Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed classic Kaposi's sarcoma (KS) involving the skin

- Non-HIV-associated disease

- HIV negative

- Measurable disease

- At least 8 KS lesions with ≥ 5 marker lesions measurable in 2 dimensions AND ≥ 3
other lesions measuring ≥ 1 cm in diameter

- Two 3 mm punch biopsies of a non-marker lesion entirely composed of KS

- Irradiated cutaneous lesions may not be used as indicator lesions

- No known active visceral KS or symptomatic KS-related edema that would preclude
function or require cytotoxic chemotherapy

PATIENT CHARACTERISTICS:

Age

- 18 and over

Performance status

- Karnofsky 70-100%

Life expectancy

- At least 12 months

Hematopoietic

- Hemoglobin ≥ 8 g/dL

- Absolute neutrophil count ≥ 1,500/mm^3

- Platelet count ≥ 100,000/mm^3

Hepatic

- Bilirubin ≤ 1.5 times upper limit of normal (ULN)

- AST and ALT ≤ 3 times ULN

Renal

- Creatinine clearance ≥ 50 mL/min

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective barrier contraception during and for 3 months
after study participation

- No hypersensitivity to valganciclovir or ganciclovir

- No other neoplasia requiring cytotoxic therapy

PRIOR CONCURRENT THERAPY:

Biologic therapy

- More than 4 weeks since prior biological therapy for KS

- No concurrent immunotherapy

Chemotherapy

- More than 4 weeks since prior chemotherapy for KS

- No concurrent chemotherapy

Endocrine therapy

- No concurrent corticosteroid treatment except for replacement doses (equivalent to 20
mg of hydrocortisone per day)

Radiotherapy

- See Disease Characteristics

- More than 4 weeks since prior radiotherapy for KS

- No concurrent radiotherapy

Surgery

- Not specified

Other

- More than 14 days since prior acute treatment for infection (other than oral thrush
or genital herpes) or other serious medical illness

- More than 60 days since prior local therapy for any KS indicator lesion unless the
lesion showed documented progression since treatment

- More than 4 weeks since prior local therapy for KS

- More than 4 weeks since prior investigational agents

- More than 4 weeks since other prior antineoplastic therapy for KS

- No other concurrent antiviral therapy

- No other concurrent investigational agents

- No other concurrent systemic therapy for KS