaches. However, if tissue rearrangement or skin graft placement is necessary to close the defect, the group believes intraoperative surgical margin assessment is necessary."

Some other studies about high risk skin cancers are noted below:

 

Carcinoma of the skin with perineural invasion
Allie Garcia-Serra, MD , Russell W. Hinerman, MD , William M. Mendenhall, MD
Departments of Radiation Oncology, University of Florida Health Service Center, PO Box 100385, Gainesville, Florida, 32610-0385

Purpose.
To evaluate the outcome and patterns of relapse in patients treated for skin carcinoma of the head and neck with either microscopic or clinical perineural invasion.Methods and Materials.  Radiotherapy alone or combined with surgery was used to treat 135 patients with microscopic or clinical evidence of perineural invasion of skin carcinoma. All patients had at least 2 years of follow-up.
Results.
The 5-year local control rates without salvage therapy were 87% with microscopic perineural invasion and 55% with clinical perineural invasion. Overall, 88% of the local failures occurred in patients with positive margins. Almost half of the recurrences in patients with microscopic perineural invasion were limited to the first-echelon regional nodes. However, only 1 of 11 patients with basal cell carcinoma with microscopic perineural invasion had a nodal failure. Ninety percent of recurrences in patients with clinical perineural invasion occurred at the primary site. Cranial nerve deficits rarely improved after successful treatment of the primary disease. Radiographic abnormalities remained stable 30% of the time when patients had clinical evidence of progressive disease.

Conclusions.
Radiotherapy in patients with skin cancer with clinical perineural invasion should include treatment of the first-echelon regional lymphatics. The risk of regional node involvement is also relatively high for patients with squamous cell carcinoma with microscopic perineural invasion. In patients with clinical perineural invasion, the poor local control rates with conventional radiotherapy suggest a need for dose escalation with or without concomitant chemotherapy. © 2003 Wiley Periodicals, Inc. Head Neck 25: 000-000, 2003

Skin cancer of the head and neck with incidental microscopic perineural invasion.

McCord MW, Mendenhall WM, Parsons JT, Flowers FP    Int J Radiat Oncol Biol Phys 1999 Feb 1;43(3):591-5

Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, USA.

PURPOSE: To address outcomes in clinically asymptomatic patients in whom the unexpected finding of microscopic perineural invasion is noted at the time of surgery. METHODS AND MATERIALS: The 35 patients included in this study had skin cancers of the head and neck treated with curative intent between January 1965 and April 1995 at the University of Florida. All patients were without clinical or radiographic evidence of perineural invasion but, at the time of biopsy or surgical excision, had the incidental finding of microscopic perineural invasion. Definitive therapy consisted of radiotherapy alone after lesion biopsy (3 patients) or surgical excision preceded (2 patients) or followed (30 patients) by radiotherapy. All patients had follow-up for at least 1 year, 13 patients (37%) had follow-up for at least 5 years. RESULTS: The 5-year local control rate was 78%. The 5-year local control rate for the few patients treated with radiotherapy alone was statistically similar to that for patients treated with surgery and radiotherapy (100% vs. 77%, p = 0.4). Multivariate analysis for factors affecting local control included sex, histology, age, treatment group, clinical T stage, initial histologic differentiation, and previously untreated vs. recurrent tumors, none of which was found to be significant. CONCLUSIONS: Both surgery plus radiotherapy and radiotherapy alone provide a relatively high rate of local control for patients with incidentally discovered perineural invasion secondary to skin cancer.

Int J Radiat Oncol Biol Phys 2000 Apr 1;47(1):89-93

Skin cancer of the head and neck with clinical perineural invasion.

McCord MW, Mendenhall WM, Parsons JT, Amdur RJ, Stringer SP, Cassisi NJ, Million RR

Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, USA.

PURPOSE: To review treatment and outcomes in 62 patients with clinical and/or gross evidence of perineural invasion from skin cancer of the head and neck. METHODS AND MATERIALS: Sixty-two patients received radiotherapy at the University of Florida as part or all of their treatment between January 1965 and April 1995. All patients had clinical signs and symptoms of perineural involvement and/or documentation of tumor extending to grossly involve nerve(s). Twenty-one patients underwent therapy for previously untreated lesions, including 12 who received radiotherapy alone and nine who had surgery with postoperative radiotherapy. Forty-one patients underwent therapy for recurrent lesions, including 18 treated with radiotherapy alone and 23 who received preoperative or postoperative radiotherapy. RESULTS: Factors on multivariate analysis that predicted local control included patient age, previously untreated vs. recurrent lesions, presence of clinical symptoms, and extent of radiotherapy fields. Recurrence patterns were predominantly local; 26 of 31 patients (84%) who developed local recurrence after treatment had recurrent cancer limited to the primary site. CONCLUSIONS: Many patients with skin cancer and symptomatic perineural invasion have disease that is incompletely resectable. Approximately half these patients will be cured with aggressive irradiation alone or combined with surgery. Age, prior treatment, and clinical symptoms influence the likelihood of cure.

Head Neck 1992 May-Jun;14(3):188-95

Electron beam therapy for skin cancer of the head and neck.

Zablow AI, Eanelli TR, Sanfilippo LJ

Radiation Oncology Department, Saint Barnabas Medical Center, Livingston, New Jersey.

We retrospectively analyzed 99 patients with 115 sites of skin cancer, predominantly involving the head and neck, treated with electron beam therapy. Our objective was to determine the local control rate, radiotherapy reactions, cosmesis, and salvage treatment. Forty-three percent of patients received radiotherapy after biopsy, 41% were treated for recurrence following other modalities of treatment, and 16% had positive margins after surgical excision. With minimum and mean follow-up of 24 and 47 months, respectively, local control was achieved in 88% of patients. Six of 14 local recurrences were salvaged by surgery (five patients) and radiotherapy (one patient) for a total local control of 93%. Serial photographs and data were available to analyze cosmesis in 56 patients. Excellent or good cosmesis was achieved in 91%. Side effects were mild and self-limiting. EBT is highly efficacious and offers excellent cosmesis.

Head Neck 1993 Jul-Aug;15(4):320-4

Radical radiotherapy for T4 carcinoma of the skin of the head and neck: a multivariate analysis.

Lee WR, Mendenhall WM, Parsons JT, Million RR

Department of Radiation Oncology, University of Florida College of Medicine, Gainesville.

Sixty-seven patients with 68 stage T4 carcinomas of the skin of the head and neck were treated with radical radiotherapy at the University of Florida between October 1964 and November 1989. Thirty-three lesions were previously untreated and 35 were recurrent. Twenty-nine lesions were squamous cell carcinomas, 37 were basal cell carcinomas, and 2 were basosquamous carcinomas. Minimum follow-up was 2 years. The 5-year local control, local control including surgical salvage, and cause-specific survival probabilities were 53%, 74%, and 75%, respectively. Local control rates with radiotherapy alone were poorer in patients with recurrent lesions (41% vs. 67%, p = .07) or bone involvement (40% vs. 62%, p = .08). Results were analyzed by multivariate methods using local control, local control with surgical salvage, and cause-specific survival as endpoints. The parameters analyzed were histology; size of primary lesion; previous treatment (previously untreated vs. recurrent); involvement of bone, nerve, or cartilage; and skeletal muscle invasion. Three important prognostic factors were identified, each predictive of poorer ultimate local control and cause-specific survival rates: (a) bone involvement (p < .01); (b) recurrent lesions (p < .01); and (c) nerve involvement (p < .02). Radiotherapy alone can control advanced carcinomas of the skin of the head and neck, although lesions that have recurred after prior treatment and those with involvement of bone or nerve are associated with a lower likelihood of cure.