Role of topical chemotherapy for primary acquired melanosis and malignant melanoma of the conjunctiva and cornea: review of the evidence and recommendations for treatment

Use of interferon alpha 2b to manage conjunctival primary acquired melanosis and conjunctival melanoma

Primary acquired melanosis (PAM) is acquired conjunctival pigmentation that can give rise to conjunctival melanoma (CM), a malignant tumor of the bulbar and palpebral conjunctiva or the caruncle. Surgical excision is the treatment of choice for this neoplasm. Topical chemotherapy is also used for patients with PAM with atypia or CM, hand in patients with recurrent or extensive disease, this may be an important option. Of the several chemotherapeutic drugs used, topical interferon alpha 2b (IFN-α2b) has become popular because of its low toxicity. Clinical evidence from case reports and case series supports the efficacy of IFN-α2b as the preferred adjuvant treatment for PAM and CM. In addition, topical IFN-α2b has been successfully applied to melanocytic tumors refractory to other treatments, such as cryotherapy and topical mitomycin C. In patients with locally advanced CM, the combination of IFN-α2b and systemic immunotherapy may serve as an alternative to exenteration. Given the low frequency of CM, long-term multicenter studies are needed to demonstrate the efficacy of IFN-α2b for preventing local recurrence and distant metastasis.

Ocular surface complications of local anticancer drugs for treatment of ocular tumors

Local chemotherapy is increasingly used, either in combination with surgery or as monotherapy, for management of ocular tumors. Yet many of the local chemotherapeutic agents used for ocular tumors are cytotoxic drugs that are frequently associated with toxicities in normal ocular tissues. Understanding and managing these side effects are important because they affect treatment tolerability, outcome and quality of vision. Herein, we review local anticancer drugs administered for the treatment of ocular tumors, with an emphasis on their toxicities to the ocular surface, adnexa and lacrimal drainage system. We provide the underlying mechanisms and management strategies for the ocular side effects. Recent innovations in anticancer immunotherapy and ocular drug delivery systems also are discussed as new potential therapeutic modalities for alleviation of side effects.

Primary melanoma of the cornea

Purpose: To present an extremely rare case of corneal melanoma.

Method: An 84-year-old female patient presented to our department with a pigmented corneal lesion in her right eye (OD), 6x4 mm, complaining of mild pain and inability of complete eyelid closure. Tumor growth had been noted the previous year. She had undergone cataract surgery in her right eye three years before, followed by an unspecified postoperative complication. Her visual acuity was 3/10 OD and 9/10 OS. Ophthalmic evaluation and ultrasonography (A- and B-scan) did not reveal any other pathology. The pigmented lesion was surgically removed and the patient underwent a protocol therapy of topical chemotherapy (mitomycin 0.03%, 2x4 for 2 weeks and dexamethasone 0.1%, 2x4 for the following 2 weeks, followed by another cycle of mitomycin 0.03%, 2x4 for another 2 weeks).

Results: The surgical removal of the lesion was uncomplicated, as was the postoperative period. The patient’s visual acuity improved to 6/10 three months postoperatively. The histologic examination revealed malignant melanoma.

Conclusions: Despite its rarity, primary melanoma of the cornea is an existing entity. Treatment of corneal melanoma consists of surgical removal and postoperative topical chemotherapy. Postoperative follow-up is mandatory.

Management Issues in Conjunctival Tumours: Conjunctival Melanoma and Primary Acquired Melanosis

Conjunctival melanoma is a rare malignant condition of the ocular surface. It is potentially lethal, with regional lymph node spread often preceding distant solid-organ metastasis. Due to its rarity and the long latency between treatment and local recurrence or the development of metastases, it is difficult to study. The literature is composed entirely of case series of varying quality, and there is significant variability in the management of this condition. This commentary attempts to distil the evidence base to provide practical management tips for the clinician.

Increased Non-Homologous End Joining Makes DNA-PK a Promising Target for Therapeutic Intervention in Uveal Melanoma

Uveal melanoma (UM) is the most common primary intraocular tumour in adults, with a mean survival of six months following metastasis. The survival rates have not improved in over 30 years. This study has shown that sister chromatid exchange (SCE) is low in UM which is likely due to a reduced expression of FANCD2. As FANCD2 can function to suppress non-homologous end joining (NHEJ), this study therefore investigated NHEJ in UM. The activation of the catalytic subunit of the NHEJ pathway protein DNA-dependent protein kinase (DNA-PK) was measured by analysing the foci formation and the ligation efficiency by NHEJ determined using a plasmid-based end-joining assay. Using small-interfering RNA (siRNA) knock-down, and chemical inhibitors of DNA-PK, the survival of primary UM cultures and two cell lines were determined. To assess the homologous recombination capacity in response to the inhibition of DNA-PK, a SCE analysis was performed. In addition, to support the findings, the messenger RNA (mRNA) expression of genes associated with NHEJ was analysed using the Cancer Genome Atlas (TCGA)-UM RNAseq data (n = 79). The NHEJ activity and DNA-PKcs activation was upregulated in UM and the inhibition of DNA-PK selectively induced apoptosis and sensitized to ionising radiation and inter-strand cross-linking agents. The inhibition of the NHEJ protein DNA-PK is lethal to UM, indicating a potentially effective therapeutic option, either alone or as a sensitizer for other treatments.

[Adjuvant therapy and interdisciplinary follow-up care of conjunctival melanoma]

BACKGROUND

Despite microscopically controlled tumor excision, malignant melanomas of the conjunctiva have a propensity for local recurrence, lymphatic spread and distant metastases.

OBJECTIVES

This review outlines the options of adjuvant therapy as well as the structure of interdisciplinary follow-up care for patients with conjunctival melanoma.

METHODS

The study provides a PubMed literature review and own clinical results.

RESULTS

In conjunctival melanoma complete tumor excision using a minimal touch technique should always be combined with adjuvant therapy, such as cryotherapy, radiotherapy, topical chemotherapy and/or immunotherapy. For locally circumscribed lesions of the bulbar conjunctiva adjuvant brachytherapy can be supplemented and for non-bulbar, extensive, diffuse or multilocular tumor growth, complementary adjuvant topical mitomycin C therapy or proton radiotherapy can be used. Novel adjuvant approaches include topical interferon alpha-2b immunotherapy, topical vascular endothelial growth factor (VEGF) inhibitors or in cases of BRAF mutations personalized therapy using selective BRAF inhibitors or in combination with mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK), MAPK/ERK (MEK) inhibitors. All patients should be integrated into an interdisciplinary follow-up care program including quarter yearly checkups in the first 5 years and psycho-oncological healthcare.

CONCLUSION

Following microscopically controlled tumor excision, adjuvant treatment using cryotherapy, radiotherapy, topical chemotherapy and/or immunotherapy as well as interdisciplinary follow-up care are mandatory for the modern management of patients with conjunctival melanoma.

Advances in the management of conjunctival melanoma

Malignant melanoma of the conjunctiva is a rare but serious condition. Over the last several years, there have been important advances in the classification, diagnosis, and treatment of this condition. Recent cytogenetic and immunohistochemical studies are increasing understanding of its tumorigenesis. Diagnosis, although still made via histopathology, has been aided with imaging techniques such as ultrasound biomicroscopy and anterior segment optical coherence tomography. Primary treatment consists of surgical excision. But adjuvant treatments with cryotherapy, topical chemotherapy, and radiation therapy have shown increased success. Sentinel lymph node biopsy has shown early promise of detecting micro-metastasis. Long term follow-up of patients with conjunctival melanoma with systemic surveillance is necessary to detect recurrences and metastases.

Management of conjunctival malignant melanoma: a review and update

Conjunctival malignant melanoma is a pigmented lesion of the ocular surface. It is an uncommon but potentially devastating tumor that may invade the local tissues of the eye, spread systemically through lymphatic drainage and hematogenous spread, and recur in spite of treatment. Despite its severity, the rarity of available cases has limited the evidence for diagnosis and management. This review will provide an overview of the epidemiology, presentation, diagnosis, management, and surveillance of conjunctival melanoma, with an emphasis on recent advances in biological therapies to treat this disease.

Local chemotherapeutic agents for the treatment of ocular malignancies

We critically analyze available peer-reviewed literature, including clinical trials and case reports, on local ocular cancer treatments. Recent innovations in many areas of ocular oncology have introduced promising new therapies, but, for the most part, the optimal treatment of ocular malignancies remains elusive.

Conjunctival melanoma: a review of conceptual and treatment advances

The aim of this study was to review the available literature and identify recent advances in the classification and management of conjunctival melanoma (CM) for clinicians working in this field. English-based articles were identified using the MEDLINE^® database, and additional cited works not detected in the initial search were also obtained. Articles were assessed according to the Australian National Health and Medical Research Council levels of evidence criteria. Review of the literature indicated that the current classification and management of CM is predominantly based upon primarily nonrandomized, single-institution, retrospective case series. While these studies provide the basis for the recent seventh edition of the tumor node metastasis staging classification, this classification more accurately reflects the current knowledge of prognostic factors for CM. Application of this revised classification system together with prospective trials will provide the opportunity for future consistent and comparable data collection across centers, and it will improve the quality of evidence upon which current classification and management of CM is based. Furthermore, the high risk of local recurrence with current standard management suggests that adjuvant therapy, particularly mitomycin C and/or brachytherapy, may improve outcomes regardless of clinical staging. Finally, the use of sentinel lymph node biopsy may have significant benefit for a select group of CM patients.

Excision with corneoscleral lamellar keratoplasty and amniotic membrane transplantation of a corneal displaced recurrent conjunctival melanoma

An 81-year-old woman with a raised pigmented nodule over her left cornea for 7 months duration was examined. Dark conjunctival pigmentation was observed in the upper bulbar fornix conjunctiva. She had previously undergone primary surgical excision of a malignant conjunctival melanoma four years earlier. The tumor separated easily from the corneal surface, but remained slightly attached to the corneoscleral surface. A corneoscleral lamellar dissection of 3 mm in width and 2 mm in depth as well as a corneoscleral lamellar keratoplasty for the reconstruction of the corneoscleral defect were performed. The wide upper bulbar and fornix conjunctiva were excised, and an amniotic membrane transplantation was performed. Biopsy revealed an invasive melanoma with a depth of 1 mm. Left, right, and inferior tumor margins of the corneoscleral lesion and the pigmentary lesion in the conjunctiva were free of the tumor. After surgery, 0.04% mitomycin was administered topically 4 times daily for 4 weeks. There was no recurrence 2 years after surgery, and systemic evaluation revealed no metastasis.

Current appraisal of conjunctival melanocytic tumors: classification and treatment

Conjunctival melanocytic tumors represent a spectrum of pigmented tumors that include benign, premalignant and malignant tumors. Conjunctival nevi are the most common pigmented tumors and are typically found in the interpalpebral bulbar conjunctiva. These lesions usually contain fine clear cysts on slit lamp biomicroscopy. Primary acquired melanosis includes lesions from increased melanin pigmentation without proliferation of melanocytes to melanoma in situ. In the new classification system, the idea is to use the term 'primary acquired melanosis' only as a clinical description, highlighting the fact that the biologic behavior of acquired melanotic lesions cannot be predicted solely based upon clinical grounds without histopathologic examination. Conjunctival melanoma represents only 5% of all melanomas arising in the ocular region and is associated with a high mortality rate. The management of primary acquired melanosis, nevi and conjunctival melanomas involves various modalities used either alone or concomitantly depending on the size and extent of the lesion.

Resistance of uveal melanoma to the interstrand cross-linking agent mitomycin C is associated with reduced expression of CYP450R

BACKGROUND

Uveal melanoma (UM) is the most common primary intraocular tumour of adults, frequently metastasising to the liver. Hepatic metastases are difficult to treat and are mainly unresponsive to chemotherapy. To investigate why UM are so chemo-resistant we explored the effect of interstrand cross-linking agents mitomycin C (MMC) and cisplatin in comparison with hydroxyurea (HU).

METHODS

Sensitivity to MMC, cisplatin and HU was tested in established UM cell lines using clonogenic assays. The response of UM to MMC was confirmed in MTT assays using short-term cultures of primary UM. The expression of cytochrome P450 reductase (CYP450R) was analysed by western blotting, and DNA cross-linking was assessed using COMET analysis supported by γ-H2AX foci formation.

RESULTS

Both established cell lines and primary cultures of UM were resistant to the cross-linking agent MMC (in each case P<0.001 in Student's t-test compared with controls). In two established UM cell lines, DNA cross-link damage was not induced by MMC (in both cases P<0.05 in Students's t-test compared with damage induced in controls). In all, 6 out of 6 UMs tested displayed reduced expression of the metabolising enzyme CYP450R and transient expression of CYP450R increased MMC sensitivity of UM.

CONCLUSION

We suggest that reduced expression of CYP450R is responsible for MMC resistance of UM, through a lack of bioactivation, which can be reversed by complementing UM cell lines with CYP450R.

Conservative resection and adjuvant plaque brachytherapy for early-stage conjunctival melanoma

BACKGROUND

To describe the outcome of patients treated by conservative surgical excision followed by adjuvant plaque brachytherapy for early-stage primary or recurrent conjunctival melanoma.

DESIGN

Retrospective, non-comparative, interventional case series.

PARTICIPANTS

We reviewed 19 eyes in 19 consecutive patients presenting with biopsy proven conjunctival melanoma with pathologic stage pT1c or less.

METHODS

Patients with primary or recurrent early-stage conjunctival melanoma were identified and treated using a conservative resection technique (tractional micro-dissection) involving avoidance of deep dissection and modest lateral clearance followed by adjuvant plaque brachytherapy.

MAIN OUTCOME MEASURE

Local recurrence and ocular complications.

RESULTS

Mean age was 55.2 years and male : female (8:11). Mean follow up was 43.1 months (range 30.1-54.3 months). All patients were treated by conservative resection followed by adjuvant Iodine-125 plaque brachytherapy. The treatment dose was 100 Gy to a depth of 1.5-3.0 mm.

OUTCOMES

median visual acuity and intraocular pressure were unchanged after surgery. Six patients experienced corneal ulceration in the immediate postoperative period. No patients experienced recurrence at the treatment site or metastases. Three patients experienced new lesions distant from the treatment site.

CONCLUSIONS

Conservative resection and adjuvant plaque brachytherapy is an effective and well-tolerated modality for the management of patients with early-stage conjunctival melanoma.

Recurrent primary acquired melanosis with atypia involving a clear corneal phacoemulsification wound

PURPOSE

To report a case of corneal primary acquired melanosis (PAM) with atypia after cataract surgery.

METHODS

Retrospective case report with literature review.

RESULTS

Excision of an elevated pigmented conjunctival lesion was performed at the time of cataract extraction by clear corneal phacoemulsification by an outside surgeon. Histopathologic examination revealed PAM with atypia. Three months after the initial surgery, recurrent melanosis involving the peripheral corneal epithelium was noted, with extension of pigment into the corneal stroma through the paracentesis site. Excision of the involved corneal epithelium and the adjacent conjunctiva was performed, and microscopically recurrent PAM with atypia was confirmed. Adjuvant cryotherapy was applied at the time of surgery, and topical mitomycin C was given postoperatively. Repeat biopsies revealed no remaining malignancy, and the intrastromal pigment has disappeared during 18 months of follow-up.

CONCLUSION

We present this case to illustrate the importance of complete evaluation and treatment of potentially atypical melanocytic conjunctival lesions before proceeding with elective intraocular surgery.

Plaque brachytherapy for the management of ocular surface malignancies with corneoscleral invasion

PURPOSE

To describe the outcome of patients treated by surgical excision followed by plaque brachytherapy for primary or recurrent ocular surface malignancies with evidence of deep margin (corneoscleral) invasion.

METHODS

Retrospective, non-comparative, interventional case series. Eleven consecutive patients presenting with biopsy-proven scleral and/or corneal stromal involvement from either conjunctival melanoma (CM) or squamous cell carcinoma (SCC) of the conjunctiva were reviewed.

RESULTS

Five patients had CM (pT3 N0 M0 [n = 3], pT4 N0 M0 [n = 2]) and six patients had SCC (T3 N0 M0 [n = 6]). Mean age was 60.8 years and male:female (3:8). Mean follow up was 23.4 months (range 12-36 months). All patients were treated with Iodine-125 plaque following biopsy-proven corneoscleral invasion on histopathology. The treatment dose was 100 Gy to a depth of 1.5-2.5 mm.

OUTCOMES

Median visual acuity and intraocular pressure were unchanged after surgery. Five patients experienced corneal ulceration in the immediate postoperative period. None experienced recurrence at the treatment site. One SCC patient and two CM patients experienced new lesions distant from the treatment site. No sight-threatening complications were observed. No patients developed distant metastases.

CONCLUSION

Plaque brachytherapy is an effective and well-tolerated modality for the management of patients with ocular surface malignancy with evidence of localized corneoscleral invasion.

Primary sebaceous carcinoma of the corneaoscleral limbus with pagetoid recurrence

We report a sebaceous carcinoma confined to the corneoscleral limbus without involvement of the eyelid. A 60-year-old man, who showed multiple masses on the corneaoscleral limbus and limbal ulceration but with normal eyelids, underwent surgical en-bloc excision of the masses. Histopathologic examination revealed a sebaceous carcinoma. Three weeks after excision, multiple pagetoid recurrences were found along the bulbar conjunctiva 2 mm away from the limbus. After the application of topical mitomycin C, the pagetoid spread regressed completely. After a 2 year follow-up, no other local or systemic recurrences were observed. This report shows that the ulcerative mass which is confined to only the corneoscleral limbus may be a sebaceous carcinoma even without eyelid involvement. Topical mitomycin C may be effective for treating pagetoid spread of sebaceous carcinoma of limbal origin.

Primary Acquired Melanosis of the Conjunctiva: Risks for Progression to Melanoma in 311 Eyes

PURPOSE

To evaluate the clinical features and risks for transformation of conjunctival primary acquired melanosis (PAM) into melanoma.

DESIGN

Noncomparative case series.

PARTICIPANTS

Three hundred eleven eyes with conjunctival PAM without melanoma at initial examination from a single-center tertiary referral center.

METHODS

Retrospective chart review with evaluation of the clinical features of PAM at initial presentation and follow-up. Times to PAM enlargement, recurrence, and transformation into melanoma were assessed using Kaplan-Meier estimates. Risk factors for these outcomes were analyzed using Cox proportional hazards regressions.

MAIN OUTCOME MEASURES

Primary acquired melanosis enlargement, recurrence, and transformation into melanoma.

RESULTS

Mean patient age at diagnosis of PAM was 56 years (range, 15-90), 62% were female, and 96% were Caucasian. The conjunctival quadrant(s) affected by PAM were temporal (57%), inferior (45%), nasal (42%), and superior (37%). The anatomic location(s) of PAM included bulbar conjunctiva (91%), limbal conjunctiva (55%), cornea (23%), forniceal conjunctiva (13%), palpebral conjunctiva (12%), and caruncle (11%). Primary acquired melanosis extended for a mean of 3 clock hours (range, 1-12). Initial management included observation (n = 194 eyes [62%]), biopsy combined with cryotherapy (n = 107 eyes [34%]), and topical chemotherapy and/or cryotherapy without biopsy (n = 10 [4%]). Of PAM that was observed, Kaplan-Meier estimates at 10 years revealed PAM enlargement in 35% and transformation into melanoma in 12%. Of those that underwent incisional or excisional biopsy, 10-year estimates of PAM recurrence and transformation into melanoma were 58% and 11%, respectively. Progression to melanoma occurred in 0% of cases of PAM without atypia, 0% of cases of PAM with mild atypia, and 13% of cases of PAM with severe atypia. Of the 9 patients with PAM who developed melanoma, none have developed systemic metastasis. Multivariable analysis revealed that the most significant factor for both PAM recurrence and progression to melanoma was extent of PAM in clock hours.

CONCLUSION

Primary acquired melanosis without atypia or with mild atypia shows 0% progression to melanoma, whereas PAM with severe atypia shows progression to melanoma in 13%. The greater the extent of PAM in clock hours, the greater the risk for transformation to melanoma.

Structure of a DNA repair substrate containing an alkyl interstrand cross-link at 1.65 A resolution

Chemotherapeutic alkylating agents, such as bifunctional nitrogen mustards and cisplatins, generate interstrand DNA cross-links that inhibit cell proliferation by arresting DNA transcription and replication. A synthetic N4C-ethyl-N4C interstrand cross-link between opposing cytidines mimics the DNA damage produced by this class of clinically important compounds and can be synthesized in large quantities to study the repair, physical properties, and structures of these DNA adducts. The X-ray structure of a DNA duplex d(CCAAC*GTTGG)2 containing a synthetic N4C-ethyl-N4C interstrand cross-link between the cytosines of the central CpG step (*) has been determined at 1.65 A resolution. This structure reveals that the ethyl cross-link in the CpG major groove does not significantly disrupt the B-form DNA helix. Comparison of the N4C-ethyl-N4C cross-linked structure with the structure of an un-cross-linked oligonucleotide of the same sequence reveals that the cross-link selectively stabilizes a preexisting alternative conformation. The conformation preferred by the cross-linked DNA is constrained by the geometry of the ethyl group bridging the cytosine amines. Characteristics of the cross-linked CpG step include subtle differences in the roll of the base pairs, optimized Watson-Crick hydrogen bonds, and loss of a divalent cation binding site. Given that the N4C-ethyl-N4C cross-link stabilizes a preexisting conformation of the CpG step, this synthetically accessible substrate presents an ideal model system for studying the genomic effects of covalently coupling the DNA strands, independent of gross alterations in DNA structure.