Inclusion Criteria

DISEASE CHARACTERISTICS:

- Patients diagnosed with cancer and experiencing chronic neuropathic pain syndrome

- Pain syndrome diagnosed by the investigator

- Pain syndrome related to the effects of cancer or its treatment (i.e.,
chemotherapy, radiotherapy, and surgery)

- Meets 1 of the following criteria:

- Need to be started on strong opioids

- Require an increase in opioid dose and are currently taking ≤ 75 mg of
total daily dose of oral morphine equivalent

- Experiencing pain for ≥ 4 weeks with an average pain score of ≥ 4 or a worst pain
score of ≥ 5 (using the 0-10 Brief Pain Inventory Scale) during the past 24 hours

- Requires strong opioids to control pain and is using an oral morphine-equivalent dose
of 0-75 mg per day, on average, including breakthrough analgesia, within the past 3
full calendar days

- Mixed pain syndrome allowed provided the neuropathic component is the predominant
pain

- Meets 1 of the following criteria:

- Receiving concurrent chemotherapy but the chronic neuropathic pain is not
related to this treatment and is not expected to improve or worsen because of
this therapy

- Received prior chemotherapy but discontinued treatment, has not received
chemotherapy within the past 7 days, and no further chemotherapy is planned

- No prior chemotherapy

PATIENT CHARACTERISTICS:

- Karnofsky performance status 40-100%

- ALT and AST ≤ 3 times upper limit of normal (ULN)

- Creatinine ≤ 2 times ULN

- No other known laboratory abnormality that, in the investigator's opinion, would
contraindicate study participation

- Not pregnant or nursing

- Fertile patients must use effective contraception

- Mini-Mental State Examination score ≥ 25/30

- Able to speak, read, and write in either English or French

- Willing to complete study diary and questionnaires

- Available for study treatment and follow up (i.e., within reasonable geographical
limits of the participating center)

- Able to swallow and tolerate oral medications

- Patients with prior exposure to methadone hydrochloride must be able to tolerate it

- No intractable nausea and vomiting

- No presence or history of unstable disease or condition that would, in the
investigator's opinion, preclude patient participation in study treatment, such as:

- Head injury

- Increased intracranial pressure

- Uncontrolled seizures

- Uncontrolled asthma

- Decompensated chronic obstructive pulmonary disease

- Untreated prostate hypertrophy

- Acute abdominal conditions

- Untreated hyperthyroidism and Addison disease

- Increased cerebrospinal fluid pressure

- Urethral stricture

- Severe cardiac arrhythmias (especially prolonged QT interval)

- Symptomatic hypotension

- Toxic psychosis

- Cor pulmonale

- Sleep apnea

- Severe obesity

- Kyphoscoliosis

- Myxedema

- Central nervous system depression

- Coma

- No history of significant alcohol, analgesic, or narcotic substance abuse within the
past 6 months

- Able physically and mentally to answer questions and comply with study treatment

- No patient who lives alone and cannot access at least 1 caregiver who can monitor on
a daily basis at home

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- More than 3 weeks since prior radiopharmaceutical treatment or radiotherapy

- Concurrent co-analgesics and medications that can affect methadone hydrochloride
metabolism allowed provided patients have been on a stable dose for the past 3-5 days
and ≥ 5 half lives have passed since any change in dose

- Not scheduled to start chemotherapy during the study treatment

- Not planning on starting or discontinuing medication associated with modified
methadone hydrochloride clearance during study treatment

- No concurrent therapeutic procedure that is likely to influence pain intensity during
the study period

- No concurrent other opioid medications

- No other concurrent methadone hydrochloride