Options for lymph node management include observation, sentinel lymph node biopsy, and elective lymph node dissection. The choice of treatment depends on clinical staging, tumor thickness, ulceration, location, and patient age, and should be managed by a melanoma specialist.
TABLE 1
Excision margins for malignant melanoma
Tumor thickness | Surgical margin | Level of evidence |
---|---|---|
In situ | 5 mm | 58 |
<1 mm | 1 cm | 1b12 |
1–4 mm | 2 cm | 1b13 |
>4 mm | 3 cm | 1b12,13 |
Systemic therapy
Dacarbazine is the accepted treatment of choice for metastatic malignant melanoma. A systematic review found no randomized controlled trials comparing systemic therapy with supportive care or placebo. Several trials used dacarbazine as the control agent and found response rates varying from 9.1% to 29% (no test agent was found superior). Combination chemotherapy should be reserved for clinical studies and trials (LOE: 1a).14
Interferon alfa-2b is used as adjuvant therapy after surgical resection. It has an overall 5-year survival advantage over placebo (46% vs. 37%; number needed to treat [NNT]= 11, P=.0237) (LOE: 1b).15 Additionally, an economic analysis of this treatment found it to be cost-effective for high-risk melanomas (LOE: 2b).16
Vaccine therapy has shown preliminary benefit in several case-control studies but needs to be investigated further before it can be recommended (LOE: 3b).17
Nonmelanoma skin cancer treatment
Overview
Treatments for nonmelanoma skin cancer include surgical excision, Mohs micrographic surgery, curettage and electrodesiccation, cryosurgery, fractionated radiotherapy, topical chemotherapy, carbon dioxide laser, photo-dynamic therapy, intralesional interferon, and retinoids.
Some of these therapies are untested or not widely available. Immunotherapy and photodynamic therapy remain experimental.18 Laser treatment offers theoretical advantages for certain patients, such as those taking anticoagulants. However, safety hazards and inconvenience limit their use even by dermatologists (LOE: 5).19
Two meta-analysis reviews have attempted to compare cure rates for treatment of basal cell carcinoma by conventional methods.20,21 In these studies, standard excision was recommended for nodular-ulcerative and superficial basal cell carcinoma <2 cm in diameter and away from the face. Consideration of Mohs surgery was recommended for larger lesions, sclerosing lesions with morpheaform histology, and for cosmetically sensitive areas where large tissue loss or recurrence would be disfiguring (eyelid, ear, nose, lips) (LOE: 1a).20 Results are summarized in Table 2.
It should be noted that lack of uniformity in the method of reporting prohibited direct comparison of recurrence rates for different treatments. No similar meta-analysis reviews of treatment for squamous cell carcinoma were found.
TABLE 2
Effectiveness of treatment modalities for basal cell carcinoma 20
Treatment modality | Raw recurrence rate %* | Mean rawrecurrence % | Cumulative 5-year recurrence rate % † |
---|---|---|---|
Surgical excision | 1.4–2.9 | N/A | 5.3 |
Mohs micrographic surgery | 0.5–1.3 | 0.8 (21/2660) | N/A |
Curettage and electrodesiccation | 3.8–18.1 | N/A | 13.2 |
Cryosurgery | 0–11.4 | 3.0 (24/798) | N/A |
N/A, not available | |||
*Absolute number of patients with recurrence divided by number of patients with primary basal cell carcinoma at start of study (unknown number lost to follow-up). | |||
†Life-table cumulative 5-year recurrence rate. |
Recurrence and metastasis
The average rate of metastasis is 3.6% for squamous cell carcinoma. However, certain nonmelanoma skin cancer lesions are at higher risk for recurrence or metastasis and merit special consideration: larger lesions, those involving a mucous membrane, and lesions located on the scalp, ears, eyelids, nose, lips, or genitals. The rate of metastasis with lesions at high-risk locations may approach 30%.5
The majority of squamous cell carcinoma is actinically induced on sun-exposed areas. Squamous cell carcinoma occurring at a chronic scar or ulcer, such as that caused by a thermal or radiation burn, is also more likely to metastasize (LOE: 5).22 Metastatic spread most commonly involves regional lymph nodes, lungs, and liver. Basal cell carcinomas have an extremely low rate of metastasis (<0.1%).23
The overall rate of recurrence is also low—less than 1% for lesions removed from the neck, trunk, and extremities.24 Risk factors for recurrence include size of lesion and morpheaform histology found with sclerosing basal cell carcinoma (with associated subclinical infiltration). Lesions of the face are at higher risk for recurrence with rates up to 43% on the lateral canthus, 33% on the superior orbital rim and brow, 24% on the ear, and 19% on the nose.18 Primary care physicians should consider referral for such high-risk lesions, depending on their level of training and experience.
Surgical excision
Surgical excision is generally considered the gold standard for evaluation and treatment of suspected skin malignancy (LOE: 5).5,6 Advantages include rapid healing, excellent cosmesis, and an option to obtain a pathological evaluation of the excised tissue.
Conversely, excision is a more time-consuming prodedure than curettage and electrodesiccation or cryosurgery, and it may sacrifice more normal tissue than Mohs surgery. A surgical margin of normal-appearing tissue is routinely excised to eliminate microscopic tumor extension.
Two studies provide objective data regarding the margins necessary to ensure tumor clearance for basal cell carcinoma and squamous cell carcinoma. Both were prospective studies using Mohs surgery as the gold standard. Histological, subclinical tumor extension was then compared with ink markings placed preoperatively on the normal-appearing skin.