Gemcitabine With or Without Docetaxel as Second-Line Therapy in Treating Patients With Metastatic or Relapsed, Unresectable Uterine or Soft Tissue Leiomyosarcoma

DISEASE CHARACTERISTICS: * Histologically confirmed uterine or soft tissue leiomyosarcoma, meeting ≥ 1 of the following criteria: * Metastatic disease * Relapsed and unresectable disease * Prior treatment with a first-line anthracycline-based chemotherapy regimen required * Relapsed disease \> 1 year after adjuvant chemotherapy is considered untreated disease * If relapsed disease occurs \< 1 year after adjuvant therapy, then adjuvant therapy is considered a first-line treatment * At least 1 measurable lesion, defined as the following: * At least 1 target lesion must be located in a non-irradiated area * Obvious disease progression within the past 6 weeks * No other uterine sarcomas, including any of the following: * Carcinosarcoma * Endometrial stroma sarcoma * Other soft tissue sarcoma * No symptomatic or known brain metastases PATIENT CHARACTERISTICS: Age * 18 and over Performance status * WHO 0-2 Life expectancy * Not specified Hematopoietic * Absolute neutrophil count ≥ 1,000/mm\^3 * Platelet count ≥ 100,000/mm\^3 Hepatic * Bilirubin ≤ 1.5 times upper limit of normal (ULN) * AST and ALT ≤ 2.5 times ULN * Alkaline phosphatase ≤ 2.5 times ULN * No specific hepatic contraindication to study treatment * Hepatitis B core and hepatitis B surface antigen negative Renal * Creatinine \< 1.5 times ULN * No specific renal contraindication to study treatment Cardiovascular * No specific cardiac contraindication to study treatment Immunologic * HIV negative * No specific allergic contraindication to study treatment * No active infection Other * Not pregnant or nursing * Fertile patients must use effective contraception * No other serious underlying pathology that would preclude study treatment * No other prior malignancy except basal cell skin cancer or carcinoma in situ of the cervix * No neurotoxicity \> grade 2 * No psychological, sociological, or geographical condition that would preclude study compliance or follow-up schedule * No prior or concurrent psychiatric illness PRIOR CONCURRENT THERAPY: Biologic therapy * More than 4 weeks since prior immunotherapy * No prior allogeneic graft or autologous graft Chemotherapy * See Disease Characteristics * More than 4 weeks since prior chemotherapy * No prior gemcitabine and/or taxane (i.e., docetaxel or paclitaxel) Endocrine therapy * More than 4 weeks since prior hormonal therapy Radiotherapy * See Disease Characteristics * More than 4 weeks since prior radiotherapy * No prior radiotherapy to the only evaluable lesion Surgery * Not specified Other * No concurrent participation in another clinical trial using an experimental agent