Tratamiento quirúrgico vs. no quirúrgico en el carcinoma basocelular

Characterisation of resistance mechanisms developed by basal cell carcinoma cells in response to repeated cycles of Photodynamic Therapy

Photodynamic Therapy (PDT) with methyl-aminolevulinate acid (MAL-PDT) is being used for the treatment of Basal cell carcinoma (BCC), but recurrences have been reported. In this work, we have evaluated resistance mechanisms to MAL-PDT developed by three BCC cell lines (ASZ, BSZ and CSZ), derived from mice on a ptch+/- background and with or without p53 expression, subjected to 10 cycles of PDT (10thG). The resistant populations showed mesenchymal-like structure and diminished proliferative capacity and size compared to the parental (P) cells. The resistance was dependent on the production of the endogenous photosensitiser protoporphyrin IX in the CSZ cell line and on its cellular localisation in ASZ and BSZ cells. Moreover, resistant cells expressing the p53 gene presented lower proliferation rate and increased expression levels of N-cadherin and Gsk3β (a component of the Wnt/β-catenin pathway) than P cells. In contrast, 10thG cells lacking the p53 gene showed lower levels of expression of Gsk3β in the cytoplasm and of E-cadherin and β-catenin in the membrane. In addition, resistant cells presented higher tumorigenic ability in immunosuppressed mice. Altogether, these results shed light on resistance mechanisms of BCC to PDT and may help to improve the use of this therapeutic approach.

In vivo evaluation of antitumoral and antiangiogenic effect of imiquimod-loaded polymeric nanoparticles

The chemotherapeutic agent imiquimod (Imq) is used to treat skin cancers, the most common type of human cancer. However, the high incidence of local and systemic side effects associated with its use as well as its low skin permeation impair patient compliance and therapeutic effectiveness To overcome these limitations, nanostructured systems such as nanoparticles can be a promising alternative. Nanoparticles are submicron particles (size less than 1000 nm) with high surface area that facilitates the interaction and cellular uptake by biological membranes. Therefore, the aim of the present work is to evaluate antiangiogenic effect and antitumoral activity of imiquimod-loaded nanoparticles compared to market Imq formulation. Polymeric nanoparticles containing Imq were obtained by the technique of precipitation of preformed polymer. Antiangiogenic activity of the formulations was determined in chicken embryo chorioallantoic membrane (CAM) and its chemopreventive potential was evaluate during multistage DMBA and croton oil model of skin carcinogenesis in mice. Nanoparticles containing Imq presented antiangiogenic activity superior than negative control, placebo dispersion and market Imq (p < 0.05) in the CAM model and also significantly reduced the number and size of papillomas compared to all other groups. These results suggest, therefore, that the obtained delivery system can be an alternative to treat diseases related to vessels formation and also potentially increase cutaneous permeation and efficacy of poor soluble drugs normally used to treat cutaneous diseases.

Analysis of effectiveness of a surgical treatment algorithm for basal cell carcinoma

BACKGROUND

Surgical excision is the treatment of choice for basal cell carcinoma and micrographic surgery considered the gold standard, however not yet used routinely worldwide available, as in Brazil. Considering this, a previously developed treatment guideline, which the majority of tumors were treated by conventional technique (not micrographic) was tested.

OBJECTIVE

To establish the recurrence rate of basal cell carcinomas treated according to this guideline.

METHOD

Between May 2001 and July 2012, 919 basal cell carcinoma lesions in 410 patients were treated according to the proposed guideline. Patients were followed-up and reviewed between September 2013 and February 2014 for clinical, dermatoscopic and histopathologic detection of possible recurrences.

RESULTS

After application of exclusion criteria, 520 lesions were studied, with 88.3% primary and 11.7% recurrent tumors. Histological pattern was indolent in 85.5%, 48.6% were located in high risk areas and 70% small tumors. Only 7.3% were treated by Mohs micrographic surgery. The recurrence rate, in an average follow-up period of 4.37 years, was 1.3% for primary and 1.63% for recurrent tumors. Study limitations: unicenter study, with all patients operated on by the same surgeon.

CONCLUSION

The treatment guideline utilized seems a helpful guide for surgical treatment of basal cell carcinoma, especially if micrographic surgery is not available.

Nonsurgical Therapies for Basal Cell Carcinoma: A Review

Basal cell carcinoma (BCC) is the most prevalent malignant tumor in humans and the local destruction of tissue that can result from excision has a significant impact on well-being. Treating BCC is costly for health care systems given the high incidence of this tumor, especially in older patients. Standard treatment involves either resection with histologic assessment of margins or Mohs micrographic surgery. Surgery is sometimes contraindicated, however, due to the presence of significant comorbidity or high cosmetic expectations. For such patients, nonsurgical treatments have become available. These alternatives can offer good local control of disease, preserve function, and achieve excellent cosmetic results.

Resistance of Nonmelanoma Skin Cancer to Nonsurgical Treatments. Part I: Topical Treatments

A wide range of treatments is now available for nonmelanoma skin cancer (NMSC), including 5-fluorouracil, ingenol mebutate, imiquimod, diclofenac, photodynamic therapy, methotrexate, cetuximab, vismodegib, and radiotherapy. All are associated with high clinical and histologic response rates. However, some tumors do not respond due to resistance, which may be primary or acquired. Study of the resistance processes is a broad area of research that aims to increase our understanding of the nature of each tumor and the biologic features that make it resistant, as well as to facilitate the design of new therapies directed against these tumors. In this article we review resistance to the authorized topical treatments for NMSC.

Photodynamic therapy in the treatment of basal cell carcinoma: a systematic review and meta-analysis

BACKGROUND/PURPOSE

This meta-analysis was designed to compare the efficacy, cosmetic outcome and safety of photodynamic therapy (PDT) with other procedures for the treatment of primary basal cell carcinoma (BCC).

METHODS

A computerized search through electronic databases was performed to search for relevant randomized controlled trials (RCTs) published before October 2013. Only RCTs that compared PDT to non-PDT for patients with BCC were selected. The risk ratios (RRs) and 95% confidence intervals (CIs) were calculated.

RESULTS

Eight studies with a total of 1583 patients met the inclusion criteria. PDT was associated with lower complete clearance rate (RR: 0.93, 95% CI: 0.89-0.98), higher 1-year recurrence rate (RR: 12.42, 95% CI: 2.34-66.02) and 5-year recurrence rate (RR: 6.79, 95% CI: 2.43-18.96) when compared with surgical excision. There was no statistically significant difference in complete clearance rate (RR: 0.92, 95% CI: 0.85-1.00), 1-year recurrence rate (RR: 1.04, 95% CI: 0.46 to 2.39) or 5-year recurrence rate (RR: 1.08, 95% CI: 0.62-1.86) when PDT was compared with cryotherapy. PDT had higher complete clearance rate compared with placebo but no statistically significant difference in complete clearance rate and 1-year recurrence rate when compared with pharmacologic treatment (topical imiquimod and 5-fluorouracil). PDT had a significantly better cosmetic outcome than surgery and cryotherapy.

CONCLUSIONS

PDT is a useful method for the treatment of BCC, more efficient than placebo and with a similar efficiency to cryosurgery and pharmacologic treatment. Even though it is less effective than surgical excision, PDT has cosmetic advantages over surgery and cryosurgery.